Objective and Subjective Intraindividual Variability in Sleep: Predisposing Factors and Health Consequences

OBJECTIVE

We investigated the factors that predispose or precipitate greater intraindividual variability (IIV) in sleep. We further examined the potential consequences of IIV on overall sleep quality and health outcomes, including whether these relationships were found in both self-reported and actigraphy-measured sleep IIV.

METHODS

In Study 1, 699 US adults completed a Sleep Intra-Individual Variability Questionnaire and self-reported psychosocial, sleep quality, and health outcomes. In Study 2, 100 university students wore actigraphy and completed psychosocial, sleep, and health surveys at multiple timepoints.

RESULTS

In cross-sectional analyses that controlled for mean sleep duration, predisposing/precipitating factors to greater IIV were being an underrepresented racial/ethnic minority (Study 1: F = 13.95, p < .001; Study 2: F = 7.03, p = .009), having greater stress (Study 2: r values ≥ 0.32, p values ≤ .002) or trait vulnerability to stress (Study 1: r values ≥ 0.15, p values < .001), and showing poorer time management (Study 1: r values ≤ -0.12, p values ≤ .004; Study 2: r values ≤ -0.23, p values ≤ .028). In addition, both studies showed that greater sleep IIV was associated with decreased overall sleep quality, independent of mean sleep duration (Study 1: r values ≥ 0.20, p values < .001; Study 2: r values ≥ 0.33, p values ≤ .001). Concordance across subjective and objective IIV measures was modest ( r values = 0.09-0.35) and similar to concordance observed for subjective-objective mean sleep duration measures.

CONCLUSION

Risk for irregular sleep patterns is increased in specific demographic groups and may be precipitated by, or contribute to, higher stress and time management inefficiencies. Irregular sleep may lead to poor sleep quality and adverse health outcomes, independent of mean sleep duration, underscoring the importance of addressing sleep consistency.

Medical malpractice litigation and daylight saving time

STUDY OBJECTIVES

Daylight saving time (DST) constitutes a natural quasi-experiment to examine the influence of mild sleep loss and circadian misalignment. We investigated the acute effects of spring transition into DST and the chronic effects of DST (compared to standard time) on medical malpractice claims in the United States over three decades.

METHODS

We analyzed 288,432 malpractice claims from the National Practitioner Data Bank. To investigate the acute effects of spring DST transition, we compared medical malpractice incidents/decisions one week before spring DST transition, one week following spring DST transition, and the rest of the year. To investigate the chronic effects of DST months, we compared medical malpractice incidents/decisions averaged across the 7-8 months of DST versus the 4-5 months of standard time.

RESULTS

With regard to acute effects, spring DST transitions were significantly associated with higher payment decisions, but not associated with the severity of medical incidents. With regard to chronic effects, the 7-8 DST months were associated with higher average payments and worse severity of incidents than the 4-5 standard time months.

CONCLUSIONS

The mild sleep loss and circadian misalignment associated with DST may influence incidence of medical errors and decisions on medical malpractice payments both acutely and chronically.

Digital Methods for Performing Daily Tasks Among Older Adults: An Initial Report of Frequency of Use and Perceived Utility

OBJECTIVE

Digital technologies permit new ways of performing instrumental activities of daily living (iADLs) for older adults, but these approaches are not usually considered in existing iADL measures. The current study investigated how a sample of older adults report using digital versus analog approaches for iADLs.

METHOD

248 older adults completed the Digital and Analog Daily Activities Survey, a newly developed measure of how an individual performs financial, navigation, medication, and other iADLs.

RESULTS

The majority of participants reported regularly using digital methods for some iADLs, such as paying bills (67.7%) and using GPS (67.7%). Low digital adopters were older than high adopters (F(2, 245) = 12.24, p < .001), but otherwise the groups did not differ in terms of gender, years of education, or history of neurological disorders. Participants who used digital methods relatively more than analog methods reported greater levels of satisfaction with their approach and fewer daily errors.

CONCLUSIONS

Many older adults have adopted digital technologies for supporting daily tasks, which suggests limitations to the validity of current iADL assessments. By capitalizing on existing habits and enriching environments with new technologies, there are opportunities to promote technological reserve in older adults in a manner that sustains daily functioning.

Internet-Enabled Behaviors in Older Adults During the Pandemic: Patterns of Use, Psychosocial Impacts, and Plans for Continued Utilization

In response to social distancing measures during the COVID-19 pandemic, there was a need to increase the frequency of internet enabled behaviors (IEBs). To date, little is known about how the pandemic impacted IEBs in older adults, a population that has historically been linked to lower digital literacy and utilization. We administered an online survey between April and July 2021 to 298 adults who were over age 50 (mean age = 73 years; 93.5% non-Hispanic white; 94% smart phone owners; 83.5% retired). Older adults self-reported IEBs for social, shopping, medical, and leisure activities during the pandemic, plans for continued use of these behaviors, and completed measures of psychosocial functioning. 66.8% of respondents reported an overall increase in IEBs during the pandemic, most notably for online meeting attendance. More frequent online meeting use was associated with less depression (r = -0.12, p = .04) and less loneliness (r = -0.14, p = .02). With regard to plans for continued use, 82.5% of the sample reported at least one IEB (M = 2.18, SD = 1.65) that they increased during the pandemic and planned to maintain over time (e.g., online shopping for household goods). Plans for continued use were more likely in participants who used IEBs more overall during the pandemic (r = 0.56, p < .001), and who frequently sought technical support on search engines (r = 0.22, p < .001), or online video sites (r = 0.16, p = .006). In summary, IEBs during the pandemic were associated with favorable psychosocial functioning and expectations for continued use in this sample of predominantly white older adults who had some baseline technological familiarity.

