Abstract

Abstract: This talk will give an overview regarding clinical memory disorders. These encompass far more than just the dementias. Amnesic disorders can be transient or persisting. They can have a neurological or a psychological basis. Concepts of memory derived from empirical psychology can be applied to these different types of memory syndrome, and examples will be given. Transient neurological (“discrete”) episodes of memory loss can arise from such causes as toxic confusional states, head injury, alcoholic “blackouts”, hypoglycaemia, post-ECT, transient global amnesia, and transient epileptic amnesia. These various syndromes characteristically affect episodic memory, and important recent investigations have highlighted the clinical characteristics of transient global amnesia and transient epileptic amnesia, including overlapping and contrasting features. Persistent, neurological memory disorder occurs in the amnesic syndrome, in which episodic memory is predominantly affected, arising from disorders such as herpes encephalitis, cerebral hypoxia, thiamine deficiency (the alcoholic Korsakoff syndrome), limbic encephalopathies, head injury, and the amnesic form of mild cognitive impairment. By contrast, in semantic dementia (progressive fluent aphasia) semantic memory is principally affected, and Alzheimer dementia commonly involves a global (episodic and semantic) impairment of memory function. Controversies exist regarding the critical site of damage causing the anterograde amnesia in the Korsakoff syndrome, and the nature of the neuropsychological deficit in focal hippocampal lesions (as in some cases of cerebral hypoxia). There is also considerable controversy concerning the neuropsychological and pathophysiological basis of retrograde amnesia, and of spontaneous confabulation. Many of these issues will be taken up in later talks. Psychogenic amnesia can be “global” or “situation-specific”. The global form affects the whole of a person's previous life, and is commonly accompanied by a loss of the sense of personal identity, as in the case of Piano Man. This form of amnesia is usually transient, but, if it becomes persistent, it is better labelled as psychogenic focal retrograde amnesia’. Situation-specific amnesia involves a discrete gap in a person's memory, usually related to a traumatic episode, as in post-traumatic stress disorder and (more controversially) in the perpetrators and victims of certain types of offence. There are now neuropsychological models of how psychogenic amnesia might arise. The remainder of the day will be devoted to: 1). theoretical debates arising in the investigation of anterograde amnesia, retrograde amnesia, and confabulation; 2). clinical, neuroimaging and neuropsychological reviews of dementia and mild cognitive impairment; and 3). an account of neuropsychological techniques of rehabilitation in memory disorders.