Five general types of evaluations will be employed over multiple study sessions at the National Center for Rehabilitative Auditory Research (NCRAR). First, a neurologist will review the subject's medical history and perform a neurologic exam to confirm MS diagnosis. Second, peripheral auditory function will be evaluated using a standard set of routine audiometric tests. Additionally, subjects will complete a case history and series of hearing handicap inventories. Third, a battery of behavioral procedures will be used to characterize central auditory processing. Fourth, auditory evoked potential studies will be performed. Emphasis here will be upon evoked potentials whose putative neural generators lie within the central auditory nervous system. Fifth, subjects will receive magnetic resonance imaging (MRI) evaluation to determine sites and amount of neural degeneration.