Chronotype in college science students is associated with behavioral choices and can fluctuate across a semester

Many students self-report that they are "night owls," which can result from neurodevelopmental delays in the circadian timing system. However, whether an individual considers themselves to be an evening-type versus a morning-type (self-reported chronotype) may also be influenced by academic demands (e.g. class start times, course load) and behavioral habits (e.g. bedtime social media use, late caffeine consumption, daytime napping). If so, then chronotype should be malleable. We surveyed 858 undergraduate students enrolled in demanding science courses at up to three time points. The survey assessed morning/evening chronotype, global sleep quality, academics, and behavioral habits. Evening and morning-type students showed similar demographics, stress levels, and academic demands. At baseline measurements, relative to morning-types, evening-types showed significantly worse sleep quality and duration as well as 22% greater bedtime social media usage, 27% greater daytime napping duration, and 46% greater likelihood of consuming caffeine after 5pm. These behavioral habits partially mediated the effects of self-reported chronotype on sleep quality/duration, even after controlling for demographic factors. Interestingly, 54 students reported switching from being at least moderate evening-types at baseline to being at least moderate morning-types later in the semester and 56 students showed the reverse pattern (6.3% of students switched from "definitely" one chronotype to the other chronotype). Evening-to-morning "chrono-switchers" consumed less caffeine after 5pm and showed significantly better sleep quantity/quality at the later timepoint. Thus, some students may consider themselves to be night owls in part because they consume caffeine later, take more daytime naps, or use more social media at bedtime. Experimental work is needed to determine whether nudging night owls to behave like morning larks results in better sleep health or academic achievement.

COVID-19-Related News Consumption Linked with Stress and Worry, but Not Sleep Quality, Early in the Pandemic

Beginning in early 2020, the novel coronavirus was the subject of frequent and sustained news coverage. Building on prior literature on the stress-inducing effects of consuming news during a large-scale crisis, we used network analysis to investigate the association between coronavirus disease 2019 (COVID-19) news consumption, COVID-19-related psychological stress, worries about oneself and one's loved ones getting COVID-19, and sleep quality. Data were collected in March 2020 from 586 adults (45.2% female; 72.9% White) recruited via Amazon Mechanical Turk in the U.S. Participants completed online surveys assessing attitudes and behaviors related to COVID-19 and a questionnaire assessing seven domains of sleep quality. Networks were constructed using partial regularized correlation matrices. As hypothesized, COVID-19 news consumption was positively associated with COVID-19-related psychological stress and concerns about one's loved ones getting COVID-19. However, there were very few associations between COVID-19 news consumption and sleep quality indices, and gender did not moderate any of the observed relationships. This study replicates and extends previous findings that COVID-19-news consumption is linked with psychological stress related to the pandemic, but even under such conditions, sleep quality can be spared due to the pandemic allowing for flexibility in morning work/school schedules.

Technology use and subjective cognitive concerns in older adults

OBJECTIVES

How technology impacts the day to day cognitive functioning of older adults is a matter of some debate. On the one hand, the use of technologies such as smartphones and social media, may lead to more subjective cognitive concerns (SCC) by promoting distractibility and reliance on devices to perform memory tasks. However, continued digital engagement in older adults may also be related to better cognitive functioning. Given these competing viewpoints, our study evaluated if frequency of digital device use was associated with greater or less subjective cognitive concerns.

METHOD

Participants were 219 adults over the age of 65 (mean age =75 years) who had internet access. Measures assessing frequency of digital device use along with SCC were administered. Hierarchical multiple regression was used to gage association between frequency of device use and SCC, controlling for relevant demographic and lifestyle factors.

RESULTS

Increased frequency of digital device use was associated with less SCC, over and above the influence of demographic factors, across cognitive (but especially in executive) domains. This effect was observed for general device usage, with no statistically significant associations were observed between texting/video call, social media use and SCC.

DISCUSSION

Results were broadly consistent with the technological reserve hypothesis in that digital engagement was associated with better experienced cognitive functioning in older adults. While device use may contribute to distractibility in certain cases, the current results add to a burgeoning literature that digital engagement may be a protective factor for cognitive changes with age.

Longitudinal trajectories of spectral power during sleep in middle-aged and older adults

Age-related changes in sleep appear to contribute to cognitive aging and dementia. However, most of the current understanding of sleep across the lifespan is based on cross-sectional evidence. Using data from the Sleep Heart Health Study, we investigated longitudinal changes in sleep micro-architecture, focusing on whether such age-related changes are experienced uniformly across individuals. Participants were 2,202 adults (age_Baseline = 62.40 ± 10.38, 55.36 % female, 87.92 % White) who completed home polysomnography assessment at two study visits, which were 5.23 years apart (range: 4-7 years). We analyzed NREM and REM spectral power density for each 0.5 Hz frequency bin, including slow oscillation (0.5-1 Hz), delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sigma (12-15 Hz), and beta-1 (15-20 Hz) bands. Longitudinal comparisons showed a 5-year decline in NREM delta (p <.001) and NREM sigma power density (p <.001) as well as a 5-year increase in theta power density during NREM (p =.001) and power density for all frequency bands during REM sleep (ps < 0.05). In contrast to the notion that sleep declines linearly with advancing age, longitudinal trajectories varied considerably across individuals. Within individuals, the 5-year changes in NREM and REM power density were strongly correlated (slow oscillation: r = 0.46; delta: r = 0.67; theta r = 0.78; alpha r = 0.66; sigma: r = 0.71; beta-1: r = 0.73; ps < 0.001). The convergence in the longitudinal trajectories of NREM and REM activity may reflect age-related neural de-differentiation and/or compensation processes. Future research should investigate the neurocognitive implications of longitudinal changes in sleep micro-architecture and test whether interventions for improving key sleep micro-architecture features (such as NREM delta and sigma activity) also benefit cognition over time.

Sleep disparities in the first month of college: implications for academic achievement

Study Objective

We investigated sleep disparities and academic achievement in college.

Methods

Participants were 6,002 first-year college students attending a midsize private university in the southern United States [62.0% female, 18.8% first-generation, 37.4% Black, Indigenous, or People of Color (BIPOC) students]. During the first 3-5 weeks of college, students reported their typical weekday sleep duration, which we classified as short sleep (<7 hours), normal sleep (7-9 hours), or long sleep (>9 hours).

Results

The odds for short sleep were significantly greater in BIPOC students (95% CI: 1.34-1.66) and female students (95% CI: 1.09-1.35), and the odds for long sleep were greater in BIPOC students (95% CI: 1.38-3.08) and first-generation students (95% CI: 1.04-2.53). In adjusted models, financial burden, employment, stress, STEM academic major, student athlete status, and younger age explained unique variance in sleep duration, fully mediating disparities for females and first-generation students (but only partially mediating disparities for BIPOC students). Short and long sleep predicted worse GPA across students' first year in college, even after controlling for high school academic index, demographics, and psychosocial variables.

