Browsing by Author "Dodge, Neil"

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    Exploring the Role of REM Sleep in Emotional Memory Consolidation amongst young adults with Fetal Alcohol Spectrum Disorder (FASD)
    (2026) Pillay, Thumira; Lipinska, Malgorzata; Thomas, Kevin; Jacobson, Joseph; Jacobson, Sandra; Dodge, Neil
    Background: Fetal alcohol spectrum disorder (FASD) is the leading preventable cause of neurocognitive deficits, with high prevalence rates in the Western Cape of South Africa. Among the critical impairments associated with FASD, disruptions in sleep and emotional memory are areas that remain underexplored in this population. Rapid eye movement (REM) sleep, both in terms of macrostructure and microstructure, plays a vital role in emotional memory consolidation. This study investigated the impact of REM sleep on emotional memory consolidation in young adults with prenatal alcohol exposure (PAE). The study characterises, for the first time, the disruption of REM sleep and emotional memory consolidation in this adult clinical group. The study also explored associations between REM sleep and emotional memory in those with and without PAE. Methods: 75 young adults (20-24) with fetal-alcohol syndrome/partial fetal-alcohol syndrome (FAS/PFAS; n=25), heavily exposed (HE; n=21); and controls (n=29), participated in the study. Participants completed the South African Affective Pictorial Scale (SA-APS) emotional memory task before and after an 8-hour sleep period. Emotional memory was assessed using false recognition (false alarm rates), correct recognition (hit rates), and recognition memory accuracy (d'). Change scores for each emotional memory variable were calculated to describe to what extent emotional memory parameters had improved or declined over a period of sleep. Polysomnographic measures (PSG) were used to measure various components of REM sleep, including its duration, proportion of total sleep, sleep onset latency, fragmentation (arousals), and relative theta power. Results: Individuals with FASD demonstrated a clear dose-dependent effect on REM onset and theta power, with a larger effect observed on theta. Those with FAS/PFAS showed shorter REM onset and less theta power. Across the entire cohort, increased sleep fragmentation was observed because of alcohol consumption, with group differences contributing to a smaller extent. Alterations in both macro- and microstructural aspects of REM sleep were observed in individuals with PAE. Notably, only non-exposed individuals showed a benefit in emotional memory consolidation, with improved recognition of negative information after sleep compared to before sleep. In contrast, the REM macrostructure was found to influence overall memory consolidation and to moderate the impact of PAE on memory performance. Additionally, REM microstructure specifically played a significant role in emotional memory consolidation, highlighting its importance in the processing of emotionally charged information. Conclusion: This study highlights the role of REM sleep in emotional memory consolidation and sheds light on the detrimental effects of PAE on sleep and memory. My findings indicate that alterations in both the macro- and microstructure of REM sleep in individuals with PAE are associated with significant disruptions in emotional memory consolidation. Specifically, while unexposed individuals showed enhanced recognition of negative emotional stimuli after sleep, this consolidation benefit was absent in the PAE group. The findings emphasize the critical role of REM sleep, particularly theta oscillations, in emotional memory consolidation, suggesting that disruptions in these processes may contribute to the cognitive and emotional challenges experienced by individuals with PAE. My findings present an opportunity to utilise sleep interventions as a tool to improve memory and emotional outcomes in those affected by PAE. Interventions such as improving sleep quality, enhancing REM sleep duration, or utilising cognitive-behavioural therapies targeting sleep could potentially mitigate some of the cognitive and emotional difficulties associated with PAE.