Quantifying Cognitive Impairment After Sleep Deprivation at Different Times of Day: A Proof of Concept Using Ultra-Short Smartphone-Based Tests

Neurocognitive consequences of adolescent sleep disruptions and their relationship to psychosis vulnerability: a longitudinal cohort study

Adolescence is a key period for neurocognitive maturation where deviation from normal developmental trajectories may be tied to adverse mental health outcomes. Cognitive disruptions have been noted in populations at risk for psychosis and are known to accompany periods of sleep deprivation. This study aims to assess the role of cognition as a mediator between sleep disruptions and psychosis risk. A cohort of 3801 high school students (51% female, mean age = 12.8, SD = 0.45 years) was recruited from 31 Montreal high schools. Measures of sleep, psychotic-like experiences, inhibition, working memory, perceptual reasoning, and delayed recall were collected from participants on a yearly basis over the five years of their high school education. A multi-level model mediation analysis was performed controlling for sex and time squared. Response inhibition was shown to be associated with, and to mediate (B = -0.005, SD = 0.003, p = 0.005*) the relationship between sleep disruptions (B = -0.011, SD = 0.004, p < 0.001*) and psychotic-like experiences (B = 0.411, SD = 0.170, p = 0.005*). Spatial working memory deficits on a given year were associated with a higher frequency of psychotic-like experiences that same year (B = -0.046, SD = 0.018, p = 0.005*) and the following year (B = -0.051, SD = 0.023, p = 0.010*), but were not associated with sleep disturbances. No significant associations were found between our variables of interest and either delayed recall or perceptual reasoning at the within person level. Findings from this large longitudinal study provide evidence that the association between sleep disruptions and psychosis risk is specifically mediated by inhibitory rather than general cognitive impairments. The association of spatial working memory, response inhibition, and sleep disruptions with psychotic-like experiences suggests that these factors may represent potential targets for preventative interventions.

Six elements test vs D-KEFS: what does "Ecological Validity" tell us?

OBJECTIVE

Extensive research shows that tests of executive functioning (EF) predict instrumental activities of daily living (IADLs) but are nevertheless often criticized for having poor ecological validity. The Modified Six Elements Test (MSET) is a pencil-and-paper test that was developed to mimic the demands of daily life, with the assumption that this would result in a more ecologically valid test. Although the MSET has been extensively validated in its ability to capture cognitive deficits in various populations, support for its ability to predict functioning in daily life is mixed. This study aimed to examine the MSET's ability to predict IADLs assessed via three different modalities relative to traditional EF measures.

METHOD

Participants (93 adults aged 60 - 85) completed the MSET, traditional measures of EF (Delis-Kaplan Executive Function System; D-KEFS), and self-reported and performance-based IADLs in the lab. Participants then completed three weeks of IADL tasks at home, using the Daily Assessment of Independent Living and Executive Skills (DAILIES) protocol.

RESULTS

The MSET predicted only IADLs completed at home, while the D-KEFS predicted IADLs across all three modalities. Further, the D-KEFS predicted home-based IADLs beyond the MSET when pitted against each other, whereas the MSET did not contribute beyond the D-KEFS.

CONCLUSIONS

Traditional EF tests (D-KEFS) appear to be superior to the MSET in predicting IADLs in community-dwelling older adults. The present results argue against replacing traditional measures with the MSET when addressing functional independence of generally high-functioning and cognitive healthy older adult patients.

Is snoozing losing? Why intermittent morning alarms are used and how they affect sleep, cognition, cortisol, and mood

Pressing the snooze button is a common way to start the day, but little is known about this behaviour. Through two studies we determined predictors and effects of snoozing. In Study 1 (n = 1732) respondents described their waking habits, confirming that snoozing is widespread, especially in younger individuals and later chronotypes. Morning drowsiness and shorter sleep were also more common for those who snooze. Study 2 was a within-subjects laboratory study (with polysomnography) on habitual snoozers (n = 31), showing that 30 min of snoozing improved or did not affect performance on cognitive tests directly upon rising compared to an abrupt awakening. Bayes factors indicate varying strengths of this evidence. Snoozing resulted in about 6 min of lost sleep, while preventing awakenings from slow-wave sleep (N3). There were no clear effects of snoozing on the cortisol awakening response, morning sleepiness, mood, or overnight sleep architecture. A brief snooze period may thus help alleviate sleep inertia, without substantially disturbing sleep, for late chronotypes and those with morning drowsiness.

