Somatosensory evoked potentials in schizophrenia. A lateralisation study.

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Neurophysiology

Background:

• Previous research suggested abnormal lateralization in somatosensory evoked potentials (SSEPs) of schizophrenic patients.
• Diagnostic criteria for schizophrenia have evolved, necessitating updated neurophysiological investigations.

Purpose of the Study:

• To compare SSEPs between individuals diagnosed with schizophrenia and healthy controls.
• To investigate the presence and degree of lateralization in SSEPs in schizophrenia.

Main Methods:

• SSEPs were recorded from 19 schizophrenic patients (defined by RDC, DSM-III, and PSE criteria) and a control group of healthy volunteers.
• Stimulation of the left and right index fingers was used to assess ipsilateral and contralateral responses.
• Analysis included peak latency, amplitude, morphology, and a percentage lateralization quotient.

Main Results:

• No significant differences in amplitude or morphology were found between schizophrenic patients and controls.
• No significant differences in peak latency for any SSEP component were observed between groups.
• The percentage lateralization quotient showed no significant differences, indicating similar lateralization patterns in both groups.
• Contralateral SSEP components were consistently larger in amplitude than ipsilateral components across both groups.

Conclusions:

• The study did not replicate previous findings of abnormal lateralization in SSEPs in schizophrenia.
• Current findings suggest that SSEP lateralization may not be a distinguishing feature of schizophrenia.
• Potential myogenic contamination in previous studies using SSEPs was highlighted as a factor to consider.