What is the role of electroencephalography in the workup of autism spectrum disorder (ASD)?

Updated: Sep 30, 2019
  • Author: James Robert Brasic, MD, MPH; Chief Editor: Caroly Pataki, MD  more...
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As stated earlier, electroencephalography is useful for ruling out seizure disorder (present in a third of children with autism), acquired aphasia with convulsive disorder (Landau-Kleffner syndrome), biotin-responsive infantile encephalopathy, and related conditions. The American Academy of Neurology and the Child Neurology Society found inadequate evidence to recommend an electroencephalogram (EEG) in all individuals with autism. [2]

Consultation with an electroencephalographer may help to determine appropriate procedures for individual cases.

A single normal EEG does not rule out a paroxysmal abnormality, such as a seizure disorder. When a routine EEG does not reveal unequivocal evidence of a seizure disorder in a patient who may have one (eg, partial seizures with complex symptomatology), specialized procedures may help to clarify the diagnosis. Measurements of electroencephalographic activity after sleep deprivation and after stimulation with light, noise, and tactile sensations using nasopharyngeal leads, as well as the use of video monitoring simultaneously with electroencephalography, may be helpful in such cases. Neurologic consultation can also be beneficial.

Indications for performing a sleep-deprived EEG with appropriate sampling of slow-wave sleep in patients with autism are clinical seizures (or suspicion of subclinical seizures) and clinically significant loss of social and communicative function, especially in toddlers and preschoolers. [2]

Admission to a specialized unit for simultaneous 24-hour video monitoring of electroencephalography and movement of the patient for a few days of assessment may facilitate the establishment of or the exclusion of diagnosis of a paroxysmal disorder. See PET Scanning in Autism Spectrum Disorders for further information, including the EEG of a boy with autism seen in the video files posted within this article. [143]

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