Speech and Language Alterations in Dementia Syndromes

Abstract

Dementia is an etiologically nonspecific syndrome characterized by acquired persistent disturbance of several areas of neuropsychological function. Once regarded as a syndrome of global intellectual loss, dementia is increasingly approached as a group of disorders with distinct neuropsychological patterns of preserved and impaired abilities reflecting disease-related regional brain involvement. The topography of histologic, biochemical, and metabolic alterations associated with individual central nervous system (CNS) disorders can be correlated with disease-related behavioral profiles. Conversely, behavioral observations are utilized to infer the geography of brain dysfunction and the etiology of the neurologic condition. Such brain—behavior correlations have reached an acceptable degree of reliability with regard to monosymptomatic deficit syndromes such as the aphasias (Benson & Geschwind, 1985) and amnesias (Benson, 1978; Damasio, Graff-Redford, Eslinger, Damasio, & Kas-sell, 1985) but are in a relatively primitive state of development in polysymptomatic disorders such as the dementias. A crude distinction has been drawn between dementias associated primarily with cortical dysfunction and those occurring with subcortical disturbances (Cummings & Benson, 1983, 1984), but more refined distinctions are necessary both to improve clinical diagnosis and management and to enhance understanding of brain—behavior relationships in the dementia syndromes.