Who am I: Sense of self in individuals with sudden-onset episodic amnesia

Abstract

Although there is an indisputable relationship between autobiographical memory (AM) and sense of self (SOS), there is still debate concerning the role of episodic and semantic forms of AM in SOS, both in the present moment and over time. In order to assess how episodic AM impairment may differentially affect aspects of SOS, this thesis aimed to examine the SOS of three individuals with varying degrees of sudden-onset episodic amnesia, which is characterised by impaired episodic AM and relatively preserved semantic AM. First, the cases were compared to matched healthy controls on the Autobiographical Interview (AI) to assess the degree of episodic AM impairment. Second, to assess different aspects of SOS we used fine-grained measures that capture various dimensions of self-concept (i.e., objective SOS in the present moment), as well as self continuity, specifically phenomenological continuity (i.e., subjective SOS over time), and two forms of semantic continuity (i.e., objective SOS over time): temporally-extended trait self-knowledge and narrative continuity. Additionally, we measured retrieval of turning point events (i.e., specific events that impact one’s life), since previous research suggest these may be related to coherence of one’s life narrative. Overall, the cases’ impairments in self-concept and all forms of continuity differed based on the degree of their episodic AM impairment. The case with the least amount of episodic AM impairment exhibited intact self-concept and phenomenological continuity, while the two cases with the more severe episodic AM impairments exhibited reductions in both their strength of self-concept and phenomenological continuity. Furthermore, while all three cases exhibited accurate current self-knowledge, one showed reduced accuracy of temporally-extended trait self-knowledge. While the cases were able to identify turning point events, in two of the cases, the quality of their turning point events differed from controls. Lastly, although all three cases exhibited reduced narrative continuity to some extent, they all maintained their ability to perceive themselves as the same person over time (i.e., diachronic unity). Crucially, the current study demonstrates although episodic AM affects one’s SOS in complex ways, one’s SOS can still persist despite these impairments.