Background:

Schizophrenia is a psychiatric disorder marked by hallucinations, delusions, cognitive deficit, apathy, and thinking disorders. Speech disturbance is one of the main diagnostic criteria during acute periods of schizophrenia. In addition, abnormalities of brain language areas have been consistently described in schizophrenic individuals. The aim of this study was to describe the linguistic performance and cerebral activity during sentence production using word pairs with high or low semantic relatedness.

Material and methods:

We recorded electrical brain activity (electroencephalography [EEG]) of 15 healthy men and 11 men with disorganized schizophrenia while they were producing sentences with high and low relatedness word pairs.

Results:

The results showed significant differences; participants in both groups had significant longer latencies to produce sentences with low than with high relatedness word pairs. Furthermore, sentences formed with low relatedness pairs were significantly longer than those formed with high relatedness word pairs in both groups. EEG parameters also showed differences; in healthy subjects, we found enhancement of absolute alpha rhythm over the occipital leads during the period preceding sentence production with high relatedness word pairs.

Conclusion:

In contrast, in schizophrenia patients producing sentences with high relatedness word pairs, it was theta and beta rhythms that were enhanced in frontal regions.