Review of methods for conducting speech research with minimally verbal individuals with autism spectrum disorder

Exploring Motor Speech Disorders in Low and Minimally Verbal Autistic Individuals: An Auditory-Perceptual Analysis

PURPOSE

Motor deficits are widely documented among autistic individuals, and speech characteristics consistent with a motor speech disorder have been reported in prior literature. We conducted an auditory-perceptual analysis of speech production skills in low and minimally verbal autistic individuals as a step toward clarifying the nature of speech production impairments in this population and the potential link between oromotor functioning and language development.

METHOD

Fifty-four low or minimally verbal autistic individuals aged 4-18 years were video-recorded performing nonspeech oromotor tasks and producing phonemes, syllables, and words in imitation. Three trained speech-language pathologists provided auditory perceptual ratings of 11 speech features reflecting speech subsystem performance and overall speech production ability. The presence, attributes, and severity of signs of oromotor dysfunction were analyzed, as were relative performance on nonspeech and speech tasks and correlations between perceptual speech features and language skills.

RESULTS AND CONCLUSIONS

Our findings provide evidence of a motor speech disorder in this population, characterized by perceptual speech features including reduced intelligibility, decreased consonant and vowel precision, and impairments of speech coordination and consistency. Speech deficits were more associated with articulation than with other speech subsystems. Speech production was more impaired than nonspeech oromotor abilities in a subgroup of the sample. Oromotor deficits were significantly associated with expressive and receptive language skills. Findings are interpreted in the context of known characteristics of the pediatric motor speech disorders childhood apraxia of speech and childhood dysarthria. These results, if replicated in future studies, have significant potential to improve the early detection of language impairments, inform the development of speech and language interventions, and aid in the identification of neurobiological mechanisms influencing communication development.

Phonemic Feature Scoring as a Tool for Progress Monitoring During Language Interventions for Children With Autism and Minimal Verbal Skills

PURPOSE

An increasing number of studies focus on verbal treatments for children with autism and minimal verbal skills. However, clinical tools for progress monitoring during interventions are lacking. The aim of this clinical focus article is to provide illustrations on the utility of a phonemic feature scoring system as a progress-monitoring tool, focusing on benefits and limitations as well as indications for use.

METHOD

Current practices for progress monitoring during language interventions with children with autism and minimal verbal skills are reviewed. A phonemic feature scoring tool is provided to aid clinicians in assessing the accuracy and consistency of expressive word productions. The authors illustrate the use of phonemic feature scoring as a progress-monitoring tool for two children with autism and minimal verbal skills, contrasting the phonemic feature scoring system to correct/incorrect, phoneme-level, and whole-word scoring.

RESULTS

Case 1 demonstrates a scenario where the child's speech intelligibility is low and clinical use of the phonemic feature scoring system captures discrete changes in speech production progress not represented by correct/incorrect, phoneme-level, and whole-word scoring. However, Case 2 represents a situation where once a child's speech intelligibility improves, the phonemic feature scoring system is no longer needed, and correct/incorrect scoring may be sufficient.

CONCLUSION

The phonemic feature scoring system allows clinicians to track phonemic feature changes in word productions and provides detailed progress monitoring information, leading to adaptations of the intervention for each individual.