Characterizing the Minimally Verbal: A Pilot Investigation of the Low-Verbal Investigatory Screener for Autism (L-VIS-A)

Background:  Approximately 30% of children with autism are considered minimally verbal (Tager-Flusberg & Kasari, 2013). At present, we lack a reliable predictor of which of those children are simply preverbal and which will remain minimally verbal. Further, there is minimal research on this population, in part because of the difficulty evaluating language skills in individuals who do not respond to language, and in part because IQ and language skills are often confounded. When research does include minimally verbal children, they are not typically characterized beyond an arbitrary cutoff such as “more or less than 5 words.” 

Objectives:  The goal of this pilot project, which was the product of an IMFAR Special Interest Group (SIG) discussion, was to develop and test a brief, simple, yes/no parent questionnaire to better characterize minimally verbal children with autism.

Methods:  Researchers and clinicians who work specifically with minimally verbal children with autism compiled a set of 30 yes/no questions to be included in a brief parental screening form. The goal of these questions was to capture the range of communicative abilities of minimally verbal children and to determine the subset of questions that best delineated those with productive communication skills from those without. This screener was administered as an interview to parents of 12 children with ASD [8 males; age M(SD) = 3.67(1.30)]. 

Results:  In this pilot sample, 9 of the 12 children had been labeled “non-verbal” by a professional. Only four of the children were said to produce fewer than 5 words (n = 3, “5-10 words”; n = 5, “More than 10 words”). Twenty of the thirty questions focused on ways children might communicate (e.g. Does your child use gestures? Does your child use pictures? Does your child follow directions? Does your child respond to his name?). For each child, the proportion of those items for which the parent responded “yes” was calculated to determine the child’s “communicative ability.” This value was reliably higher among children with more than 5 words, t(10) = 3.55, p < .05. Even within groups, there was a significant range in communicative abilities. Children with fewer than 5 words: M = .38, range .13 - .60; children with more than 5 words: M = .82, range .42 - 1.0.

Conclusions:  These results represent a proof of concept for a screening tool to characterize in detail the communication skills among minimally verbal children. The range of communicative approaches used within a group of children largely defined as “non-verbal” supports the claims that this population is highly heterogeneous. Though it cannot replace formal language testing, a brief screening form has significant potential utility for researchers attempting to better characterize minimally verbal participants and for clinicians making recommendations regarding speech and language services. When sufficient data are available, principle component analyses will be used to identify which questions have the greatest utility for characterizing children with minimal verbal abilities. Ultimately, this screener will provide a low-cost but effective tool for predicting risk for remaining minimally verbal.