Longitudinal study of central motor conduction time following stroke: 2. Central motor conduction measured within 72 h after stroke as a predictor of functional outcome at 12 months

A longitudinal study was performed on 118 first-ever stroke patients to evaluate neurophysiological measurements of central motor conduction time (CMCT) in the period immediately following stroke as predictors of functional outcome and mortality at 12 months. Measurements of CMCT were made as described in the accompanying article (Heald et al., 1993, Brain, 116, 1355-1370), in which the following three groups of patients were recognized within 12-72 h after the onset of symptoms: normal response group, delayed response group and no response group. Neurophysiological and clinical investigations were commenced 12-72 h (designated as day 1) after the onset of symptoms and repeated at set time intervals up to 12 months. The subjects were examined neurologically and assessed using the Motricity Index for muscle strength, the Nine-hole Peg Test to measure manual dexterity, the Barthel Score for activities of daily living and the modified Rankin Scale for functional outcome. The duration of stay in hospital and the occurrence of stroke-related death were noted. During the first week following stroke, absence of responses correlated closely with the patient's symptoms and neurological observations of abnormal muscle tone and tendon reflexes. Correlations were made in the three groups of patients of functional scores at day 1 and at 12 months. Patients with normal CMCT had consistently higher scores throughout the 12 month period and achieved significantly better functional recovery. Patients with no responses showed poor performance in neurological and functional tests throughout the 12 month period. Patients with delayed CMCT had neurological and functional scores intermediate between those of the other two groups, but outcome at 12 months was similar to those in the normal response group. Where the threshold to cortical stimulation was abnormally high, functional outcome was generally poor. Mortality was highest in the group with absent responses and the survivors spent the longest period in hospital. In conclusion, the observation of normal or delayed CMCT at day 1 identifies a group of patients with a high probability of survival and functional recovery. The absence of responses to cortical stimulation at day 1 identifies a group of patients who are at high risk of poor functional recovery at 12 months and greater probability of stroke-related death during this period.