Short Description or Definition
The amnestic syndromes are a group of neurologic disorders characterized by a dense global amnesia. This amnesia is comprised of an inability to form new memories (anterograde amnesia) and an inability to retrieve old memories (retrograde amnesia) (Anterograde Amnesia and Retrograde Amnesia). A unique feature of these disorders is that the dense memory loss occurs within the context of relatively preserved intelligence, language, attention, and perceptual abilities.
The amnestic syndromes can be classified according to cause or site of damage. Possible etiologies include herpes simplex encephalitis, anoxia, Wernicke-Korsakoff syndrome, cerebrovascular accidents, anterior communicating artery aneurysm (ACoA), and tumors. These disorders can give rise to amnesia by damaging any of an array of structures, such as the medial temporal lobes (including the hippocampus), the midline diencephalic nuclei, and the basal forebrain, or by disrupting...