Lesson 1: Foundations
This lesson covers the foundational knowledge that anchors everything else on the TExES Deafblind EC–12 (185) exam: what causes deafblindness and the terminology used to classify it, the theorists whose philosophies shape instruction and assessment for deafblind learners, the true range of vision and hearing within this population, the research-based practices that promote learning and access, and the clinical, functional, and legal definitions that determine eligibility for services. Domain I accounts for approximately 25% of your exam, and the concepts in this lesson reappear inside scenario questions across every other domain.
Learning Outcomes
By the end of this lesson, you will understand key philosophical, historical, and legal foundations in the education of learners who are deafblind.
- Identify key deafblind etiologies and correctly apply the terminology of congenital versus adventitious conditions.
- Describe the key theories and philosophies that guide instruction and access for deafblind learners, including the work of Jan van Dijk, Lilli Nielsen, and Barbara Miles, and the child-guided approach to evaluation.
- Explain the range of vision and hearing among deafblind learners and the variety of backgrounds and perspectives within this population.
- Apply key research findings and practices that promote learning, engagement, communication, and access for deafblind learners.
- Distinguish the clinical, functional, and legal definitions that determine eligibility and services for learners who are deafblind, blind or visually impaired, or D/deaf or hard of hearing.
(1) DEAFBLIND ETIOLOGIES AND TERMINOLOGY
(A) Congenital vs. Adventitious: The Terminology That Frames Everything
Two terms classify when deafblindness begins, and the distinction drives nearly every instructional decision you will make. Etiology is the cause or origin of a condition; onset is when the condition begins.
CONGENITAL DEAFBLINDNESS
Congenital means present at or before birth. In deafblind education, what matters most is not the strict medical meaning but the educational distinction between prelingual and postlingual onset: a child can acquire deafblindness after birth yet still be considered prelingual if the combined loss occurs before language develops. Conversely, a child who loses senses after establishing language — even in early childhood — is considered postlingual (adventitious). Do not treat "congenital" and "before language develops" as interchangeable; a child born hearing and sighted who loses both senses at age two is not congenitally deafblind but may still be prelingually deafblind.
- The child has never had full sensory access to language models
- Concepts, communication, and attachment must all be built through touch, movement, and residual senses from the start
- Examples: CHARGE syndrome, congenital rubella syndrome, congenital CMV, complications of extreme prematurity
ADVENTITIOUS (ACQUIRED) DEAFBLINDNESS
Adventitious (also called acquired) means the combined loss occurs later in life, after the child has developed some language and stored visual or auditory experience.
- The learner brings existing concepts, memories, and often an established language to instruction
- Instruction builds on prior knowledge while teaching new access modes (tactile sign, braille)
- Examples: Usher syndrome with later vision loss, meningitis, traumatic brain injury, progressive conditions
On the Exam: What matters most educationally is the age of onset relative to language development, not the specific diagnosis. A child who loses both senses before acquiring language faces fundamentally different learning demands than a learner who acquired spoken or signed language first. Expect items that ask you to reason from onset, not from the medical label.
(B) Major Etiology Categories
Etiologies of deafblindness fall into four broad categories. Know the category structure and the flagship examples in each.
| Category | Key Examples |
|---|---|
| Genetic / syndromic | CHARGE syndrome and Usher syndrome (both detailed below); also Down syndrome, Trisomy 13 and Trisomy 18, Goldenhar syndrome, Norrie disease, Bardet-Biedl syndrome, Stickler syndrome, Cornelia de Lange syndrome, Wolf-Hirschhorn syndrome, and Alstrom syndrome. |
| Prenatal / congenital infections (the TORCH group) | Congenital rubella syndrome (historically a leading cause of deafblindness before widespread vaccination; now rare in countries with strong immunization programs), cytomegalovirus (CMV) (now generally cited as the leading non-genetic/infectious cause of congenital deafblindness in the United States; its prominence relative to rubella is a direct result of vaccination reducing rubella's incidence), toxoplasmosis, herpes, syphilis, and Zika virus. |
| Prematurity and birth complications | Retinopathy of prematurity (ROP) (abnormal retinal blood vessel growth in infants born very early), hypoxia or asphyxia at birth, very low birth weight, and intraventricular hemorrhage. |
| Postnatal / adventitious causes | Meningitis, encephalitis, traumatic brain injury, stroke, tumors, and degenerative or progressive conditions that erode vision, hearing, or both over time. |
(C) Two Syndromes to Know Cold: CHARGE and Usher
CHARGE SYNDROME
The most common cause of congenital deafblindness in the United States. CHARGE is an acronym for the cluster of features that can occur together:
| C | Coloboma (a gap or cleft in a structure of the eye, such as the iris or retina, affecting vision) |
| H | Heart defects |
| A | Atresia of the choanae (blockage of the nasal passages) |
| R | Retardation of growth and/or development — Note: the original CHARGE acronym is an older mnemonic. Modern diagnostic criteria (Verloes and others) emphasize coloboma, choanal atresia, cranial nerve anomalies, and characteristic external ears as the major diagnostic features; the acronym letter R is retained for familiarity but the syndrome is now diagnosed by a broader clinical and genetic profile, not solely by checking all seven acronym features. |
| G | Genital abnormalities |
| E | Ear anomalies (outer, middle, or inner ear differences, frequently with hearing loss and balance involvement) |
Because both the eyes (coloboma) and the ears (ear anomalies with hearing loss) are commonly affected, and because balance and medical needs are often involved, CHARGE produces complex, individually variable profiles present from birth.
