Does the 10-20 System Fit into EEG Registrations of Children with Cerebral Dysmorphy?

A ten-year-old girl with mental retardation due to holoprosencephaly was sent to the EEG department with the question of whether there were epileptiform abnormalities. Electrodes were attached according to the 10-20 System. Quite surprisingly there was a well-developed alpha rhythm with a maximum in the central regions. In the occipital parietal regions there was predominant low amplitude beta and theta activity, on the right more than on the left. There were no epileptiform abnormalities. Afterwards the MR1 of the child was studied. There was a semiholoprosencephaly with severely disturbed normal brain localization. There was an anterior displacement of both hemisphere and an anterior displacement of the cerebellum. Proper interpretation of an EEG registered with the 10-20 System in children with severe cerebral malformation is only possible with knowledge of the disturbed anatomy. [ABSTRACT FROM AUTHOR]