Treatment of patients with cervical and upper thoracic incomplete spinal cord injury using repetitive transcranial magnetic stimulation

Purpose: To evaluate the short- and long-term effectiveness of repetitive transcranial magnetic stimulation with parameters based on results of comparative neurophysiological studies in patients with incomplete spinal cord injury. Results may help to understand mechanisms responsible for regeneration of the incomplete spinal cord after injury. Methods: Repetitive transcranial magnetic stimulation sessions (three to five sessions per month for not less than 5 months) to 15 patients with C4-Th2 incomplete spinal cord injury were applied with individually designed parameters. One session consisted of bilateral stimulation of the primary motor cortex (for 10 min each with 800 stimuli in 2-s lasting trains and the inter-train intervals of 28 s) with frequency at 20–22 Hz and stimulus strength that was 70%–80% of the resting motor threshold (0.84–0.96 T). Recordings of surface electromyography at rest and during the attempt of maximal muscle contractions and motor evoked potentials were performed from abductor pollicis brevis and tibialis anterior muscles bilaterally. Amplitude parameters of surface electromyography and motor evoked potentials were used as outcomes. All neurophysiological tests were comparatively applied before and after treatment. Results: Decrease in surface electromyography amplitudes recorded at rest from abductor pollicis brevis (p = 0.009), increase in surface electromyography amplitudes during maximal contraction of abductor pollicis brevis (p = 0.03) and increase in motor evoked potential parameters recorded from abductor pollicis brevis (p = 0.04) were found. Conclusion: Proposed repetitive transcranial magnetic stimulation algorithm reduced the increased muscle tension in upper extremity muscles, improved the function of upper extremity muscle motor units and slightly improved the transmission of efferent neural impulses within spinal pathways. Besides functional recovery in descending spinal pathways, repetitive transcranial magnetic stimulation may also inhibit inevitable pathological changes in nerves.