Preserved corticospinal conduction without voluntary movement after spinal cord injury

Case report.

To identify preserved corticomotor connection in chronic spinal cord injury (SCI) in the absence of clinically observable movement.

Rehabilitation Hospital and Medical Research Institute, NY, USA.

The motor-evoked potential (MEP) response to transcranial magnetic stimulation (TMS) was recorded using surface electromyography from the right biceps brachii, extersor carpi radialis (ECR), flexor carpi radialis (FCR) and abductor pollicis brevis (APB) muscles in a 31-year-old male traumatic SCI chronic patient-ASIA B, injury level C5. Motor power scores were additionally obtained from a clinician blinded to the results of TMS.

TMS could consistently elicit MEPs of normal latency, phase and amplitude, in the severely affected ECR muscle but not the similarly affected FCR muscle. The response in proximal and unaffected biceps muscle was larger than the healthy subject, whereas no response was obtained in the distal APB muscle as expected.

TMS can identify residual pathways not apparent from clinical assessment alone, which may have prescriptive value for rehabilitation.