Correlation Between Somatosensory Evoked Potentials and Outcomes of the Putaminal Hemorrhages

We traced median nerve somatosensory evoked potential(SSEP) in 57 patients with putaminal hemorrhage from February, 1986 to January, 1991 for evaluation of relationship between SSEP findings and Glasgow outcome scale. 1) All patients with normal SSEP, prolonged central condution time and low ampulitude of cortical wave at affected side with small sized putaminal hemorrhage had good recovery to grade I. 2) Nine out of 25 patients with flat cortical wave of SSEP in small sized putaminal hemorrhage recovered to grade I. 3) All patients with moderate or large sized putaminal hemorrhage had flat cortical wave at affected side, none of them improved to grade I. It suggested that SSEP tracing in putaminal hemorrhage seemed to be valuable for evaluation of prognosis.

Normal Data of Somatosensory Evoked Potential by Posterior Tibial Nerve Stimulation

This study was undertaken to obtain the normal somatosensory evoked potential pattern from stimulation of the posterior tibial nerve in order to provide basic data for clinical use in diagnosis and management of patients with brain and spinal cord lesions. Thirty-six patients, free of neurological disease and 14 volunteers were tested with 4-Channel Nicolet CA 1000 Clinical Averager. There were 26 male and 24 female, ranging in height from 156 to 178 centimeter, with a mean height of 165.2 centimeter. The results were as follows: 1) All lumbar waves(LP1, LN1) and early cortical waves(P1, N1, P2, N2) were easily identified in all of normal subjects, but P3 was obtaind in 52% of them. 2) Mean latency of each wave was P1(38.10msec.+/-2.23), N1(47.04msec.+/-2.18), P2(N59.98msec.+/-2.97), N2(76.48msec.+/-4.97), LP1(17.99msec.+/-1.75) and LN1(20.72msec.+/-1.53). 3) There was significant correlations between height of individuals and latency of the P1 and LP1. 4) Conduction time between LN1and P1 was 16.55msec. (1.03 and mean latency of left to right difference was 0.23msec.+/-0.19.

Clinical Evaluation of Evoked Potentials in Cerebrovascular Diseases

With 4-Channel Nicolet-CA 1000 clinical averager, somatosensory evoked potentials(SSEP) and brainstem auditory evoked potentials(BAEP) were studied in 40 patients with intracerebral hematoma and 40 patients with cerebral infarction. SSEP was more sensitive response in putamen(20/23) or thalamic(6/7) hemorrhage and infarction of middle cerebral artery territory(13/28). in contrast BAEP was high percentage in abnormality in brainstem or cerebellar lesion. Cortical wave(N18) was usually not traceable in large size of hematoma or having midline shift in brain CT scan. There was close correlation between the severity of motor weakness and abnormality of SSEP. The best neurological outcome was found in the patients of P24 wave formation. In our results, SSEP and BAEP seemed to be very useful for evaluation of stroke patients.