Résumé :
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Communication n° 555. Neuromuscular disorders (NMD) are a heterogeneous group of diseases of motor unit with muscle weakness as the predominant clinical sign. Difficulties in gait are one of the most early and frequent complaints and often the main contributor to disability in patients with NMD. The gait disorders in NMD have been studied to some extend only in patients with Duchenne muscular dystrophy (DMD). A broader clinical consensus on evaluation and management of gait disorders in NMD has not been reached even in patients with DMD. Therefore, we asked ourselves whether we could define characteristic gait disturbances in patients with specific NMD and if detected abnormalities could be explained solely with pattern and extend of muscle weakness. For that purpose, we used clinical gait analysis (kinematics, kinetics and dynamic EMG) and isokinetic dynamometer (maximal voluntary contraction-MVC) in 4 patients with NMD with different pattern of muscle involvement (SMA III, DM1, FSHD and Becker MD) and a healthy volunteer. MVC in hip, knee and ankle in concentric /concentric mode at 60º/s for flexion/extension were in hip: 20/21 % of healthy control in BMD, 16/22% in DM1, not possible/11 % in SMA and not possible/10 % in FSHD; in knee: 3/5 % in BMD, 20/17% in DM1, 9/3 % in SMA and 8/14 % in FSHD; and plantar flexion/dorsal flexion in ankle 14/17 % in BMD, 5/17 % in DM1, 15/30 % in SMA and 24/23 % of healthy control in FSHD. Yet, the walking speed was similar (0,77 in BMD; 0,65 in DM1; 0,78 in SMA; 0,82 in FSHD vs. 1,31 m/s in healthy control) and power generated in plantar flexion in the third rocker was in all patients between 1,6 - 1,8 Watt/kg (3,2 Watt/kg in healthy control). Patients in the study used different strategies to achieve functional gait like changes in kinematics (cadence, step length and width, step time) and changes in compensatory muscle activation. We conclude that the gait analysis supported by isokinetic dynamometry can disclose different compensatory mechanisms used by patients with NMDs to negotiate gait problems.
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