Vocal and finger reaction times in stutterers and nonstutterers: differences and correlations.

The purposes of this study were (a) to assess whether the slower reaction times of stutterers are related to the etiology of the disorder or whether they are a by-product of it, and (b) to see if previously reported correlations between vocal and manual reaction times resulted from large numbers of trials. Fourteen adult stutterers and matched controls said "uh" or pressed a button in response to the offset of tones varying randomly in duration. Ten trials were used. The stutterers were significantly slower in both speech and nonspeech tasks, but the correlations between voice and manual reaction times were not significant. This suggested that stutterers' slower reaction times may be obtained without using large numbers of trials and that the correlation between the two tasks may depend on the number of trials used. The stutterers showed a significantly larger difference between vocal and manual reaction times than the nonstutterers. This suggested that the slower reaction times of stutterers are not entirely a by-product of the disorder.