Monitoring sleep depth: analysis of bispectral index (BIS) based on polysomnographic recordings and sleep deprivation

Abstract

The assessment and management of sleep are increasingly recommended in the clinical practice. Polysomnography (PSG) is considered the gold standard test to monitor sleep objectively, but some practical and technical constraints exist due to environmental and patient considerations. Bispectral index (BIS) monitoring is commonly used in clinical practice for guiding anesthetic administration and provides an index based on relationships between EEG components. Due to similarities in EEG synchronization between anesthesia and sleep, several studies have assessed BIS as a sleep monitor with contradictory results. The aim of this study was to evaluate objectively both the feasibility and reliability of BIS for sleep monitoring through a robust methodology, which included full PSG recordings at a baseline situation and after 40h of sleep deprivation. Results confirmed that the BIS index was highly correlated with the hypnogram (0.89±0.02), showing a progressive decrease as sleep deepened, and an increase during REM sleep (awake: 91.77±8.42; stage N1: 83.95±11.05; stage N2: 71.71±11.99; stage N3: 42.41±9.14; REM: 80.11±8.73). Mean and median BIS values were lower in the postdeprivation night than in the baseline night, showing statistical differences for the slow wave sleep (baseline: 42.41±9.14 vs post-deprivation: 39.49±10.27; p=0.02). BIS scores were able to discriminate properly between deep (N3) and light (N1, N2) sleep. BIS values during REM overlapped those of other sleep stages, although EMG activity provided by the BIS monitor could help to identify REM sleep if needed. In conclusion, BIS monitors could provide a useful measure of sleep depth in especially particular situations such as intensive care units, and they could be used as an alternative for sleep monitoring in order to reduce PSG-derived costs and to increase capacity in ambulatory care.

Validity of an under-mattress sensor for objective sleep measurement in critically ill patients: a prospective observational study

“…Although PSG is the standard objective method for measuring sleep quality and quantity, its technical difficulty, high cost, and intolerability to patients make it impractical for its routine implementation in the ICU [11,12]. Although several studies have sought to report alternative methods of sleep monitoring, they have not yet been established [12][13][14][15]. The Richards-Campbell Sleep Questionnaire (RCSQ) is one of the simplest methods of subjective evaluation [3,12,16] and has been shown to correlate with PSG parameters [17].…”

Effects of dexmedetomidine on sleep quality of patients after surgery without mechanical ventilation in ICU

“…[9] The bispectral index (BIS) can be used as a practical and simplified tool to evaluate natural sleep depth. However, BIS only can be used to identifying stage N3 with satisfactory sensitivity and specificity but is limited by its inability to distinguish REM sleep from wake.…”

Nonpharmacological Interventions for Sleep Promotion on Preterm Infants in Neonatal Intensive Care Unit: A Systematic Review

“…PSG is the gold standard to sleep measurement (Gimenez et al, ), and the included study (Welcha et al, ) showed that family nurturing can increase frontal brain activity during sleep, which can help to understand the mechanism of the intervention more clearly. However, few studies used this objective sleep measurement in this review.…”