Article

Rhythmic auditory cueing improves certain gait symptoms of
Parkinson's disease (PD). Cues are typically stimuli or beats with a fixed
inter-beat interval. We show that isochronous cueing has an unwanted side-effect
in that it exacerbates one of the motor symptoms characteristic of advanced PD.
Whereas the parameters of the stride cycle of healthy walkers and early patients
possess a persistent correlation in time, or long-range correlation (LRC),
isochronous cueing renders stride-to-stride variability random. Random stride
cycle variability is also associated with reduced gait stability and lack of
flexibility. METHOD: To investigate how to prevent patients from acquiring a
random stride cycle pattern, we tested rhythmic cueing which mimics the
properties of variability found in healthy gait (biological variability). PD
patients (n=19) and age-matched healthy participants (n=19) walked with three
rhythmic cueing stimuli: isochronous, with random variability, and with
biological variability (LRC). Synchronization was not instructed. RESULTS: The
persistent correlation in gait was preserved only with stimuli with biological
variability, equally for patients and controls (p's<0.05). In contrast, cueing
with isochronous or randomly varying inter-stimulus/beat intervals removed the
LRC in the stride cycle. Notably, the individual's tendency to synchronize steps
with beats determined the amount of negative effects of isochronous and random
cues (p's<0.05) but not the positive effect of biological variability.
CONCLUSION: Stimulus variability and patients' propensity to synchronize play a
critical role in fostering healthier gait dynamics during cueing. The beneficial
effects of biological variability provide useful guidelines for improving
existing cueing treatments.
CI - Copyright A(c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS