ABSTRACT
Amnesic syndrome describes patients with profound inability in day-to-day remembering and with varying degrees of remote or retrograde memory impairment whose memory-related disability exists in the context of comparatively spared cognitive and intellectual function. The disorder exists separately from generalized dementia, and from language or attentional disturbance, and has distinct characteristics. We now know that the amnesic syndrome does not affect all kinds of memory, and, conversely, that memory-disordered patients without full-blown amnesia may have less severe impairment in critical cognitive processes that normally support remembering. It is now known that the amnesic syndrome can follow damage to three major functional systems of the brain: the medial temporal lobe/hippocampal memory system, the diencephalon, and the basal forebrain. The chapter reviews the characteristics and anatomic bases for these "three amnesias." It considers whether these three different disorders, or variations on a core amnesic syndrome.
