JRRD at a Glance

Review of physiological motor outcome measures in spinal cord injury using transcranial magnetic stimulation and spinal reflexes

Peter H. Ellaway, PhD, et al.

Figure. Threshold values for eliciting motor-evoked potentials

This article reviews methods developed as part of a clinical initiative on improving outcome measures for assessment of motor function in subjects with spinal cord injury (SCI). Physiological motor outcome measures originally developed for limbs-transcranial magnetic stimulation (TMS) of the motor cortex to elicit motor-evoked potentials (MEPs) and mechanical stimulation to elicit spinal reflexes-have been extended to trunk muscles. The impetus for this development was the lack of a motor component assessment for the thoracic myotomes in the American Spinal Injury Association examination. Application of TMS to assessment of limb muscles is reviewed, followed by consideration of its application to assessment of paravertebral and intercostal muscles. Spinal reflex testing of paravertebral muscles is also described. The principal markers for the thoracic SCI motor level that have emerged from this clinical initiative are (1) the threshold of MEPs in paravertebral muscles in response to TMS of the motor cortex, (2) the facilitation pattern and latency of MEPs in intercostal muscles during voluntary expiratory effort, and (3) the absence of long-latency reflex responses and exaggeration of short-latency reflex responses in paraspinal muscles.

Volume 44 Number 1 2007
Pages 69 — 76

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