Cyclical muscle vibration in MS to improve walking

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Objective - The primary objective of this pilot study is to explore the feasibility of cyclical vibration of leg muscles to improve walking after multiple sclerosis (MS). In addition, determine the feasibility of vibration in addressing typical gait deficits that involve strength and coordination of multiple joints (hip, knee and ankle) required for negotiating uneven terrain normally encountered during activities of daily living. Vibration is perhaps the most potent mechanical stimulus for activating muscle spindle primary afferent nerves (Ia). This causes excitability of corticospinal projections to the target muscles while the α-efferents to antagonists are inhibited. Recent neuroscientific research has shown that neuroplastic changes in the cerebral cortex and in other parts of the CNS are necessarily linked to motor skill retraining in the affected limbs. Research plan and methodology - A vibration system consisting of up to 4 vibrators per leg that can be selectively activated during walking and timed relative to the appropriate phases of gait, as identified by simple wearable sensors (accelerometers, foot-floor contact pressure) will be implemented. Twelve subjects with gait deficits at the hip, knee and ankle from MS will be recruited and quantitative gait analyses of their walking will be assessed at baseline. Six subjects will undergo gait training with cyclic vibration, emulating timing of normal muscle activity, and six control subjects (matched by walking speed) without vibration and gait training. After 12 session of gait training, gait evaluation will be repeated. Subjects will serve as their own control. Data of treatment and control groups will also be pooled for comparison. Extent of gait correction with vibration or no training will be compared to individual’s volitional function without vibration at baseline. The primary outcome measures of walking speed, hip-knee coordination and gait symmetry will be assessed before and after intervention. In addition, vibration will be monitored for untoward sensations and physiological changes in blood pressure and heart rate for safety. Clinical significance - The need for new interventions to correct gait deficits and maintain walking in 50 to 75% of patients with MS is huge with prevalence of 400,000 in US and over 16,000 veterans being treated at VHA. Often, the resulting gait deficits are severe enough that the current standard of care is insufficient to significantly improve their walking performance. This adversely affects their personal independence, societal participation, quality of life and overall health. This pilot study will provide preliminary data on the efficacy and safety of cyclical vibration of the lower extremity muscles in patients with MS. The facilitatory effects of vibration are expected to carryover so that only intermittent vibration treatment to maintain improvements in gait will be required. Except for simple foot drop correction, currently available interventions do not assist with propulsion or other gait components such as hip-knee coordination necessary to improve gait. This simple vibration system, if effective, has a potential for quick and easy translation into clinical practice.