Onset and termination of accessory facial movements during stuttering

In this study the onset and offset times of seven types of accessory facial movements during oral and silent prolongations were described in three severe stutterers. For each observed facial movement the onset and offset times were determined by means of slow motion analysis of video-recorded speech samples. For two of the three subjects significant differences in the onset and offset times at the various facial movements were found; however, no consistent patterns in the separate facial movements could be observed. On the contrary, the onset of most facial movements appeared to be located at the very start and their offset at the end of the stuttering moment. The implications of these findings with respect to the function of accessory facial movements in stuttering are discussed.