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.