Final answer:
EEG is a medical technique that measures the electrical activity of the brain using electrodes placed on the scalp, useful for studying sleep patterns and disorders.
Step-by-step explanation:
Electroencephalography (EEG) is a medical technique used to measure the electrical activity of the brain. This is done by placing an array of electrodes around a person's head. The signals received from these electrodes are used to produce a printout of the brain's electrical activity, known as brainwaves. The printout includes details on the frequency and amplitude of the brainwaves, with millisecond accuracy. The EEG is particularly valuable for researchers studying sleep patterns in individuals with sleep disorders, as it helps to gain an understanding of the brain's overall activity without needing to pinpoint the exact location of said activity.