Effects of Speech Cues on Acoustics and Intelligibility of Korean-speaking Children with Dysarthria

The motor speech disorder of dysarthria is present in a substantial number of children with cerebral palsy (CP), leading to speech intelligibility deficits, which may negatively affect the children’s communication and quality of life. Few studies to date have examined strategies for increasing intelligibility in children with dysarthria, and most have focused on English speakers. Thus, questions regarding the effects of speech cueing strategies in speakers of other languages are under-explored. The purpose of this study was to determine if (Korean translations of) two cues, “speak with your big mouth,” targeting greater articulatory excursion, and “speak with your strong voice,” targeting greater vocal intensity, would elicit changes in speech acoustics and intelligibility in Korean-speaking children with dysarthria secondary to CP. Fifteen Korean-speaking children with dysarthria repeated word- and sentence-level stimuli in habitual, big mouth, and strong voice conditions. Intelligibility was assessed through the ease-of-understanding (EoU) ratings and percentage of words correctly transcribed (PWC) by 90 blinded listeners. Results indicated significantly greater vocal intensity and greater utterance duration in the cued conditions, demonstrating the children’s ability to vary their speech styles in response to the two cues. Furthermore, word-level EoU gains following both cues and sentence-level EoU gains following the strong voice cue suggest potential intelligibility benefits of the cues in this population. Gains in PWC were not statistically significant, and considerable variability in the children’s responses to the cues was noted overall. These findings contribute to the limited knowledge base for speech-language pathologists working with Korean speaking children. The variability in responses points to the importance of assessing each child’s stimulability to cues aimed to enhance intelligibility. Further clinical and theoretical considerations, including cross-linguistic implications, are discussed.