Fig. 1.

Lower limb motor activity generated by epidural lumbar SCS. (A) Drawing of a cylindrical epidural lead with four contacts (black rectangles) placed over the posterior aspect of the lumbar spinal cord. (B) Locomotor-like EMG activities of paralyzed lower limb muscles elicited by sustained epidural lumbar SCS at 25 Hz and 10 V in a supine position. Q: quadriceps, Ham: hamstrings, TA: tibialis anterior, TS: triceps surae. Induced relative knee movements (Knee mov.) are documented by a position sensor trace; deflection up indicates knee flexion. Data derived from a subject with chronic, motor-complete (AIS B), mid-thoracic (motor level: T8) traumatic SCI [56]. (C) Extension movement and associated EMG activity induced by epidural lumbar SCS at 10 Hz and 10 V. The subject's lower limb had been placed in a flexed position prior to the onset of stimulation (see vertical arrow along the time-axis). The goniometer trace (Knee angle) illustrates the generated extension movement. Data derived from a subject with chronic, motor-complete (AIS A), mid-thoracic (motor level: T6) traumatic SCI in supine position [75]. (D) Lower limb EMG activity induced by manually assisted, body-weight supported treadmill walking without (left side) and with additional epidural lumbar SCS. The treadmill belt speed was 0.36 m/s. The subject wore a parachute harness connected to counterweights which supported him vertically over the treadmill and provided 50% body weight support. Two physiotherapists manually imposed the stepping motions on the moving treadmill belt. No independent functional movements were produced. Black horizontal bars indicate stance phases. Subject with chronic, motor-complete (AIS A), low-cervical (motor level: C6) traumatic SCI [78].