Autobiographical memory and episodic future thinking after moderate to severe traumatic brain injury

Abstract

Converging evidence suggests that autobiographical memory and episodic future thinking share a common neurocognitive basis. Although previous research has shown that traumatic brain injury (TBI) can impair the ability to remember the personal past, episodic future thinking has not previously been systematically examined within this population. In this study, we examined the ability to remember events in the personal past and the ability to imagine possible events in the personal future in a sample of moderate‐to‐severe TBI patients. We present data on nine patients and nine healthy controls, who were asked to report a series of events that had happened to them in the past and a series of events that might happen to them in the future. Transcriptions were scored according to a reliable system for categorizing internal (episodic) and external (semantic) information. For each event described, participants also completed two modified Autobiographical Memory Questionnaire items to assess self‐reported phenomenal qualities associated with remembering and imagining. In addition, TBI patients underwent neuropsychological assessment. Results revealed that TBI patients recalled/imagined proportionally fewer episodic event‐specific details for both past and future events compared to healthy controls (η2p = 0.78). In contrast, there were no group differences in ratings of phenomenal characteristics. These results are discussed in relation to theories suggesting that remembering and imagining the future are the expression of the same underlying neurocognitive system.

Disruption of temporally extended self-memory system following traumatic brain injury

“…Bach and David, 2006;Nochi, 1998;Tyerman and Humphrey, 1984). This result seems in contrast with a previous TBI study by Rasmussen and Berntsen (2014) reporting a decline in episodic details, but not in semantic details for past and future events, thus, suggesting that the semantic component of SMS was spared in TBI. It was proposed that patients' future thinking could be based on stereotypical and rigid routines, which, in turn, contributed to the behavioral inflexibility and poor goal attainment often associated with TBI.…”

“…This deficit was independent of the difficulties in basic verbal fluency, general semantic skills and speed processing, thus seemingly arguing in favour of a global disruption of the temporally extended SMS in TBI. Simultaneous difficulties in episodic re-experiencing and episodic pre-experiencing, in keeping with our predictions, are indicative of altered mental time travel (Tulving, 2002), mirroring the profile already observed in amnesic clinical populations Hassabis et al, 2007;Maguire et al, 2010), and more recently in non-amnesic ones, such as TBI (Rasmussen and Berntsen, 2014). All these patients generally present the inability to extract sensory-perceptual details from previously experienced events, and to integrate episodic details within the appropriate scenario for future episodic simulations.…”

“…It was suggested that the TBI patients employed ineffective search strategies, which resulted in disruption of retrieval processes, especially regarding specific events. As mentioned before, the previous study by Rasmussen and Berntsen (2014) revealed a deficit of production for episodic details in both past and future time periods in TBI patients compared to controls, but semantic self-knowledge and the mechanisms of deficits were not fully explored.…”

“…According to the literature on AM after TBI (Carlesimo et al, 1998;Coste et al, 2011;Knight and O'Hagan, 2009;Piolino et al, 2007), and the high degree of similarity between recalling the past and imagining the future (Schacter et al, 2008;Suddendorf et al, 2009;Szpunar, 2010), even in TBI (Rasmussen and Berntsen, 2014), we expected deficits in TBI patients for the evocation of both semantic and episodic self-representations regardless of the time period tested (past, recent, future).…”

Alterations in autobiographical memory for a blast event in Operation Enduring Freedom and Operation Iraqi Freedom veterans with mild traumatic brain injury.

“…Moreover, examining the integrity of autobiographical memory more broadly may illuminate how mTBI affects the generation of autobiographical details for experiences that are less salient than the one sampled here. Some studies have demonstrated more pervasive autobiographical memory deficits in moderate to severe TBI (Piolino et al, 2007;Rasmussen & Berntsen, 2014), but little is known about autobiographical memory in mTBI.…”