Contribution of Sleep Disruption to Memory Impairment and Emotion Dysregulation in Fetal Alcohol Spectrum Disorders

ABSTRACT Prenatal alcohol exposure (PAE) is associated with a broad range of adverse and enduring consequences, including impaired learning and memory and altered responses to emotion-laden events (i.e., emotion dysregulation). Although sleep problems are often noted in epidemiological studies and clinical case

reports relating to fetal alcohol spectrum disorders (FASD), they have not been well characterized using objective methodologies, such as polysomnography (PSG). Moreover, no studies have explored possible associations between sleep problems and memory and emotional regulation impairments in FASD. Investigation of these associations is warranted because healthy sleep is known to play a critical role in the

consolidation of newly-acquired declarative memories and to attenuate emotional reactivity to affectively- valenced stimuli. The proposed study will be the first to investigate sleep architecture and its relation to memory consolidation and emotional regulation in FASD. 90 young adults (18-21 yr of age; 30 fetal alcohol

syndrome (FAS) or partial FAS (PFAS), 30 non-syndromal heavily-exposed, and 30 non-exposed controls) will be recruited from PI Sandra Jacobson’s and Co-I Joseph Jacobson’s well-characterized Cape Town, South Africa, FASD cohort, which has been followed longitudinally since infancy. The data will be collected

in PI Thomas’s Sleep Sciences Laboratory at the University of Cape Town. Cape Town is an excellent venue for this study given the unusually large number of individuals with heavy PAE and FAS available at a single site and the availability of a state-of-the-art PSG-equipped laboratory. Sleep data will be obtained

over three consecutive nights. The 1st (adaptation) night will allow participants to acclimate to the sleep laboratory’s environment and to sleeping with monitoring equipment attached. Sleep on the 2nd night will be preceded by learning trials of standard declarative memory tests, which have been found to be affected by

PAE, and will be followed in the morning by delayed recall trials. This procedure will allow us to examine associations between sleep disruption and memory consolidation. Sleep on the 3rd night will be preceded by initial viewing of valenced pictures and will be followed in the morning by viewing of the same stimuli.

Psychophysiological measurement during both pre- and post-sleep viewing will allow us to examine associations between sleep disruption and affective arousal/emotion regulation. The aims are (1) to characterize sleep architecture of young adults with FASD; (2) to test the hypothesis that reductions in

slow-wave sleep (SWS) percentage will mediate PAE-related disruptions in memory consolidation; and (3) to test the hypothesis that reductions in rapid eye movement (REM) sleep percentage will mediate PAE- related alterations in emotional reactivity to previously-viewed emotionally-valenced pictures. If the

predicted associations are observed, sleep-based interventions may offer important and novel pathways for addressing deficits in declarative memory and emotion regulation in FASD.