[Short-latency somatosensory evoked potentials in patients with hypertensive intracerebral hemorrhage: clinical availability of N20 component].

Short-latency Somatosensory Evoked Potentials (SSEPs) were studied in 14 patients with putaminal hemorrhage and 17 patients with thalamic hemorrhage. After median nerve stimulation SSEPs were recorded from the electrodes placed on C3', C4' (2cm behind C3 or C4 of the internal 10-20 system respectively), and Cv7. (Reference was the linked ears.) Erb's potential was also recorded from the Erb's point using the contralateral one as the reference. The patients were classified into three groups according to central conduction time laterality index (CCT LI). CCT LI = (CCT on the affected side which is defined as the interpeak latency between N13 and N20)--(CCT on the non affected side). Group 1: CCT LI < or = 0.73 (it means within normal limit); Group 2: CCT LI > 0.73 (it means the significant latency delay of the N20 on the affected side); Group 3: CCT LI is not available (because the N20 was abolished on the affected side). We analyzed retrospectively the localization of the hematoma on CT scans, the degree of motor and sensory disturbance of the upper extremity in each group. Of the 14 patients with putaminal hemorrhage, 5 were in group 1; 3 were in group 2; 6 were in group 3. Patients in group 1 had a localized hematoma within the pallido-putamen complex. Patients in group 2 had a hematoma compressing the posterior limb of the internal capsule. Patients in group 3 had a hematoma involving the posterior limb of the internal capsule and had severer motor disturbance than those in group 1 or group 2.(ABSTRACT TRUNCATED AT 250 WORDS)