Duration of phonation under changing stress conditions in stuttering and nonstuttering adults

To investigate whether stutterers exhibit difficulties in producing changing prosodic patterns flexibly, nine adult stutterers and nine adult non-stutterers had to utter a simple three-syllabic test word repeatedly with stress on the second syllable. In one experimental condition the subjects were unexpectedly required to shift stress from the second to the first syllable, while in another experimental condition they were unexpectedly required to shift stress from the second to the third syllable. In contrast to non-stutterers, stutterers were generally unable to shift stress immediately from one syllable to another with respect to one main suprasegmental aspect of prosody (duration of phonation). These results are interpreted as supporting the view of stuttering as a prosodic disturbance.