Long term cassette EEG monitoring of childhood seizures.

We studied the clinical efficacy of 4-channel cassette recording of the EEG for 105 children being evaluated for possible seizures or further clarification of a known seizure disorder. Compared to the conventional EEG, 24 hour cassette EEG (C-EEG) studies yielded new diagnostic electroclinical information for 21 percent of the children (22 patients). For 41 percent of cases, the C-EEG findings considerably broadened the clinical knowledge of the disorder and provided a basis for therapy modification. In the remaining 38 percent, no significant electrical or clinical events occurred so that C-EEG studies yielded no new important information. The utility of C-EEG was greatest for younger patients with generalized epilepsies whereas older children with partial epilepsies constituted the majority of diagnostic failures. These findings demonstrate that C-EEG recording may contribute useful information concerning childhood paroxysmal disorders, and underscore the importance of careful patient selection.