DIFFERENCES IN BIMANUAL COORDINATION ASSOCIATED WITH STUTTERING

The motor coordination of adults who stutter was examined in the perfo rmance of a bimanual movement task. Fifteen subjects who stutter and 1 5 matched subjects who do not stutter performed three trials of a bima nual finger movement task. Subjects were required to produce a flexion and extension movement of the metacarpophalangeal joint of each index finger in rhythm to a metronome. The rate of movement increased durin g the 70 s trial. Stutterers could maintain movements at the prescribe d rate as well as nonstutterers; however, stutterers moved with less a mplitude and peak velocity. In addition, dynamical analysis revealed t hat subjects who stutter exhibited greater relative phase variability than subjects who do not stutter. These results shed new light on the mixed results of earlier studies on nonspeech motor performance of ind ividuals who stutter and suggest that there are strategic differences as well as coordination differences that should be observable across a variety on motor tasks requiring coordination of multiple effecters, (C) 1997 Elsevier Science B.V.