Motor and Gait Improvement in Patients With Incomplete Spinal Cord Injury Induced by High-Frequency Repetitive Transcranial Magnetic Stimulation

Abstract

Objective:To assess the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) on lower extremities motor score (LEMS) and gait in patients with motor incomplete spinal cord injury (SCI). Method: The prospective longitudinal randomized, double-blind study assessed 17 SCI patients ASIA D. We assessed LEMS, modified Ashworth Scale (MAS), 10-m walking test (10MWT), Walking Index for SCI (WISCI II) scale, step length, cadence, and Timed Up and Go (TUG) test at baseline, after the last of 15 daily sessions of rTMS and 2 weeks later. Patients were randomized to active rTMS or sham stimulation. Three patients from the initial group of 10 randomized to sham stimulation entered the active rTMS group after a 3-week washout period. Therefore a total of 10 patients completed each study condition. Both groups were homogeneous for age, gender, time since injury, etiology, and ASIA scale. Active rTMS consisted of 15 days of daily sessions of 20 trains of 40 pulses at 20 Hz and an intensity of 90% of resting motor threshold. rTMS was applied with a double cone coil to the leg motor area. Results: There was a significant improvement in LEMS in the active group (28.4 at baseline and 33.2 after stimulation; P = .004) but not in the sham group (29.6 at baseline, and 30.9 after stimulation; P = .6). The active group also showed significant improvements in the MAS, 10MWT, cadence, step length, and TUG, and these improvements were maintained 2 weeks later. Following sham stimulation, significant improvement was found only for step length and TUG. No significant changes were observed in the WISCI II scale in either group. Conclusion: High-frequency rTMS over the leg motor area can improve LEMS, spasticity, and gait in patients with motor incomplete SCI.

Supraspinal Control Predicts Locomotor Function and Forecasts Responsiveness to Training after Spinal Cord Injury

“…To date, three studies of this type have been published related to walking, [16][17][18] as well as a case study related to lower extremity muscle activity. 120 Two studies using transcranial direct current stimulation (tDCS) followed by locomotor training showed mixed results.…”

“…17 In a study of repetitive TMS (rTMS) applied over the leg motor area in persons with American Spinal Injury Association Impairment Scale (AIS) D injury classification, 17 subjects were randomized to either rTMS or sham-tTMS. 18 Both groups also received locomotor training. The study concluded that rTMS was associated with improvements in walking speed, lower extremity motor scores, and spasticity that were not observed in the sham-rTMS group.…”

“…For this reason, recent studies have begun to target supraspinal control mechanisms in both animal models 12,13 and humans. [14][15][16][17][18] The increasing appreciation for the importance of supraspinal contributions to locomotor function in persons with SCI derives from studies that have shown the influence of volitional control on walking. Evidence is accumulating for the value of clinical measures of volitional control in predicting future walking function, in forecasting responsiveness to training, and delineating the variables that correlate with walking capacity.…”

Long-term paired associative stimulation can restore voluntary control over paralyzed muscles in incomplete chronic spinal cord injury patients

“…For example, PAS pulse pairs are delivered once every 5 s. Repetitive TMS (rTMS) without concomitant PNS can have positive effects in incomplete SCI patients for 2-3 weeks; 11,12 however, in SCI patients, high-intensity TMS is needed to effectively activate the corticospinal tract, 13 and long-term use of high-frequency and high-intensity rTMS may be contraindicated for SCI patients with head injury, as rTMS reduces the seizure threshold. 13,14 In contrast, PAS utilizes less risky low-frequency TMS.…”

“…[15][16][17][18] Studies of rTMS and transcranial direct cortical stimulation are also based on patients with preserved voluntary activity in the muscles under investigation. 11,12,18 PAS induces plasticity in humans without concomitant effort by the subject; 4 we thus hypothesized that long-term PAS could be a technique that could affect also those muscles which are fully paralyzed.…”