96. Corticospinal reserve measured with the H-coil predicts walking impairment in progressive multiple sclerosis Academic Article uri icon

abstract

  • Walking impairment affects multiple sclerosis (MS) patients and impacts their quality of life. Despite a known relationship between objective and subjective walking measures, gait and neurophysiological motor parameters relationships remains to be explored. 50 progressive MS people underwent functional and neurophysiological assessments: 10-meters-walking-test (10 mWT), 2 and 6 min-walking-test (2 mWT, 6 mWT), modified-Ashworth-scale (MAS), spasticity and pain numerical-rating-scale (NRS), fatigue-severity-scale (FSS), expanded-disability-status-scale (EDSS), and 12-items-MS-walking-scale (MSWS-12). A walking-fatigability-index (WFi, performance decay from 2 to 6 min during 6 mWT) was calculated according to the formula: [(2 mWT ∗ 3 − 6 mWT)/2 mWT ∗ 3]. Resting-motor-threshold (RMT, the lowest intensity for evoking an electromyographic or visually-evident muscle activation) was obtained using a H-coil. Correlations were explored using the Spearman-rho coefficient (significance set at p = 0.05). RMT correlated positively with the 10 mWT ( p = 0.012) and with MSWS-12 ( p = 0.005), and negatively with the 2 mWT (p = 0.016), but not with 6 mWT, nor with fatigue (FSS) or fatigability (WFi). WFi significantly correlated with disability (EDSS; p p = 0.007). RMT, as measure of pyramidal reserve, is correlated with subjective impact of MS on walking, predicting walking speed rather than endurance or fatigability, the latter being associated with disability and spasticity. The lack of association between subjective fatigue and objective fatigability suggests different mechanisms underling the two phenomena.

publication date

  • January 1, 2016