Electroencephalographic abnormalities in Rett syndrome.

Electroencephalograms were performed on 11 girls with Rett syndrome between the ages of 4 and 14 years. Electroencephalographic abnormalities included slowing and disorganization of background activity while awake, multifocal epileptiform discharges maximal over the central and temporal regions, and intermittent, high-amplitude discharges followed by relative attenuation of background activity during sleep. Electroencephalographic patterns were remarkably similar in all patients and may be of diagnostic assistance in suspected cases.