CENTRAL MOTOR CONDUCTION STUDIES IN INTERNAL CAPSULE AND CORONA RADIATA INFARCTION

Clinical and evoked-potential studies in internal capsule and corona r adiata infarction are lacking. We report the results of a clinical and central motor conduction time (CMCT) study in 16 patients with intern al capsule and 17 with computed tomography (CT)-proven corona radiata infarction. Patient's outcome was defined at the end of 3 months on th e basis of the Barthel Index score. Four patients with type A capsular infarction (middle third of posterior limb of internal capsule) all h ad severe weakness, while 2 also had persistently unrecordable CMCT an d poor outcome. Twelve patients with type B internal capsular infarcti on (genu, anterior limb, anterior or posterior third of posterior limb ) had a milder degree of weakness, and CMCT was recordable in 9. At 3 months' follow-up, however, CMCT was recordable in all 12 patients. Al l of these patients had a partial (n = 4) or complete (n = 5) recovery . Thirteen patients with type A corona radiata infarction (middle thir d of corona radiata) had more pronounced weakness, and CMCT was unreco rdable in all of these patients except 1 on initial examination. Follo w-up after 3 months was possible in 8 patients, and CMCT became record able in 3. One of these patients had complete, 3 partial, and 4 poor r ecovery. In type B corona radiata infarction (anterior or posterior th ird of corona radiata), the clinical signs and CMCT did not follow a r egular pattern. Clinical and CMCT abnormalities in internal capsular i nfarction followed a more predictable pattern compared with those in c orona radiata infarction. A less predictable pattern of weakness and C MCT change in corona radiata infarction may be attributed to a less de finite organisation of motor pathways compared with the internal capsu le.