EEG frequency patterns associated with hallucinations in schizophrenia and "creativity" in normals.

This study attempts to define EEG power spectral patterns associated with hallucinatory behaviors in schizophrenia. Six unmedicated schizophrenics with Schneiderian criteria were interviewed and their tongue potentials were monitored and recorded on FM tape. Eye movements and tongue potentials were monitored and segments with artifacts were not used. Consecutive 4-sec intervals of EEG were analyzed in the frequency domain using fast Fourier transorm methods and serial power spectra plots obtained. The intrusiveness of the hallucinatory experience may be similar to the sudden internal experience of perceptual resolution in a creative task. Six normal controls were similarly monitored and analyzed while responding to tests of "creativity." In the 4-sec interval prior to reports of hallucinatory experiences, a frequency pattern of predominatly delta and theta power was found in 71.7% of the EEG segments. In the control group, 78.1% of the EEG segments preceding a creative response demonstrated a similar low frequency pattern which also differed significantly from the base line EEG frequency pattern.