Use of electromyography to optimize Lokomat settings for subject-specific gait rehabilitation in post-stroke hemiparetic patients: A proof-of-concept study.

Objectives: While generic protocols exist for gait rehabilitation using robotic orthotics such as the Lokomat, several settings - guidance, body-weight support (BWS) and velocity - may be adjusted to individualize patient training. However, no systematic approach has yet emerged. Our objective was to assess the feasibility and effects of a systematic approach based on electromyography to determine subject-specific settings with application to the strengthening of the gluteus maximus muscle in post-stroke hemiparetic patients.

Methods: Two male patients (61 and 65 years) with post-stroke hemiparesis performed up to 9 Lokomat trials by changing guidance and BWS while electromyography of the gluteus maximus was measured. For each subject, the settings that maximized gluteus maximus activity were used in 20 sessions of Lokomat training. Modified Functional Ambulation Classification (mFAC), 6-minutes walking test (6-MWT), and extensor strength were measured before and after training.

Results: The greatest gluteus maximus activity was observed at (Guidance: 70% -BWS: 20%) for Patient 1 and (Guidance: 80% - BWS: 30%) for Patient 2. In both patients, mFAC score increased from 4 to 7. The additional distance in 6-MWT increased beyond minimal clinically important difference (MCID=34.4m) reported for post-stroke patients. The isometric strength of hip extensors increased by 43 and 114%.

Conclusion: Defining subject-specific settings for a Lokomat training was feasible and simple to implement. These two case reports suggest a benefit of this approach for muscle strengthening. It remains to demonstrate the superiority of such an approach for a wider population, compared to the use of a generic protocol.