Somatosensory evoked potentials (SSEPs) in various groups of cerebro-vascular ischaemic disease

Fifty-eight patients suffering from cerebrovascular ischaemic diseases were examined by means of somatosensory evoked potentials (SSEPs). The early components during the first 50 msec were evaluated (N13, P15, N20, P28, CCT = N13-N20). The patients were divided into 4 groups according to the affected vascular region and the reversibility of the symptoms. Reversible ischaemic attacks in the vertebro-basilar artery region: 16 patients. Reversible ischaemic attacks in the internal carotid artery region: 14 patients. Non-reversible ischaemic deficits in the internal carotid artery region: 16 patients. Diffuse vascular encephalopathy: 12 patients. The two groups suffering from reversible ischaemic attacks did not show any significant SSEP differences, either when the right and left sides were compared, or when the groups were compared to a control group. Patients with non-reversible ischaemic deficits of the carotid artery system showed a significant difference of the N20-P28 amplitude compared to controls; it was increased on the non-affected side. The latencies of N20 and CCT showed a significant increase on the affected side; P15 components revealed significant delays on both sides. In patients with diffuse vascular encephalopathy significant delays of N13 and P15 were found on both sides, whereas the CCT was unaffected on both sides. The results are discussed in view of the topologic aspects and reversibility of symptoms.