Cognitive performance in DSWPD patients upon awakening from habitual sleep compared with forced conventional sleep

Abstract

Difficult early morning awakening is one of the defining symptoms of delayed sleep-wake phase disorder. It is accompanied by low cognitive arousal and drowsiness resulting in difficulty concentrating and focusing attention upon awakening. We designed the current study to quantitate cognitive performance (i.e. omissions, commissions, reaction time [average and variability]) and cognitive domains (i.e. focused attention, sustained attention, impulsivity and vigilance) with Conners' Continuous Performance Test II during both habitual and conventional (00:00-07:00 hr) sleep-wake schedule in young adult patients with delayed sleep-wake phase disorder (n = 20, mean age = 24.8 years, SD = 3.0) and controls (n = 16, mean age = 24.4 years, SD = 3.4). Conners' Continuous Performance Test II was administered after awakening and in the afternoon during both habitual and conventional conditions. In-laboratory polysomnography was performed for 2 nights. We assessed sleep, tiredness, chronotype and depression using questionnaires. Saliva was sampled for dim light melatonin onset measurements. Repeated-measures ANOVAs were applied for the Conners' Continuous Performance Test II measures with group (patient/control), time (afternoon/morning) and condition (habitual/conventional schedule) as fixed factors. Patients with delayed sleep-wake phase disorder had reduced reaction times, especially in the morning, greater response speed variability, and made more omission and commission errors compared with controls. Patients with delayed sleep-wake phase disorder also had reduced focused attention, especially upon forced early awakening. The short total sleep time of patients with delayed sleep-wake phase disorder could not statistically explain this outcome. In conclusion, we observed a state-dependent reduced ability to focus attention upon early morning awakening in patients with delayed sleep-wake phase disorder. Patients also had more omissions, longer reaction time and increased RT variability after habitual sleep, suggesting a possible small cognitive trait dysfunction in delayed sleep-wake phase disorder.

Habitual Sleep, Social Jetlag, and Reaction Time in Youths With Delayed Sleep–Wake Phase Disorder. A Case–Control Study

“…However, whereas the controls performed better (faster with fewer lapses) in the morning, the DSWPD group performed poorer. The fact that the morning RTT was administered several hours after awakening (rise time at 07:00 h, testing at 10:00 h), suggests that the poor morning performance in the participants with DSWPD was not merely a transient effect of sleep inertia as has been suggested by Solheim et al (2018). These performance decrements are thus likely to be present throughout a school or workday of individuals with DSWPD, significantly affecting their daytime functioning.…”

“…Few studies have investigated such time of day variations in performance in individuals with DSWPD by objectively measuring performance at different times of day in experimental, controlled settings. In a recent study, Solheim et al (2018) showed impaired morning performance on a sustained reaction time task in individuals with DSWPD, particularly following forced awakenings. However, since the participants in that study were tested immediately after awakening, the authors attributed the findings to sleep inertia, a transient period of confusion and reduced alertness following forced awakenings (Tassi and Muzet, 2000), rather than to the synchrony effect or effects of sleep curtailment.…”

<p>Impact of Mandatory Wake Time on Sleep Timing, Sleep Quality and Rest-Activity Cycle in College and University Students Complaining of a Delayed Sleep Schedule: An Actigraphy Study</p>

“…34 Sleep restriction and higher circadian sleep propensity amplify the effects of sleep inertia on vigilance levels, 35 and both late chronotypes and DSWPD patients may present greater sleep inertia after forced awakenings compared to individuals with an earlier sleep schedule. 16,36 Subjective sleep quality was lower for the nights with mandatory WT in the two groups, which is interesting considering that sleep efficiency measured with actigraphy was identical in the two night conditions. Differences between objective and subjective evaluation of sleep quality have also been observed in previous studies on E-types and DSWPD patients.…”

Delayed sleep-wake rhythm is associated with cognitive dysfunction, social dysfunction, and deteriorated quality of life in patients with major depressive disorder

“…Although the reason for this inconsistency among the studies was unclear, the composite score of the BACS-J might be representative of cognitive dysfunction in patients with MDD. Because few studies have shown a relationship between a delayed sleep-wake phase and cognitive dysfunction ( 7 ), it is difficult to interpret this result. One possible explanation for this relationship was that the delayed sleep-wake phase, which usually caused physical and mental dysfunction, daytime sleepiness, and loss of concentration, might deteriorate daytime cognitive function.…”

“…Insomnia and circadian rhythm dysfunction, especially delayed sleep-wake rhythm, were commonly observed in patients with MDD ( 6 ). Recent studies have suggested that the delayed sleep-wake phase is likely to worsen depressive symptoms and cognitive dysfunctions ( 7 ). However, few studies have assessed influences of the delayed sleep-wake phase on depressive symptoms and functional impairment in patients with MDD.…”