Functional outcome following spinal cord injury: Significance of motor-evoked potentials and ASIA scores

Abstract

Objective: Prediction of outcome of ambulatory capacity and hand function in tetraplegic patients with spinal cord injury (SCI) using neurologic examination, according to the protocol of the American Spinal Injury Association (ASIA) and motor-evoked potentials (MEP). Design: Correlation study on a prospective cohort. Setting: SCI center, university hospital. Patients: Thirty-six patients with acute and 34 with chronic SCI. Outcome Measures: (1) ASIA motor and sensory scores, (2) MEP recordings of upper and lower limb muscles, and (3) outcome of ambulatory capacity and hand function. Results: In acute and chronic SCI, both the initial ASIA scores and the MEP recordings were significantly related ( p < .0001) to the outcome of ambulatory capacity and hand function. In tetraplegic patients, the MEP of the abductor digiti minimi muscle (Spearman correlation coefficient, .75; p < .0001) and the ASIA motor score for the upper limbs (Spearman correlation coefficient, .83; p < .0001) were most related to the outcome of hand function. Ambulatory capacity could be predicted by the ASIA motor score of the lower limbs (Spearman correlation coefficient, .78; p < .0001) and by MEP recordings of the leg muscles (Spearman correlation coefficient, .77; p < .0001). In patients with acute SCI, for the period 6 months posttrauma, the ASIA motor score increased significantly (ANOVA, p < .05), whereas the ASIA sensory scores and MEP recordings were unchanged (ANOVA, p > 0.1). Conclusion: Both ASIA scores and MEP recordings are similarly related to the outcome of ambulatory capacity and hand function in patients with SCI. MEP recordings are of additional value to the clinical examination in uncooperative or incomprehensive patients. The combination of clinical examination and MEP recordings allows differentiation between the recovery of motor function (hand function, ambulatory capacity) and that of impulse transmission of descending motor tracts.