In the past when scholars have reflected on the psychological impact of dementia they have frequently referred to the loss of the “self” in dramatic and devastating terms, using language such as the “unbecoming of the self” or the “disintegration” of the self. In a new review released as a preprint at PsyArXiv, an international team of psychologists led by Muireann Irish at the University of Sydney challenge this bleak picture which they attribute to the common, but mistaken, assumption “that without memory, there can be no self” (as encapsulated by the line from Hume: “Memory alone… ‘tis to be considered… as the source of personal identity”).
In their review, Irish and her colleagues, including doctoral candidate and lead author Cherie Strikwerda-Brown, present a more optimistic perspective based on their analysis of the research literature on autobiographical memory loss in people with Alzheimer’s Disease, people with Semantic Dementia, and others with Frontotemporal Dementia. “Overall,” they write, “… the self is not entirely lost in dementia, with distinct elements of preservation emerging contingent on life epoch and dementia syndrome”.
Central to the authors’ argument is that our autobiographical memories, upon which our sense of self is based, are made up of two interdependent elements: the episodic (the subjective sense of having experienced past events) and the semantic (a factual knowledge of what happened), certain aspects of which are to some extent spared across different types of dementia and different epochs of one’s life.
In people with dementia of the Alzheimer’s type, they explain that there is often (especially in the early to moderate stages of the illness) a sparing of autobiographical knowledge, particularly from earlier in life. Specifically, so-called “general event memories” are spared, such as remembering “I used to go dancing on Fridays” or “I used to work as a teacher in my twenties and thirties” – even though a subjective sense of having lived those past experiences is lost. Irish and her colleagues say that this preserved semantic knowledge, including of one’s own traits and preferences, can provide a sense of “narrative self-continuity” and helps explain why social abilities can remain relatively intact for many years after a diagnosis of Alzheimer’s.
That’s not to say there are no problems with the sense of self: “They [people with Alzheimer’s] may display an out of date self-schema, in that ‘who I was’ becomes ‘who I am’, and this non-updated framework governs their everyday behaviour,” the authors write, pointing to anecdotal cases of people with Alzheimer’s acting out roles from earlier in their lives, such as believing they are still a nurse (rather than retired) or a mother (rather than grandmother).
Conversely, Irish and her colleagues explain how people with Semantic Dementia lose much of their factual knowledge about themselves, especially from their more distant past, while they retain their recent, subjectively experienced episodic memories, especially for the last year or so.
These first-hand experiential memories for recent lived experiences – together with a general, temporally unspecified knowledge of the kind of events they experience frequently – can provide another basis for a consistent sense of self, albeit one that is largely rooted in the present and recent past. In turn, this time-limited sense of self may help explain the rigid behaviours and routines often observed in people with Semantic Dementia – a preference for wearing the same clothes, for instance, and always going to the same places at the same time of week.