Introduction

Category I of the Praxis Special Education: Foundational Knowledge (5355) exam addresses human development and individual learning differences, accounting for 26% of the total score, which is 32 of the 120 questions. Competency 1A specifically focuses on human development and developmental milestones: the theories that explain how children grow, the predictable sequences of typical development across cognitive, language, social-emotional, and physical domains, the characteristics associated with each of the 13 IDEA disability categories, and the ways disability affects development across all domains. Mastery of this competency provides the conceptual foundation for everything else in special education practice: assessment, IEP goal-writing, instructional planning, and collaboration all depend on a deep understanding of how children develop and how disabilities alter that trajectory.

This lesson covers the major developmental theories tested on the Praxis 5355, detailed milestone sequences from birth through adolescence, the defining characteristics of each IDEA disability category, the critical principle of within-group variability, and how various disabilities affect each domain of development. The exam frequently presents scenario-based questions in which you must identify which theoretical framework best explains a teacher's decision, recognize whether a student's profile fits a particular disability category, or determine how a disability's impact on development should shape instructional choices. Understanding these concepts at a deep, applied level, not merely memorizing definitions, is the goal of this lesson.

(1) Theories of Human Development

Developmental theory provides the conceptual lens through which special educators understand why children behave and learn as they do. The Praxis 5355 tests several foundational theories, and exam questions will often describe classroom scenarios and ask you to identify which theoretical perspective best applies. The five frameworks below are the most heavily tested.

Piaget's Cognitive Development Theory

Jean Piaget proposed that children actively construct knowledge through direct interaction with their environment. He described cognitive development as a series of qualitatively distinct stages, each characterized by a particular way of thinking that represents a fundamental reorganization of mental structure rather than simply the accumulation of more knowledge.

Sensorimotor Stage (birth–2 years): Infants and toddlers learn through sensory experience and motor action. The major achievement of this stage is object permanence, the understanding that objects continue to exist even when they are out of sight (typically achieved around 8–12 months). By the end of this stage, children begin to use mental representations.
Preoperational Stage (2–7 years): Children use symbols (language and pretend play) but cannot yet perform logical operations. Key features include egocentrism (difficulty taking another's perspective), centration (focusing on one dimension of a problem at a time), animism (attributing life to inanimate objects), and inability to conserve (understand that quantity remains constant despite changes in appearance). The classic conservation task, showing that pouring water into a differently shaped container doesn't change the amount, reveals the limits of preoperational thinking.
Concrete Operational Stage (7–11 years): Children can perform logical operations on concrete objects and events. They master conservation, can classify objects by multiple attributes simultaneously (classification), understand reversibility (the relationship between addition and subtraction), and can arrange objects in order (seriation). Thinking remains tied to physical reality; abstract reasoning is limited.
Formal Operational Stage (12+ years): Adolescents develop abstract reasoning, hypothetical-deductive thinking, and systematic problem-solving. They can reason about possibilities, not just realities, and engage in metacognition, thinking about their own thought processes.
Schemas, Assimilation, and Accommodation: Piaget described cognitive development as the ongoing refinement of schemas (mental frameworks). Children use assimilation to fit new information into existing schemas and accommodation to modify schemas when new information cannot be assimilated. The balance between these two processes, equilibration, drives cognitive growth.

Exam Connection: The Praxis 5355 may ask you to identify which Piagetian stage a student is functioning in based on a behavioral description, or to recognize why a student with an intellectual disability who is chronologically a teenager may be functioning at a preoperational level. Piaget viewed development as primarily driven by biological maturation and direct experience; the child is an active constructor of knowledge.

Vygotsky's Sociocultural Theory

Lev Vygotsky argued that cognitive development is fundamentally a social process. Children learn by interacting with more knowledgeable others (parents, teachers, peers) and internalizing the tools and language of their culture. This perspective is especially influential in special education because it provides a framework for understanding how instruction, not just maturation, drives learning.

Zone of Proximal Development (ZPD): The ZPD is the range between what a child can accomplish independently (the lower boundary) and what the child can accomplish with support from a more knowledgeable other (the upper boundary). Effective instruction targets skills within the ZPD; too easy produces no growth, too difficult exceeds the learner's current capacity. For students with disabilities, accurately identifying the ZPD through dynamic assessment is essential for designing appropriate IEP goals.
Scaffolding: Scaffolding refers to the temporary, adjustable support a teacher or peer provides to help a learner accomplish a task within their ZPD. Effective scaffolding is calibrated to the learner's current level and gradually withdrawn (faded) as competence increases. Examples include graphic organizers, think-alouds, sentence starters, and physical prompts. Scaffolding is one of the most important concepts in special education instruction.
Private Speech: Young children often talk aloud to themselves while solving problems. Vygotsky viewed this "private speech" as an internalization of the social dialogue of instruction; children essentially direct themselves using language that originated in interactions with others. Private speech gradually becomes internalized as silent verbal thought by middle childhood. Children with language-based learning disabilities or ADHD may have difficulty with this internalization.
Language as a Tool: Vygotsky emphasized language as the primary cognitive tool through which humans think and regulate behavior. This has profound implications for students with speech/language impairments or autism spectrum disorder, whose language differences may affect not just communication but also self-regulation and thinking.
Mediated Learning: Humans do not interact with the world directly but through cultural tools and signs (language, number systems, writing). This is why literacy, a culturally constructed system, is so central to academic development and why students with reading disabilities face cascading challenges across all academic content areas.

Exam Connection: Vygotsky's framework is the theoretical basis for practices like peer-mediated learning, collaborative problem-solving, and instructional scaffolding, all of which appear on the Praxis 5355. Questions may ask you to identify the ZPD in a scenario or explain why a teacher gradually reduces prompting as a student masters a skill.

Erikson's Psychosocial Theory

Erik Erikson proposed that development unfolds across eight stages, each defined by a psychosocial crisis, a tension between two opposing outcomes. Successful navigation of each stage contributes to a healthy sense of identity and social-emotional competence; failure to resolve a stage leaves lasting psychological challenges. The first five stages are most relevant to school-age children and adolescents.

Trust vs. Mistrust (birth–18 months): Infants develop a basic sense of trust when caregivers are reliably responsive and nurturing. When caregiving is inconsistent or neglectful, mistrust develops. This foundational stage sets the stage for all subsequent attachment and relationship patterns, providing critical context for understanding children who have experienced early neglect or trauma.
Autonomy vs. Shame and Doubt (18 months–3 years): Toddlers develop a sense of independence and self-control through exploration. Overly restrictive or critical caregiving produces shame and self-doubt. Children with significant motor or cognitive disabilities may face particular challenges during this stage if their attempts at independence are frequently thwarted.
Initiative vs. Guilt (3–6 years): Preschoolers develop the capacity for purposeful activity and leadership. When initiative is consistently punished or criticized, children develop guilt about their desires and ambitions. For children who frequently fail at tasks due to learning difficulties, this stage can result in reduced initiative and learned helplessness.
Industry vs. Inferiority (6–12 years): School-age children focus on mastery of academic and social skills. Success builds a sense of competence (industry); repeated failure or comparison to peers produces feelings of inadequacy (inferiority). This is the most critical stage for children with learning disabilities, as ongoing academic struggle directly threatens their developing sense of industry. Special educators must build in multiple opportunities for success and emphasize growth over comparison.
Identity vs. Role Confusion (12–18 years): Adolescents explore who they are across multiple domains (academic, social, vocational). Students with disabilities may face particular identity challenges related to their disability label, social differences, and uncertainty about their adult roles. Transition planning during this stage is essential.

Exam Connection: The Praxis 5355 may present questions about why a student with a learning disability develops negative self-concept or avoids academic tasks. Erikson's Industry vs. Inferiority stage provides the theoretical explanation: chronic academic failure threatens the developing sense of competence. Questions may also address the role of emotional safety and relationship quality in supporting students through these developmental crises.

Bronfenbrenner's Ecological Systems Model

Urie Bronfenbrenner proposed that child development cannot be understood in isolation; it occurs within a nested system of environmental contexts that interact with and shape each other. This bioecological model is the theoretical foundation for family-centered practice, community-based supports, and the emphasis on collaboration in special education.

Microsystem: The immediate settings in which the child directly participates: family, classroom, peer group, neighborhood. The microsystem has the most direct influence on development. For students with disabilities, the quality of teacher-student relationships, family support, and peer acceptance within the microsystem are powerful determinants of outcomes.
Mesosystem: The relationships and interactions between different microsystems, such as the connection between home and school. When parents are actively involved in IEP meetings and communicate regularly with teachers, the mesosystem is strong. Breakdowns in home-school communication weaken the mesosystem and often undermine student progress.
Exosystem: Settings that affect the child indirectly: a parent's workplace, the school board's budget decisions, community service agencies. A parent who works two jobs may have less time for IEP involvement, and school district budget cuts may reduce available support services; both are exosystem factors that affect a student's educational experience without the student being directly involved.
Macrosystem: Broader cultural values, laws, and social attitudes. IDEA, the ADA, and cultural beliefs about disability and education all operate at the macrosystem level. Cultural attitudes toward disability vary significantly across communities and affect how families respond to diagnosis, involvement in special education, and expectations for their children's futures.
Chronosystem: The dimension of time, how changes over time within systems affect development. A student who experiences a parent's divorce, a school change, or a new diagnosis at different points in development will experience different impacts depending on their developmental stage at the time.

