LSA for children with severe speech sound disorders

In this study, the authors aimed to evaluate whether language sample analysis (LSA) can accurately capture the expressive language profile of preschool children with severe speech impairment. The children in the sample were 3–5 years old, with receptive language within normal limits, but very low language comprehensibility (< 50%; no-context).
An approximately 20-minute language sample of 50–100 utterances was taken (most had 100+ utterances) and analyzed by two trained students. Results indicate that you can use LSA for severe speech impairment—even in children with very low comprehensibility. Of course, you can't use all the same analyses, but you can still analyze some things, so the tool shouldn't be avoided.
Between the two transcribers, exact word agreement was often low—meaning, one person thought the child said ‘where’, while the other transcriber thought she said ‘here’. But there was excellent agreement for word and syllable presence. From this, one can analyze mean length of utterance in words (MLUw) and mean syllables per utterance, which provide the clinician insight into the child’s expressive language ability. The authors additionally summarize which standardized and non-standardized scores correlated closely with LSA measures, so the clinician may weigh various options for testing. The authors do note that there will be children for whom modified LSA still doesn’t adequately capture their expressive language skills—e.g. those kids whose verbal expressive language is extremely minimal, but who are able to form multi-word utterances using AAC.
The authors remind us that many “severe speech” kids require language therapy—and we need to know what language to be treating, even though their speech is difficult to understand. We can’t simply work on semantics and single-word utterances if these children are capable of producing much longer utterances. Without good measurement tools, clinicians are at risk of setting language goals either too low or too high for these children. 

See: Binger, C., Ragsdale, J., & Bustos, A. (2016). Language Sampling for Preschoolers with Severe Speech Impairment. American Journal of Speech-Language Pathology. Advance online publication. doi: 10.1044/2016_AJSLP-15-0100.