Effects of Lexical and Somatosensory Feedback on Long-Term Improvements in Intelligibility of Dysarthric Speech.

Purpose: Intelligibility improvements immediately following perceptual training with dysarthric speech using lexical feedback are comparable to those observed when training uses somatosensory feedback (Borrie & Schäfer, 2015). In this study, we investigated if these lexical and somatosensory guided improvements in listener intelligibility of dysarthric speech remain comparable and stable over the course of 1 month. Method: Following an intelligibility pretest, 60 participants were trained with dysarthric speech stimuli under one of three conditions: lexical feedback, somatosensory feedback, or no training (control). Participants then completed a series of intelligibility posttests, which took place immediately (immediate posttest), 1 week (1-week posttest) following training, and 1 month (1-month posttest) following training. Results: As per our previous study, intelligibility improvements at immediate posttest were equivalent between lexical and somatosensory feedback conditions. Condition differences, however, emerged over time. Improvements guided by lexical feedback deteriorated over the month whereas those guided by somatosensory feedback remained robust. Conclusions: Somatosensory feedback, internally generated by vocal imitation, may be required to affect long-term perceptual gain in processing dysarthric speech. Findings are discussed in relation to underlying learning mechanisms and offer insight into how externally and internally generated feedback may differentially affect perceptual learning of disordered speech.

The Role of Somatosensory Information in Speech Perception: Imitation Improves Recognition of Disordered Speech.

PURPOSE: Perceptual learning paradigms involving written feedback appear to be a viable clinical tool to reduce the intelligibility burden of dysarthria. The underlying theoretical assumption is that pairing the degraded acoustics with the intended lexical targets facilitates a remapping of existing mental representations in the lexicon. This study investigated whether ties to mental representations can be strengthened by way of a somatosensory motor trace. METHOD: Following an intelligibility pretest, 100 participants were assigned to 1 of 5 experimental groups. The control group received no training, but the other 4 groups received training with dysarthric speech under conditions involving a unique combination of auditory targets, written feedback, and/or a vocal imitation task. All participants then completed an intelligibility posttest. RESULTS: Training improved intelligibility of dysarthric speech, with the largest improvements observed when the auditory targets were accompanied by both written feedback and an imitation task. Further, a significant relationship between intelligibility improvement and imitation accuracy was identified. CONCLUSIONS: This study suggests that somatosensory information can strengthen the activation of speech sound maps of dysarthric speech. The findings, therefore, implicate a bidirectional relationship between speech perception and speech production as well as advance our understanding of the mechanisms that underlie perceptual learning of degraded speech.

Comparing acquisition of and preference for manual signs, picture exchange, and speech-generating devices in nine children with autism spectrum disorder.

OBJECTIVE: To compare how quickly children with autism spectrum disorder (ASD) acquired manual signs, picture exchange, and an iPad/iPod-based speech-generating device (SGD) and to compare if children showed a preference for one of these options. METHOD: Nine children with ASD and limited communication skills received intervention to teach requesting preferred stimuli using manual signs, picture exchange, and a SGD. Intervention was evaluated in a non-concurrent multiple-baseline across participants and alternating treatments design. RESULTS: Five children learned all three systems to criterion. Four children required fewer sessions to learn the SGD compared to manual signs and picture exchange. Eight children demonstrated a preference for the SGD. CONCLUSION: The results support previous studies that demonstrate children with ASD can learn manual signs, picture exchange, and an iPad/iPod-based SGD to request preferred stimuli. Most children showed a preference for the SGD. For some children, acquisition may be quicker when learning a preferred option.