Dementia due to multiple sclerosis

**Definition:** Dementia due to multiple sclerosis is a neurodegenerative disease due to the cerebral effects of multiple sclerosis, a demyelinating disease. Onset of symptoms is insidious and not secondary to the functional impairment attributable to the primary disease (i.e., multiple sclerosis). Cognitive impairments vary according to the location of demyelination but typically include deficits in processing speed, memory, attention, and aspects of executive functioning.