USHER SYNDROME
The most common cause of hereditary (genetic) deafblindness. Its signature pattern: congenital sensorineural hearing loss (hearing loss originating in the inner ear or auditory nerve, present at birth) combined with progressive vision loss from retinitis pigmentosa (a degenerative retinal condition that first destroys night vision, then narrows the visual field). A child with Usher syndrome typically begins life as a Deaf or hard-of-hearing child (the hearing loss is congenital) and becomes deafblind gradually as the retinitis pigmentosa progresses. This mixed profile makes Usher the classic exam example of progressive/acquired vision loss developing on top of a congenital hearing loss — the deafblindness itself is adventitious (the vision loss is acquired), but the underlying hearing loss is congenital. Do not describe Usher syndrome as a clean example of adventitious deafblindness; the more precise framing is that it represents a condition where one loss is congenital and the other is progressive.
| Type | Hearing | Vision | Balance |
|---|---|---|---|
| Type 1 | Profound deafness at birth | Vision loss begins in childhood | Balance problems (vestibular involvement) |
| Type 2 | Moderate to severe loss at birth | Vision loss begins later (adolescence or adulthood) | Normal balance |
| Type 3 | Progressive hearing loss | Progressive vision loss | Variable |
Common Trap: Do not confuse the two superlatives. CHARGE = most common cause of congenital deafblindness in the US. Usher = most common cause of hereditary deafblindness. An item that swaps those descriptors is testing exactly this distinction.
(2) KEY THEORIES AND PHILOSOPHIES
(A) Jan van Dijk: Movement-Based Learning and the Child-Guided Approach
Jan van Dijk, a Dutch educator, pioneered a movement-based (co-active movement) approach grounded in secure attachment: before a deafblind child can communicate symbolically, the child must first experience safe, responsive, shared movement with a trusted adult. Learning progresses through stages:
Shared movement in close body contact; the adult responds to and joins the child's own movements
Adult and child move together side by side, sharing one activity with gradually increasing distance
The child reproduces a modeled action later, showing mental representation
Gestures, including "characterizing gestures" drawn from the child's own experience, then more formal symbols
Van Dijk also originated the child-guided approach to assessment, covered in subtopic (D) below. Remember the pairing: van Dijk is both the movement theorist and the assessment innovator.
(B) Lilli Nielsen: Active Learning and the Little Room
Lilli Nielsen, a Danish educator and psychologist, developed the Active Learning approach. Her core idea: the child must be an active doer, not a passive recipient. Real learning comes from the child's own self-initiated exploration, not from an adult moving the child through activities.
- Children with significant visual impairment often do not spontaneously reach out and explore, because the environment gives them no reason or feedback to do so.
- Nielsen's answer was to engineer environments that reward independent exploration.
- Her signature environment is the Little Room: a resonance board (a thin wooden platform that amplifies vibration and sound from the child's movements) topped by a small three-sided enclosure with motivating objects suspended within easy reach, so every small movement produces immediate tactile and auditory feedback.
- The adult's role is to prepare the environment and then step back, allowing the child to self-initiate, repeat, compare, and experiment.
On the Exam: If a scenario describes hanging objects within a child's reach on a resonance board so the child can discover and explore them independently, the credited theorist is Nielsen. If the scenario describes an adult joining and building on the child's movements in close body contact, the credited theorist is van Dijk.
