Dynamic Assessment for AAC: A Clinician's Guide Across the Lifespan

Communication is a fundamental human right, but for individuals with complex co-occurring medical, developmental, and neurological diagnoses, exercising that right often means working through significant barriers just to express a need, join a conversation, or maintain a relationship.¹ Dynamic assessment offers a strengths-based, individualized way through those barriers, uncovering what's possible for a person through augmentative and alternative communication (AAC) and giving you the evidence you need to support functional communication across the lifespan. The evidence is consistent on one point: the more severe someone's communication deficit, the more they stand to gain from AAC support, well beyond autism and across every stage of life.

Communication assessment

Research consistently shows that AAC does not prevent or limit the acquisition of verbal language. Consider AAC interventions across all severity levels, from mild to profound, of cognitive and social disabilities.²

Supplemental measures

A study reviewing methods of assessing executive function in traumatic brain injury found use of self-report scales, such as the Awareness Questionnaire and the Patient Competency Rating Form, to address cognitive, metacognitive, behavioral, and emotional dysfunction during rehabilitation.⁵

Supplemental measures should also capture social-emotional impact, quality of life, and the individual's own preferences. The family and care team are often the primary source of clinical information, but you carry an ethical responsibility to advocate throughout the assessment process as well.

Using a structured AAC evaluation process, you can:

• Ensure the assessment is systematic, objective, and evidence-based

• Support person-centered assessment tailored to each communicator's strengths and environment

• Increase the likelihood of identifying the right AAC system and securing funding

• Facilitate interdisciplinary collaboration through a shared framework

These tools all serve the same purpose, giving you a defensible starting point for goal-setting and intervention.

Conducting the AAC evaluation

You won't do this alone. Evaluation draws on the whole care team, not just the speech-language pathologist, and follows a structured process from first contact to final recommendation.

Interdisciplinary collaboration

In a study of 1,494 patients with amyotrophic lateral sclerosis (ALS), the most needed assistive technology devices were wheelchairs (65 percent), orthoses (52 percent), bathroom adaptations (49 percent), and communication devices (46 percent), all of which require close coordination among the speech therapist, physical therapist, occupational therapist, and equipment vendor to reach daily use.⁶ Loop in the rest of the team early, so a recommended device doesn't stall once it's time to program and deliver it.

Here are the key things to include:

• Recent speech-language evaluation

• Relevant diagnoses from physicians, if applicable

• Occupational therapy (OT) and physical therapy (PT) reports supporting access needs

• School reports, individualized education programs (IEPs), and communication data

• Caregiver, paraprofessional, and/or aide interviews documenting communication breakdowns

An AAC evaluation should describe an individual's difficulties with:

• Expressing wants and needs across activities of daily living (ADLs) and instrumental activities of daily living (IADLs)

• Reporting pain, illness, or emergencies

• Participating in education and work

• Social interaction

• Self-advocacy

• Medical decision-making

Avoid emphasizing academic benefits alone. Insurance typically funds speech-generating devices (SGDs) for functional communication, not educational achievement.

During the AAC evaluation

1. Demonstrate multiple communication functions: Show that the individual needs AAC for requesting, rejecting, asking questions, commenting, social interaction, reporting information, and self-advocacy.

2. Trial appropriate devices: Trial one or more devices and collect objective data on accuracy, speed, independence, fatigue, and navigation success.

3. Rule out lower-tech alternatives: Document why the person cannot adequately meet communication needs using gestures alone, communication books, picture boards, basic speech apps, or partner-dependent systems. Trial the lower-tech, multimodal option before assuming the person needs the highest-tech device available.

4. Address device features specifically: Justify each requested feature and tie every feature to a functional communication need (eye gaze, switch access, touch access, keyguard, mounting system, alternative access software, or durable medical-grade device).

5. Show generalization across settings: Document a functional communication need in the home, community, medical appointments, school, employment, and vocational programs. Insurance reviewers want evidence of need across settings, for example with unfamiliar listeners or loud environments.

