[Statistical spectral study of alpha rhythms: modifications due to the tardive action of a hypnotic (author's...

In a simple blind study to evaluate electroencephalographic criteria objectively, and to continue characterization of psychotropic compounds, 5 mg of nitrazepam, a hypnotic derivative, was given to seven subjects the night before the recording. We noted that in most subjects there was a reduction in the spectral intensity of the alpha rhythm, associated with a greater frequency instability, several hours after the absorption of nitrazepam. This corresponds to the tardive hypnotic action of the psychotrope, the importance of which is wellknown at the present time. In the same way as the increase in rapid rhythms, the slipping of 0.5 c/s of the dominant alpha frequency to the top could be characteristic of the action of nitrazepam.