(C) Barbara Miles: Hands as the Voice and Eyes of the Deafblind Child
Barbara Miles focused the field's attention on the hands of the deafblind child. For a learner without reliable distance senses, the hands do triple duty:
the hands act as eyes and ears
exploring is how concepts form
the hands act as the voice
- Because the hands carry so much of the child's perception and expression, adults must treat them with respect: never grab, force, or manipulate them.
- Miles championed hand-under-hand interaction: the adult's hands rest gently under the child's hands, inviting the child to follow, feel, and withdraw at will. This builds trust and preserves the child's control.
- She framed every tactile exchange as genuine conversation: a back-and-forth with turn-taking, pauses, and shared attention, not a one-way delivery of instruction.
(D) The Child-Guided Approach to Evaluation
Standardized, norm-referenced tests assume the child can see the stimulus, hear the directions, and respond within a fixed time. Those assumptions fail for deafblind learners, so results routinely underestimate what these children know. The child-guided approach, originated by van Dijk, replaces those assumptions with observation of the child on the child's own terms.
| Traditional Standardized Testing | Child-Guided Assessment |
|---|---|
| The examiner directs; the child must follow a fixed protocol | The assessor follows the child's lead, joining activities the child initiates |
| Assumes typical vision and hearing to access test items | Uses the child's preferred sensory channels and natural interactions |
| Yields scores compared to norms built on sighted-hearing children | Yields a portrait of interests, biobehavioral states (levels of arousal and alertness), learning channels, memory, interaction style, and problem solving |
| Unfamiliar setting, unfamiliar examiner, time pressure | Natural settings, familiar routines, observation of spontaneous behavior |
On the Exam: When an item asks for the most appropriate way to evaluate a learner who is deafblind, the credited answer follows the child's lead in natural interaction and observes spontaneous behavior. Distractors that rely on standardized norm-referenced instruments administered under standard conditions are wrong because those instruments assume sensory access the child does not have.
(3) THE RANGE OF VISION AND HEARING, AND THE DIVERSITY OF LEARNERS
(A) Deafblindness Is a Spectrum, Not Total Darkness Plus Total Silence
The single most important corrective to popular assumptions: deafblindness is a spectrum, not total deafness plus total blindness. Very few deafblind learners have no usable vision and no usable hearing at all. Any combination can occur:
HEARING RANGE
From mild hearing loss through profound deafness; stable or fluctuating or progressive; with or without benefit from hearing aids or cochlear implants.
VISION RANGE
From low vision (reduced acuity or restricted field) through total blindness; stable or progressive; sometimes affected by lighting, contrast, or fatigue.
What defines deafblindness functionally is the combination: the two impaired distance senses (vision and hearing, the senses that bring information from beyond arm's reach) cannot fully compensate for each other. A child with hearing loss alone leans on vision; a child with vision loss alone leans on hearing. A deafblind child has neither reliable fallback, so incidental learning collapses and access must be engineered deliberately.
(B) Dimensions of Diversity Within the Population
No two deafblind learners present alike. Expect exam scenarios to vary learners along these dimensions:
| Dimension | Range You Will See |
|---|---|
| Age of onset | Congenital (before language) through adventitious (after language and experience) |
| Degree and stability | Mild to profound loss in each sense; stable, fluctuating, or progressive (as in Usher syndrome, where planning must anticipate future loss) |
| Additional disabilities | Many deafblind learners have additional physical, medical, or cognitive disabilities; others have none |
| Communication modes | Speech, sign language, tactile sign (sign received through the hands), gestures, object symbols, print, braille, or a combination |
| Cultural and linguistic background | Families vary in home language, culture, beliefs about disability, and priorities for the child |
| Identity and perspective | Some learners and families identify with Deaf culture (capital-D Deaf, a linguistic-cultural community centered on sign language); others view hearing loss medically and do not; identity must be respected either way |
Common Trap: Distractors often treat "deafblind" as one uniform profile: total loss, one communication mode, one right program. The credited answer nearly always individualizes: it starts from this learner's residual vision and hearing, onset history, communication mode, and family perspective.
(4) RESEARCH-BASED PRACTICES FOR LEARNING, ENGAGEMENT, COMMUNICATION, AND ACCESS
(A) The Practices the Research Converges On
Decades of research and practice with deafblind learners converge on a consistent set of high-leverage practices. Each one addresses the same root problem: without reliable distance senses, the learner cannot pick up information, language, or social routines incidentally.
