amnesic syndrome

amnestic syndrome, amnestic-confabulatory syndrome a mental disorder characterized by impaired memory with anterograde and sometimes retrograde amnesia in a normal state of consciousness; i.e., the syndrome does not include the impaired memory seen in dementia or delirium. There may be disorientation, confabulation, and lack of insight into the memory deficit. The most common cause is thiamine deficiency from chronic alcohol abuse (Wernicke-Korsakoff syndrome), but it may also result from any pathological process causing bilateral damage to parts of the medial temporal lobe or diencephalon, such as the hippocampal formations, mammillary bodies, or dorsal medial nuclei of the thalamus. Other causes include head trauma, brain tumors, infarction, cerebral hypoxia, carbon monoxide poisoning, and herpes simplex encephalitis. Called also dysmnesic s.