White matter disease and dementia

Dementia is a common occurrence in patients with disorders affecting cerebral hemispheric white matter. Relatively little is known, however, about the specific pattern of neurobehavioral changes associated with abnormal white matter function. This review examines in detail the neurobehavioral features of a common white matter disease, multiple sclerosis (MS). The neuropsychological characteristics of MS-related dementia are compared and contrasted with those observed in three other white matter disorders (acquired immune deficiency syndrome, Binswanger's disease, and closed head injury) to determine if "white matter dementia" should be recognized as a unique diagnostic entity distinct from other dementing conditions. Finally, possible mechanisms by which white matter disease affects behavior are proposed.