ArticleFrontiers in human neuroscience2022
EEG Lempel-Ziv complexity varies with sleep stage, but does not seem to track dream experience.
Article in Frontiers in human neuroscience, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
17 citing papers in PubMed, 1 synthesis or guideline pooled it.
- The Caffeinated Brain Part 2: The Effect of Caffeine on Sleep-Related Electroencephalography (EEG)-A Systematic and Mechanistic Review.Nutrients · 2026Pooled it
- The entropic brain today.Brain : a journal of neurology · 2026Review
- Cognitive Processing and EEG Complexity.Entropy (Basel, Switzerland) · 2026Review
- Temporal signatures of thought-neurodynamics distinguish on- and off-task thoughts.Communications biology · 2026Article
- Electrophysiological effects of psilocybin co-administered with midazolam.Translational psychiatry · 2026Article
- State-Dependent CNN-GRU Reinforcement Framework for Robust EEG-Based Sleep Stage Classification.Biomimetics (Basel, Switzerland) · 2026Article
- Rapid eye movement sleep displays distinct fractal dynamics between phasic and tonic states.Neuroscience of consciousness · 2026Article
- "Awe-scillations": EEG spectral and complexity representations of awe.bioRxiv : the preprint server for biology · 2025Article
- Forehead and In-Ear EEG Acquisition and Processing: Biomarker Analysis and Memory-Efficient Deep Learning Algorithm for Sleep Staging with Optimized Feature Dimensionality.Sensors (Basel, Switzerland) · 2025Article
- Two-Dimensional Image Lempel-Ziv Complexity Calculation Method and Its Application in Defect Detection.Entropy (Basel, Switzerland) · 2025Article
- A repeated awakening study exploring the capacity of complexity measures to capture dreaming during propofol sedation.Scientific reports · 2025Article
- Entropy of difference works similarly to permutation entropy for the assessment of anesthesia and sleep EEG despite the lower computational effort.Journal of clinical monitoring and computing · 2025Article
- We are the Sensors of Consciousness! A Review and Analysis on How Awakenings During Sleep Influence Dream Recall.Nature and science of sleep · 2025Article
- The Constrained Disorder Principle May Account for Consciousness.Brain sciences · 2024Review
- Psychedelics and disorders of consciousness: the current landscape and the path forward.Neuroscience of consciousness · 2024Article
- Altered brain dynamics index levels of arousal in complete locked-in syndrome.Communications biology · 2023Article
- Sensory modality defines the relation between EEG Lempel-Ziv diversity and meaningfulness of a stimulus.Scientific reports · 2023Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
In a recent electroencephalography (EEG) sleep study inspired by complexity theories of consciousness, we found that multi-channel signal diversity progressively decreased from wakefulness to slow wave sleep, but failed to find any significant difference between dreaming and non-dreaming awakenings within the same sleep stage (NREM2). However, we did find that multi-channel Lempel-Ziv complexity (LZC) measured over the posterior cortex increased with more perceptual ratings of NREM2 dream experience along a thought-perceptual axis. In this follow-up study, we re-tested our previous findings, using a slightly different approach. Partial sleep-deprivation was followed by evening sleep experiments, with repeated awakenings and immediate dream reports. Participants reported whether they had been dreaming, and were asked to rate how diverse, vivid, perceptual, and thought-like the contents of their dreams were. High density (64 channel) EEG was recorded throughout the experiment, and mean single-channel LZC was calculated for each 30 s sleep epoch. LZC progressively decreased with depth of non-REM sleep. Surprisingly, estimated marginal mean LZC was slightly higher for NREM1 than for wakefulness, but the difference did not remain significant after adjusting for multiple comparisons. We found no significant difference in LZC between dream and non-dream awakenings, nor any significant relationship between LZC and subjective ratings of dream experience, within the same sleep stage (NREM2). The failure to reproduce our own previous finding of a positive correlation between posterior LZC and more perceptual dream experiences, or to find any other correlation between brain signal complexity and subjective experience within NREM2 sleep, raises the question of whether EEG LZC is really a reliable correlate of richness of experience as such, within the same sleep stage.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.