Exam Connection: Bronfenbrenner's model explains why special education is not just about the student in isolation but requires family involvement, community partnerships, and awareness of cultural context. Praxis 5355 questions about collaboration with families, culturally responsive practice, and the impact of poverty or trauma on student development all reflect Bronfenbrenner's ecological framework.

Behavioral Theory (Behaviorism)

Behaviorism, developed by John Watson and extended by B.F. Skinner, focuses on observable behavior and the environmental events that control it. While cognitive and sociocultural theories have grown in prominence, behavioral principles remain foundational to special education practice, particularly for students with autism spectrum disorder, emotional and behavioral disorders, and intellectual disabilities.

Operant Conditioning: Skinner demonstrated that behavior is shaped by its consequences. Behaviors that are followed by positive consequences (reinforcement) increase in frequency; behaviors that are followed by negative consequences (punishment) decrease. This simple framework underlies Applied Behavior Analysis (ABA), token economies, behavioral contracts, and countless classroom management strategies used in special education.
Positive Reinforcement: Providing a desired consequence following a target behavior to increase its future probability. Effective reinforcers are individualized; what reinforces one student may be neutral or even aversive to another. Common reinforcers include verbal praise, preferred activities, tokens, and sensory input (for students with ASD).
Negative Reinforcement: Removing an aversive stimulus following a behavior to increase that behavior. A student who escapes a difficult writing task by engaging in disruptive behavior has been negatively reinforced; the disruption increased because it successfully removed the aversive demand. Understanding escape-maintained behavior is critical for designing effective behavior intervention plans (BIPs).
Punishment: Positive punishment adds an aversive stimulus following a behavior to reduce it (for example, a verbal reprimand); negative punishment removes a desired stimulus (for example, loss of recess). IDEA emphasizes positive behavioral supports and discourages aversive interventions, particularly for students with disabilities.
Extinction: Withholding reinforcement for a previously reinforced behavior to reduce it. If a student's attention-seeking behavior has been maintained by teacher attention, systematically ignoring the behavior (while reinforcing appropriate alternatives) can extinguish it. Extinction often produces an initial "extinction burst," a temporary increase in behavior before it decreases.
Antecedent-Behavior-Consequence (ABC) Analysis: The foundation of functional behavioral assessment (FBA). Identifying what happens before a behavior (antecedents) and after a behavior (consequences) reveals the function of the behavior, what it achieves for the student. Most behaviors serve one of four functions: access to tangibles, escape/avoidance, attention, or sensory stimulation.

Exam Connection: The Praxis 5355 frequently tests knowledge of reinforcement, the difference between positive and negative reinforcement (a commonly confused pair), and the application of behavioral principles in school settings. Negative reinforcement is not punishment; it involves removing something unpleasant to increase a behavior.

(2) Typical Developmental Milestones

Understanding typical developmental milestones is essential for identifying when development deviates from expected patterns, a core skill for special educators involved in child study teams, eligibility evaluations, and progress monitoring. The Praxis 5355 expects candidates to know milestone sequences across four domains: cognitive, language, social-emotional, and physical (motor), from infancy through adolescence.

Cognitive Development Milestones

Cognitive milestones reflect the development of thinking, memory, attention, problem-solving, and the ability to represent the world mentally. They follow the sequence described by Piaget but also include specific skill benchmarks assessed in educational and clinical settings.

Birth–12 months: Responds to familiar faces and voices; tracks moving objects; explores objects by mouthing and manipulating; demonstrates cause-and-effect understanding (shaking a rattle); develops object permanence (begins searching for hidden objects around 8–12 months); imitates simple gestures.
12–24 months: Uses trial-and-error problem-solving; engages in simple pretend play (feeding a doll); points to pictures in books when named; follows two-step directions with familiar routines; begins symbolic play; demonstrates basic sorting (puts like objects together).
2–3 years: Engages in elaborate pretend play with narrative sequences; matches shapes and colors; understands concepts of "more" and "less"; completes simple puzzles (3–4 pieces); sorts by one attribute (color or shape); begins to understand time concepts (today, tomorrow).
3–5 years: Counts 10 or more objects; understands quantity concepts (more, fewer, the same); identifies some letters; shows early phonological awareness (rhyming, syllable clapping); draws a person with at least 6 parts; understands time concepts (yesterday, today, tomorrow); asks "why" questions constantly (curiosity-driven inquiry).
5–7 years: Reads simple words; performs basic addition and subtraction with concrete objects; classifies objects by multiple attributes; demonstrates conservation of number (understands that 5 objects spread out is still 5); follows multi-step instructions; begins planning and self-monitoring during tasks.
7–12 years: Reads to learn across content areas; performs multi-step math operations; understands figurative language (idioms, metaphors); demonstrates logical reasoning with concrete problems; develops sustained attention for 20–30 minutes on structured tasks; engages in systematic study strategies.
12+ years: Abstract reasoning fully emerges; can consider hypothetical situations; engages in deductive reasoning; develops metacognitive strategies; plans and self-regulates multi-step academic projects; understands complex cause-and-effect relationships across social, historical, and scientific contexts.

Exam Connection: The Praxis 5355 may present a student profile and ask you to identify which cognitive milestones are delayed or absent. A student who has not achieved conservation by age 8 or who cannot engage in abstract reasoning by age 14 is demonstrating atypical cognitive development, which should prompt further evaluation.

Language and Communication Milestones

Language development spans receptive language (understanding what is heard) and expressive language (producing spoken, written, or signed communication). Receptive language consistently develops ahead of expressive language at every stage. Speech and language are distinct: speech refers to the physical production of sounds, while language refers to the rule-governed system of symbols and their meanings.

Birth–6 months: Responds to voice; startles to loud sounds; coos and makes vowel sounds; social smiling in response to familiar faces; begins turn-taking in vocal exchanges (protoconversation).
6–12 months: Babbles with consonant-vowel combinations (ma-ma, ba-ba); produces varied intonation patterns that mimic conversation; responds to own name; understands "no"; uses gestures (waving, pointing by 12 months); joint attention emerges (following caregiver's point or gaze).
12–18 months: First words appear (mama, dada, common objects); vocabulary of 5–15 words; understands simple instructions ("Come here," "Give me the ball"); uses gestures to augment communication; responds to simple questions.
18–24 months: Vocabulary grows rapidly (vocabulary explosion); uses 50+ words; begins combining two words ("more juice," "daddy go"); follows two-step commands; points to pictures when named; strangers can understand about 50% of speech.
2–3 years: Produces 3–4 word utterances; uses pronouns (I, you, me); asks simple questions; vocabulary of 200–1,000 words; strangers understand 75% of speech; uses plurals and past tense (with errors such as "goed," "mouses").
3–5 years: Uses 4–6 word sentences; tells simple stories with beginning-middle-end; uses most phonemes correctly (some articulation errors persist until age 7–8); understands complex sentences; asks "why," "when," "how"; uses language for a variety of functions (requesting, commenting, questioning, narrating).
5–7 years: Speech is fully intelligible; produces complex sentences with conjunctions and relative clauses; understanding of figurative language begins to emerge; phonological awareness is solid (can segment, blend, delete phonemes); reading acquisition is underway.
7–12 years: Vocabulary expands dramatically through reading; understands and uses idioms, metaphors, and sarcasm; produces extended discourse (multi-paragraph writing, multi-turn conversation); narrative structure becomes sophisticated.
12+ years: Metalinguistic awareness (can analyze language as an object); abstract language comprehension is fully developed; argumentative and persuasive language emerges; registers shift appropriately across social contexts.

TEST READY TIP

Red flags that the Praxis 5355 expects you to recognize for a speech-language referral include no babbling by 9 to 12 months, no single words by 15 to 16 months, no two-word phrases by 24 months, and any loss of previously acquired language skills at any age. The most conservative threshold for babbling is 9 months, while 12 months is the outermost acceptable boundary; a child with no babbling at 12 months is unquestionably delayed, and earlier referral is appropriate. These are automatic triggers for speech-language evaluation.

Exam Connection: The Praxis 5355 may present a case study of a child whose language development deviates from these milestones and ask you to identify the appropriate next step. Early identification of language delay is critical because language is foundational to literacy, social interaction, and self-regulation.