Conclusions

Higher education should address sleep health early in college to help remove barriers to success and reduce disparities.

Rapid sleep education: If you could tell people one thing about sleep, what should it be?

Informal learning settings such as museums provide unique opportunities for educating a local community about sleep. However, in such settings, information must be capable of immediately inciting interest. We developed a series of sleep "icebreakers" (brief, informal facts) to determine whether they elicited interest in sleep and encouraged behavioural change. There were 859 participants across three cross-sectional samples: (a) members of the local museum; (b) Mechanical Turk workers who responded to a "sleep" study advertisement; and (c) Mechanical Turk workers who responded to a "various topics" study advertisement that did not mention sleep. All three samples demonstrated high interest in sleep topics, though delayed recall of the icebreakers was strongest in participants who expected to learn about the sleep topics. Icebreaker interest ratings were independent of age, gender and race/ethnicity, suggesting that sleep is a topic of universal interest. Importantly, regardless of demographics and sample, the more the icebreakers interested the participants, the more likely participants were to indicate willingness to donate to a sleep exhibit, change their sleep behaviours, and post to social media. Thus, sleep icebreakers can rapidly elicit people's interest, and future outreach efforts should couple icebreakers with opportunities for subsequent personalized learning.

Validation of a nonwearable device in healthy adults with normal and short sleep durations

STUDY OBJECTIVES

To determine the accuracy of early and newer versions of a nonwearable sleep tracking device relative to polysomnography and actigraphy, under conditions of normal and restricted sleep duration.

METHODS

Participants were 35 healthy adults (mean age = 18.97; standard deviation = 0.95 years; 77.14% female; 42.86% White). In a controlled sleep laboratory environment, we randomly assigned participants to go to bed at 10:30 pm (normal sleep) or 1:30 am (restricted sleep), setting lights-on at 7:00 am. Sleep was measured using polysomnography, wristband actigraphy (the Philips Respironics Actiwatch Spectrum Plus), self-report, and an early or newer version of a nonwearable device that uses a sensor strip to measure movement, heart rate, and breathing (the Apple, Inc. Beddit). We tested accuracy against polysomnography for total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset.

RESULTS

The early version of the nonwearable device (Beddit 3.0) displayed poor reliability (intraclass correlation coefficient [ICC] < 0.30). However, the newer nonwearable device (Beddit 3.5) yielded excellent reliability with polysomnography for total sleep time (ICC = 0.998) and sleep efficiency (ICC = 0.98) across normal and restricted sleep conditions. Agreement was also excellent for the notoriously difficult metrics of sleep onset latency (ICC = 0.92) and wake after sleep onset (ICC = 0.92). This nonwearable device significantly outperformed clinical-grade actigraphy (ICC between 0.44 and 0.96) and self-reported sleep measures (ICC < 0.75).

CONCLUSIONS

A nonwearable device showed better agreement than actigraphy with polysomnography outcome measures. Future work is needed to test the validity of this device in clinical populations.

CITATION

Hsiou DA, Gao C, Matlock RC, Scullin MK. Validation of a nonwearable device in healthy adults with normal and short sleep durations. J Clin Sleep Med. 2022;18(3):751-757.

Using smartphone technology to improve prospective memory functioning: A randomized controlled trial

BACKGROUND

A decline in the ability to perform daily intentions-known as prospective memory-is a key driver of everyday functional impairment in dementia. In the absence of effective pharmacological treatments, there is a need for developing, testing, and optimizing behavioral interventions that can bolster daily prospective memory functioning. We investigated the feasibility and efficacy of smartphone-based strategies for prospective memory in persons with cognitive impairment.

METHODS

Fifty-two older adults (74.79 ± 7.20 years) meeting diagnostic criteria for mild cognitive impairment or mild dementia were enrolled in a 4-week randomized controlled trial. Participants were trained to use a digital voice recorder app or a reminder app to off-load prospective memory intentions. Prospective memory was assessed using experimenter-assigned tasks (e.g., call the laboratory on assigned days), standardized questionnaires, and structured interviews. Secondary dependent measures included days of phone and app usage, acceptability ratings, quality of life, and independent activities of daily living.

RESULTS

Participant ratings indicated that the intervention was acceptable and feasible. Furthermore, after the four-week intervention, participants reported improvements in daily prospective memory functioning on standardized questionnaires (p < 0.001, η_p²  = 0.285) and the structured interview (p < 0.001, d = 1.75). Participants performed relatively well on experimenter-assigned prospective memory tasks (51.7% ± 27.8%), with performance levels favoring the reminder app in Week 1, but reversing to favor the digital recorder app in Week 4 (p = 0.010, η_p²  = 0.079). Correlational analyses indicated that greater usage of the digital recorder or reminder app was associated with better prospective memory performance and greater improvements in instrumental activities of daily living (completed by care partners), even when controlling for condition, age, baseline cognitive functioning, and baseline smartphone experience.

CONCLUSIONS

Older adults with cognitive disorders can learn smartphone-based memory strategies and doing so benefits prospective memory functioning and independence.

Bedtime Music, Involuntary Musical Imagery, and Sleep

Many people listen to music for hours every day, often near bedtime. We investigated whether music listening affects sleep, focusing on a rarely explored mechanism: involuntary musical imagery (earworms). In Study 1 (N = 199, mean age = 35.9 years), individuals who frequently listen to music reported persistent nighttime earworms, which were associated with worse sleep quality. In Study 2 (N = 50, mean age = 21.2 years), we randomly assigned each participant to listen to lyrical or instrumental-only versions of popular songs before bed in a laboratory, discovering that instrumental music increased the incidence of nighttime earworms and worsened polysomnography-measured sleep quality. In both studies, earworms were experienced during awakenings, suggesting that the sleeping brain continues to process musical melodies. Study 3 substantiated this possibility by showing a significant increase in frontal slow oscillation activity, a marker of sleep-dependent memory consolidation. Thus, some types of music can disrupt nighttime sleep by inducing long-lasting earworms that are perpetuated by spontaneous memory-reactivation processes.

