Speech breathing in stuttering: Some classic and new analyses
By M. Ho, A. Smith, and S. McGarvey
Stuttering is a breakdown in the smooth flow of speech, which reflects the failure of the nervous system to generate the appropriate command signals to muscles for fluent speech to continue. Aberrant behaviors in articulatory, laryngeal, and respiratory systems have been observed during disfluent speech of individuals who stutter (IWS). One hypothesis about the physiological bases of stuttering is that there are ongoing, ever-present differences in their speech production systems, such that, even during fluent speech, they show signs of instability and/or differences in underlying control processes. We used respiratory inductance plethysmography (RIP) to examine reading and conversational speech breathing in ten IWS and ten non-stuttering matched controls. A new method for volume calibration of rib cage (RC) and abdomen (AB) signals, the pseudoinverse calculation, is introduced. We measured inspiratory and expiratory phase volumes and durations, inspiratory flow, spectra of volume and flow, onset of voicing relative to expiration, and correlations of RC and AB volumes. Breath pause locations relative to linguistic boundaries were examined in five rate conditions. No differences were found between IWS and non-stuttering controls on any measure. The present study suggests that IWS generally show speech breathing parameters in the normal range.