6. Include caregiver and team support: Document the family training plan, caregiver involvement, school or team support, and any opportunities for daily device use. Building AAC into an existing family routine, rather than treating it as a separate therapy task, is often what makes daily carryover realistic. It's the difference between a device that gets used every day and one that sits in a drawer.

Establishing medical necessity

With trial data, documented limitations, and evidence of need across settings in hand, translate that work into a fundable Letter of Medical Necessity (LMN) connecting the diagnoses to functional communication limitations, safety, independence, and participation.

Insurer definitions and DME criteria

Insurers define medical necessity in varying ways, but coverage typically requires meeting durable medical equipment (DME) criteria, designed for repeated, long-term use (at least a five-year expected lifespan) and serving a primarily medical purpose rather than the needs of the general population.⁸

SGDs vs. iPads: AAC considerations for clinical decision-making

Because DME status hinges on medical purpose, a dedicated SGD and an iPad running AAC software aren't interchangeable for funding, even when they look similar on the surface.

Building a strong LMN

Frame the LMN around clinical signs and symptoms, functional communication needs across settings, and why less expensive alternatives are insufficient. Insurers most often deny claims for unclear medical necessity, insufficient trials, lack of objective data, unjustified features, or a report leaning too heavily on academic benefit, so counter this with evidence that the individual can't meet daily communication needs through speech alone, needs a dedicated SGD for consistent access, and uses the device for health and safety communication.

Strong statements make the case directly. For example:

"The patient is unable to independently communicate medical concerns, pain, or emergency information using natural speech." 

"A dedicated SGD is medically necessary to provide reliable communication across settings."

Clinical outcomes: beyond assessment

Dynamic assessment succeeds when it opens opportunities for the person in front of you, helping them express their thoughts, advocate for themselves, and participate more fully in their communities. Through thoughtful assessment and strong clinical advocacy, you help ensure that every individual has access to one of the most fundamental human rights: the ability to communicate.

References

1. National Joint Committee for the Communication Needs of Persons with Severe Disabilities. (2024). NJC Communication Bill of Rights (3rd ed.). PDF.

2. Desch, L. W., Hobart-Porter, L. J., Houtrow, A., & Council on Children With Disabilities. (2025, June). Prescribing assistive technology: Focus on children with complex communication needs: Clinical report. Pediatrics, 156(1), Article e2025072216. https://doi.org/10.1542/peds.2025-072216

3. American Speech-Language-Hearing Association. (2024, September). ASHA's National Outcomes Measurement System (NOMS): Clinician user guide—SLP healthcare. https://www.asha.org/siteassets/noms/noms-slp-clinician-user-guide.pdf

4. Lasker, J. P., & Garrett, K. L. (2007, February). Using the Multimodal Communication Screening Test for Persons with Aphasia (MCST-A) to guide the selection of alternative communication strategies for people with aphasia. Aphasiology, 20(2–4), 217–232. https://doi.org/10.1080/02687030500473411

5. Cicerone, K., Levin, H., Malec, J., Stuss, D., & Whyte, J. (2006, July). Cognitive rehabilitation interventions for executive function: Moving from bench to bedside in patients with traumatic brain injury. Journal of Cognitive Neuroscience, 18(7), 1212–1222. https://doi.org/10.1162/jocn.2006.18.7.1212

6. Funke, A., Spittel, S., Grehl, T., Grosskreutz, J., Kettemann, D., Petri, S., Weyen, U., Weydt, P., Dorst, J., Ludolph, A. C., Baum, P., Oberstadt, M., Jordan, B., Hermann, A., Wolf, J., Boentert, M., Walter, B., Gajewski, N., Maier, A., ... Meyer, T. (2018, January). Provision of assistive technology devices among people with ALS in Germany: A platform-case management approach. Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 19(5–6), 1–9. https://doi.org/10.1080/21678421.2018.1431786

7. Garrett, K., Beukelman, D., & Low-Morrow, D. (2009, July). A comprehensive augmentative communication system for an adult with Broca's aphasia. Augmentative and Alternative Communication, 5(1), 55–61. https://doi.org/10.1080/07434618912331274976

8. American Speech-Language-Hearing Association. (n.d.). Funding for Communication Services and Supports. https://www.asha.org/njc/funding-for-services/