Exit light, enter night: Investigating sleep and long-term memory in SDAM

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Stephanie Simpson^1,2 (stephanie.simpson@mail.utoronto.ca), Daniel Baena Pérez^3,4, Brian Murray^5,6, Stuart Fogel^3,4, Brian Levine^2,5; ¹Department of Psychology, University of Toronto, Toronto, ²Rotman Research Institute at Baycrest Health Sciences, Toronto, ³School of Psychology, University of Ottawa, Ottawa, ⁴Sleep Research Unit, The Royal's Institute of Mental Health Research, Ottawa, ⁵Department of Medicine (Neurology), University of Toronto, Toronto, ⁶Division of Neurology, Sunnybrook Health Sciences Centre, Toronto

Severely Deficient Autobiographical Memory (SDAM) is a developmental syndrome whereby healthy individuals lack subjective re-experiencing of episodes from their past, although factual learning and everyday functioning is intact. Comparison of autobiographical memory recall across groups is hampered by lack of control over memory selection. In the present study, participants with SDAM and matched comparison participants (N = 9 per group) completed an audio-guided, staged museum-like tour of artworks and installations at Baycrest Hospital. True/ False recognition memory for the sequences (order) and features (perceptual details) of tour items was serially tested via four independent online recognition memory tests across time (immediately, 12 hours, 1 week, 1 month). The neural correlates of sleep-related memory transformation were examined by overnight polysomnography between the first two assessments, yielding measures of sleep macrostructure (duration) and microstructure (spindles, slow-waves, phase coupling). People with SDAM had normal or higher memory performance over the first two test sessions, including sleep-related mnemonic enhancement, followed by a steep decline after one week, especially for sequence memory. This mirrors prior findings in which autobiographical memory deficits in SDAM were most reliably observed for remote time periods. We did not observe any significant group differences in sleep neurophysiology. These results suggest that the mnemonic impairment of SDAM is characterized by accelerated forgetting following intact initial processing of real-life events.

Topic Area: LONG-TERM MEMORY: Episodic