Article

Walking in time with a metronome is associated with improved
spatiotemporal parameters in hemiparetic gait; however, the mechanism linking
auditory and motor systems is poorly understood.
OBJECTIVE: Hemiparetic cadence
control with metronome synchronization was examined to determine specific
influences of metronome timing on treadmill walking. METHODS: A
within-participant experiment examined correction processes used to maintain heel
strike synchrony with the beat by applying perturbations to the timing of a
metronome. Eight chronic hemiparetic participants (mean age = 70 years; standard
deviation = 12) were required to synchronize heel strikes with metronome pulses
set according to each individual's comfortable speed (mean 0.4 m/s). During five
100-pulse trials, a fixed-phase baseline was followed by 4 unpredictable
metronome phase shifts (20% of the interpulse interval), which amounted to 10
phase shifts on each foot. Infrared cameras recorded the motion of bilateral heel
markers at 120 Hz. Relative asynchrony between heel strike responses and
metronome pulses was used to index compensation for metronome phase shifts.
RESULTS: Participants demonstrated compensation for phase shifts with convergence
back to pre-phase shift asynchrony. This was significantly slower when the error
occurred on the nonparetic side (requiring initial correction with the paretic
limb) compared with when the error occurred on the paretic side (requiring
initial nonparetic correction). CONCLUSIONS: Although phase correction of gait is
slowed when the phase shift is delivered to the nonparetic side compared with the
paretic side, phase correction is still present. This may underlie the utility of
rhythmic auditory cueing in hemiparetic gait rehabilitation.

Langue : ANGLAIS