Remote Evaluation of Sleep and Circadian Rhythms in Older Adults With Mild Cognitive Impairment and Dementia: Protocol for a Feasibility and Acceptability Mixed Methods Study

BACKGROUND

Sleep disturbances are a potentially modifiable risk factor for neurodegenerative dementia secondary to Alzheimer disease (AD) and Lewy body disease (LBD). Therefore, we need to identify the best methods to study sleep in this population.

OBJECTIVE

This study will assess the feasibility and acceptability of various wearable devices, smart devices, and remote study tasks in sleep and cognition research for people with AD and LBD.

METHODS

We will deliver a feasibility and acceptability study alongside a prospective observational cohort study assessing sleep and cognition longitudinally in the home environment. Adults aged older than 50 years who were diagnosed with mild to moderate dementia or mild cognitive impairment (MCI) due to probable AD or LBD and age-matched controls will be eligible. Exclusion criteria include lack of capacity to consent to research, other causes of MCI or dementia, and clinically significant sleep disorders. Participants will complete a cognitive assessment and questionnaires with a researcher and receive training and instructions for at-home study tasks across 8 weeks. At-home study tasks include remote sleep assessments using wearable devices (electroencephalography headband and actigraphy watch), app-based sleep diaries, online cognitive assessments, and saliva samples for melatonin- and cortisol-derived circadian markers. Feasibility outcomes will be assessed relating to recruitment and retention, data completeness, data quality, and support required. Feedback on acceptability and usability will be collected throughout the study period and end-of-study interviews will be analyzed using thematic analysis.

RESULTS

Recruitment started in February 2022. Data collection is ongoing, with final data expected in February 2024 and data analysis and publication of findings scheduled for the summer of 2024.

CONCLUSIONS

This study will allow us to assess if remote testing using smart devices and wearable technology is a viable alternative to traditional sleep measurements, such as polysomnography and questionnaires, in older adults with and without MCI or dementia due to AD or LBD. Understanding participant experience and the barriers and facilitators to technology use for research purposes and remote research in this population will assist with the development of, recruitment to, and retention within future research projects studying sleep and cognition outside of the clinic or laboratory.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/52652.

Diurnal variation in variables related to cognitive performance: a systematic review

PURPOSE

The aim of this review was to assess current evidence regarding changes in cognitive function according to time-of-day (TOD) and assess the key components of research design related to manuscripts of chronobiological nature.

METHODS

An English-language literature search revealed 523 articles through primary database searches, and 1868 via organization searches/citation searching. The inclusion criteria were met by eleven articles which were included in the review. The inclusion criteria set were healthy adult males, a minimum of two timepoints including morning and evening, cognitive measures of performance, and peer-reviewed academic paper.

RESULTS

It was established that cognitive performance varies with TOD and the degree of difference is highly dependent on the type of cognitive task with differences ranging from 9.0 to 34.2% for reaction time, 7.3% for alertness, and 7.8 to 40.3% for attention. The type of cognitive function was a determining factor as to whether the performance was better in the morning, evening, or afternoon.

CONCLUSION

Although some studies did not establish TOD differences, reaction time and levels of accuracy were highest in the evening. This implies that cognitive processes are complex, and existing research is contradictory. Some studies or cognitive variables did not show any measurable TOD effects, which may be due to differences in methodology, subjects involved, testing protocols, and confounding factors. No studies met all requirements related to chronobiological research, highlighting the issues around methodology. Therefore, future research must use a rigorous, approach, minimizing confounding factors that are specific to examinations of TOD.

