Karen Konkoly’s research while affiliated with Northwestern University and other places

Nightmares are a common symptom in narcolepsy that has not been targeted in prior clinical trials. This study investigated the efficacy of Cognitive Behavioural Therapy for Nightmares (CBT‐N), adapted for narcolepsy, in a small group of adults. Given the high prevalence of lucid dreaming in narcolepsy, we added a promising adjuvant component, targeted lucidity reactivation (TLR), a procedure designed to enhance lucid dreaming and dream control. Using a multiple baseline single‐case experimental design, adults with narcolepsy and frequent nightmares (≥3/week, N = 6) were randomised to a 2 or 4 week baseline and received seven treatment sessions (CBT‐N or CBT‐N + TLR). Across the groups, there was a large effect size (between‐case standardised mean difference [BC‐SMD] = −0.97, 95% CI −1.79 to −0.14, p < 0.05) for reduced nightmare frequency from baseline (M = 8.38/week, SD = 7.08) to posttreatment (M = 2.25/week, SD = 1.78). Nightmare severity improved significantly with large effect sizes on sleep diaries (BC‐SMD = −1.14, 95% CI −2.03 to −0.25, p < 0.05) and the Disturbing Dream and Nightmare Severity Index ( z = −2.20, p = 0.03, r = −0.64). Treatment was associated with a reduction for some participants in sleep paralysis, sleep‐related hallucinations, and dream enactment. NREM parasomnia symptoms ( z = −2.20, p = 0.03, r = −0.64) and self‐efficacy for managing symptoms ( z = −2.02, p = 0.04, r = −0.58) improved significantly with large effect sizes. Participants who underwent TLR ( n = 3) all recalled dreams pertaining to their rescripted nightmare. In interviews, participants noted reduced shame and anxiety about sleep/nightmares. This study provides a proof of concept for the application of TLR as a therapeutic strategy with clinical populations, as well as preliminary evidence for the efficacy of CBT‐N in treating narcolepsy‐related nightmares.

In regard to the paired associate learning task (PAL) conducted in experiment 1, Rhodes asks why day 6 and 7 results were separated. Our decision to analyze the learning performance on day 6 separately from the overnight change (day 7–6) stems from the fact that we wanted to examine the effects of sleep prior to learning on encoding [1–5], without including the effects of subsequent sleep on consolidation [6–10]. Our participants encoded-word pairs on day 6 of the eye mask manipulation, and then underwent an immediate performance test on all learned pairs which provided a clean measure of the impact of the manipulation on their encoding. We then re-tested them on these same word pairs on day 7 after a night of consolidation across sleep, again with eye mask, or control mask. Day 7 performance was therefore influenced both by having been tested on day 6 (allowing re-encoding) and by the impact of overnight consolidation and did not provide a clean measure of encoding. We did, however, use these data to examine the impact of the eye mask on overnight change (day 7–6), as reported in the manuscript and noted by Rhodes.

Electroencephalography (EEG) studies of dreaming are an integral paradigm in the study of neurocognitive processes of human sleep and consciousness, but they are limited by the number of observations that can be collected per study. Dream studies also involve substantial methodological and conceptual variability which poses problems for the integration of results. To address these issues, we present the DREAM database—an expanding collection of standardized datasets on human sleep EEG combined with dream report data—with an initial release of 18 datasets, totaling 2331 data points. Each datum consists, at minimum, of sleep electroencephalography (≥20 s, ≥100 Hz, ≥2 electrodes) up to the time of waking and a standardized dream report classification of the subject’s reported sleep experience. This database will provide access to a larger pool of data than any single research group can collect and increase the statistical power of studies focusing on the neural correlates of dreaming. It will also provide useful criteria for methodological choices in future dream laboratory research projects.

Ambient light can influence sleep structure and timing. We explored how wearing an eye-mask to block light during overnight sleep impacts on memory and alertness, changes that could benefit everyday tasks like studying or driving. In Experiment 1, ninety-four 18–35-year-olds wore an eye-mask while they slept every night for a week and underwent a control condition in which light was not blocked for another week. Five habituation nights were followed by a cognitive battery on the sixth and seventh days. This revealed superior episodic encoding and an improvement on alertness when using the mask. In Experiment 2, thirty-five 18–35-year-olds used a wearable device to monitor sleep with and without the mask. This replicated the encoding benefit and showed that it was predicted by time spent in slow wave sleep. Our findings suggest that wearing an eye-mask during overnight sleep can improve episodic encoding and alertness the next day.

Memories of waking-life events are incorporated into dreams, but their incorporation is not uniform across a night of sleep. This study aimed to elucidate ways in which such memory sources vary by sleep stage and time of night. Twenty healthy participants (11 F; 24.1 ± 5.7 years) spent a night in the laboratory and were awakened for dream collection approximately 12 times spread across early, middle, and late periods of sleep, while covering all stages of sleep (N1, N2, N3, REM). In the morning, participants identified and dated associated memories of waking-life events for each dream report, when possible. The incorporation of recent memory sources in dreams was more frequent in N1 and REM than in other sleep stages. The incorporation of distant memories from over a week ago, semantic memories not traceable to a single event, and anticipated future events remained stable throughout sleep. In contrast, the relative number of recent versus distant memory sources changed across the night, independently of sleep stage, with late-night dreams in all stages having relatively more remote memory sources than dreams earlier in the night. Qualitatively, dreams tended to repeat similar themes across the night and in different sleep stages. The present findings clarify the temporal course of memory incorporations in dreams, highlighting a specific connection between time of night and the temporal remoteness of memories. We discuss how dream content may, at least in part, reflect the mechanisms of sleep-dependent memory consolidation.