Amnesia

Abstract

This paper describes the clinical features of selected examples of organic and psychogenic amnesia, and it discusses the nature of the dysfunction that these amnesias entail. The anterograde component of organic amnesia involves a severe impairment in acquiring (or learning) new information, rather than accelerated forgetting, and this may reflect an underlying limbic or neurochemical dysfunction. Retrograde amnesia has a basis which is (at least partially) independent of anterograde amnesia--in some patients, it appears to involve a failure to reconstruct past experience from contextual cues, and this may reflect a super-imposed frontal dysfunction. Two types of confabulation are discussed, one of which ('provoked') is a normal response to poor memory, and the other ('spontaneous') appears to reflect incoherent, context-free retrieval, associated with more severe frontal pathology. It is argued that many cases of psychogenic amnesia may resemble organic amnesia, in that they result from an impaired acquisition of information at the time of initial input, perhaps thereby predisposing the subject to subsequent retrieval difficulties.

A Case of Persistent Generalized Retrograde Autobiographical Amnesia Subsequent to the Great East Japan Earthquake in 2011

“…Although the possibility that he suffered from head injury when the earthquake attacked him cannot be excluded, no obvious findings indicative of previous brain trauma were detected by brain MRI. Physical and neurological examinations excluded any other somatic problems associated with organic amnesia [2, 5]. He is fully alert, and no psychiatric disorders associated with amnesic symptoms [2] are indicated.…”

“…The differentiation of psychogenic from organic amnesia is not always easy, as both may be combined [5]. Recently, this dichotomy has been criticized [9, 10], and many researchers refer to the term “functional” to indicate the block of a function, triggered by either physical or psychic trauma [11].…”

When Rey-Osterrieth’s Complex Figure Becomes a Church: Prevalence and Correlates of Graphic Confabulations in Dementia

“…According to this theory, failures in the executive control of retrieval and plausibility judgment, along with disorganization of autobiographical memory, and individual emotional and motivational biases, all contribute to generate a spontaneous confabulation. While some degree of memory impairment seems to be essential [5, 27], frontal dysfunction appears to be frequent [4, 28] but perhaps not necessary and certainly not sufficient [5, 11], at least as far as a general deficit in executive control on retrieval or response monitoring are concerned. Recently, a more specific frontal deficit causing confabulating retrieval has been proposed, operating in conjunction with memory impairment [29].…”

“…So far, there is no universally accepted definition for confabulations, but recently Metcalf et al [3] defined them as ‘statements or actions that involve distortions of memories’ and explained them as a consequence of deficits of memory and executive control of retrieval. A traditional distinction is made between ‘spontaneous’ confabulations, when subjects produce untrue stories without apparent prompting, and ‘provoked’ confabulations, when subjects try to respond to direct questions probing faulty or imprecise memories [5]. According to this definition, confabulations at neuropsychological tests are to be considered as provoked confabulations.…”

Memory and Self–Neuroscientific Landscapes

“…The end of the 19th century brought a major impetus in diagnosing patients as having “hysteria” [344–351] and a new wave in diagnosing this condition came with the First World War [352]. Nowadays we have various overlapping terms to describe the symptomatology of amnesic conditions without concomitant brain damage: “psychogenic amnesia” [353], “dissociative amnesia” [354], “functional amnesia” [95, 355–358], and “mnestic block syndrome” [164–169] are expressions used partly interchangeably, though there are of course differences between them. “Functional amnesia” implies that the amnesia has a function for the affected—it is a more neutral term and can include patients with and without additional (manifest) brain damage.…”