Relation between finger reaction time and voice reaction time in stuttering and nonstuttering children and adults.

Nine stutterers and nine nonstutterers at each of three age levels (5 years, 9 years, and 18 years and above) responded to the onset of 21 1-kHz tones by depressing the index finger of their preferred hand on a response key. Finger reaction times (FRTs) were measured to the nearest millisecond and compared to the voice reaction times (VRTs) obtained from the same subjects. Increased speed and stability of the finger reaction times were observed as an inverse function of age for both groups. The stutterers, as a group, exhibited mean FRTs which were significantly longer and more variable than those of the nonstutterers at each of the three age levels. High correlations also were found between the finger and voice reaction scores for both the stutterers and the nonstutterers. Results support the inference that some stutterers may exhibit difficulty in the consistent execution of motor control strategies common to both speech and nonspeech movements.