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. 2021 Apr 1;17(4):719-727.
doi: 10.5664/jcsm.9056.

Are sleep paralysis and false awakenings different from REM sleep and from lucid REM sleep? A spectral EEG analysis

Greta Mainieri  1   2 , Jean-Baptiste Maranci  1   3   4 , Pierre Champetier  1   4   5 , Smaranda Leu-Semenescu  1 , Ana Gales  1 , Pauline Dodet  1 , Isabelle Arnulf  1   3   4
Affiliations

Are sleep paralysis and false awakenings different from REM sleep and from lucid REM sleep? A spectral EEG analysis

Greta Mainieri et al. J Clin Sleep Med. .

Abstract

Study objectives: To determine the polysomnography characteristics during sleep paralysis, false awakenings, and lucid dreaming (which are states intermediate to rapid eye movement [REM] sleep and wake but exceptionally observed in sleep laboratory).

Methods: In 5 participants, we captured 5 episodes of sleep paralysis (2 time marked with the ocular left-right-left-right code normally used to signal lucid dreaming, 1 time marked by an external noise, and 2 retrospectively reported) and 2 episodes of false awakening. The sleep coding (using 3-second mini-epochs) and spectral electroencephalography analysis were compared during these episodes and normal REM sleep as well as wakefulness in the same 4 of 5 participants and vs lucid REM sleep in 4 other patients with narcolepsy.

Results: During episodes of sleep paralysis, 70.8% of mini-epochs contained theta electroencephalography rhythm (vs 89.7% in REM sleep and 21.2% in wakefulness), 93.8% contained chin muscle atonia (vs 89.7% in REM sleep and 33.3% in wakefulness), and 6.9% contained rapid eye movements (vs 11.9% in REM sleep and 8.1% in wakefulness). The electroencephalography spectrum during sleep paralysis was intermediate between wakefulness and REM sleep in the alpha, theta, and delta frequencies, whereas the beta frequencies were not different between sleep paralysis and normal REM sleep. The power spectrum during false awakening followed the same profile as in sleep paralysis.

Conclusions: The predominant theta electroencephalography rhythm during sleep paralysis and false awakenings (with rare and lower alpha rhythm) suggests that the brain during sleep paralysis is not in an awake but in a dreaming state.

Keywords: REM sleep; false awakenings; sleep paralysis.

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Conflict of interest statement

All authors have seen and approved this manuscript. The authors report no conflicts of interest.

Figures

Figure 1
Figure 1. An episode of sleep paralysis.
An episode of sleep paralysis signaled by the left–right–left–right (LRLR ocular coding, vertical arrow) horizontal eye movements (the same code is often used to signal lucid dreaming in lucid dreamers), with clear theta rhythms on the EEG, as shown here in a 30-second epoch of polysomnography. From top to bottom, EEG (Fp1/A2, C3/A2, and C3/O1 channels with their filters and amplitudes), electro-oculography (EOG 1: right superior canthus/A2; EOG2: left inferior canthus/A2) and electromyography (EMG1). Green vertical lines rule every second of clock time. EEG = electroencephalography, REM = rapid eye movement.
Figure 2
Figure 2. Polysomnography monitoring during a 5-minute episode of sleep paralysis.
The upper part of the figure displays the neurophysiological channels of a single 30-second epoch, corresponding below to the period shown in black brackets (from top to bottom; EEG channels in black color, Fp1/A2, C3/A2 and O1/; EOG right and left in red color, and EMG of the chin (green) and right and left tibialis anterior (purple); the lower part correspond to 5 min of the respiratory and heart monitoring during the full episode of sleep paralysis, with corresponding visible events in black boxes. EEG = electroencephalography, EOG = electro-oculography.
Figure 3
Figure 3. Global EEG power spectrum.
Global EEG power spectrum during 5 episodes of sleep paralysis (SP, black line) vs wakefulness (red line) and REM sleep (blue line) in 3 patients; during 2 episodes of false awakening (FA, green line) vs REM sleep (blue line) and wakefulness (red line) in two patients (B); during lucid REM sleep (orange line) vs REM sleep (blue line) and wakefulness (red line) in 5 other, different patients with narcolepsy (C). EEG = electroencephalography, REM = rapid eye movement.
See this image and copyright information in PMC

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