The Prospective Sleeping Brain: Age-Related Differences in Episodic Future Thinking and Frontal Sleep Spindles

Sleep spindles are a physiological marker of off-line memory consolidation. In young adults, sleep spindles are preferentially responsive to encoded information that is tagged as having future relevance. Older adults, on the other hand, show reduced capacity for future simulation and alterations in sleep physiology. Healthy young adults (n = 38) and older adults (n = 28) completed an adaptation night, followed by two in-laboratory polysomnography nights, in which they mentally simulated future events or remembered past events, recorded via written descriptions. We quantified the degree of future/past thinking using linguistic analysis of time orientation. In young adults, greater future thinking was linked to greater spindle density, even when controlling for gender, age, and word count (rp = .370, p = .028). The opposite was true for older adults, such that greater future thinking was associated with reduced spindle density (rp = -.431, p = .031). These patterns were selective to future thinking (not observed for past thinking). The collective findings implicate an impaired interaction between future relevance tagging and sleep physiology as a mechanism by which aging compromises sleep-dependent cognitive processing.

Preserving prospective memory in daily life: A systematic review and meta-analysis of mnemonic strategy, cognitive training, external memory aid, and combination interventions

OBJECTIVE

To preserve or improve independent functioning in older adults and those with neurocognitive impairments, researchers and clinicians need to address prospective memory deficits. To be effective, prospective memory interventions must restore (or circumvent) the underlying attention and memory mechanisms that are impaired by aging, brain injury, and neurodegeneration. We evaluated two decades of prospective memory interventions for efficacy, time/resource costs, and ecological validity.

METHOD

We systematically reviewed 73 prospective memory intervention studies of middle- to older-aged healthy adults and clinical groups (N = 3,749). We also rated the ecological validity of each study's prospective memory assessment/task using a newly developed scale. When possible (72% of studies), we estimated effect sizes using random-effects models and Hedges' g.

RESULTS

We identified four categories of prospective memory interventions, including mnemonic strategy, cognitive training, external memory aid, and combination interventions. Mnemonic strategy (g = .450) and cognitive training (g = .538) interventions demonstrated efficacy. Combination interventions showed mixed results (g = .254), underscoring that "more is not always better." External memory aids demonstrated very positive outcomes (g = .805), though often with small-sample, case-series designs. Prospective memory assessments had high ecological validity in external memory aid studies (84%), but not in mnemonic strategy (14%), cognitive training (20%), or combination intervention (50%) studies, p < .001, ηp2 = .33.

CONCLUSIONS

Everyday prospective memory can be meaningfully improved, perhaps particularly with external memory aids, but larger trials are required to optimize treatments, increase adherence, and broaden implementation in daily life. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Sleep health early in the coronavirus disease 2019 (COVID-19) outbreak in the United States: integrating longitudinal, cross-sectional, and retrospective recall data

BACKGROUND

The outbreak of coronavirus disease 2019 (COVID-19) caused substantial changes in lifestyle, responsibilities, and stressors. Such dramatic societal changes might cause overall sleep health to decrease (stress view), to remain unchanged (resilience view), or even to improve (reduced work/schedule burden view).

METHODS

We addressed this question using longitudinal, cross-sectional, and retrospective recall methodologies in 699 American adult participants in late March 2020, two weeks following the enactment of social distancing and shelter-in-place policies in the United States.

RESULTS

Relative to baseline data from mid February 2020, cross-sectional and longitudinal analyses demonstrated that average sleep quality was unchanged, or even improved, early in the pandemic. However, there were clear individual differences: approximately 25% of participants reported that their sleep quality had worsened, which was explained by stress vulnerability, caregiving, adverse life impact, shift work, and presence of COVID-19 symptoms.

CONCLUSIONS

Therefore, the COVID-19 pandemic has detrimentally impacted some individuals' sleep health while paradoxically benefited other individuals' sleep health by reducing rigid work/school schedules such as early morning commitments.

0344 Age-Related Longitudinal Trajectories in NREM and REM Spectral Power

Introduction

Knowledge of how aging impacts sleep physiology is based almost exclusively on cross-sectional studies. Longitudinal studies, by contrast, can inform how macro- and micro-features of NREM and REM sleep change dynamically across time in individual trajectories. For the current work, we conducted quantitative EEG analyses from a longitudinal polysomnography study to inform age-related trajectories in sleep macro- and micro-architecture.

Methods

We conducted a secondary data analysis on 2208 participants in the Sleep Heart Health Study (mean age =62.47, SD=10.46, 55.30% females). Participants underwent one night of in-home polysomnography recording during two study visits (M=5.21 years apart, SD=0.53). Spectral power density was calculated for each 0.5 Hz frequency bin for NREM and REM sleep separately.

Results

In cross-sectional analyses, older chronological age was significantly associated with worse sleep macro-architecture. Plots of the individual trajectories over 5 years, however, revealed considerable inter-individual variability in whether sleep physiology was preserved or declined. Interestingly, there were strong associations between the longitudinal changes in power density in NREM and REM sleep (slow oscillations: r=.53 [.50-.56]; delta: r=.58 [.55-.60]; alpha: r=.69 [.67-.71]; sigma: r=.74 [.73-.76]; beta: r=.82 [.80-.83]; ps&lt;.001). The strongest NREM-REM association was for theta band power (r=.85 [.83-.86]), particularly in the 5.5-6.0 Hz bin (r=.94, [.94, .95]).

Conclusion

There is substantial inter-individual variability in how aging impacts sleep physiology. Nevertheless, within individuals, power density declines similarly across NREM and REM stages, with nearly perfect convergence for theta activity, indicating a common age-related neurobiological mechanism.

Support

The National Sleep Research Resource is supported by NIH HL114473.

0212 Questionnaire Assessment of Intraindividual Variability in Sleep: Inconsistent Sleep Can Be Worse Than Short Average Sleep

Introduction

The consequences of short sleep are well-documented, but recent evidence indicates that night-to-night consistency in sleep may be just as important. For the current work, we developed an intraindividual variability in sleep (IIV) questionnaire to make IIV measurement possible in single-time-point studies. We investigated whether self-reported IIV explained unique variance in sleep quality and health beyond average total sleep time (TST), focusing on a critical transition period (first semester of college) in which high variability was predicted.

