The effects of fluency-evoking conditions on voicing onset types in persons who do and do not stutter.
Voicing onset changes between control conditions and three fluency-evoking conditions (choral reading [CHORAL], delayed auditory feedback [DAF], and noise [NOISE]) were studied in 12 persons who do not stutter and 10 who do stutter. Voicing onsets were distinguished physiologically using airflow prior to voicing, with zero airflow prevoicing categorized as hard and the rest as breathy. Persons who stutter were more fluent under all fluency-evoking conditions than control conditions. Speaking under fluency-evoking conditions did not significantly increase the overall proportion of breathy onsets from control conditions for either group. However, looking only at hard onsets in the control condition, we found that both groups changed significantly more to breathy (p = 0.001) under CHORAL and NOISE. In persons who stutter, onset type was not associated with whether a word was produced fluently or dysfluently in the control condition. Also, no relationship was found between onsets changing to breathy under fluency-evoking conditions and onsets changing to fluent. The results suggest that although fluency-evoking conditions can modify some voicing onset behaviors, these modifications do not relate to improvements in fluency.
Stager
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Voice and Speech Section, National Institute of Deafness and Other Communication Disorders, Bethesda, Maryland 20892-1407, USA.
Ludlow
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D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010699:Phonation; D012720:Severity of Illness Index; D013068:Speech Production Measurement; D013342:Stuttering / Q000175:diagnosis*; D013997:Time Factors