Abstracts

RATIONALE: In addition to its role in evaluating autistic spectrum children for seizures, different EEG techniques are being used increasingly commonly in the evaluation of autistic children for underlying epileptic disorders, such as the Landau-Kleffner Syndrome or epileptic aphasia. By retrospective review, we set out to determine the relative rates that epileptiform activity was discovered according to which EEG technique was used: awake only EEG, awake/asleep EEG, and 24 hour ambulatory EEG telemetry.
METHODS: We performed a computer search of the medical records of children with the diagnosis of autism, pervasive developmental disorder, or Asperger syndrome at the Floating Hospital for Children at Tufts-New England Medical Center, for patients seen between March 2000 and March 2002. Medical records were reviewed and all children in whom a standard EEG or 24 hour ambulatory EEG had been obtained were included; children in whom such studies were obtained in order to evaluate possible or definite seizures were excluded, however. Each EEG study was classified as to whether epileptiform activity was identified.
RESULTS: Sixty-five children with autism spectrum disorders and without suspicion of seizures in whom at least one EEG study had been done were identified. None of the 12 awake only EEGs exhibited epileptiform activity (mean age 4.5 years). Among EEGs in which both wakefulness and sleep were recorded, five (12%) of 42 showed epileptiform activity (mean age 3.9 years). Among 11 ambulatory EEG recordings of 24 or more hours duration, none exhibited epileptiform activity (mean age 4.3 years). Thus, the rate at which epileptiform activity on EEG was found among children in whom sleep was recorded was relatively low, five (9%) of 53 children.
CONCLUSIONS: Routine EEGs including sleep appeared fairly good at picking up epileptiform activity in such children. Ambulatory telemetry, which should be a more [dsquote]thorough[dsquote] technique, did not pick up any cases despite the fact that deeper and longer duration sleep was recorded. We intend to carry out a larger study in order to ascertain the frequency of epileptiform activity in children with autistic spectrum disorders comparing the yields of these two techniques.