[Early somatosensory evoked potentials in ischemic cerebrovascular diseases--I: Methodology, patients, normal group and review of the literature].

Somatosensory evoked potentials (SEP) were examined in 140 patients suffering from cerebro-vascular ischemic disease. Patients were classified in 1. asymptomatic stenosis/occlusion, 2. complicated migraine, 3. transient ischemic attacks (TIA), 4. reversible ischemic neurologic deficit (RIND), 5. completed stroke and 6. Multiinfarct-dementia. Normal SEP values were obtained from 26 age-correlated normal persons without a history of neurologic or psychiatric disease. The findings were correlated to clinical data, EEG, Single-Photon Emission and Transmission Computertomography (SPECT, TCT). SEP were done by stimulation of the median nerve. We evaluated central conduction time (CCT), amplitude ratio (AR) and number of phases (PHAS) of cortical potentials within 50 ms. Also quotient of amplitude ratio left stimulation side to right stimulation side (AR l/r) was calculated. EEG were recorded by 19 electrodes according to the 10-20 scheme, focal signs and diffuse changes were evaluated. In TCT the location of hypodense lesions was evaluated. SPECT was performed by application of J123 IMP and Tc99 HMPAO as a tracer. Focal decrease of tracer uptake compared to the compartment was evaluated. Results of animal experiments and clinical studies are discussed in respect of patients and methods.