Multiple and complex disabilities

5 min read · BoK 1BC· p. 31–32

Learning objectives (3)

Define multiple disabilities and describe their typical characteristics
Explain the US legal exclusion of deaf-blindness from the multiple disabilities category
Identify AT approaches for people with multiple or complex disabilities

Why it matters

Most disability categories in the BoK address a single condition type. Multiple and complex disabilities represent the reality that many people live with simultaneous conditions whose combined impact exceeds any single-category barrier. Accessibility planning for this population requires individualized, multi-dimensional solutions. (BoK p. 31)

What are multiple disabilities?

Multiple disabilities refers to the concurrent presence of two or more significant disability conditions that together create complex and interconnected support needs. The combination — not the sum of the individual conditions — defines the category. (BoK p. 31)

Common combinations include:

Physical and cognitive disabilities (e.g., cerebral palsy with intellectual disability).
Sensory and motor disabilities (e.g., low vision with mobility impairment).
Cognitive and behavioral disabilities (e.g., intellectual disability with autism).

Because the conditions interact, solutions designed for any one condition alone may be insufficient. A person who is blind and has significant intellectual disability may need tactile AT, but the cognitive demands of standard screen reader operation may also exceed their capacity.

Impact across developmental areas

The BoK describes multiple disabilities as affecting several developmental areas simultaneously: (BoK p. 32)

Communication: may require AAC, simplified language, and multiple communication channels.
Motor skills: may require physical AT, adapted seating, and modified access to ICT.
Self-care: may require environmental modifications and personal support.
Cognition: may require simplified content, prompting, and structured routines.
Social skills: may require predictable social environments and structured interaction supports.

The US deaf-blindness exclusion

In US federal law (specifically the Individuals with Disabilities Education Act), deaf-blindness is treated as a separate category distinct from “multiple disabilities.” This matters for educational planning and legal classification, even though deaf-blindness clearly involves dual sensory impairments. The BoK notes this exclusion because it affects how students with combined hearing and vision loss are classified and served in educational settings. (BoK p. 31)

AT for multiple and complex disabilities

AT selection for multiple disabilities is highly individualized. The BoK identifies the following principles and examples: (BoK p. 32)

Reduce complexity: simplify interfaces to the minimum needed for the specific tasks.
Programmable keyboards: allow custom key assignments for users who cannot manage a full keyboard layout but can reliably operate a smaller set of controls.
Combination devices: some AT serves multiple functions — a switch that controls both communication (AAC output) and environment control.
Team-based planning: AT selection typically involves a multidisciplinary team — speech-language pathologist, occupational therapist, and accessibility specialist — rather than a single practitioner.

Real-world example

A young adult with cerebral palsy (affecting all four limbs) and intellectual disability needs to use a public transit app. Standard AT options are insufficient: the motor demands of touchscreen use exceed her ability, and the cognitive demands of the app’s multi-step interface exceed her working memory. A solution involves a simplified version of the app accessed via switch scanning, with programmable macros for her three most common routes. Neither motor AT nor cognitive simplification alone would provide full access — the solution must address both simultaneously.

Key terms

Multiple disabilities: The presence of two or more significant disability conditions occurring simultaneously, producing complex and interrelated support needs. (BoK p. 31)
Complex needs: Support requirements arising from multiple co-occurring disabilities that cannot be addressed by any single disability-specific solution. (BoK p. 31)
Developmental areas: The functional domains — communication, motor, self-care, cognition, and social skills — in which multiple disabilities create combined impact. (BoK p. 32)
Programmable keyboard: An input device whose keys can be assigned custom functions or macros to simplify interaction for users who cannot manage a full standard keyboard layout. (BoK p. 32)

Check yourself

Under US federal law (IDEA), deaf-blindness is treated as a separate disability category rather than as a subset of multiple disabilities. Which statement correctly explains the BoK's reason for noting this?

Because deaf-blindness involves only one functional domain (sensory), it cannot be considered multiple disabilities
The legal classification affects how students with combined vision and hearing loss are categorized and served in US educational settings
The BoK considers deaf-blindness to be less severe than other multiple disabilities and therefore separately classified
Deaf-blindness has no AT solutions, so it cannot be addressed within the multiple disabilities framework

.cy-island-wrapper { display: none; }JavaScript is required for the interactive quiz. Here are the questions for reference:

a) Because deaf-blindness involves only one functional domain (sensory), it cannot be considered multiple disabilities
b) The legal classification affects how students with combined vision and hearing loss are categorized and served in US educational settings — correct answer
c) Deaf-blindness has no AT solutions, so it cannot be addressed within the multiple disabilities framework
d) The BoK considers deaf-blindness to be less severe than other multiple disabilities and therefore separately classified

Explanation: The Individuals with Disabilities Education Act (IDEA) classifies deaf-blindness as its own category rather than a subset of "multiple disabilities." The BoK notes this because it affects educational classification and service planning in the US. Practitioners working in educational settings need to know that a child with combined hearing and vision loss may be classified as "deaf-blind" rather than under "multiple disabilities" (BoK p. 31).

An AT specialist is selecting technology for a user with cerebral palsy affecting all four limbs and intellectual disability. The user cannot use a standard keyboard or touchscreen and cannot navigate a multi-step interface independently. Which AT approach does the BoK identify as appropriate for users with combined motor and cognitive disabilities?

a) Select the best motor AT (switch scanning) and the best cognitive AT (prompting app) separately, with no integration needed
b) Provide a simplified interface accessible via switch scanning with minimal steps, reflecting both motor and cognitive needs simultaneously — correct answer
c) Focus on the motor disability first; address cognitive barriers only if the motor solution is insufficient
d) Refer the user to a medical team before selecting any AT, since multiple disabilities require medical clearance

Explanation: The BoK's approach to multiple disability AT requires integrated solutions that address both conditions simultaneously. For a user with combined motor and cognitive disabilities, this means an interface simplified for cognitive access that is also operable by switch scanning — not two separate solutions laid on top of each other (BoK p. 32).

The BoK mentions programmable keyboards as an AT solution for users with multiple or complex disabilities. What makes a programmable keyboard specifically useful for this population?

a) Programmable keyboards are louder and easier to hear, which helps users with auditory processing issues
b) Programmable keyboards allow keys to be assigned custom functions or macros, reducing the complexity and number of keystrokes required for common tasks — correct answer
c) Programmable keyboards include built-in screen readers, making them a complete AT solution
d) Programmable keyboards are only useful for users with motor impairments and provide no benefit for cognitive disabilities

Explanation: Programmable keyboards allow customization of key assignments, enabling users with limited motor ability or cognitive impairments to operate a computer with a simplified set of dedicated keys. For users with multiple disabilities, this reduces both the physical demands (fewer and larger keys) and the cognitive demands (fewer choices, direct one-key actions) of standard keyboard use (BoK p. 32).

Sources

BoK references

Section 1BC — IAAP CPACC Body of Knowledge v4.0 (Oct 2023), p. 31–32