- Relationship first. Build a trusting relationship and secure attachment before pushing skill instruction. For a child whose world arrives mainly through touch, interaction with a trusted person is the foundation on which all communication and learning rest.
- Predictable routines with anticipation cues. Use consistent, repeated routines so the learner can predict what happens next, and mark each activity with anticipation cues: object cues (a real object associated with an activity, such as a spoon for mealtime) and touch cues (a consistent touch on the body signaling what is about to happen). Predictability reduces anxiety and turns the day into learnable structure.
- Generous wait time. Deafblind learners gather and process information through slower, sequential tactile channels. After a cue or a turn, pause far longer than feels natural and watch for responses in any form: a stilling of the body, a hand movement, a vocalization, a change in breathing.
- Hand-under-hand guidance. Place your hands under the learner's hands and invite exploration, rather than grabbing and manipulating the learner's hands (hand-over-hand). Hand-under-hand is respectful, preserves the learner's control, and keeps the hands free to perceive.
- Move along the communication continuum. Support progress from presymbolic communication (body movement, muscle tension, natural gestures, real objects) toward symbolic communication (formal gestures, signs, pictures, words, braille), always building on forms the learner already uses.
- Provide access through an intervener and direct teaching. A trained intervener (a paraprofessional with specialized deafblind training who provides one-to-one access support) bridges the learner to information, communication, and the wider social world. Whatever sighted-hearing peers learn incidentally (who entered the room, what caused a noise, how peers greet each other) must be taught directly.
On the Exam: Credited answers about deafblind instruction almost always feature one of these markers: trusted relationship, predictable routine, object or touch cue, extended wait time, hand-under-hand, building from the learner's current communication form, or intervener-provided access. Distractors typically feature hand-over-hand manipulation, rushed pacing, novel activities without cues, or the assumption that the learner will "pick it up" from the environment.
(5) CLINICAL, FUNCTIONAL, AND LEGAL DEFINITIONS FOR ELIGIBILITY AND SERVICES
(A) Three Lenses on the Same Learner
Vision and hearing loss can each be described three ways, and eligibility decisions draw on all three. Keep the lenses straight:
| Lens | What It Describes | Typical Evidence |
|---|---|---|
| Clinical | Measured medical status of the sense organ and pathway | Visual acuity (e.g., 20/200) and visual field measurements from an eye specialist; an audiogram reporting hearing thresholds in decibels (dB) |
| Functional | How the person actually uses vision and hearing in real activities and environments | Functional vision evaluation and functional listening evaluation: observation across settings, lighting, noise levels, and tasks |
| Legal | Statutory thresholds and definitions that determine eligibility for services and benefits | Legal blindness criteria; IDEA disability category definitions |
Two children with identical clinical measurements can function very differently, which is why educational planning leans heavily on the functional lens even when eligibility paperwork cites clinical and legal criteria.
(B) The IDEA Definitions You Must Know
The Individuals with Disabilities Education Act (IDEA) defines the federal disability categories used for special education eligibility. Notice that every IDEA definition ends with the same hinge: the impairment must adversely affect educational performance.
| IDEA Category | Core of the Definition |
|---|---|
| Deaf-blindness | Concomitant (occurring together) hearing and visual impairments whose combination causes such severe communication and other developmental and educational needs that the child cannot be accommodated in special education programs designed solely for children with deafness or solely for children with blindness. |
| Visual impairment including blindness | An impairment in vision that, even with correction, adversely affects educational performance. The category includes both partial sight and blindness. |
| Deafness | A hearing impairment so severe that the child is impaired in processing linguistic information through hearing, with or without amplification, adversely affecting educational performance. |
| Hard of hearing (hearing impairment) | A hearing impairment, whether permanent or fluctuating, that adversely affects educational performance but is not included under the definition of deafness. |
On the Exam: The deaf-blindness definition turns on the word combination. Eligibility as deafblind does not require total loss of either sense; it requires that the two losses together create needs that a deaf-only or blind-only program cannot meet. Also note the convention D/deaf: capital-D Deaf signals membership in the signing Deaf cultural community, while lowercase deaf describes the audiological status.
(C) The Numbers: Legal Blindness and Degrees of Hearing Loss
LEGAL BLINDNESS (memorize both prongs)
- Best-corrected visual acuity of 20/200 or worse in the better eye (the person sees at 20 feet what a typically sighted person sees at 200 feet), OR
- A visual field of 20 degrees or less (severe tunnel vision), regardless of acuity.
