What tests show the brain's electrical activity?
- Electroencephalogram (E.E.G.) - Small metal disks
(electrodes) are placed at strategic locations on a person's scalp. The
electrodes can detect the electrical activity in the form of impulses
that are then transcribed to paper. By observing such impulse
characteristics as intensity (the size of the impulse), duration (the
width of the impulse), frequency (how often impulses occur during a
given time) and location (what region of the brain produces these
impulses), an EEG can provide valuable information about underlying
problems in the brain.
- Evoked response test -
A diagnostic procedure that provides a measurement of the brain's
ability to process and react to different sensory stimuli. A doctor
evokes a visual response by flashing a light or checkerboard pattern in
front of a patient. For auditory evoked responses, a doctor produces a
sound in one of the patient's ears. For bodily evoked responses, one of
the nerves in an arm or leg is electrically stimulated. The responses
from these sensory stimuli can indicate abnormal areas of the brain.