Abstract

Objective: In this study, the relationship between neurological soft signs and P300 components was explored in patients with schizophrenia. Method: 22 first-episode schizophrenia patients who were evaluated according to DSM-IV criteria and whose disease lasted at least six months, and a group of 22 healthy controls were included in this study. In both groups, neurophysiological measurements were performed to investigate the P300 potentials and Neurological Evaluation Scale (NES) was applied to detect neurological soft signs. Scale for the Assessment of the Negative Symptoms (SANS) and Scale for the Assessment of the Positive Symptoms (SAPS) were applied only to the schizophrenia group. Results: Results revealed that first episode schizophrenia group had higher NES total and subscale scores, lower P300 amplitude and longer P300 latency compared to healthy controls. NES scores with the highest significant difference from healthy controls were Total NES and NES motor sequencing subscale. When the first-episode schizophrenia group is compared with the control group by the P300 components, difference of P300 amplitude was more significant than difference of P300 latency. It was also found that NES scores and P300 values were not correlated with clinical variables in the patient group. Conclusion: These findings indicate that pathology of these biological markers was found at the beginning of the disease and was not effected by clinical variables. This result can be interpreted as the pathologies exhibited with NES and P300 measurements could not be state but trait characteristics. Within soft neurological signs the most pathological results were obtained from motor sequencing subscale and its relationship with P300 amplitude was statistically significant. These findings indicate that the high scores of motor sequencing subscale which is thought to be sign of prefrontal pathology can be better explained with problems about attention.

Key words: Schizophrenia, neurological soft signs, P300