Timing and intensity variability in the metronomic speech of stuttering and nonstuttering speakers.

The timing and intensity variability of 8 adults who stutter and 8 age-matched fluent speakers was investigated under metronomic conditions. Participants were required to produce double or triple-stress patterns at a slow speech rate (1 syllable/870 ms) when repeating the syllable /staet/or/straet/nine times. Measures that are sensitive to cyclic rather than overall variation in syllable timing and intensity were employed. Specifically, durational variation between successive syllable onsets as well as intensity variation of the beginning consonant and vowel in successive syllables were computed. Results revealed that, although intensity variation was similar, the timing of successive syllables of persons who stutter was significantly more variable than that of persons who do not stutter. These outcomes are discussed in relation to previous experiments of timing control of persons who stutter and normally fluent persons during metronomic stimulation.