EMBARGOED FOR RELEASE UNTIL 4 PM ET, April 16, 2002
Routine Overnight EEG Monitoring Not Warranted in Autistic Children
Denver, Colo. -
Though controversial, children with autistic syndrome may be subjected unnecessarily to overnight EEG testing for the identification of Landau-Kleffner syndrome (LKS), the deterioration of language ability associated with clinical or electrical seizure activity. According to research presented at the 54th Annual Meeting of the American Academy of Neurology, this type of monitoring is unwarranted except in highly selected cases. "We found the incidence of the diagnostic criteria for LKS to be miniscule in overnight studies of 334 patients studied with the indication of autism spectrum disorder," says study author Phillip Pearl, MD, of Children''s National Medical Center in Washington, DC. "This suggests to us that this kind of testing may not the most effective way to diagnose LKS among children with autism." Of 894 Children''s National Medical Center patients monitored over 3.5 years, 334 (37%) were identified as having autism spectrum disorder and studied to rule out LKS. Of these, 83 (25%) had abnormal EEGs, with 63 (19%) exhibiting epileptiform activity. The overnight EEG studies identified epileptiform activity during sleep in 56 of the 63 patients; none of these tracings revealed electrographic status epilepticus during slow-wave sleep, regarded as a diagnostic criterion for LKS. "Overnight EEG monitoring in autistic children is challenging on multiple accounts, and oftentimes requires sedation for the child to undergo the hook-up procedure.These studies are unwarranted as a routine investigation for children with autism," says Pearl. Landau-Kleffner syndrome, or acquired epileptiform aphasia, represents a disorder that can be distinguished from autism on several accounts, according to Pearl. While the children may not have clinical seizures at all, there are clinical clues that allow a neurologist to suspect this syndrome. "We recommend overnight EEG monitoring in selected patients with autistic syndrome, specifically those with significant regression or fluctuation in language functioning," explains Pearl.