Temporal organization of syllables in paced and unpaced speech in children and adolescents who stutter.

Purpose: Speaking with an external rhythm has a tremendous fluency-enhancing effect in people who stutter. The aim of the present study is to examine whether syllabic timing related to articulatory timing (c-center) would differ between children and adolescents who stutter and a matched control group in an unpaced vs. a paced condition.

Methods: We recorded 48 German-speaking children and adolescents who stutter and a matched control group reading monosyllabic words with and without a metronome (unpaced and paced condition). Analyses were conducted on four minimal pairs that differed in onset complexity (simple vs. complex). The following acoustic correlates of a c-center effect were analyzed: vowel and consonant compression, acoustic intervals (time from c-center, left-edge, and right-edge to an anchor-point), and relative standard deviations of these intervals.

Results: Both groups show acoustic correlates of a c-center effect (consonant compression, vowel compression, c-center organization, and more stable c-center intervals), independently of condition. However, the group who stutters had a more pronounced consonant compression effect. The metronome did not significantly affect syllabic organization but interval stability improved in the paced condition in both groups.

Conclusion: Children and adolescents who stutter and matched controls have a similar syllable organization, related to articulatory timing, regardless of paced or unpaced speech. However, consonant onset timing differs between the group who stutters and the control group; this is a promising basis for conducting an articulatory study in which articulatory (gestural) timing can be examined in more detail.