Methods

First-semester college students (N=126, Mage=18.28, 75.40% females) completed an IIV questionnaire in which participants indicated their average sleep duration, then estimated how much their sleep duration deviated from their average duration for each day of a typical week. We quantified IIV as the mean day-to-day change in sleep. Participants also completed standard questionnaires on global sleep quality, social jetlag, daytime sleepiness, depression, and stress.

Results

Participants reported substantial IIV in their sleep durations (M=1.77 hours, SD=0.86) that was largely distinguishable from measures of social jetlag (r=.25) and average TST (r=-.18). Patterns of IIV differed across race/ethnicities: in white/Asian students, IIV was strongly associated with social jetlag (r=-.44) whereas in underrepresented minority students, IIV and social jetlag were separate constructs (r=-.03), suggesting that fluctuations in the latter group occur across all days of the week. Greater IIV was associated with significantly worse global sleep quality (r=.24, p=.01), stress (r=.20, p=.03), and depression, r=.20, p=.03). These associations were significant after adjusting for average TST, and only marginally reduced when controlling for social jetlag.

Conclusion

IIV in sleep/wake patterns can be captured using a questionnaire, and such measurement provides unique explanatory power to understanding sleep quality and mental health. Future research is needed to compare IIV questionnaire data to actigraphy data and to understand the underlying mechanisms by which inconsistent sleep detrimentally affects individuals.

Support

National Science Foundation (NSF 1920730)

0369 Sleep Disparities are Established by the First Month of College

Introduction

Short and poor quality sleep are particularly common in college students, likely impacting their ability to persist and succeed in difficult courses. In the current study, we investigated demographic-based sleep differences (sleep disparities) and demographic-based academic differences (achievement gaps) in first-semester college students, with the goal of informing whether sleep disparities contribute to achievement gaps.

Methods

From 2017 to 2018, first-semester undergraduate students at Baylor University completed the New2BU Survey [N=6,048, 61.9% female, 18.7% first-generation, 23.8% underrepresented racial/ethnic minority (URM)]. Data collection occurred within three to five weeks of classes beginning. The survey included self-reported weekday total sleep time (TST), which we classified as short sleep (≤6.9 hours), normal sleep (7-9 hours), or long sleep (&gt;9 hours). Semester GPA data were obtained from university records for students’ first 4 semesters.

Results

There was evidence for both achievement gaps and sleep disparities. The risk for short sleep was increased in female students (p&lt;.001; OR=1.20, 95%CI: 1.08-1.33), first-generation students (p=.02; OR=1.17, 95%CI: 1.03-1.33), and URM students (p&lt;.001; OR=1.32, 95%CI: 1.16-1.50). The risk for long sleep increased substantially in first-generation students (p=.003, OR=1.92, 95%CI: 1.25-2.97) and URM students (p&lt;.001; OR=2.41, 95%CI: 1.57-3.70), but not in female students (OR=0.88, 95%CI: 0.59-1.30). First-generation and URM students showed a 0.2-0.3 GPA reduction each semester relative to comparison groups (ps&lt;.001), but short sleep and long sleep predicted GPA data up to four semesters later. Sleep-GPA correlations were modest in size (rs=.10-.14), but remained significant even after controlling for numerous demographic variables, high school GPA, and college entrance test scores.

Conclusion

Sleep disparities are noteworthy within the first month of college, and predictive of academic performance across four semesters. Addressing sleep health in all students—but particularly female, first-generation, and URM students—may increase academic success, bridge achievement gaps, and reduce health disparities.

Support

National Science Foundation (DRL 1920730)

0197 Chronotype is Influenced by Behavioral Choices and Can Fluctuate Across the Semester in STEM Students

Introduction

A delay in endogenous biological rhythms is assumed to cause undergraduate students to be “night owls,” but neurodevelopmental effects may only partially explain chronotype (circadian preference). Instead, perceived chronotype in students may result from poor sleep hygiene practices including bedtime social media use, afternoon caffeine consumption, and daytime napping. If so, then chronotype should be malleable in students to the extent that behavioral choices change.

Methods

We surveyed 1,120 undergraduate students who were enrolled in STEM courses across up to 3 time points during the semester. The survey assessed perceived chronotype (morning/evening type), global sleep quality, and daily habits that impact alertness and sleep hygiene (e.g., social media usage and timing, caffeine consumption and timing, and napping behavior).

Results

Relative to Morning Types, students who perceived themselves as being Evening Types showed 23.1% greater bedtime social media usage (t=3.14, p=.002), 35.1% greater daytime napping duration (t=4.44, p&lt;.001), and a 44 minute later average time of caffeine consumption (even though total caffeine consumption was reduced; t=2.30, p=.022). Evening Types also reported lower subjective health (t=3.55, p&lt;.001), with 14.2% of the association between chronotype and subjective health being mediated by bedtime social media use (direct effect: b=0.050, p=.002; indirect effect: b=0.009, p&lt;.05). Ninety-one students reported switching from being Evening Types at baseline to Morning Types at a later survey; those who switched to Morning Types used less social media and consumed less caffeine after 5pm and they showed significant improvements across the semester in sleep duration, sleep quality, and exam scores (ps&lt;.05).

Conclusion

Perceived chronotype is related to social media and caffeine consumption behaviors and is modifiable. Students who perceive themselves as night owls may find better health and academic success if they behave like morning larks.

Support

National Science Foundation (DRL 1920730)

0391 Gateways, Disparities, and Finals Week, Oh My! Translating Sleep Science from the Laboratory to the Classroom

Introduction

Organic chemistry can be an insurmountable “gateway” course for otherwise-qualified students in pre-health pathways. Recent data indicate that organic chemistry increases drop-out risk for females and underrepresented minority students (URMs), raising the provocative possibility that sleep disparities are an underrecognized contributor to achievement gaps in gateway STEM courses.

Methods

In Study 1, 481 students enrolled in organic chemistry courses completed sleep questionnaires at the beginning, midpoint, and end of the semester. In Study 2, non-chemistry majors were randomly assigned to normal sleep (8 hours) or sleep restriction (5.5 hours) before taking an organic chemistry virtual lecture and test. In Study 3, 35 students wore actigraphy for five nights and could earn extra credit on a mid-semester test by averaging ≥8 hours of sleep; actigraphy sleep durations were compared to 40 active-control students who only received sleep education.

