Rhythmic auditory stimulation modulates gait variability in Parkinson's disease

Abstract

Patients with Parkinson's disease (PD) walk with a shortened stride length and high stride-to-stride variability, a measure associated with fall risk. Rhythmic auditory stimulation (RAS) improves stride length but the effects on stride-to-stride variability, a marker of fall risk, are unknown. The effects of RAS on stride time variability, swing time variability and spatial-temporal measures were examined during 100-m walks with the RAS beat set to 100 and 110% of each subject's usual cadence in 29 patients with idiopathic PD and 26 healthy age-matched controls. Carryover effects were also evaluated. During usual walking, variability was significantly higher (worse) in the patients with PD compared with the controls (P < 0.01). For the patients with PD, RAS at 100% improved gait speed, stride length and swing time (P < 0.02) but did not significantly affect variability. With RAS at 110%, reductions in variability were also observed (P < 0.03) and these effects persisted 2 and 15 min later. In the control subjects, the positive effects of RAS were not observed. For example, RAS increased stride time variability at 100 and 110%. These results demonstrate that RAS enables more automatic movement and reduces stride-to-stride variability in patients with PD. Further, these improvements are not simply a by-product of changes in speed or stride length. After walking with RAS, there also appears to be a carryover effect that supports the possibility of motor plasticity in the networks controlling rhythmicity in PD and the potential for using RAS as an intervention to improve mobility and reduce fall risk.

Frequency-Velocity Mismatch: A Fundamental Abnormality in Parkinsonian Gait

“…Our model-based explanation of the PD gait deficiency is different from the prevalent view, which assumes that increased step frequency compensates for a primary scaling defect in PD locomotion (Hausdorff et al 2007;Morris et al 1994Morris et al , 1996Morris et al , 1998Morris et al , 2005. This conclusion was primarily based on the smaller slope of the stride length/step frequency relationship in PD than that in normal subjects (Morris et al 1996).…”

Gait dynamics in Parkinson’s disease: Common and distinct behavior among stride length, gait variability, and fractal-like scaling

“…126 Recently, we examined the effects of RAS on gait variability in patients with PD and age-matched healthy controls. 63 When RAS was set to the subject's usual-walking rate, stride length and gait speed increased in PD patients. However, variability, which was relatively higher in the patients with PD compared to controls, did not improve significantly in response to RAS at this rate.…”

Effectiveness of Exercise on Functional Mobility in Adults with Cerebral Palsy: A Systematic Review

“…24,25 RAS proved to be more effective than traditional NDT methods for correcting gait patterns in ambulatory adults with CP, as indicated by an increase in gait speed. 15 The literature supported the use of RAS for PT rehabilitation and improvement of functional mobility with other neurologic populations, including people with Parkinson's disease [26][27][28][29][30][31] and those undergoing post-stroke 32,33 rehabilitation. The four remaining studies showed no statistically significant differences and trivial effect sizes between the control and experimental groups.…”