Social-Emotional Development Milestones

Social-emotional development encompasses the ability to form relationships, regulate emotions, understand others' perspectives, and navigate social interactions. This domain is foundational to all other learning; a child who cannot regulate emotions or form trusting relationships with teachers and peers cannot fully access academic instruction.

Birth–6 months: Social smiling emerges between 6–8 weeks; responds differentially to familiar vs. unfamiliar faces; beginning of attachment; expresses basic emotions (distress, interest, joy); participates in face-to-face social play.
6–12 months: Stranger anxiety emerges (6–9 months); separation anxiety increases and peaks between 9–18 months; shows clear attachment preferences; social referencing (looks to caregiver to interpret ambiguous situations); joint attention established.
12–24 months: Plays alongside peers (parallel play) rather than with them; strong attachment to primary caregivers; imitates peer behavior; beginning of empathy (comforts others who appear distressed); self-recognition in mirror (18 months).
2–3 years: Begins cooperative play in brief episodes; asserting autonomy (strong-willed behavior); emotional outbursts common (tantrums) due to limited self-regulation and language; developing awareness of own gender identity; increasing interest in peer play.
3–5 years: Engages in cooperative play with role assignment; follows simple game rules; shows empathy; begins perspective-taking (though still limited); can identify basic emotions in others; self-regulation improving but easily overwhelmed; friendship formation begins.
5–7 years: Understands others' perspectives more accurately; navigates peer conflicts with words; group play with sustained rule-following; self-concept developing around academic and social competence; emotional regulation improves significantly.
7–12 years: Strong peer relationships with same-age companions; loyalty and fairness valued; self-esteem linked to perceived competence in school and social domains; social comparison becomes prominent; gender-segregated peer groups common.
12+ years: Identity development (Erikson's Identity vs. Role Confusion); peer group centrality; romantic relationships begin; emotional intensity increases with puberty; risk-taking behavior increases; development of moral reasoning and social justice awareness.

Exam Connection: The Praxis 5355 may ask about the relationship between attachment quality and later social-emotional development, or about why a student with an emotional behavioral disorder struggles with peer relationships. Understanding these developmental sequences helps you recognize when social-emotional development is significantly delayed or atypical.

Physical and Motor Development Milestones

Motor development follows two major principles: cephalocaudal development (control proceeds from head downward: head control precedes trunk control, which precedes leg control) and proximodistal development (control proceeds from the body's center outward: trunk control precedes shoulder, then elbow, then wrist, then finger control). These principles explain why children achieve gross motor milestones before fine motor milestones at every stage.

Birth–6 months: Lifts head in prone position (1–2 months); rolls from stomach to back (4–5 months); reaches and grasps objects; sits with support; palmar grasp (3–6 months).
6–12 months: Sits independently (6–8 months); crawls (8–10 months); pulls to standing; cruises along furniture; pincer grasp emerges (9–12 months); transfers objects hand-to-hand; first steps (9–15 months range).
12–24 months: Walking independently; climbing stairs with support (2 feet per step); runs (though unsteadily); throws a ball; scribbles with crayon; stacks 2–4 blocks; turns pages (sometimes several at once).
2–3 years: Runs smoothly; jumps with both feet; kicks a ball; rides a tricycle; walks up and down stairs alternating feet; draws circles and crosses; strings large beads; uses spoon and fork.
3–5 years: Hops on one foot; skips; catches a bounced ball; draws a recognizable person; cuts with scissors; begins writing letters (though often reversed and inconsistently sized); dresses and undresses independently.
5–7 years: Refined running, jumping, hopping, and skipping; rides bicycle; ties shoes; forms letters and numbers consistently; handwriting becomes legible; manipulates small objects with precision.
7–12 years: Athletic skill refinement; team sports participation; fine motor precision for cursive writing and detailed artwork; developing strength and endurance; puberty onset at the end of this range for many students.
12+ years: Puberty-related physical changes (may temporarily affect coordination); adult-level motor capacity developing; fine motor skills fully refined.

Exam Connection: The Praxis 5355 may present a student who cannot perform motor tasks expected at their age, for instance, a 7-year-old who cannot cut with scissors or a 10-year-old whose handwriting remains illegible. These motor differences are relevant to determining whether a student needs occupational therapy, whether accommodations like keyboard access are appropriate, or whether motor delays are a characteristic of their primary disability category.

Adaptive Behavior

Adaptive behavior refers to the collection of conceptual, social, and practical skills that people have learned to function in their everyday lives. For individuals with exceptionalities, including developmental disabilities, autism spectrum disorder, and physical or other health disabilities, adaptive behavior needs are a central consideration in eligibility determination and educational planning. The three domains of adaptive behavior are conceptual skills (language, literacy, money concepts, time concepts), social skills (interpersonal skills, responsibility, self-esteem, following rules), and practical skills (activities of daily living like eating, dressing, mobility, and occupational skills).

For students with intellectual disability, deficits in adaptive behavior are a defining criterion alongside intellectual functioning. For students with autism spectrum disorder, adaptive behavior challenges often include difficulty with daily living skills, social problem-solving, and self-care routines even when intellectual ability is average or above. For students with physical or other health disabilities, adaptive behavior needs may center on mobility, self-care, and using assistive devices to complete daily routines.

In the classroom, adaptive behavior needs become evident when a student cannot independently manage routines that peers of the same age handle. For example, a second-grade student with autism may need explicit instruction in tying shoes, using the restroom independently, and navigating the lunch line, while a ninth-grade student with intellectual disability may need direct teaching in using public transportation, managing money, and making safe choices. For a kindergarten student with cerebral palsy, adaptive behavior instruction may focus on using switches to control a powered wheelchair and communicating basic needs through a speech-generating device.

COMMON TRAP

Test-takers often confuse adaptive behavior with academic achievement. Adaptive behavior is about everyday functional skills for independent living, not performance on school subjects. A student with a high IQ can still have significant adaptive behavior deficits, and a student with intellectual disability may have strong adaptive skills in one domain and weak skills in another. On the exam, questions about adaptive behavior will involve self-care, communication in daily contexts, socialization, and functional academics like telling time and using money.

Exam Connection: The Praxis 5355 will present scenarios involving students who struggle with daily living tasks, social skills in natural settings, or functional communication. You must be able to identify adaptive behavior deficits as distinct from academic or cognitive deficits, and understand that adaptive behavior instruction is a critical component of the IEP for many students with disabilities.

(3) Environmental and Biological Factors Influencing Development

Development and learning are shaped by a complex interaction of environmental and biological factors beyond the disability itself. The Praxis 5355 expects you to understand how these factors independently and jointly influence student behavior and academic performance.

Environmental Factors Beyond the Disability

Environmental factors include the physical, social, economic, and cultural contexts in which a child grows and learns. These factors can either support or impede development regardless of whether a student has a disability.

Poverty: Economic hardship affects development through multiple pathways: reduced access to nutritious food (affecting brain development and attention), limited access to books and educational materials, housing instability leading to school mobility, and limited access to healthcare. For a student with a learning disability in a low-income family, the combined effects of poverty and disability can compound academic risk, making early intervention and school-based supports even more critical. Research shows that children from low-income families hear dramatically fewer words in early childhood than peers from higher-income families, a gap that affects language development before school entry.
Trauma: Exposure to abuse, neglect, domestic violence, community violence, or other adverse childhood experiences (ACEs) affects brain development, stress response systems, attention, memory, and emotional regulation. A student who has experienced trauma may be in a chronic state of hypervigilance, which manifests as difficulty concentrating, exaggerated startle responses, or withdrawal. For a student with an emotional disturbance who has also experienced trauma, the behavioral manifestations may be more severe and require trauma-informed instructional approaches that prioritize safety and predictability.
Family stress: Parental mental health issues, chronic illness, marital conflict, or the stress of raising a child with a disability can affect parenting consistency and emotional availability. When a family is under significant stress, a student may have less support at home for homework, consistent sleep schedules, and positive behavioral modeling. Special educators should be aware of family stressors because they affect home-school communication, homework completion, and attendance.
Nutrition and healthcare access: Chronic malnutrition, lead exposure, and lack of preventive healthcare affect cognitive development and school performance. For example, iron deficiency anemia in early childhood is associated with lasting cognitive deficits. Students without regular healthcare may have undetected vision or hearing problems that mimic learning disabilities.
Community resources: Access to quality early childhood programs, after-school programs, libraries, and safe recreational spaces supports development. Conversely, communities with high crime rates or limited resources may restrict opportunities for healthy development.

Exam Connection: The Praxis 5355 may present a case study of a student who is struggling academically and ask you to identify environmental factors, distinct from the disability, that are contributing to the struggle. The correct answer will often involve poverty, trauma, family stress, or inadequate nutrition rather than the disability label itself.

Biological Factors, Other Disabilities, and Self-Regulation

Biological factors include genetics, brain structure and function, prenatal exposure to toxins or infections, birth complications, and the neurological underpinnings of learning and behavior. These factors interact with other disabilities and with self-regulation to affect behavior and academic performance.

Genetic conditions: Conditions such as Down syndrome, fragile X syndrome, and Williams syndrome are associated with specific cognitive and behavioral profiles. A student with fragile X syndrome may have both intellectual disability and characteristic physical features, and may require supports for sensory processing, attention, and anxiety in addition to academic instruction.
Prenatal factors: Fetal alcohol spectrum disorders (FASD) result from prenatal alcohol exposure and are associated with intellectual disability, learning difficulties, memory deficits, and behavioral challenges. Maternal infection during pregnancy, certain medications, and exposure to environmental toxins can also affect brain development.
Neurological factors: Differences in brain structure, connectivity, and neurotransmitter function underlie many disabilities. For example, dyslexia is associated with differences in the left hemisphere language processing regions; ADHD is associated with reduced activity in prefrontal cortex regions that govern executive function.
Other disabilities: The presence of a primary disability increases the likelihood of co-occurring conditions. A student with a hearing impairment may also have a learning disability; a student with cerebral palsy may have an intellectual disability; a student with autism frequently has co-occurring anxiety, ADHD, and gastrointestinal issues. Each additional condition multiplies the complexity of the student's educational needs.
Self-regulation: Self-regulation refers to the ability to manage one's emotions, attention, and behavior to achieve goals. It includes skills such as inhibiting impulses, sustaining attention, shifting attention flexibly, planning, and monitoring one's own performance. Self-regulation is affected by both biological factors (executive function deficits in ADHD, autism, and TBI) and environmental factors (consistent routines, predictable expectations).

For example, a fourth-grade student with ADHD has a biological predisposition to weak impulse control and sustained attention. When seated near a window with distracting activity outside, the environment further taxes his self-regulation. His teacher implements a behavior intervention plan that includes preferential seating, a visual schedule, and a token system for staying on task. This combination of biological understanding and environmental modification supports his self-regulation and academic performance.

TEST READY TIP

Self-regulation is a distinct construct from both behavior and intelligence. A student can have high intellectual ability yet poor self-regulation, such as a gifted student with ADHD who blurts out answers and has difficulty completing long-term projects. Exam scenarios will frequently describe students who have the ability but cannot consistently use it due to poor self-regulation. The appropriate intervention is explicit self-regulation instruction (goal-setting, self-monitoring, self-reinforcement) combined with environmental supports.

Exam Connection: The Praxis 5355 will ask you to identify how biological factors, other disabilities, and self-regulation interact to affect behavior and academic performance. You should be able to distinguish between a student who cannot do a task (skill deficit) and a student who will not do a task (performance deficit, often related to self-regulation or motivation). Understanding this distinction drives the selection of instructional versus behavioral interventions.

(4) Auditory and Information Processing Skills

The Praxis 5355 includes content on how disabilities affect auditory and information processing skills. These processing skills are the foundation for receiving, interpreting, storing, and retrieving information, and deficits in any of these areas significantly impact learning across all academic content.

Auditory Processing

Auditory processing refers to how the brain recognizes and interprets information presented through sound, particularly speech. A student with an auditory processing disorder has normal hearing sensitivity (the ears detect sound) but difficulty making sense of the sounds (the brain misinterprets or cannot organize them). This is distinct from a hearing impairment, which involves reduced ability of the ear to detect sound.

Phonological awareness: The ability to recognize and manipulate the sound structure of words, including rhyming, segmenting words into individual sounds (phonemes), and blending sounds to form words. This skill is foundational to reading development. A student with weak phonological awareness has difficulty decoding words, which cascades into poor reading fluency and comprehension. For example, a first-grade student who cannot segment the word "cat" into /k/, /a/, /t/ will struggle to sound out unfamiliar words when reading.
Auditory discrimination: The ability to tell the difference between similar sounds. A student who cannot discriminate /b/ from /d/ or /p/ from /b/ will have difficulty following spoken directions accurately and may confuse similar-sounding words in reading and spelling.
Auditory memory: The ability to hold and process auditory information. Students with weak auditory memory may only remember the first or last part of a multi-step direction. For example, when a teacher says "take out your math book, turn to page 45, and complete problems 1 through 10," the student may remember only "take out math book" and then become lost.
Auditory sequencing: The ability to remember the order of sounds and words. Difficulty in this area affects following multi-step instructions, understanding of stories and lectures, and performing procedures in the correct order (such as long division or scientific experiments).

In the classroom, a student with auditory processing disorder may appear to be inattentive, as if they are not listening, when in fact they are struggling to decode the stream of incoming speech. The student may frequently say "what?" or ask for repetition, have difficulty understanding in noisy environments, and respond inconsistently to questions.

Information Processing

Information processing refers to the system through which the brain takes in information, stores it, and retrieves it when needed. The major components are sensory registration, working memory, and long-term memory. Each processing skill can be affected by disability.

Sensory registration: The initial intake of information through the senses. Sensory processing differences, common in autism spectrum disorder and ADHD, affect how strongly or weakly information is registered. A student who is hypersensitive to sound may become overwhelmed by classroom noise and be unable to process the teacher's instruction; a student who is hyposensitive may fail to register relevant stimuli, such as a fire alarm or the teacher's voice.
Working memory: The system that holds and manipulates information for a few seconds while it is being used. Working memory is like the mental workspace. Students with poor working memory lose the thread of multi-step tasks, have difficulty following complex instructions, and struggle with math problems that require holding intermediate results. Working memory deficits are common in SLD, ADHD, intellectual disability, and TBI. For example, a third-grade student solving 17 plus 25 may forget to carry the 1 because he cannot hold both the sum of 5+7 and the next step in mind simultaneously.
Processing speed: The rate at which the brain processes information. Slow processing speed means a student needs more time to take in information, understand it, and respond. This affects everything from reading fluency to the speed of completing classwork and tests. A student with slow processing speed is not less intelligent; the student simply works at a slower pace. Extended time on tests and reduced volume of work are appropriate accommodations.
Long-term memory and retrieval: The ability to store information over time and retrieve it when needed. Students with retrieval deficits may study a spelling list and know the words at home but be unable to recall them during a test. They may have difficulty accessing previously-learned math facts quickly, which compromises higher-order problem solving because automatic recall of basic facts is a prerequisite.

Exam Connection: The Praxis 5355 will describe students who have difficulty following directions, remembering what was taught, or processing auditory information, and ask you to identify the underlying processing deficit or the appropriate accommodation. You should understand that accommodations such as written directions to supplement verbal directions, extended time, reduced length of assignments, and visual aids compensate for processing deficits.

(5) Sensory Impairments and Physical/Health Exceptionalities: Family and Community Interaction

Sensory impairments and physical or health exceptionalities extend their impact beyond the classroom into how individuals interact with their families and communities. The Praxis 5355 expects you to understand these broader impacts, as they affect family systems, community participation, and the nature of collaboration between educators and families.

Impact on Family Interactions

When a child has a sensory impairment (hearing, vision, deaf-blindness) or a physical or health exceptionality, family dynamics and interactions are affected in concrete ways.

Communication modalities: A child who is deaf and whose family does not know sign language faces significant barriers to everyday family communication. Dinner-table conversation, family stories, and casual emotional expression are inaccessible. If only one family member learns sign language, the child's communication is mediated through that single person. In families where the child uses an augmentative and alternative communication (AAC) device, all family members must learn how to program and support the device. For a family with a preschool child who is hard of hearing, the parent may need to learn techniques for getting the child's attention (tapping on the shoulder) before speaking and positioning the child so the child can see the speaker's face.
Daily caregiving demands: Physical and health exceptionalities increase the intensity of daily caregiving. A student with a severe orthopedic impairment may require assistance with eating, toileting, dressing, and transferring between positions. A student with a chronic illness like cystic fibrosis requires daily respiratory therapy and medication. These demands are stressors on parents and siblings and reduce the time and energy available for other family functions. A parent of a child who requires tracheostomy care or tube feeding performs medical procedures at home, and siblings may take on caregiving roles.
Sibling adjustment: Siblings of children with significant health or sensory needs may experience reduced parental attention, increased household responsibility, and complex feelings of jealousy, guilt, and protectiveness. Special educators who communicate openly about the disability and strengths of the child can help families address these sibling dynamics.
Emotional impact on parents: Receiving a diagnosis of a severe visual or hearing impairment or a physical disability involves a grieving and adjustment process. Parents may cycle through shock, denial, anger, and eventual acceptance. The ongoing demands of medical appointments, therapy sessions, and advocacy at school add chronic stress. Families who are also managing poverty or lack of access to healthcare face compounded challenges.

Impact on Community Interaction

Community interaction includes participation in religious services, recreation, sports, cultural events, and neighborhood activities. Sensory and physical impairments create barriers to these community experiences.

