Communication-based assessment for persons with severe disabilities, including autism spectrum disorder (ASD), always should be conducted with several key principles in mind.
Generally, practitioners use observational methods and structured procedures to assess the communication abilities and needs of persons with severe disabilities and ASD. Observations can provide invaluable information about individuals with disabilities as well as their partners and environments. Observations may be most useful when examiners generate guiding questions before the observation period. Unfortunately, observations are limited to what happens during a given session or what appears in a written record.
Structured procedures include communication sampling, informant assessment, and standardized assessment. Structured communication sampling is a tool for eliciting emergent communication (both nonsymbolic and emergent symbolic). During structured sampling, the individual with disabilities is provided with tempting communication opportunities that make responses near obligatory. An example might be eating in front of an individual without offering food. There is a rich literature base supporting structured sampling with persons with severe disabilities and ASD.
Informant assessment typically involves questioning friends and family members about an assessment candidate's communication-related abilities, needs, and expectations. Informant assessment can be conducted in an interview format and frequently uses established tests designed for infants and toddlers (e.g., the Receptive-Expressive Emergent Language Scale-Third Edition [REEL-3]; Bzoch, League, & Brown, 2003). A caveat of informant-based procedures is the limited reliability of the informant. That is, informants often over- or underrepresent the communication abilities of persons with severe disabilities and ASD.
Finally, standardized tools should be considered when assessing emergent communication abilities. These tools apply (or allow for) elicitation procedures that generate data useful for decision making specific to treatment eligibility and direction. Instruments that have been designed specifically for persons with disabilities are useful for individuals with less conventional communication abilities.
Just as with observations, there are limitations to structured assessment procedures, such as the unnaturalness of tasks/contexts and the unfamiliarity of examiners..
Individuals with disabilities, including autism, are entitled to a communication assessment regardless of their functioning level. This principle is central to the Individuals with Disabilities Education Act 2004 and a cornerstone of best practice as described by the National Joint Committee for the Communication Needs of Persons with Severe Disabilities.
Bzoch, K. R., League, R., & Brown, V. Receptive-Expressive Emergent Language Test, Third Edition (REEL-3). (2003). Austin, TX: PRO-ED.
Siegel-Causey, E., & Bashinski, S. M. (1997). Enhancing initial communication and responsiveness of learners with multiple disabilities: A tri-focus framework for partners. Focus on Autism and Other Developmental Disabilities, 12, 105–120.
Siegel-Causey, E., & Wetherby, A. (1993). Nonsymbolic communication. In M. E. Snell (Ed.), Instruction of students with severe disabilities (4th ed., pp. 290–318). New York: Macmillan.