The authors sought to determine whether basic patterns of muscle activation for speech were similar in preschool children who stutter and in their fluent peers. Across both speaking tasks, lip muscle activation was similar in Children who stutter (CWS) and Children who do not stutter (CWNS) in overall amplitude, bilateral synchrony, and degree of right–left asymmetry. EMG amplitude was reduced during disfluent compared with fluent conversational speech of CWS, and there was no evidence of tremor in the disfluencies of CWS. These results support the assertion that stuttering in young children arises from the command signals that control the timing and amplitude of muscle activity. The results indicate that no frank abnormality is present in muscle activation patterns in preschoolers who stutter.
Walsh, Bridget & Smith, Anne. (2013). Oral Electromyography Activation Patterns for Speech Are Similar in Preschoolers Who Do and Do Not Stutter. Journal of Speech, Language, and Hearing Research, 56, 1441-1454.