Physical accessibility: Community spaces such as parks, museums, houses of worship, and friends' homes may not be wheelchair accessible. A student with a mobility impairment may not be able to attend a friend's birthday party at a playground with only stairs, or may be excluded from team sports that require typical motor skills.
Communication access: A student who is deaf cannot fully access a community theater production without sign language interpretation or captioning. A student who is blind cannot access written community announcements or navigate unfamiliar spaces without orientation and mobility training. Community members who do not know how to communicate with a student who uses AAC may inadvertently exclude the student from conversations.
Social inclusion: Community exclusion can be subtle. A student with a chronic health condition that requires a restricted diet (for example, a student with celiac disease) may not be able to participate in a community cookout. A student with sensory sensitivities may be unable to attend a community fireworks display or a movie theater due to noise levels, resulting in social isolation.
Parental advocacy in the community: Parents often become advocates to secure accessible community spaces and programs. They may need to educate coaches, religious leaders, and recreation program directors about their child's needs, a process that is time-consuming and can be emotionally draining.
Orientation and mobility for visual impairments: For a student who is blind, independent travel within the community (crossing streets, using public transportation, navigating a grocery store) requires systematic instruction in orientation and mobility. This instruction is essential to community participation and is provided in schools through O&M specialists.

Exam Connection: The Praxis 5355 may present a scenario in which a family has difficulty participating in community events because of a child's sensory or physical needs. The correct answer will involve understanding the specific barrier and the support that facilitates the child's and family's community engagement. For a student who is deaf, the family might need to learn sign language; for a student in a wheelchair, the community needs to ensure physical accessibility; for a student with severe health needs, the school should coordinate supports that extend into the home and community.

(6) Adapting the Learning Environment: Specialized Health Care and Placement

The Praxis 5355 requires knowledge of how to adapt the learning environment to provide optimal learning opportunities for individuals with exceptionalities. This includes understanding specialized health care supports in educational settings and the various placement options along the continuum of services.

Specialized Health Care Supports in Educational Settings

Many students with physical and health exceptionalities require specialized health care supports during the school day. These supports are typically described in the student's IEP and are provided by school nurses, trained school personnel, or related service providers. The purpose of these supports is to keep students safe and healthy so they can access their education.

Catheterization: A student with a neurogenic bladder (for example, due to spina bifida) may require clean intermittent catheterization to empty the bladder several times daily. School personnel must be trained in this procedure, which carries risk of urinary tract infection if not performed hygienically. A designated private location must be available.
Tracheostomy care: A student with severe breathing difficulties may have a tracheostomy tube that requires suctioning, cleaning, and monitoring. Trained personnel must be available throughout the school day, and emergency protocols must be in place in case the airway becomes obstructed.
Medication administration: Schools routinely administer medications prescribed for chronic conditions. This includes daily medications for ADHD (e.g., methylphenidate), insulin for a student with type 1 diabetes, rescue inhalers for asthma, emergency medications such as epinephrine (EpiPen) for severe allergies, and seizure rescue medications (e.g., midazolam) for students with epilepsy. School personnel must be trained in the specific medication, its side effects, and emergency procedures. For example, a high school student with diabetes will need to check blood glucose levels before lunch and possibly administer a bolus of insulin through an insulin pump; school staff are trained to respond to hypoglycemia (shaking, confusion, unconsciousness) by providing a fast-acting sugar source immediately.
Ventilator support: Some students with severe neuromuscular conditions (e.g., spinal muscular atrophy) require ventilatory support during the school day, whether continuously or intermittently. This requires coordination with the family's home health provider, school nursing staff, and emergency responders.
Tube feeding: Students who cannot eat orally may receive nutrition through a gastrostomy tube (G-tube). School staff must be trained to administer feedings safely, in a way that prevents aspiration and infection, and to document intake and output.
Oxygen therapy: A student with chronic lung disease may require supplemental oxygen delivered by nasal cannula. School personnel must monitor oxygen saturations and equipment.
Seizure action plans: Students with seizure disorders, whether the seizures are controlled or not, require a written seizure action plan specifying the student's usual seizure type, first aid steps, and emergency medication use. Staff must be trained to recognize seizure activity that requires sending for emergency medical services.

These specialized health care supports are part of the student's educational program and are addressed in the IEP or a separate health plan (Section 504 plan, which is applicable in some cases). The school nurse is a critical member of the IEP team for students with complex health needs.

COMMON TRAP

Test-takers sometimes assume that all medically fragile students need to be placed in separate facilities. The opposite is true: with appropriate health supports in place, most students with health needs can participate in general education and typical school activities. The requirement is to provide the necessary specialized training and support, not to exclude the student. On the exam, a student who needs daily catheterization or seizure medication can and should attend a general education class where the required trained personnel and emergency plan are available.

Exam Connection: The Praxis 5355 may describe a student with a specific health condition and ask which specialized health support the school is responsible for providing. You must be able to connect the health condition to the appropriate school-based support, such as G-tube feeding for a student with severe oral motor difficulties, insulin management for a student with diabetes, or suctioning and emergency response for a student with a tracheostomy.

Placement Options and the Continuum of Services

IDEA requires that students with disabilities be educated in the least restrictive environment (LRE) to the maximum extent appropriate. The LRE concept means that students should be educated with peers without disabilities whenever appropriate, with separate settings used only when the nature or severity of the disability prevents satisfactory progress in the general education setting with the use of supplementary aids and services. The continuum of placement options ranges from full inclusion in general education to residential and home/hospital settings, and each student's placement is determined individually by the IEP team.

General education classroom with consultation: The student is in the general education classroom for the full day. A special education teacher provides consultative support to the general education teacher, who receives strategies and accommodations to implement. This is the most inclusive and least restrictive setting. For example, a fourth-grade student with mild dyslexia may receive consultation from the learning specialist who meets with the general education teacher weekly to review the student's progress and suggest multisensory reading strategies.
General education classroom with co-teaching: General and special education teachers jointly deliver instruction to a class that includes students with and without disabilities. Models include one-teach-one-assist, station teaching, parallel teaching, and team teaching. For example, in a sixth-grade math class, the general educator introduces the concept, and the special educator works with a small group of struggling learners within the classroom, or both teachers alternate teaching the whole group while circulating to monitor progress.
General education classroom with in-class resource support: A special education teacher or paraprofessional comes into the general education classroom to provide direct support to individual students. For example, a paraprofessional may be assigned to support a second-grade student with autism during literacy centers, prompting the student to stay on task and assist with independent reading.
Resource room (pull-out): The student spends part of the school day in a special education classroom and part in the general education classroom. The resource room is typically used for explicit, intensive instruction in areas of deficit (e.g., reading, math, study skills). For example, a third-grade student with SLD in reading may receive 45 minutes of daily intensive phonics instruction in the resource room and spend the rest of the day in general education.
Self-contained classroom: The student is in a special education classroom for most or all of the school day, often for students with more intensive needs. The self-contained class may have a lower student-to-teacher ratio and staff trained in specific instructional and behavioral strategies. For example, a kindergarten student with severe autism who requires intensive one-to-one behavioral and communication support may receive most instruction in a specialized autism classroom, joining general education for art, music, and lunch.
Special day school: A separate school building serving only students with disabilities. A student may attend a special day school when the local school cannot meet their needs, such as a high school student with severe emotional disturbance who needs a therapeutic environment with a lower student-teacher ratio, a full-time mental health counselor, and a behavior specialist on site.
Residential placement: A 24-hour setting where students live and receive education and therapeutic services, such as a residential school for students with severe emotional disturbance or a state school for students with deaf-blindness. This is considered the most restrictive placement.
Home and hospital placement: Education provided at home or in a hospital for students who are unable to attend school due to serious illness or medical conditions. For example, a student undergoing chemotherapy for leukemia may receive home instruction through a district-provided teacher for a period of months.

Placement decisions must be reviewed at least annually. The principle of LRE requires that every placement choice be made only after considering whether the student can succeed in a less restrictive environment with appropriate supplementary aids and services. Placement cannot be changed solely because a student needs more staff attention, because of a lack of staff training, or based on an administrative decision.

TEST READY TIP

LRE has a specific legal meaning: it is a presumption that the student should be educated with nondisabled peers, and the school must provide supplementary aids and services to make that possible. The IEP team is required to document why a more restrictive setting is necessary and include a statement of the extent to which the student will not participate with nondisabled peers. On the exam, any answer suggesting that a student with a disability should be placed in a separate setting without prior consideration of supports in the general education setting is likely to be incorrect.

Exam Connection: The Praxis 5355 will ask you to identify the most appropriate placement for a given student based on the student's characteristics and needs, as well as the principle of LRE. You must be able to match student needs to the continuum of services, starting from the least restrictive option that can meet those needs. For example, a student with a mild learning disability who only needs weekly support would not be placed in a self-contained classroom; a student with severe aggressive behavior that disrupts the general education environment significantly might require a self-contained or therapeutic setting.