Results

In Study 1 (classroom), URM and female students earned lower organic chemistry grades than comparison students, p&lt;.001. Baseline weekday sleep duration predicted test grades across the semester, and students who improved their weekday sleep subsequently improved their organic chemistry grades. In Study 2 (laboratory), mild sleep loss impaired meta-cognitive judgments of organic chemistry learning, a potential causal mechanism for reduced persistence in chemistry courses. In Study 3 (classroom), when better sleep behaviors were incentivized by extra credit, students slept an hour longer/night than control groups (7.8 vs 6.8 hours, p&lt;.001). These benefits persisted 1 month later into finals week when sleep behaviors were not externally incentivized (7.3 vs 6.3 hours, p=.001). Improving sleep improved performance on difficult short answer questions after correcting for pre-final grades (Madjusted=78% vs 72%, p=.04).

Conclusion

Sleep disparities contribute to achievement gaps in gateway STEM courses, but incentives can reverse poor sleep habits. University administrators should develop and implement behavioral change programs to reduce sleep disparities.

Support

National Science Foundation (DRL 1920730)

0101 Episodic Future Thinking Triggers Age-Related Differences in Spindles and Slow Oscillations

Introduction

In young adults, sleep spindles are theorized to represent memory consolidation. Spindle density may be especially prominent when young adults encode information that has future relevance. Older adults, on the other hand, show reduced capacity for future thinking and deficits in sleep-dependent memory consolidation. To advance these literatures, we investigated whether the process of mentally simulating the future (versus remembering the past) was associated with subsequent alterations to sleep microarchitecture in young and older adults.

Methods

64 healthy adults aged 18–84 completed a polysomnography adaptation night followed by two in-laboratory experimental nights. On both nights, participants completed the Modified Future Crovitz Test (MFCT) in which they mentally simulated only future events or remembered only past events (night order counterbalanced). To quantify the extent of future/past thinking, we conducted linguistics analyses on tense (future/past) using LIWC 2015 software.

Results

On the future-thinking night, young adults with greater future-tense MFCT scores showed significantly greater spindle density across frontal, midline, and central sites (r=.42 to r=.51), even when controlling for age, gender, and total word count (all ps &lt; .01). The opposite was true for middle-to-older aged adults; greater future-tense MFCT scores were associated with less spindle density across midline and central sites after controlling for age, gender, and word count (r=-.44 to r=-.46, ps&lt;.05). However, while spindle density decreased, frontal slow oscillations increased in older adults with greater future-tense MFCT scores (r=.39, p&lt;.05). On the past-thinking night, spindle density and slow oscillations were unrelated to past-tense or future-tense MFCT scores for either age group.

Conclusion

Age-related deficits in memory consolidation may be due to impaired tagging of information as having future relevance, or impaired physiological responses during sleep to wake-based tagging. Addressing encoding—spindle interactions may inform why cognitive functioning declines in some adults more than others.

Support

Sleep Research Society Foundation

0193 Sleep Health Across Religions: A Consideration of Bidirectional Processes

Introduction

The psychology of religion literature indicates that religious engagement is beneficial to physical and mental health. Such effects might be mediated by sleep health, which causally affects mood, cognitive, and immune functioning. However, few studies have investigated whether religiosity is associated with better sleep, and no studies have considered the reverse causal direction: better sleep may impact religious behaviors or perceptions.

Methods

We conducted a secondary data analysis of 1,501 participants in Wave 5 of the Baylor Religion Survey (BRS-5). Completed in Spring 2017, the BRS-5 used Address Based Sample methodology to derive a population-based sample. The survey included questions on religious affiliation, behaviors, and perceptions (e.g., certainty of Heaven). Additionally, participants rated their difficulty falling asleep and their average total sleep time. We investigated whether participants were meeting AASM/SRS consensus guidelines of 7–9 hours/night.

Results

Religious affiliation was associated with sleep duration, but not in the predicted direction. Atheists/Agnostics (73%) were significantly more likely to report meeting consensus sleep duration guidelines than religiously-affiliated individuals (65%), p&lt;.05. For example, Atheists/Agnostics reported better sleep duration than Catholics (63%, p&lt;.01) and Baptists (55%, p&lt;.001). Atheists/Agnostics also reported less difficulty falling asleep at night than Catholics (p=.02) and Baptists (p&lt;.001). The effects persisted when controlling for age and were particularly evident in members of African American congregations. Perceptions of getting into Heaven were significantly higher in participants who obtained better sleep duration, p&lt;.05, but interestingly, such beliefs/perceptions were unrelated to difficulty falling asleep at night, suggesting that better sleep may lead to these perceptions rather than vice versa.

Conclusion

In contrast to predictions, religious affiliation was associated with significantly poorer sleep health. Poor sleep health has implications for physical and mental health, and seemingly also religious perceptions/beliefs. Future experimental work is required to disentangle the causal direction of sleep-religiosity associations.

Support

The Baylor Religion Survey was supported by the John Templeton Foundation.

Classical music, educational learning, and slow wave sleep: A targeted memory reactivation experiment

Poor sleep in college students compromises the memory consolidation processes necessary to retain course materials. A solution may lie in targeting reactivation of memories during sleep (TMR). Fifty undergraduate students completed a college-level microeconomics lecture (mathematics-based) while listening to distinctive classical music (Chopin, Beethoven, and Vivaldi). After they fell asleep, we re-played the classical music songs (TMR) or a control noise during slow wave sleep. Relative to the control condition, the TMR condition showed an 18% improvement for knowledge transfer items that measured concept integration (d = 0.63), increasing the probability of "passing" the test with a grade of 70 or above (OR = 4.68, 95%CI: 1.21, 18.04). The benefits of TMR did not extend to a 9-month follow-up test when performance dropped to floor levels, demonstrating that long-term-forgetting curves are largely resistant to experimentally-consolidated memories. Spectral analyses revealed greater frontal theta activity during slow wave sleep in the TMR condition than the control condition (d = 0.87), and greater frontal theta activity across conditions was associated with protection against long-term-forgetting at the next-day and 9-month follow-up tests (rs = 0.42), at least in female students. Thus, students can leverage instrumental music-which they already commonly pair with studying-to help prepare for academic tests, an approach that may promote course success and persistence.

