Usually an EEG is done both during wakefulness and during sleep. The duration of the recording depends on what information your doctor is trying to obtain. The recording may last 30 minutes or may last as long as several days or more. The electrodes are attached to wires that connect to a computer that records the electrical activity. The EEG technologist attaches several flat metal discs (electrodes) to different places on the head using a sticky paste to hold the electrodes in place. The electrodes are applied to the patient’s scalp while he or she lies on an exam table or sits in a chair. How is an EEG done?Īn EEG can be done in a hospital, clinic, or at home by an EEG technologist. In those cases, the reduction or elimination of seizures through appropriate treatment has the potential to improve behavior, cognition, and development. In some cases severe seizures may also disrupt the brain in ways that lead to developmental delays.

Why do seizures occur at such high rates in autism and other neurodevelopmental disorders? The disturbance to the brain that leads to developmental delays also predisposes the brain to develop seizures. An abnormal EEG occurs in about 2-4% of the general population but in 50-80% of those with autism. As an example, epilepsy occurs in 1-2% of the general population but in 20-40% of those with autism. The occurrence of seizures in individuals with neurodevelopmental disorders is much higher than in the typically-developing population. Why are EEGs frequently recommended for individuals with neurodevelopmental conditions like autism, intellectual developmental disorder, or global developmental delay? If a seizure, what type of seizure (this is helpful in deciding how to proceed with treatment)?Īre there subclinical seizures (seizures that have no clear outward manifestation)?Īre there areas of abnormal electrical activity that may be impacting cognition, behavior, and/or development?Īn EEG also provides information about an individual’s sleep – in particular, the brain’s progression through the different stages of sleep and whether this is disturbed. A diagnosis of epilepsy (or seizure disorder) is given when an individual has two or more seizures that are not secondary to fever, trauma, infection, or metabolic illness.Īre the episodes seizures or another type of event? Seizures occur suddenly and may appear as abnormal movements, reduced responsiveness, staring spells, or a wide variety of other symptoms. They generally appear as brief interruptions to a person’s ongoing behavior.

Seizures are defined as transient episodes of excessive, disorderly discharge of neurons, primarily in the cerebral cortex (which is the outer layer of brain tissue). The most common reason for an EEG is to aid in the diagnosis of seizures.

What can an eeg show that an mri cannot