(7) The 13 IDEA Disability Categories

The Individuals with Disabilities Education Act (IDEA) establishes 13 disability categories through which students may qualify for special education services. The Praxis 5355 expects candidates to know the defining characteristics, eligibility criteria, and educational implications of each category. Students must not only have a disability that fits one of these categories but must also demonstrate that the disability adversely affects their educational performance and that they require specially designed instruction.

Intellectual Disability (ID)

Characterized by significant limitations in both intellectual functioning and adaptive behavior, manifesting before age 18. Adaptive behavior encompasses conceptual skills (reading, money management, time concepts), social skills (interpersonal skills, responsibility, self-esteem), and practical skills (activities of daily living, occupational skills).

Mild ID (IQ 50–55 to approximately 70): Most students with mild ID learn academic skills up to approximately the 6th grade level with appropriate support. They typically require support with complex social and financial decisions in adulthood but can live semi-independently.
Moderate ID (IQ 35–40 to 50–55): Functional academic skills (reading survival words, functional math) are achievable. Adults typically require supported employment and supervised living arrangements.
Severe ID (IQ 20–25 to 35–40): Communication, self-care, and safety skills are primary instructional targets. Extensive support is required across settings.
Profound ID (IQ below 20–25): Intensive, lifelong support is required for all basic life functions. Instruction focuses on basic communication, sensory responses, and comfort.
Educational implications: Differentiated curriculum, task analysis, systematic instruction, community-based instruction, functional curriculum, supported employment transition planning.

Specific Learning Disability (SLD)

A disorder in one or more of the basic psychological processes involved in understanding or using language (spoken or written), which manifests as significant difficulty in listening, thinking, speaking, reading, writing, spelling, or doing mathematical calculations. SLD is not due to intellectual disability, sensory impairment, emotional disturbance, cultural factors, environmental disadvantage, or limited English proficiency.

Types: Dyslexia (reading), dysgraphia (written expression), dyscalculia (mathematics), plus SLDs affecting listening comprehension, oral expression, and basic reading skills.
Identification approaches: Discrepancy model (significant gap between IQ and achievement) and Response to Intervention/Multi-Tiered Support Systems (RTI/MTSS), which identifies students who fail to respond adequately to evidence-based general education interventions.
Educational implications: Explicit, systematic instruction in the deficit area; assistive technology; extended time; reduced-distraction environment; multisensory instructional methods.
SLD is the largest IDEA category, representing approximately 33–35% of students receiving special education services.

Speech or Language Impairment (SLI)

A communication disorder, including stuttering, impaired articulation, language impairment, or voice impairment, that adversely affects educational performance. This category is distinct from autism spectrum disorder (which may include communication differences) and is the second most common IDEA category.

Articulation disorders: Difficulty producing specific speech sounds correctly (substitutions, omissions, distortions). Common errors include /r/ and /l/ persisting beyond the typical developmental window.
Fluency disorders: Disruptions in the flow of speech, including stuttering (repetitions, prolongations, blocks) and cluttering (rapid, irregular speech rate).
Language disorders: Difficulties with the form of language (phonology, morphology, syntax), content (semantics/vocabulary), or use (pragmatics/social language). Language disorders may affect both receptive and expressive language.
Voice disorders: Abnormal pitch, quality, or loudness affecting social communication.
Educational implications: Services provided by a speech-language pathologist (SLP); classroom accommodations for oral expression and listening comprehension; assistive and augmentative communication (AAC) for students with severe language impairments.

Emotional Disturbance (ED)

Characterized by one or more of the following conditions over a long period of time and to a marked degree that adversely affects educational performance: inability to learn not explained by other factors; inability to build or maintain satisfactory interpersonal relationships; inappropriate types of behavior or feelings; pervasive mood of unhappiness or depression; tendency to develop physical symptoms or fears associated with school or personal problems. Includes schizophrenia.

Does NOT include: Social maladjustment (conduct disorder without emotional disturbance, which remains a debated exclusion in the field).
Common conditions within ED: Anxiety disorders, depression, bipolar disorder, oppositional defiant disorder, conduct disorder, and schizophrenia.
Educational implications: Positive behavioral supports and interventions (PBIS); therapeutic supports; social-emotional learning curricula; structured, predictable environments; crisis intervention plans; collaboration with mental health professionals.
Important distinction: Behavior must be chronic, severe, and pervasive (not just a response to temporary circumstances) and must adversely affect educational performance to qualify under ED.

Autism Spectrum Disorder (ASD)

A developmental disability characterized by persistent deficits in social communication and social interaction across multiple contexts, combined with restricted, repetitive patterns of behavior, interests, or activities. Symptoms must be present in the early developmental period (though they may not fully manifest until social demands exceed capacity) and cause clinically significant impairment in social, occupational, or other important areas of functioning.

Social communication deficits: Difficulties with social-emotional reciprocity (back-and-forth conversation, sharing interests), nonverbal communicative behaviors (eye contact, facial expressions, gestures), and developing and maintaining relationships.
Restricted and repetitive behaviors (RRBs): Stereotyped or repetitive motor movements or speech; insistence on sameness; highly restricted and fixated interests; hyper- or hyporeactivity to sensory input.
Wide spectrum: ASD ranges from individuals who are nonspeaking with significant intellectual disability to highly verbal individuals with average or above-average IQ. All presentations share the core features of social communication differences and RRBs, but severity and manifestation vary enormously.
Educational implications: Visual supports; structured environments; explicit social skills instruction; ABA-based interventions; sensory accommodations; AAC for nonspeaking students; transition planning; strength-based approaches capitalizing on intense interests.

Orthopedic Impairment (OI)

A severe orthopedic impairment that adversely affects educational performance. Includes impairments caused by congenital anomalies (clubfoot, absence of a limb), impairments caused by disease (poliomyelitis, bone tuberculosis), and impairments from other causes (cerebral palsy, amputations, fractures, or burns causing contractures).

Cerebral palsy (CP) is the most common cause of OI in school-aged students, a group of permanent movement disorders appearing in early childhood due to brain damage before, during, or shortly after birth.
Educational implications: Physical accessibility; assistive technology (switches, eye-gaze devices, power wheelchairs); adapted physical education; occupational therapy for fine motor and daily living skills; physical therapy for mobility; alternative assessment methods.

Traumatic Brain Injury (TBI)

An acquired injury to the brain caused by an external physical force, resulting in total or partial functional disability or psychosocial impairment that adversely affects educational performance. TBI applies to open or closed head injuries resulting in impairments in cognition, language, memory, attention, reasoning, abstract thinking, judgment, problem-solving, sensory and perceptual or motor abilities, psychosocial behavior, physical functions, information processing, or speech.

Does NOT include: Brain injuries that are congenital or degenerative, or brain injuries induced by birth trauma.
Educational implications: TBI recovery is often nonlinear; students may show improvement over time. Instruction must be flexible and re-evaluated frequently. Cognitive fatigue, memory difficulties, and behavior changes are common challenges. Extended time, reduced workload, frequent breaks, and explicit memory strategies are key supports.

Other Health Impairment (OHI)

Having limited strength, vitality, or alertness (including heightened alertness to environmental stimuli) that results in limited alertness with respect to the educational environment, due to chronic or acute health problems such as asthma, attention deficit hyperactivity disorder (ADHD), diabetes, epilepsy, heart conditions, hemophilia, lead poisoning, leukemia, nephritis, rheumatic fever, sickle cell anemia, and Tourette syndrome.

ADHD is the most common condition served under OHI, though students with ADHD may also qualify under other categories (SLD, ED) if those conditions also apply.
Educational implications: Vary by the specific health condition. For ADHD: preferential seating, reduced-distraction environment, chunked assignments, movement breaks, behavioral supports. For epilepsy: seizure response plans, seizure diary, medication administration. For diabetes: blood glucose monitoring, snack access, flexibility for health management.

Visual Impairment Including Blindness (VI)

An impairment in vision that, even with correction, adversely affects educational performance. Includes both partial sight and blindness.

Educational implications: Braille instruction (for students with insufficient functional vision for print); large print materials; magnification devices; orientation and mobility instruction; screen reader technology; expanded core curriculum (ECC) addressing disability-specific skills such as social interaction, recreation and leisure, and use of assistive technology.
Orientation and mobility (O&M) specialists provide instruction in safe, independent travel, a related service unique to students with visual impairments.

Hearing Impairment (HI) and Deafness

Deafness means a hearing impairment so severe that the student is impaired in processing linguistic information through hearing, with or without amplification, that adversely affects educational performance. Hearing impairment refers to impairment in hearing (whether permanent or fluctuating) that adversely affects educational performance but is not included under the definition of deafness.

Educational implications: Sign language interpreter services; FM systems; captioning; audiological services; speech-language therapy; social-emotional support (communication access in peer interactions); Deaf culture and identity considerations; ASL instruction when appropriate.
Communication approaches: The field involves significant ongoing debate about oral and spoken language approaches, sign-supported speech, and bilingual-bicultural (ASL and English) approaches. Special educators must be culturally responsive and involve families in communication decisions.

