The neurophysiological basis of the discrepancy between objective and subjective sleep during the sleep onset period: an EEG-fMRI study

Abstract

Subjective perception of sleep is not necessarily consistent with electroencephalography (EEG) indications of sleep. The mismatch between subjective reports and objective measures is often referred to as "sleep state misperception." Previous studies evince that this mismatch is found in both patients with insomnia and in normal sleepers, but the neurophysiological mechanism remains unclear. The aim of the study is to explore the neurophysiological basis of this mechanism, from the perspective of both EEG power and functional magnetic resonance imaging (fMRI) fluctuations. Thirty-six healthy young adults participated in the study. Simultaneous EEG and fMRI recordings were conducted while the participants were trying to fall asleep in an MRI scanner at approximately 9:00 pm. They were awakened after achieving stable N1 or N2 sleep, or after 90 min without falling into stable sleep. Next they were asked to recall their conscious experiences from the moment immediately prior to awakening. Sixty-one instances of scheduled awakenings were collected: 21 of these after having achieved stable stage N2 sleep; 12, during stage N1 sleep; and, 20 during the waking state. Relative to those awakenings without subjective-objective discrepancy (n = 27), these awakenings with discrepancy (n = 14) were associated with lower θ power, as well as higher α, β, and γ power. Moreover, we found that participants who exhibited the discrepancy, compared with those who did not, evinced a higher amplitude of low-frequency fluctuation levels in the prefrontal cortex. These results lend support to the conjecture that the subjective-objective discrepancy is associated with central nervous system hyperarousal.

Analysis of Clinical Characteristics and Polysomnography Indicators of Obstructive Sleep Apnea–Hypopnea Syndrome Patients Based on Sleep Perception Types

“…We assume that the transitions of sleep cycle affect sleep perception, and the judgment of sleep cycles is accomplished through EEG activity. Previous studies have found that there is a connection between sleep perception and EEG, which reflects that the amplitude of low-frequency waves in the prefrontal cortex of negative sleep perception patients is higher than that of the normal control group, and the activity of alpha wave and gamma wave is strengthened (18). In 1982, MG Terzano et al proposed an alternating pattern of EEG circulation during sleep, which is a periodic EEG change in NREM sleep.…”

How Does Fitbit Measure Brainwaves

“…The discrepancy between the two is often referred to as "sleep state misperception" [36]. Such misperception commonly exists among healthy adults [40] but could be more pronounced in pregnant women [76] and in clinical populations with Alzheimer disease, depression and sleep problems [38,44,62,71,87]. As we will show later in the findings, the discrepancy between objective measurements and subjective sleep experience adds an extra layer of complexity for participants to assess the credibility of sleep data.…”

“…Regardless of measuring the same phenomenon, subjective sleep quality and objective sleep quality are only moderately correlated [40,90]. The discrepancy between the two is often referred to as "sleep state misperception" [36].…”

“…For sleep stages, on the other hand, many participants tended to judge the credibility of the unperceivable objective measures based on subjective sleep satisfaction-something they were certain of. Even though the correlations between subjective feeling and objective measures are typically only moderate [40,90], many participants assumed a proportional relationship between how restorative they felt about their sleep and the ratio of deep sleep. Consequently, they questioned the believability of extremely low ratio of deep sleep indicated by the medical report and favored data from consumer devices that showed a higher ratio.…”

Can spectral power predict subjective sleep quality in healthy individuals?

“…Interestingly, the positive effect of slow wave sleep on memory retention is also attenuated in older individuals (Cherdieu, Reynaud, Uhlrich, Versace, & Mazza, ), supporting the hypothesis of a change in the function of slow waves. Increased alpha power in sleep, on the other hand, has previously been identified as a marker of poor sleep quality/sleep state misperception in younger adults (Hsiao et al., ). It would be interesting for further research to investigate whether our finding that this relationship seems to be absent in older adults can be replicated.…”