Stable abnormalities in the lateralisation of early cortical somatosensory evoked potentials in schizophrenic patients.

During the investigation of somatosensory evoked cortical potentials arising from a complex vibro-tactile stimulus to the forefingers, an abnormal lack of lateralisation of response was found in 10 out of 21 schizophrenic patients. Eight patients with severe affective illness all had the expected degree of lateralisation of cortical potentials, as did 12 out of 15 normals. Three normals and 3 schizophrenic patients had a loss of lateralisation of the evoked response on stimulation of one hand but a normal lateralisation on stimulation of the other. The considerable technical problems of this and related techniques are discussed, but it is suggested that further exploration of this technique is justified. At this stage, no conclusion can be drawn about the cause of the abnormalities.