Deaf-Blindness (DB)

A combination of hearing and visual impairments causing such severe communication and other developmental and educational needs that they cannot be accommodated in programs solely for children with deafness or children with blindness.

Educational implications: Interveners (one-on-one support persons trained in deaf-blind communication); tactile communication systems (tactile sign language, objects of reference, braille); highly specialized, intensive supports; state deaf-blind technical assistance projects provide consultation.
Note: Students with deaf-blindness do not need to be completely deaf and completely blind; the combination of vision and hearing losses must together create the severe educational impact described in the definition.

Multiple Disabilities (MD)

Concomitant impairments (such as intellectual disability combined with orthopedic impairment) the combination of which causes such severe educational needs that they cannot be accommodated in programs designed solely for one of the impairments. Does not include deaf-blindness (which has its own category).

Educational implications: Highly individualized, team-based instruction; integrated therapy services; functional curriculum; augmentative and alternative communication (AAC); intensive support across all settings; person-centered planning for transition.

Developmental Delay (DD)

A category available for children ages 3 through 9, and at states' discretion, from birth (Part C early intervention) and up to age 9 or as permitted by state law. States may choose to use this category for children aged 3–5, while other states permit it through age 9. States can set their own age limits within the federal allowance. Students in this category are experiencing significant developmental delays in one or more areas: physical development, cognitive development, communication development, social or emotional development, or adaptive development.

Purpose: Allows young children to receive early childhood special education services while evaluation continues to determine whether a more specific categorical label applies. This avoids premature labeling and allows time for intervention to demonstrate its effectiveness.
Important: States set their own definitions for what constitutes a "significant developmental delay" and for the maximum age of eligibility; criteria vary by state. Once a student reaches the maximum age for DD eligibility in their state, they must qualify under a specific IDEA category to continue receiving services.

(8) Similarities and Differences Among Students with Disabilities

One of the most important principles in special education, and one directly tested on the Praxis 5355, is that disability categories describe groups of students who share certain characteristics, but there is enormous variability within every group. No two students with the same disability category are identical in their strengths, challenges, or support needs.

Within-Group Variability and Heterogeneity

Within-group variability refers to the range of performance, characteristics, and needs among students who share a disability label. This variability is a defining feature of every IDEA category, not an exception.

ASD example: The autism spectrum includes a student who is nonspeaking, requires total assistance for daily living, and engages in intense self-stimulatory behavior alongside a student who is highly verbal, attends general education classes with minimal support, and has an advanced technical interest. Both students have ASD, but their educational needs are almost entirely different.
SLD example: Students with specific learning disability may have average or above-average cognitive ability alongside a severe deficit in one academic area (reading decoding), or they may have a profile of multiple academic weaknesses. The term "learning disabled" does not describe a uniform population.
ID example: Even within the "mild intellectual disability" range, students vary enormously in their adaptive behavior strengths, communication profiles, behavioral patterns, and academic potential. Curriculum decisions must be driven by individual assessment, not categorical assumptions.
Practical implication: The IEP is individualized precisely because the disability label alone does not prescribe instruction. Effective special educators use assessment data to understand each student's unique profile of strengths and needs.

Exam Connection: The Praxis 5355 tests whether candidates understand that disability categories are not homogeneous groups. Questions may present a scenario in which an educator makes a decision based on a student's label alone (without considering the individual's actual profile) and ask you to identify the problem with that approach.

Person-First Language and Identity-First Language

Person-first language places the person before the disability, as in "student with autism" rather than "autistic student." The intent is to emphasize the person's humanity and individuality before their disability status. Person-first language has been the standard in special education professional practice and in IDEA itself for decades.

Examples of person-first language: "student with intellectual disability" rather than "intellectually disabled student," "child who is blind" rather than "blind child," "individual with autism spectrum disorder" rather than "autistic individual."
Identity-first language: Many members of the Deaf community and many autistic self-advocates strongly prefer identity-first language ("autistic person," "Deaf person"), arguing that disability is an integral part of their identity, not something separate from them. The Praxis 5355 primarily reflects person-first language conventions, but candidates should be aware that identity-first language preferences exist and are respected within communities.
On the Praxis exam: Use person-first language unless the question specifically involves Deaf culture or a community that has expressed a preference for identity-first language. In professional documentation (IEPs, evaluation reports), person-first language is the standard.

Avoiding Stereotyping and Strength-Based Perspectives

Effective special educators resist applying categorical stereotypes and instead approach each student from a strength-based perspective, identifying what the student can do and building from that foundation rather than focusing exclusively on deficits.

Avoiding stereotyping: Not all students with ASD have savant skills, not all students with Down syndrome are affectionate and social, and not all students with learning disabilities have low self-esteem. Category characteristics describe group-level tendencies, not individual certainties.
Strength-based assessment: Uses ecological inventories, portfolio assessment, and student interviews to identify genuine strengths across academic, social, communicative, and functional domains. Strengths become the foundation for instructional planning and serve as motivational levers.
Universal Design for Learning (UDL): A strength-based, proactive approach to curriculum design that anticipates learner variability and provides multiple means of engagement, representation, and action and expression from the outset, rather than retrofitting accommodations after instruction fails.
Cultural responsiveness: Student strengths, communication styles, and learning preferences are shaped by cultural background. Effective special educators recognize cultural assets (bilingualism, collectivist values, oral tradition) as strengths rather than deficits.

(9) Impact of Disability on Overall Development

Disabilities rarely affect a single developmental domain in isolation. Understanding how different disability categories affect cognitive, language, social-emotional, and physical development, including secondary characteristics and co-occurring conditions, is essential for comprehensive IEP planning and the content of the Praxis 5355.

How Intellectual Disability Affects Development Across Domains

Cognitive: Reduced capacity for abstract reasoning, working memory limitations, slower rate of skill acquisition, difficulty generalizing learned skills to new settings or contexts. Information processing is slower; students may require more repetition and distributed practice than peers.
Language: Delayed language acquisition; receptive language typically stronger than expressive language; limited syntactic complexity; vocabulary limited relative to age peers; pragmatic language (social use of language) may be relatively stronger in mild ID.
Social-emotional: May have age-appropriate social desires (wanting friendships, romantic relationships) but limited social skills to achieve them; susceptibility to peer victimization and social exploitation; emotional regulation typically developing on a slower timeline; risk of co-occurring depression and anxiety due to awareness of difference.
Physical and motor: Many students with mild-moderate ID have typical motor development; some syndromic causes (Down syndrome, Angelman syndrome) are associated with hypotonia (low muscle tone), gross motor delays, and fine motor challenges.
Secondary characteristics: Heightened risk of bullying; susceptibility to false confessions and social manipulation; disproportionate rates of co-occurring ADHD, anxiety disorders, and behavioral challenges.

How Autism Spectrum Disorder Affects Development Across Domains

Cognitive: Cognitive profiles are highly variable; some students have intellectual disability, some have average IQ, some have above-average IQ. Many students with ASD have an uneven cognitive profile (islets of exceptional ability alongside significant deficits). Executive function difficulties (planning, flexibility, working memory) are very common regardless of IQ level.
Language: Range from completely nonspeaking to highly verbal. Even verbal students may have significant pragmatic language difficulties (difficulty with conversation turn-taking, understanding nonliteral language, adjusting register). Echolalia (immediate or delayed repetition of heard speech) is common in developing communicators with ASD.
Social-emotional: Core deficits in social communication and reciprocity; difficulty reading nonverbal social cues; theory of mind differences (difficulty understanding others' mental states, perspectives, and intentions); may have intense desire for social connection despite social skill challenges; co-occurring anxiety disorders are extremely common (estimated 40–50% of individuals with ASD).
Physical and motor: Sensory processing differences affect responses to sensory input (hyper- or hyposensitivity to sound, touch, taste, vestibular input, proprioception); fine and gross motor differences are common; gastrointestinal issues have a high prevalence in ASD; seizure disorders co-occur in approximately 20–30% of individuals with ASD.

How Specific Learning Disability Affects Development Across Domains

Cognitive: Average to above-average overall cognitive ability, but significant weaknesses in one or more specific cognitive processes (phonological processing, processing speed, working memory, rapid automatic naming). The discrepancy between potential and achievement is characteristic of SLD.
Language: Reading-based SLDs (dyslexia) involve deficits in phonological awareness, phonological memory, and or rapid naming that impair the reading decoding process. Language-based SLD affects listening comprehension and expressive language as well as literacy.
Social-emotional: Chronic academic failure significantly impacts self-esteem and self-efficacy. Rates of anxiety and depression are elevated. Learned helplessness, the belief that effort will not produce success, is a risk when students repeatedly fail despite effort. Teacher-student relationship quality is a powerful protective factor.
Physical and motor: Dysgraphia (written expression SLD) frequently co-occurs with fine motor difficulties. Sensory processing differences may co-occur. Overall physical development is typically not directly affected by SLD.