Sleep duration and perceptions of sleep quality in British Army recruits during basic training - an observational analysis

Introduction

Sleep is critical to the health, wellbeing and performance of military personnel during basic training. This two-part study evaluated sleep-wake patterns and sleep disturbances in junior soldiers (JS) and infantry recruits in Autumn 2021 (study 1), and non-infantry recruits in spring 2022 (study 2).

Methods

During studies 1 and 2, validated wearable technology combined with a sleep diary was used to quantify sleep-wake indices, sleep disturbances and perceptions of sleep quality. Sleep diary data was analysed descriptively. A series of repeated-measures ANOVAs examined differences in objective sleep-wake indices. Correlation analysis determined associations between time in bed (TIB) and total sleep time (TST).

Results

Significant (p < 0.05) differences in most sleep-wake indices were observed between weeks of basic training for all cohorts. Strong positive correlations between TIB and TST were observed for each cohort across basic training (r = 0.681 - 0.970, p < 0.001), with longer TST associated with greater TIB. The mean±SD sleep duration (hours and mins [hm]) for JS (06:22 ± 00:27hm), non-infantry (05:41 ± 00:47hm) and infantry (05:46 ± 00:34hm) recruits across basic training was consistently below national recommendations. The mean±SD bed and wake times for JS (bedtime: 23:01 ± 00:32hm; awake: 05:34 ± 00:10hm), non-infantry (bedtime: 23:38 ± 01:09hm; awake: 04:47 ± 00:58hm), and infantry (bedtime: 23:13 ± 00:29hm; awake: 05:38 ± 00:26hm) recruits varied across weeks of basic training, with over 80% reporting "fairly bad" or "very bad" sleep quality and frequent periods of "dozing off" during daytime activity. The most commonly reported sleep disturbing factors identified during basic training involved: late-night military admin (e.g., ironing, boot cleaning, kit set up etc), early morning wake times, extraneous noise, light and hot room temperatures within the primary sleeping environment, bed/mattress discomfort, muscle soreness and feelings of stress and anxiety.

Discussion/Conclusion

Our findings contribute to the existing evidence that long-term sleep loss is pervasive during initial military training programmes. The average sleep durations indicate chronic and unrecoverable sleep loss which would be expected to significantly impair physical and cognitive military performance, and increase the risk of injury, illness and attrition rates during basic training. Changes in the design and scheduling of basic training programmes to enable, at the least, minimum sleep recommendations to be met, and to improve sleep hygiene in the primary sleeping environment are warranted.

Problematic technology use and sleep quality in young adulthood: novel insights from a nationally representative twin study

STUDY OBJECTIVES

Digital technology use is associated with poor sleep quality in adolescence and young adulthood although research findings have been mixed. No studies have addressed the association between the two using a genetically informative twin design which could extend our understanding of the etiology of this relationship. This study aimed to test: (1) the association between adolescents' perceived problematic use of digital technology and poor sleep quality, (2) whether the association between problematic use of technology and poor sleep quality remains after controlling for familial factors, and (3) genetic and environmental influences on the association between problematic use of technology and poor sleep quality.

METHODS

Participants were 2232 study members (18-year-old twins) of the Environmental Risk (E-Risk) Longitudinal Twin Study. The sample was 48.9% male, 90% white, and 55.6% monozygotic. We conducted regression and twin difference analyses and fitted twin models.

RESULTS

Twin differences for problematic use of technology were associated with differences for poor sleep quality in the whole sample (p < 0.001; B = 0.15) and also when we limited the analyses to identical twins only (p < 0.001; B = 0.21). We observed a substantial genetic correlation between problematic use of technology and sleep quality (rA = 0.31), whereas the environmental correlation was lower (rE = 0.16).