Aftereffects and deactivation of completed prospective memory intentions: A systematic review

Prospective memory, the ability to perform an intended action in the future, is an essential aspect of goal-directed behavior. Intentions influence our behavior and shape the way we process and interact with our environment. One important question for research on prospective memory and goal-directed behavior is whether this influence stops after the intention has been completed successfully. Are intention representations deactivated from memory after their completion, and if so, how? Here, we systematically review 20 years of research on intention deactivation and so-called aftereffects of completed intentions across different research fields to offer an integrative perspective on this topic. We first introduce the currently dominant accounts of aftereffects (inhibition vs. retrieval) and illustrate the paradigms, findings, and interpretations that these accounts developed from. We then review the evidence for each account based on the extant research in these paradigms. While early studies proposed a rapid deactivation or even inhibition of completed intentions, more recent studies mostly suggested that intentions continue to be retrieved even after completion and interfere with subsequent performance. Although these accounts of aftereffects seem mutually exclusive, we will show that they might be two sides of the same coin. That is, intention deactivation and the occurrence of aftereffects are modulated by a multitude of factors that either foster a rapid deactivation or lead to continued retrieval of completed intentions. Lastly, we outline future directions and novel experimental procedures for research on mechanisms and modulators of intention deactivation and discuss practical implications of our findings. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Sleep Duration and Sleep Quality in Caregivers of Patients With Dementia: A Systematic Review and Meta-analysis

IMPORTANCE

In the United States, 16 million family caregivers provide long-term care for patients with dementia. Although one's physical, mental, and cognitive health depends on sleep, many caregivers experience chronic stress, and stress is typically associated with worse sleep quantity and quality.

OBJECTIVE

To quantify the extent, nature, and treatability of sleep problems in dementia caregivers.

DATA SOURCES

PubMed and Scopus databases were systematically searched for articles published through June 2018 using the following keywords: caregiver or spouse or caretaker AND sleep or circadian AND dementia or Alzheimer. Backward citation tracking was performed, and corresponding authors were contacted for additional data to conduct meta-analyses and pooled analyses.

STUDY SELECTION

Two reviewers independently screened 805 studies to identify those that reported sleep duration or sleep quality in caregivers of patients with dementia.

DATA EXTRACTION AND SYNTHESIS

Following the PRISMA guidelines, 2 reviewers independently extracted data from all studies and conducted National Heart, Lung, and Blood Institute study quality assessments. Meta-analyses with random-effects models were performed to evaluate sleep duration, sleep quality, and sleep interventions in dementia caregivers.

MAIN OUTCOMES AND MEASURES

Sleep quality and total sleep time were measured by polysomnography, actigraphy, and self-report.

RESULTS

Thirty-five studies were analyzed with data from 3268 caregivers (pooled mean age [SD of sample means], 63.48 [5.99] years; 76.7% female) were analyzed. Relative to age-matched control noncaregiver adults, caregivers had lower sleep durations akin to losing 2.42 to 3.50 hours each week (Hedges g = -0.29; 95% CI, -0.48 to -0.09; P = .01). Sleep quality was significantly lower in caregivers (Hedges g = -0.66; 95% CI, -0.89 to -0.42; P < .001), but caregivers who underwent sleep intervention trials had better sleep quality than caregivers who did not receive a sleep intervention (Hedges g = 0.35; 95% CI, 0.20-0.49; P < .001).

CONCLUSIONS AND RELEVANCE

Sleep debt is known to have cumulative associations with physical, mental, and cognitive health; therefore, poor sleep quality in dementia caregivers should be recognized and addressed. Although the caregiving role is stressful and cognitively demanding by its nature, better sleep quality was observed in caregivers who received low-cost behavioral interventions.

Rapid eye movement sleep mediates age-related decline in prospective memory consolidation

STUDY OBJECTIVES

Prospective memory, or remembering to execute future intentions, accounts for half of everyday forgetting in older adults. Sleep intervals benefit prospective memory consolidation in young adults, but it is unknown whether age-related changes in slow wave activity, sleep spindles, and/or rapid eye movement (REM) sleep mediate hypothesized effects of aging on prospective memory consolidation.

METHODS

After an adaptation night, 76 adults aged 18-84 completed two experimental nights of in-laboratory polysomnography recording. In the evening, participants encoded and practiced a prospective memory task and were tested the next morning. On a counterbalanced night, they encoded and practiced a control task, and were tested the following morning.

RESULTS

Increasing age predicted worse prospective memory consolidation (r = -.34), even when controlling for encoding, speed, and control-task performance (all ps < .05). Frontal delta power, slow oscillations, and spindle density were not related to prospective memory consolidation. REM sleep duration, however, explained significant variance in prospective memory consolidation when controlling for age (∆R2 = .10). Bootstrapping mediation showed that less REM sleep significantly mediated the aging effect on prospective memory consolidation [b = -.0016, SE = 0.0009 (95% confidence interval [CI] = -0.0042 to -0.0004)]. REM sleep continued to mediate 24.29% of the total effect of age on prospective memory after controlling for numerous demographic, cognitive, mental health, and sleep variables.

CONCLUSION

Age-related variance in REM sleep is informative to how prospective memory consolidation changes with increasing age. Future work should consider how both REM sleep and slow wave activity contribute, perhaps in a sequential or dynamic manner, to preserving cognitive functioning with increasing age.

