Anosognosia for Amnesia in Dementia

The featured paper is ‘Anosognosia for Amnesia as a Clue to Understand the Nature of Dementia’ by Atsushi Yamadori and freely available here. The paper is slightly unusual in that it combines observations of people with dementia, with a brief review of the literature and exposition of a speculative hypothesis on the relationship between consciousness and dementia.

The initial section of the article describes the authors observations of people with dementia at the same time as drawing inferences from these observations. In this sense, the paper reminded me of some of the early psychoanalytic papers where the subject’s speech, thoughts and dreams are described for the reader in detail before the outline of the theory extrapolated from these inferences. Yamadori describes his personal observations of people with dementia, noting that the presentation would vary from day to day and the manner in which questions were addressed to the person. Thus Yamadori argues that by phrasing questions or conversation in a particular way, a clear response is elicited. However this area of investigation can be addressed through the use of qualitative research methodology.

Yamadori discusses anosognosia for amnesia, the inability to recognise memory and how this is affected in different conditions. Thus he suggests that in ‘Global Confusion’ there is no insight, in clear consciousness there is awareness of amnesia and in ‘apparently clear but mildy confused consciousness’ the person is ‘unaware of amnesia’ and that there is a temporal progression from global confusion through mildly confused consciousness to clear consciousness. The terms used are vague. For instance we might ask if global confusion is equivalent to a delirium in which case there are operationalised definitions and a reference to diagnostic classifications within the article would be appropriate.

Yamadori then goes onto suggest that consciousness is a self-referential emergent system with the person being aware of their ‘mental contents’. By ‘mental contents’, Yamadori is referring to psychological constructs such as memory and attention. Interestingly the discussion about emergent properties of  a system was one of the main areas of focus by Niall MacLaren in his book ‘Humanizing Madness’ in which he argues that the ‘mind’ is not an emergent property but is intead an intended product of the biology.

Yamadori suggest that consciousness is intact even if there is an impairment in a mental capacity, if the person is aware of this impairment. As the awareness of an impairment is equivalent to insight, Yamadori is in effect saying that consciouness is associated with intact insight. However insight itself is dependent upon a person’s understanding of health and illness. Therefore we could argue on this basis that learning about non-scientific models of psychological functioning could lead to an impairment of consciousness which doesn’t make sense intuitively. When discussions turn to consciousness, things get a little difficult if there isn’t a tight definition, as the ambiguity of the concept is sufficient to allow many possible interpretations.

Despite all of the reservations outlined above, Yamadori does in the conclusion come up with an interesting suggestion, namely that as the number of functional mental contents decreases so consciousness has access to fewer mental contents. Consciousness builds a consistent representation from the remaining functions and it is this completion that causes a person to lose insight into amnesia. In Freudian terms a variation on this argument could be used. Thus amnesia would be likely to lead to anxiety and therefore, a defence is used in the form of denial. However from a biological perspective we could also argue that if certain modules for specific functions are not available, neither is the corresponding ability to have associated experiences. Thus if the visual cortex is affected then we should not be able to experience colours (depending on the part affected), motion or form etc. An interesting debate that occurs in this area is whether the brain region itself is required for this experience or a separate area where the memories are stored e.g. the hippocampus. Returning to Yamadori’s point though and adapting it slightly, could our mind be bringing different experiences together in a structured way to build a self-consistent representation of the world. Quite possibly. There is something to be said for a paper such as this which moves quickly through many different areas, in each area possibly too quickly, but in the end coming up with an interesting insight that is the result of this journey.

Steps to Treatment = 6 (Further evidence incorporated into model, testable model created, experimental testing, appropriate theoretically informed intervention created, intervention tested successfully (or not), incorporation into policy)


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The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.


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