A recording of the brain’s electrical activity made primarily to rule out other causes of the symptoms of Parkinson’s disease. In the person with Parkinson’s the EEG result is generally normal, although some people have a diffuse slowing of electrical activity (slowing throughout the brain rather than in just one area) and disturbed patterns during sleep. Most neurological conditions that cause changes in the brain’s electrical activity alter specific kinds of activity or generate characteristic patterns. An EEG cannot diagnose Parkinson’s either to confirm or rule out the disease but becomes one of numerous clinical tools that help doctors differentiate, or distinguish, Parkinson’s from other neurological conditions.
A neurologist is most likely to request an EEG when the person’s symptoms are not clear-cut or when the person is younger than age 50. clinical research trials often include EEG among the range of measures used to evaluate investigational treatments and drugs, however. The objective to provide the greatest amount of data possible for researchers, as well as to make sure the treatment or drug is not causing adverse effects in the brain’s functions. A neurosurgeon may request an EEG before a surgical procedure such as deep brain stimulation (DBS), pallidotomy, and thalamotomy.
A routine EEG takes about an hour. The neurologist may request that the person limit sleep before the EEG. sleep deprivation ensures that samples of awake, drowsy, and asleep states can all be obtained. This is important because the transition from awake to asleep often accentuates certain kinds of brain disturbances, particularly those of many seizure disorders. During an EEG, a technician applies electrodes to specific locations on the scalp and forehead with a conductive glue. There is no discomfort. The person lies on bed in a darkened room (and can fall asleep) while a machine receives the electrical signals from the electrodes and outputs them onto graph paper to create a visual representation. The neurologist then interprets the patterns.
