Sleep science (Sao Paulo, Brazil)
January 1, 2022
Ravindra P. Nagendra, Talakad N. Sathyaprabha, Bindu M Kutty
11 citations
Long-term Vipassana meditators show increased slow-wave (N3) and REM sleep compared to non-meditators. Evening cortisol levels are similar between groups, but early morning cortisol, diurnal dehydroepiandrosterone (DHEA), and melatonin are significantly higher in meditators. Diurnal DHEA correlates significantly with N3 sleep in meditators. Higher diurnal DHEA despite comparable cortisol suggests that long-term meditation modulates the hypothalamic-pituitary-adrenal (HPA) axis, influencing sleep architecture. This provides evidence for exploring mindfulness meditation as an intervention for insomnia.
Sleep science (Sao Paulo, Brazil)
January 1, 2022
Michael Raduga
8 citations
During lucid dreams, people can intentionally produce facial muscle activity that corresponds to specific spoken words. Four experienced lucid dreamers, in a laboratory, said the phrase "I love you" while awake and again while lucid dreaming. Electromyographic (EMG) recordings from facial and neck muscles showed that the "I" sound triggered distinctive activity in the submentalis area, while "you" did so in the orbicularis oris, both during wakefulness and during the dream. The patterns were observed in most cases, suggesting that only highly distinctive, EMG-signature phrases can be detected from dream vocalizations. This indicates the possibility of creating an artificial EMG language for real-time decoding during lucid dreams.
Sleep science (Sao Paulo, Brazil)
December 1, 2023
Michael Raduga, Andrey Shashkov
1 citation
Lucid dreaming occurs when metacognition arises during REM sleep. Standard verification requires multiple sensors. Researchers hypothesized that preagreed frontalis movements (PAFMs)—raising the eyebrows three times—could be seen on a single EEG sensor. Five volunteers induced lucid dreams and signaled using both standard eye movements and PAFMs. All participants sent signals from eight lucid dreams. PAFMs were equally distinctive on most EEGs but depended on accurate instruction, exhibited two EEG patterns, and caused immediate awakening when the dream was unstable. PAFMs are less consistent than eye movements but can verify lucid dreaming with only one EEG sensor when polysomnography is unavailable.
Sleep science (Sao Paulo, Brazil)
December 1, 2023
Julia Ribeiro Da Silva Vallim, Gabriela Sant'Ana Lima, Gabriel Natan Pires et al.
Mindfulness-based interventions can reduce anxiety, depression, and chronic pain, but their effect on sleep is not well established. Sleep can be measured subjectively (questionnaires, logs) or objectively (actigraphy, polysomnography). A review of 193 articles found that most studies (78%) used only subjective sleep measures, which show higher variability and uncertainty and moderate to nonexistent agreement with objective measures. This reliance on subjective assessment may create a misperception about mindfulness effects on sleep. Future research should emphasize objective measurements while acknowledging that subjective measures remain useful for some aspects of the sleep-mindfulness relationship.
Sleep science (Sao Paulo, Brazil)
December 1, 2024
Deenadayalan Boopalan, Venugopal Vijayakumar, Govindasamy Karuppasamy et al.
Cyclic meditation (CM), a practice combining physical postures with relaxation techniques, appears to improve sleep quality. A review of five studies involving 277 participants in India found CM effective, with effect sizes ranging from 0.56 to 4.90. The studies included healthy volunteers, people with type 2 diabetes, alcohol dependence, and caregivers of special needs children. The evidence suggests CM can enhance sleep, but more rigorous randomized controlled trials are needed before it can be strongly recommended as a standalone intervention for sleep disturbance.
Sleep science (Sao Paulo, Brazil)
December 1, 2023
Ann Marie Wagner, Anne Richards, Christine Chiros et al.
A brief intervention combining imagery rehearsal therapy with narrative therapy principles reduced nightmare frequency and intensity in eight veterans with PTSD-related nightmares. After a single 60-minute rescripting session and four weeks of homework, participants reported significant decreases in nightmare frequency and intensity, along with improvements in nightmare distress, coping, sleep quality, and overall PTSD symptoms. These pilot results suggest the approach is effective for veterans, though larger controlled trials are needed to confirm effectiveness.
Sleep science (Sao Paulo, Brazil)
March 1, 2023
William E. Kelly
Nightmare proneness—a stable tendency to have frequent nightmares—and general psychological distress are distinct but related constructs. In a cross-sectional study of 254 young adults, nightmare proneness remained linked to nightmares, nightmare distress, cardiac symptoms, sleep fragmentation, perceived physical health, perceived stress, and Type-D personality even after controlling for psychological distress. Conversely, distress remained connected only to perceived stress and Type-D personality after controlling for nightmare proneness. Nightmare distress, physical health, and nightmare proneness predicted cardiac symptoms, while posttraumatic nightmares, sleep fragmentation, distress, perceived stress, Type-D personality, and chest pain predicted nightmare proneness. These results support the idea that nightmare proneness involves hyperarousal, vulnerability to stressors, and concretization of vague internal states.
Sleep science (Sao Paulo, Brazil)
January 1, 2021
Sudheer Tale, Akash Kumar, Lokesh Kumar Saini et al.
A 42-year-old man with a past psychotic episode presented with recurrent sleepwalking and prolonged incomplete sleep paralysis. Polysomnography showed moderate obstructive sleep apnea and alpha wave intrusion during sleep. His medications (divalproate 1000 mg/day and olanzapine 5 mg/day) were tapered and discontinued. Symptoms improved with clonazepam 0.5 mg at bedtime, even without CPAP compliance.
Sleep science (Sao Paulo, Brazil)
January 1, 2019
Michael Schredl, Anja S Goeritz
Nightmare distress—the sleep or mood disturbances that make nightmares a clinical problem—depends on more than just how often nightmares occur. A survey of 2,492 adults found that heightened emotional reactivity, measured as neuroticism, contributes to global nightmare distress, supporting the neurocognitive model of Levin and Nielsen (2007). Recurring nightmares linked to a waking-life event were associated with even higher distress. The authors suggest future research use diagnostic interviews to better understand nightmare disorder and its related variables.