Individual differences in physiologic measures are stable across repeated exposures to total sleep deprivation

Abstract

Some individuals show severe cognitive impairment when sleep deprived, whereas others are able to maintain a high level of performance. Such differences are stable and trait‐like, but it is not clear whether these findings generalize to physiologic responses to sleep loss. Here, we analyzed individual differences in behavioral and physiologic measures in healthy ethnic‐Chinese male volunteers (n = 12; aged 22–30 years) who were kept awake for at least 26 h in a controlled laboratory environment on two separate occasions. Every 2 h, sustained attention performance was assessed using a 10‐min psychomotor vigilance task (PVT), and sleepiness was estimated objectively by determining percentage eyelid closure over the pupil over time (PERCLOS) and blink rate. Between‐subject differences in heart rate and its variability, and electroencephalogram (EEG) spectral power were also analyzed during each PVT. To assess stability of individual differences, intraclass correlation coefficients (ICC) were determined using variance components analysis. Consistent with previous work, individual differences in PVT performance were reproducible across study visits, as were baseline sleep measures prior to sleep deprivation. In addition, stable individual differences were observed during sleep deprivation for PERCLOS, blink rate, heart rate and its variability, and EEG spectral power in the alpha frequency band, even after adjusting for baseline differences in these measures (range, ICC = 0.67–0.91). These findings establish that changes in ocular, ECG, and EEG signals are highly reproducible across a night of sleep deprivation, hence raising the possibility that, similar to behavioral measures, physiologic responses to sleep loss are trait‐like.

Steady-State Pupil Size Varies with Circadian Phase and Sleep Homeostasis in Healthy Young Men

“…According to our results, steady-state pupil size is therefore among the retinal parameters modified with time-of-day, sleep-need, and circadian phase, together with levels of visual pigments, GABA, dopamine, melatonin, visual sensitivity (all reviewed in [45,52]), PLR [13,14], blink rate, or eye opening [54]. The variation in visual sensitivity and PLR may be of importance in the context of our study.…”

Automatic sleep staging using ear-EEG

“…This builds on an assumption that measurements from one night will have similar characteristics to those from a different night. This seems like a reasonable assumption, given the literature [ 22 – 24 ]. As shown in Fig.…”

“…It seems safe to say that it will at the very least be comparable to the ‘Leave-one-out’-scheme described here, but possibly much closer to the ‘Individual’ scheme. Based on studies concerning individual differences in physiological measures during sleep [ 22 – 24 ], it seems likely that intra-subject variability will be low. In this scenario, one could imagine uses where a single night (possibly just a day-time nap) with both PSG and ear-EEG could be used to calibrate a classifier to each individual user.…”

Differential Kinetics in Alteration and Recovery of Cognitive Processes from a Chronic Sleep Restriction in Young Healthy Men

“…Indeed, the ability to cognitively resist to the deleterious effects of TSD seems to be a trait-like phenomenon (Van Dongen et al, 2004 ; Chee and Tan, 2010 ; Rupp et al, 2012 ; Chua et al, 2014b ; Xu et al, 2016 ) with potential genetic (Viola et al, 2007 ; Groeger et al, 2008 ; Goel and Dinges, 2012 ), neurobiological (Yeo et al, 2015 ) and/or psychological profiles (Killgore et al, 2007b ). More recently, Chua et al’s ( 2014a , b ) apostrophe studies (2014) demonstrated that subjects more vulnerable to the deleterious effects of TSD on sustained attention capacities show slower and more variable time response and lapses when they are well rested (Chua et al, 2014a , b ). We go one step further with this study, by demonstrating similar individual vulnerability in a chronic sleep-restricted situation but with a significant implication of both age and subject’s capacity to fight sleepiness on morning failures of sustained attention and only of subject’s capacity for executive ones.…”

“…Interestingly, with accumulated time awake, sleep pressure increases sleepiness and sustained attention performance is still possible but at the cost of decreasing speed and increasing the number of lapses in PVT, leading to greater intra- and inter-variability (Doran et al, 2001 ; Van Dongen et al, 2004 , 2012 ). Some recent studies have pointed out the fact that TSD amplified individual differences in sustained attention performances that already existed, to a lesser extent, during baseline hours (Chua et al, 2014a , b ; Yeo et al, 2015 ). Since individual differences in working memory deficits (Mu et al, 2005a ; Chee et al, 2006 ) and no significant interference and facilitation in sensori-motor decision-making (Simon task) have been reported in subjects submitted to TSD (Bratzke et al, 2012 ), some authors have called into question the claim that sleep loss primarily degrades executive functions and reasoning (Lim and Dinges, 2010 ; Horne, 2012 ; Basner et al, 2013 ; Jackson et al, 2013 ).…”