CONCLUSIONS

Adolescent reported problematic use of digital technology is associated with poor sleep quality-even after controlling for familial factors including genetic confounds. Our results suggest that the association between adolescents' sleep and problematic digital technology use is not accounted for by shared genetic liability or familial factors but could reflect a causal association. This robust association needs to be examined in future research designed to test causal associations.

A narrative review of the pathophysiology and impacts of insufficient and disrupted sleep

Background

Despite substantial ramifications of insufficient sleep on mental and physical health and general well-being, many individuals are unaware of what constitutes sufficient sleep, or of the short- and long-term extent of sleep deficiency effects, including those that may not be perceived as fatigue.

Objectives and procedures

This review describes the physiology of sleep, defines healthy standards, reviews the pathophysiology and health hazards of acute and chronic sleep insufficiency, and offers concepts for improving individual sleep hygiene. Online databases were searched to extract literature pertaining to sleep, sleep insufficiency, fatigue, and health, with emphasis on literature published in the preceding 5 years.

Results

The detrimental effects of acute and chronic sleep loss vary in their range and impact. Individuals often obtain a substandard quantity of sleep, a problem that is poorly recognized by individuals and society. This lack of recognition perpetuates a culture in which sleep insufficiency is accepted, resulting in serious and substantial negative impacts on mental and physical health.

Conclusion and clinical relevance

Sleep management is one of the most fundamental and changeable aspects of personal health. Improving awareness of the important physiological roles of sleep, healthy sleep habits, and the consequence of insufficient sleep is essential in promoting general well-being and mental and physical health.

Sleep disturbances in individuals with down syndrome: An overview

Down Syndrome, or Trisomy 21, is one of the most common birth defects, with 6,000 babies born annually with Down Syndrome in the U.S. One of many health risk factors individuals with Down Syndrome experience is sleep issues, ranging from poor sleep quality to high prevalence of obstructive sleep apnea. This literature review aims to review these sleep challenges in this population and explore consequences and treatment options.

Olfactory function testing before and after anesthesia

This study aimed to determine whether anesthesia would affect olfactory function. Patients who were admitted for surgical intervention that did not include the nasal cavity and paranasal sinuses were included in this prospective cohort study. Structured medical history was taken from the patients, including the following: age, sex, smoking history, alcohol intake, current medications, and sleep deficits prior to surgery. Before surgery, patients were asked for a self-rating of their olfactory function. Olfactory function was also measured using Sniffin' Sticks comprising measures of odor threshold, discrimination, and identification. The mean interval between olfactory tests was 6 days (range 3-12 days). Seventy-three patients were included in the study, 34 men and 39 women. Olfactory scores were consistent before and after surgery as indicated by correlative analyses (p < 0.05). Odor thresholds, discrimination, identification, and composite TDI scores did not change significantly, whereas odor identification scores increased (p = 0.011) after surgery. In conclusion, post-operative olfactory scores remained stable. However, identification scores exhibited a slight increase which can be attributed to a retest effect. Overall, the present results indicate that surgery outside of the nasal and paranasal sinus region performed in general anesthesia has no major effect on the sense of smell.

Discharging select patients without an escort after ambulatory anesthesia: identifying return to baseline function

PURPOSE OF REVIEW

The current standard of care requires ambulatory surgical patients to have an escort for discharge. Recent studies have started to challenge this dogma. Modern ultrashort acting anesthetics have minimal psychomotor effects after a couple of hours. Driving simulator performance and psychomotor testing return to baseline as soon as 1 h following propofol sedation.

RECENT FINDINGS

Two recent reports of actual experience with thousands of patients found no increase in complications in patients who were discharged without escort or drove themselves from a sedation center. These studies suggest discharge without escort may be safe in select patients but a method to identify appropriate patients remains undefined.

SUMMARY

A reliable test to document return of function might allow safe discharge without an escort. Currently, there is intense interest in developing reliable, inexpensive, easy to administer psychomotor function testing to improve workplace safety and legally define the effects of drugs on driving impairment. Future studies may be able to adapt this technology and develop a validated test for residual anesthetic impairment.