Evoked Potential Testing
Sensory evoked potentials may be ordered to test nerve pathways in the brain and spinal cord. These studies measure electrical activity in response to stimulation of sight, sound, or touch. When the brain is stimulated by sight, sound, or touch, signals travel along the nerves to the brain. Electrodes detect the signals. There are three types of tests, measuring responses to visual, auditory, and electrical stimuli. Evoked potentials involve placing adhesive disc electrodes over the scalp, back, neck and other locations.
These electrodes record the electrical activity from the spinal cord and brain. Different stimuli may be used: brief electrical impulses to nerves in the arms or legs (somatosensory evoked potentials); a flashing checkerboard pattern on a computer monitor screen (visual evoked potentials); clicking noises and tones via earphones (brainstem auditory evoked potentials). They can indicate the presence of disease or degeneration, and help determine the location of the problem.
Evoked potentials are helpful in the diagnostic work up of:
- Multiple sclerosis
- Genetic neurological disorders
- Optic nerve conditions
- Diseases of the spinal cord