How Emotional and Behavioral Disabilities Affect Development Across Domains

Cognitive: Direct effects on learning are mediated through attention, working memory, and executive function. Anxiety consumes cognitive resources (worry thoughts intrude on task engagement). Depression reduces motivation, energy, and information processing speed. ADHD directly impairs sustained attention, impulse control, and working memory.
Language: Social communication is often affected; students with ED may misinterpret social situations (hostile attribution bias: interpreting neutral peer behavior as threatening), have difficulty with pragmatic language, or use language that escalates rather than de-escalates conflict.
Social-emotional: The primary domain affected. Difficulty forming and maintaining relationships; poor emotional regulation; low frustration tolerance; co-occurring substance use (in adolescence); trauma histories are prevalent (adverse childhood experiences are common among students with ED).
Physical and motor: Somatic complaints (headaches, stomachaches) are common. Physical manifestations of anxiety include rapid heartbeat, shortness of breath, and nausea. Depression may manifest as fatigue, changes in appetite, and psychomotor slowing.

Co-Occurring Conditions and Secondary Characteristics

Many students with disabilities have co-occurring conditions, two or more qualifying conditions that affect development simultaneously. Understanding co-occurrence is important for designing comprehensive, individualized supports.

ASD + ID: Approximately 31–38% of individuals with ASD also have intellectual disability. This combination requires particularly comprehensive planning, including AAC, structured environments, and intensive behavioral supports.
SLD + ADHD: Up to 30–50% of students with ADHD also have co-occurring SLD. Both conditions affect academic performance but require different intervention approaches (behavioral supports for ADHD, evidence-based reading instruction for dyslexia).
ID + psychiatric disorders: Rates of co-occurring psychiatric disorders in individuals with ID are 3–4 times higher than in the general population (a phenomenon called "dual diagnosis" in this context). Diagnosis can be challenging because students may have limited ability to describe internal experiences.
TBI + ED: Traumatic brain injury frequently results in emotional and behavioral changes, including irritability, impulsivity, depression, and anxiety. These behavioral effects may be misinterpreted as willful misbehavior without understanding the neurological basis.
Physical disabilities + secondary psychological effects: Students with orthopedic impairments, chronic illness (OHI), or sensory disabilities face a higher risk of depression, anxiety, and social isolation due to physical limitations, medical procedures, and social exclusion.

Exam Connection: The Praxis 5355 may ask you to recognize secondary characteristics or co-occurring conditions in a student scenario. Disability impacts ripple across domains: a student with a physical disability may also need social-emotional support, and a student with an emotional disability may also need cognitive supports.

(10) Key Takeaways

Piaget's stages are sequential and qualitative: Children progress through sensorimotor, preoperational, concrete operational, and formal operational stages, each representing a fundamentally different way of thinking, not just more information.
Vygotsky's ZPD drives effective instruction: Instruction should target the zone between independent and assisted performance; scaffolding provides temporary support within the ZPD and is gradually faded as competence grows.
Erikson's Industry vs. Inferiority is critical for school-age students: Chronic academic failure threatens the development of industry (competence) and may produce lasting inferiority; special educators must engineer success and build self-efficacy.
Bronfenbrenner's ecology explains why context matters: Family, school, community, culture, and time all shape development; effective special education addresses multiple ecological levels, not just the student in isolation.
Behavioral principles underlie many special education practices: Reinforcement (positive and negative), extinction, and functional behavioral assessment are foundational tools; negative reinforcement removes something unpleasant to increase behavior, and it is not punishment.
Language milestones provide critical red flags: No babbling by 9 to 12 months, no words by 15 to 16 months, no two-word phrases by 24 months, and any loss of language are referral triggers.
Adaptive behavior is distinct from academics: It covers conceptual, social, and practical skills for daily living and is a primary focus for students with ASD, ID, and physical or health disabilities.
Environmental factors beyond disability matter: Poverty, trauma, family stress, nutrition, and community resources all influence development and learning and must be addressed in educational planning.
Self-regulation affects behavior and academics: The ability to manage attention, emotions, and impulses is foundational to success and is often a target of instruction for students with a range of disabilities.
Auditory and information processing deficits impact learning: Deficits in working memory, processing speed, and phonological processing are common across disability categories and require instructional accommodations.
Sensory and physical impairments affect families and communities: Communication access, physical accessibility, and caregiver demands are central issues for students with sensory or health needs.
Specialized health care supports are part of the school day: Schools provide services such as catheterization, tracheostomy care, medication administration, and tube feeding for students who need them.
LRE and the continuum of services guide placement: Students should be educated with nondisabled peers to the maximum extent appropriate, with a range of supports and placements available.
The 13 IDEA categories each have distinct definitional criteria: SLD is the largest category; Developmental Delay is time-limited (ages 3 through 9, or as states define); Emotional Disturbance requires chronic, pervasive impact on educational performance; TBI requires an external physical cause.
Within-group variability is enormous: Disability labels describe group tendencies, not individual certainties; the IEP must be built from individual assessment data, not categorical assumptions.
Person-first language is the professional standard: Place the person before the disability in professional contexts; be aware that some disability communities (Deaf community, many autistic self-advocates) prefer identity-first language.
Disability impacts ripple across all developmental domains: No disability affects only one domain; special educators must assess and support the whole student, including cognitive, language, social-emotional, physical, and adaptive development.
Co-occurring conditions are common: ASD + ID, SLD + ADHD, and many other combinations require educators to plan for multiple, overlapping sets of needs simultaneously.
Secondary characteristics are predictable: Social isolation, depression, anxiety, and reduced self-esteem are common secondary characteristics for students across disability categories; these require proactive support, not just academic intervention.

Quick Reference Card

Developmental language red flags: No babbling by 9–12 months, no single words by 15–16 months, no two-word phrases by 24 months, loss of language at any age.
Social smiling emergence: Typically appears at 6–8 weeks, not earlier.
Stranger anxiety appears at 6–9 months, and separation anxiety peaks at 9–18 months.
Adaptive behavior covers conceptual, social, and practical daily living skills, distinct from academic achievement.
Environmental factors influencing development include poverty, trauma, family stress, nutrition, and community resources.
Self-regulation involves managing attention, emotion, and impulses; deficits affect both behavior and academic performance.
Auditory processing involves phonological awareness and memory; working memory and processing speed are key information-processing skills.
Specialized health care in schools includes catheterization, tracheostomy care, medication administration, tube feeding, and ventilation.
LRE continuum: General education with supports, resource room, self-contained class, special day school, residential, home and hospital, with movement only as needed.

What You'll Learn

Free Study Guide - Lesson 1

Introduction

(1) Theories of Human Development

Piaget's Cognitive Development Theory

Vygotsky's Sociocultural Theory

Erikson's Psychosocial Theory

Bronfenbrenner's Ecological Systems Model

Behavioral Theory (Behaviorism)

(2) Typical Developmental Milestones

Cognitive Development Milestones

Language and Communication Milestones

Social-Emotional Development Milestones

Physical and Motor Development Milestones

Adaptive Behavior

(3) Environmental and Biological Factors Influencing Development

Environmental Factors Beyond the Disability

Biological Factors, Other Disabilities, and Self-Regulation

(4) Auditory and Information Processing Skills

Auditory Processing

Information Processing

(5) Sensory Impairments and Physical/Health Exceptionalities: Family and Community Interaction

Impact on Family Interactions

Impact on Community Interaction

(6) Adapting the Learning Environment: Specialized Health Care and Placement

Specialized Health Care Supports in Educational Settings

Placement Options and the Continuum of Services

(7) The 13 IDEA Disability Categories

Intellectual Disability (ID)

Specific Learning Disability (SLD)

Speech or Language Impairment (SLI)

Emotional Disturbance (ED)

Autism Spectrum Disorder (ASD)

Orthopedic Impairment (OI)

Traumatic Brain Injury (TBI)

Other Health Impairment (OHI)

Visual Impairment Including Blindness (VI)

Hearing Impairment (HI) and Deafness

Deaf-Blindness (DB)

Multiple Disabilities (MD)

Developmental Delay (DD)

(8) Similarities and Differences Among Students with Disabilities

Within-Group Variability and Heterogeneity

Person-First Language and Identity-First Language

Avoiding Stereotyping and Strength-Based Perspectives

(9) Impact of Disability on Overall Development

How Intellectual Disability Affects Development Across Domains

How Autism Spectrum Disorder Affects Development Across Domains

How Specific Learning Disability Affects Development Across Domains

How Emotional and Behavioral Disabilities Affect Development Across Domains

Co-Occurring Conditions and Secondary Characteristics

(10) Key Takeaways

Quick Reference Card

Unlock the Complete Study Guide

More Praxis 5355 Resources