An electroencephalogram (EEG) is a medical test that measures the brain’s electrical activity. This non-invasive procedure involves placing sensors on the scalp to detect electrical signals from brain cells. These signals are recorded and displayed as wavy lines. A sleep-deprived EEG is a specialized version of this test, performed after an individual has had significantly less sleep than usual.
Understanding the Need for a Sleep-Deprived EEG
Doctors often recommend a sleep-deprived EEG when a routine EEG might not provide enough diagnostic information. The primary reason for this specialized test is to make abnormal brain activity more apparent. Sleep deprivation can increase the likelihood of detecting subtle electrical patterns in the brain characteristic of conditions like epilepsy or other seizure disorders.
Certain types of seizures may not always show up during a standard EEG. By inducing sleep deprivation, the brain’s electrical patterns change, potentially triggering or enhancing the abnormal discharges associated with these conditions. This technique aims to reveal interictal epileptiform abnormalities, which are irregular electrical patterns occurring between clinical seizures, improving diagnostic accuracy.
The Sleep-Deprived EEG Procedure and Duration
The sleep-deprived EEG procedure involves a preparation phase followed by the recording, with the entire appointment lasting a few hours. The actual recording time is usually between one and two hours. Preparation for the test involves specific instructions, such as avoiding caffeine after midnight and ensuring hair is clean. Individuals are asked to limit their sleep significantly, which might mean staying awake all night or getting no more than four hours of sleep.
Upon arrival, a technologist measures the head and marks areas on the scalp where electrodes will be placed. These electrodes are attached using a water-soluble paste, a generally painless process. Once in place, the recording begins, with the patient relaxing in a comfortable chair or on a bed. During the test, the technician may ask the patient to perform activation procedures, such as deep breathing or looking at flashing lights, as these can sometimes provoke abnormal brain activity. A key part of the sleep-deprived EEG is the attempt to fall asleep during the recording, as sleep can reveal brainwave patterns not present during wakefulness.
After the EEG: What Happens Next
Once the recording is complete, the technologist removes the electrodes from the scalp. Any residual paste or gel can be easily washed out with shampoo at home. Due to the intentional sleep deprivation, it is common to feel drowsy after the test. For safety, it is recommended to have someone else drive you home and to avoid driving yourself for the rest of the day.
The recorded brainwave patterns are then analyzed by a neurologist, who interprets the findings. This analysis takes time, so results are not typically available immediately. Patients can expect to receive their results within a few days to a week or two, depending on the facility. Following the interpretation, a follow-up appointment with the referring doctor is usually scheduled to discuss the results and determine any next steps in diagnosis or treatment.