Gait Symmetry in Subjects with Multiple Sclerosis: 10:15AM-10:30AM: 587

MS does not affect both sides of the body equally, which can result in asymmetrical gait.

PURPOSE: To compare gait symmetry measures in subjects with MS with age matched healthy control subjects. It was hypothesized that the MS subjects would be less symmetrical than healthy control subjects.

METHODS: Gait analysis was performed on each of 13 subjects with MS (age 44.4 ± 10.6yrs, height 167.0±8.7cm, mass 79.1 ± 20.1kg, EDSS 3.5 ± 0.7) and 8 controls (age 40.9 ± 8.6 yrs, height 167.4±14.6cm, mass 72.6 ± 14.2kg). Two conditions were collected: Fresh and Fatigued. The Fresh condition was collected first, while the Fatigued condition was collected following a walking protocol designed to increase self-ratings of fatigue and perceived exertion. Approximately 15 gait cycles for each condition were collected and time normalized to the stride cycle (100 data points). Gait cycles were averaged to provide one ensemble average for each subject and condition. Paired data points from the right and left waveforms (for controls) and from the affected and unaffected sides (of MS subjects) of sagittal plane hip, knee, and ankle data were analyzed using an eigenvector approach to determine the following gait symmetry measures: trend similarity, phase shift, minimum trend similarity, range amplitude ratio, and range offset. The values at the hip, knee, and ankle were then summed to determine composite symmetry values for each leg. Differences between the Fresh condition for the MS subjects and controls were analyzed using a one-tailed independent samples t-test. Changes between Fresh and Fatigued conditions for the MS subjects were analyzed using a one-tailed dependent samples t-test. The difference between Fresh and Fatigued conditions for the MS subjects was correlated with EDSS.

RESULTS: MS subjects are generally more asymmetrical than the healthy controls. The waveform trend similarity was significantly worse in the MS subjects, the phase shift was significantly greater in the MS subjects, and the waveform trend similarity adjusted for phase shift was also significantly worse in MS subjects. MS subjects generally became more asymmetrical in the fatigued condition; range amplitude ratio became significantly more asymmetrical (p<.05) while there was a trend for the waveform trend and the phase shift to become worse with fatigue. There was not a significant relationship between the EDSS and the symmetry measures for subjects with MS.

CONCLUSION: In general, MS subjects have greater asymmetry than healthy control subjects.