Electroglottographic and acoustic waveforms of voice onset in stutterers

The first few glottal pulses in the stuttered and fluent tokens of voiced utterances by stutterers were analyzed and compared with the initial voice pulses in the same utterances by nonstutterers. Signals analyzed were the impedance changes across the glottis during voice initiation via electroglottography (EGG) and the acoustic waveforms. In single-cycle analysis of vocal fold vibration, normal speakers evidenced abrupt decrease in impedance with increasing vocal fold contact, and a more gradual increase in impedance as the folds opened. Stutterers, when perceived as fluent, followed the same pattern as normals. Extremely aberrant EGG patterns often accompanied stuttering episodes, with idiocyncratic strategies revealed for breaking the stuttering block. The envelope for the first EGG cycles differed from normal for some stutterers. Some of the severe stutterers showed patterns of gradual buildup of EGG amplitude after a block, whereas the mild stutterers and normal controls showed a more abrupt envelope. When fluent, all speakers had EGGs with abrupt envelopes and a more stable open phase for each cycle. EGG activities will be related to their acoustic correlates. [Work supported by NIH.]