Diagnostic values of short latency somatosensory evoked potentials in stroke.

ABSTRACT

Short latency somatosensory evoked potentials (SSEPs) were elicited by stimulation of the median and tibial nerves in 55 patients with cerebrovascular diseases. There were 28 males and 27 females. The mean age was 52.7+14.9 years (range 20-83). Every patient presented as an acute hemiplegic with and without sensory loss. The CT findings were classified into 6 groups, thalamic, internal capsule, subcortical white matter, basal ganglia, occlusion of proximal branch of middle cerebral artery and transient ischemic attack. The abnormality rate of median SSEPs was 63.6 percent (35/55) and tibial SSEPs was 67.3 percent (37/55). In thalamic stroke both median and tibial SSEPs abnormality rates were 80 percent (8/10), in ganglionic stroke the rates were 75 percent (9/12). The internal capsule abnormality rates were 75 percent (9/15). Subcortical white matter there was 57.1 percent (4/7) and 80 percent (8/10) in occlusion of the main branch of middle cerebral artery. The SSEPs specificity, positive and negative predictive values between cerebral hemorrhage and infarction were 42.8, 47.4 and 87.2 percent respectively. Hence, SSEPs might be of value in localizing anatomical lesions but not to differentiate between hemorrhagic and ischemic stroke.