Electroencephalographical study of the Rett syndrome with special reference to the monorhythmic theta activities in adult patients.

The long-term course of the EEG in the Rett syndrome is documented with reference to past studies. The monorhythmic theta activities in the waking state which were characteristically seen in adults with the Rett syndrome were investigated in patients aged between 27 and 28, using auto power spectra. They were often suppressed when the patients were excited or strained. Then the suppression was thought to elevate their conscious levels. The theta activities were often suppressed by calling, but not easily suppressed by other stimuli, especially the somatosensory stimuli of pain and touch. There were also abnormal findings in the ABR and blink reflexes. In the Rett syndrome we, therefore, suspect there are disturbances in the brain stem functions especially in the ascending reticular activating system which is related to elevation of the conscious level.