Surface EMG and related measures in normal and vocally hyperfunctional speakers.

Surface electromyographic (EMG) signals were detected from the laryngeal area of 7 normal and 7 vocally hyperfunctional speakers during rest, two resisted-force maneuvers, vowel production, and connected speech. Vowel fundamental frequency, absolute and relative period perturbation, laryngeal-palpation ratings, and harshness ratings were acquired as well. The two groups differed significantly on all EMG measures except those associated with the resisted-force maneuvers, the vowel EMG-to-rest EMG ratio, and the speech EMG-to-rest EMG ratio. Moderately high correlations were evident between selected clinical measures and speech EMG values.