Effects of a new radio frequency-controlled neuroprosthesis on gait symmetry and rhythmicity in patients with chronic hemiparesis.

OBJECTIVE To assess the effects of a new neuroprosthesis (NESS L300) designed to ameliorate foot drop on gait symmetry and rhythmicity during walking. DESIGN Twenty-four patients (mean age: 54.0 +/- 13.5 yrs) with chronic hemiparesis (5.8 +/- 5.2 yrs) whose walking was impaired by foot drop. Subjects walked for 6 mins while wearing force-sensitive insoles, once with and once without the neuroprosthesis, in randomized order. Additional assessments with the neuroprosthesis were conducted after using the device for 4 and 8 wks. Walking speed, swing, and stride time were determined, along with a gait asymmetry index and stride time variability-both markers of gait stability and fall risk. RESULTS While wearing the neuroprosthesis, the gait asymmetry index instantly improved by 28% (from 0.58 +/- 0.30 to 0.42 +/- 0.22) and by 45% (to 0.32 +/- 0.20; P < 0.001) after 8 wks. Stride time variability decreased by 23% immediately (from 5.7 +/- 2.9% to 4.4 +/- 1.3%) and by 33% (to 3.8 +/- 1.4%; P = 0.002) after 8 wks. Walking speed improved initially by 17% (from 0.53 +/- 0.24 to 0.62 +/- 0.22 m/sec) and after 8 wks by 34% (to 0.71 +/- 0.25 m/sec; P < 0.001). CONCLUSIONS The studied neuroprosthesis enhances gait and improves dynamic stability in chronic hemiparetic patients, supporting the idea that this is a viable treatment option in the rehabilitation of patients with foot drop.