Either prong alone qualifies. The field prong matters for conditions like retinitis pigmentosa, where central acuity can remain good while the usable field shrinks drastically.
Degrees of hearing loss (thresholds in dB HL, the decibel hearing level scale used on an audiogram):
| Degree | Threshold Range (dB HL) |
|---|---|
| Normal | −10 to 15 |
| Slight / Minimal | 16–25 (Note: classification systems vary; some sources label this range "minimal" and begin "mild" at 26 dB. The boundaries shown here follow one widely cited framework — know that exact cutoffs differ by source and jurisdiction.) |
| Mild | 26–40 |
| Moderate | 41–55 |
| Moderately severe | 56–70 |
| Severe | 71–90 |
| Profound | 91 and above |
(D) Why the Functional Definition Casts a Wider Net
- State deafblind projects and the national deaf-blind child count use a functional definition of deafblindness that is often broader than strict clinical or legal thresholds.
- Under a functional definition, a child qualifies when combined vision and hearing loss, in whatever degree, limits access to information and communication in daily functioning, even if the child is not legally blind and is not audiologically deaf.
- Practical consequence: a child can receive deafblind project services and appear on the deaf-blind child count based on functional combined loss, and children with progressive conditions can be counted before the losses reach clinical severity.
Common Trap: A distractor may deny a child deafblind services because the child "is not legally blind" or "is not profoundly deaf." That reasoning applies the wrong lens. Eligibility for deafblind services rests on the combined functional impact, not on meeting each sense's most severe threshold separately.
BRINGING IT TOGETHER
- Classify onset first: congenital (before birth or before language) versus adventitious (after language and experience); onset relative to language development drives instruction more than the diagnosis itself.
- Anchor etiologies by category: genetic/syndromic (CHARGE, Usher), TORCH infections (rubella, CMV), prematurity (ROP), and postnatal causes (meningitis, TBI).
- Match the theorist to the signature: van Dijk = movement and attachment (resonance → co-active movement → non-representational reference → deferred imitation → natural gestures → symbolization) plus child-guided assessment; Nielsen = Active Learning and the Little Room; Miles = hands as the child's voice and eyes, hand-under-hand conversation.
- Deafblindness is a spectrum defined by the combination of two impaired distance senses; learners differ in onset, degree, stability, additional disabilities, communication mode, culture, and identity.
- Effective practice engineers what incidental learning would otherwise provide: trust, routines, cues, wait time, hand-under-hand, communication growth, and intervener-supported access.
- Keep the three definitional lenses separate: clinical (measured), functional (used in real life), legal (statutory); IDEA deaf-blindness turns on the word combination, and functional definitions for deafblind services are broader than legal thresholds.
Quick Reference Card: Foundations
- Congenital = present at or before birth (before language develops); adventitious = acquired after some language and experience; age of onset relative to language is the key educational variable.
- CHARGE syndrome = most common cause of congenital deafblindness in the US (Coloboma · Heart defects · Atresia of the choanae · Retardation of growth/development · Genital abnormalities · Ear anomalies).
- Usher syndrome = most common cause of hereditary deafblindness: congenital sensorineural hearing loss + progressive retinitis pigmentosa; Type 1 profound deafness + balance problems + childhood vision loss, Type 2 moderate-severe loss + later vision loss + normal balance, Type 3 both losses progressive.
- Theorist signatures: van Dijk = resonance → co-active movement → symbolic communication + child-guided assessment; Nielsen = Active Learning + Little Room (self-initiated exploration); Miles = hands as voice/eyes + hand-under-hand conversation.
- Deafblindness is a spectrum: any combination of mild-to-profound hearing loss with low vision-to-total blindness; the defining feature is that the two distance senses cannot compensate for each other.
- Core practices: relationship and secure attachment first · predictable routines + object/touch cues · generous wait time · hand-under-hand (never hand-over-hand grabbing) · presymbolic → symbolic growth · intervener access + direct teaching of what peers learn incidentally.
- Legal blindness = best-corrected acuity 20/200 or worse in the better eye OR visual field 20 degrees or less; hearing loss degrees: mild 26–40, moderate 41–55, severe 71–90, profound 91+ dB HL.
- IDEA deaf-blindness = concomitant hearing + visual impairments whose combination creates needs a deaf-only or blind-only program cannot meet; the functional definition used by state deafblind projects and the national child count is broader than clinical/legal thresholds.