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

Abstract

Study objectives:To determine the polysomnography characteristics during sleep paralysis, false awakenings and lucid dreaming (which are states intermediate to REM sleep and wake but exceptionally observed in sleep laboratory). Methods:In 5 subjects, 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 three seconds mini-epochs) and spectral EEG analysis were compared during these episodes and normal REM sleep as well as wakefulness in the same four among these five subjects, and vs. lucid REM sleep in four other patients with narcolepsy.Results: During episodes of sleep paralysis, 70.8 % of mini-epochs contained theta EEG 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 EEG 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 EEG 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. 4 BRIEF SUMMARYCurrent Knowledge/Study Rationale: Sleep paralysis is commonly viewed as an awake brain with a complete muscle atonia, but EEG analysis during sleep paralysis is exceptional.Study Impact: Our polysomnography and spectral analysis of time-marked sleep paralyses suggest that the brain during sleep paralysis is not in an awake but in a dreaming state. This may explain why hallucinations are often associated with sleep paralysis.

Dreaming of the sleep lab

“…The specific case of false awakenings, which were very frequent in our study, is also consistent with the suggestion that LIDs are influenced by heightened REM sleep arousal. False awakenings were suggested to be a hyper-aroused REM sleep state [ 48 ], as recently evidenced by spectral EEG analysis [ 49 ]. Moreover, false awakenings frequently occur in association with lucid dreams [ 48 , 50 – 53 ] and sleep paralysis [ 50 , 53 ] both of which have also been proposed to be highly aroused, hybrid states with features of both REM sleep and waking [ 54 , 55 ].…”

Predictive coding, multisensory integration, and attentional control: A multicomponent framework for lucid dreaming

“…Such imbalance between sleep-like and wake-like patterns during sleep appears to be a common denominator of a wider variety of pathological sleep states ( SI Appendix , Table S1 ). In particular, relatively increased wake-like EEG activity was also observed in nightmare disorders ( 66 , 67 ), insomniac complaints ( 68 – 70 ), and sleep paralysis ( 71 , 72 ).…”

“…Besides small population samples, studies featured methodological differences and a small number of scalp recording sites, and they often focused on specific (e.g., alpha) or narrow frequency ranges ( 4 ). The few sleep EEG studies consistently reported reduced sleep regulation signs and to some extent, increased wake-like activity in LD vs. non-LD, such as reduced power ( 71 , 81 , 82 ) and synchrony ( 82 ) in (1- to 4-Hz) low frequencies or increased alpha ( 83 ), parietal beta ( 84 ), or gamma ( 13 ) activity; however, the increase in fast frequencies (beta and gamma) was questioned more recently ( 82 , 85 ). Interestingly, lucid dreams were mainly observed ( 1 ) during phasic REM (i.e., REM periods with increased ocular activity).…”

Nothingness Is All There Is: An Exploration of Objectless Awareness During Sleep

“…Moreover, even while sleeping we are not totally occluded from processing external stimuli and some sleep stages allow more perceptual processing than others. There is also research indicating a connection between the presence of altered states of consciousness during sleep, such as pre-lucid dreams (Tyson et al, 1984), sleep onset hallucinations (Takeuchi et al, 1994), sleep paralysis and false awakenings (Mainieri et al, 2020), and higher levels of alpha activity, which in turn has been linked to more external sensory perception (Tyson et al, 1984;Conduit et al, 1997;Darracq et al, 2018). Thus, we could speculate that during the state described by our participants, there was some integration of external stimuli which could have given place to some of the characteristic "Non-modal sensations" reported, such as those involving what could be considered as esoteric or mystical-like elements like "feeling the nothingness" or a "felt inner sound" (elements that could be taken to go above or beyond the realm of "reality" or what is possible in the natural world).…”