Neurological assessment in spinal cord injury

Precise and reliable neurologic assessment is a necessary tool for determining the extent and pattern of recovery after SCI. Recently agreed upon international standards establish a uniform neurologic classification to measure clinical outcomes. They are currently in use in three multicenter studies in more than 40 SCI centers in the United States. The Model System SCI centers report the use of these measures, such as impairment grades and neurologic levels, in almost 15,000 cases over the past 20 years and, more recently, motor scores in 3,500 patients. The NASCIS II multicenter trial on methylprednisolone used motor and sensory scores as endpoints in close to 500 patients, but have incorporated the international standards, which include a disability measure, in NASCIS III. The study of ganglioside effectiveness also is using these measures in many patients. In more focused studies, neurologic assessment soon after injury can predict walking in motor complete injuries based on pin prick sensation, and in motor incomplete injuries based on impairment grade and age. Eventual upper extremity function can be estimated based on the motor examination within 72 hours of injury. Both the motor score and motor level are more reliable in predicting upper extremity function than the single sensory level. This presumably reflects the greater importance of motor recovery on functional outcome. The proximal muscles of the lower extremities caudal to the lesion site recover before distal muscles, and this may be mediated by axons descending in the ventral tracts, which control primarily proximal rather than distal muscles. These axons may be preferentially spared and/or have greater capacity to compensate than those present in the lateral columns. In conclusion, standard neurologic assessment in SCI is extremely valuable in monitoring recovery in order to prognosticate functional outcome, evaluate effectiveness of drug interventions, and provide valuable clues to possible underlying mechanisms of recovery. The elucidation of these mechanisms will aid in the refinement of current treatments and development of new strategies to enhance neurologic recovery and functional outcome.