Improving Intelligibility in Childhood Apraxia of Speech Through Communication Partner Training

Perceptual learning, improved understanding, of a degraded speech signal is driven by speech predictability. A hallmark feature of childhood apraxia of speech (CAS) is speech variability and inconsistency. This initial case study examined whether both naive and familiar listeners can improve their understanding of a child with CAS through perceptual training.

Speech recordings were collected from a 4-year-old boy with CAS and presented to listeners within a structured pretest-training-posttest paradigm. In Experiment 1, naive listeners (n = 44) received training using speech produced either by the child with CAS (experimental condition) or by an age- and sex-matched typically developing child (control condition). In Experiment 2, familiar listeners (n = 15; caregivers, teachers, and therapists of the child with CAS) completed the same CAS training used in the experimental condition of Experiment 1. Intelligibility was operationalized as percent words correct based on listener transcription of speech produced by the child with CAS before (pretest) and after (posttest) training.

In Experiment 1, naive listeners who received CAS training showed significant intelligibility improvements following training, as reflected in higher percent words correctly identified after versus before training. No such improvement was observed for the listeners in the control training group. In Experiment 2, familiar listeners demonstrated significant intelligibility improvement following CAS training, and these gains were larger than naive listeners.

Case study findings provide initial evidence that perceptual training can improve the intelligibility of a child with CAS for communication partners. This suggests that despite the speech signal variability that is characteristic of CAS, there is sufficient predictability to support learning and, furthermore, that this learning response is not constrained by partner familiarity.