The 8-Hour Challenge: Incentivizing Sleep during End-of-Term Assessments

Sleep is critical to physical health, mental well-being, attention, and creativity. During the week of final exams, however, fewer than 10% of undergraduate students maintain the recommended average of 8 hours/night (or, even the recommended minimum of 7 hours/night). For students completing multifaceted projects in studio-based majors (e.g., interior design, architecture, graphic design, studio art), anecdotal and questionnaire data suggest that the end-of-semester reduction in sleep duration may be even worse. One potential solution is to offer students an incentive to maintain healthy sleep durations. We offered interior design students, who were enrolled in a freshman-level graphics studio course, an optional extra credit incentive to maintain optimal sleep durations for five nights leading up to the due date of their final project. If participants maintained an average sleep duration of ≥ 8.0 hours for five nights, they would earn extra credit. By contrast, if they slept an average of 7.0-7.9 hours, there would be no grade change, and if they slept an average of ≤ 6.9 hours, they were instructed that they would lose points (no points were actually deducted). Of the 28 students enrolled in the course, 22 students attempted the challenge (78.6%), and we monitored their sleep duration objectively using wristband actigraphy devices. We compared their sleep duration to that of a group of 22 non-incentivized students enrolled in the same program. In the non-incentivized comparison group, very few students averaged 8 hours (9%) or even 7 hours (14%) of sleep per night. In dramatic contrast, the eight-hour challenge increased the percentage of 8-hour and 7-hour sleepers to 59% and 86%, respectively. Participants who took the eight-hour challenge slept an average of 98 minutes more each night than non-incentivized students and 82 minutes more than they self-reported to sleeping during the semester. The substantial increase in nightly sleep duration did not come at a cost to project performance. Individuals who opted in to the sleep challenge performed as well on the final project as students who did not opt in, and students who showed more consistent sleep (i.e., fewer nights of poor sleep followed by rebound sleep) performed better than students who showed inconsistent sleep. Thus, even during highly stressful "deadline" weeks, students can maintain healthy sleeping patterns without exacting a cost on their project performance.

Short sleep and late bedtimes are detrimental to educational learning and knowledge transfer: An investigation of individual differences in susceptibility

Good sleep hygiene practices, including consistent bedtimes and 7-9 h of sleep/night, are theorized to benefit educational learning. However, individuals differ in how much sleep they need, as well as in their chronotype preference. Therefore, some students may be more vulnerable to the cognitive effects of sleep loss, later bedtimes and nonpreferred times of learning than others. One prominent example is the debate regarding whether sleep loss and later bedtimes affect classroom learning more in female or male students. To inform this gender-and-sleep-loss debate, we developed a virtual college-level lecture to use in a controlled, laboratory setting. During Session 1, 78 undergraduate students were randomly assigned to take the lecture at 12:00 (noon condition) or 19:30 (evening condition). Then participants wore wristband actigraphy for 1 week to monitor average and intraindividual variability in sleep duration, bedtime and midpoint of sleep. During Session 2, participants completed a test at the same time of day as Session 1. The test included basic questions that were similar to trained concepts during the lecture (trained items) as well as integration questions that required application of learned concepts (knowledge-transfer items). Bayesian analyses supported the null hypothesis that time of learning did not affect test performance. Collapsed across time of testing, regression analyses showed that shorter sleep durations and later bedtimes explained 13% of the variance in test performance. Longer sleep durations and earlier bedtimes predicted better test performance primarily in females, younger students and morning-types. Interestingly, students with above-median fluid intelligence scores were resilient to short sleep and late bedtimes. Our findings indicate that both sleep and circadian factors should be addressed to optimize educational learning, particularly in the students who are most susceptible to sleep loss.

Dynamic Contributions of Slow Wave Sleep and REM Sleep to Cognitive Longevity

Purpose of review

The purpose of this paper was to address how sleep changes with aging, with the broader goal of informing how REM sleep and slow wave activity mechanisms interact to promote cognitive longevity.

Recent findings

We conducted novel analyses based on the National Sleep Research Resource database. Over approximately five years, middle-to-older aged adults, on average, showed dramatically worse sleep fragmentation, a steady decrease in slow wave sleep, and yet a small increase in REM sleep. Averaging across participants, however, masked a major theme: Individuals differ substantially in their longitudinal trajectories for specific components of sleep. We considered this individual variability in light of recent theoretical and empirical work that has shown disrupted sleep and decreased slow wave activity to impair frontal lobe restoration, glymphatic system functioning, and memory consolidation. Based on multiple recent longitudinal studies, we contend that preserved or enhanced REM sleep may compensate for otherwise disrupted sleep in advancing age.

Summary

The scientific community has often debated whether slow wave activity or REM sleep mechanisms are more important to cognitive aging. We propose that a more fruitful approach for future work will be to investigate how REM and slow wave processes dynamically interact to affect cognitive longevity.

Thought probes during prospective memory encoding: Evidence for perfunctory processes

For nearly 50 years, psychologists have studied prospective memory, or the ability to execute delayed intentions. Yet, there remains a gap in understanding as to whether initial encoding of the intention must be elaborative and strategic, or whether some components of successful encoding can occur in a perfunctory, transient manner. In eight studies (N = 680), we instructed participants to remember to press the Q key if they saw words representing fruits (cue) during an ongoing lexical decision task. They then typed what they were thinking and responded whether they encoded fruits as a general category, as specific exemplars, or hardly thought about it at all. Consistent with the perfunctory view, participants often reported mind wandering (42.9%) and hardly thinking about the prospective memory task (22.5%). Even though participants were given a general category cue, many participants generated specific category exemplars (34.5%). Bayesian analyses of encoding durations indicated that specific exemplars came to mind in a perfunctory manner rather than via strategic, elaborative mechanisms. Few participants correctly guessed the research hypotheses and changing from fruit category cues to initial-letter cues eliminated reports of specific exemplar generation, thereby arguing against demand characteristics in the thought probe procedure. In a final experiment, encoding duration was unrelated to prospective memory performance; however, specific-exemplar encoders outperformed general-category encoders with no ongoing task monitoring costs. Our findings reveal substantial variability in intention encoding, and demonstrate that some components of prospective memory encoding can be done "in passing."

The smartphone in the memory clinic: A study of patient and care partner's utilisation habits

Smartphones have potential as cognitive aids for adults with cognitive impairments. However, little is known about how patients and their care partners utilise smartphones in their day-to-day lives. We collected self-reported smartphone utilisation data from patients referred for neuropsychological evaluations (N = 53), their care partners (N = 44), and an Amazon Mechanical Turk control sample (N = 204). Patient participants were less likely to own a smartphone than controls, with increasing age associated with less utilisation of smartphone features in all groups. Of the patients who owned smartphones, spontaneous use of cognitive aid features (e.g., reminders and calendars) occurred on only a monthly-to-weekly basis; by comparison, patients reported utilising social/general features (e.g., email and internet) on a weekly-to-daily basis. Individuals referred for geriatric cognitive disorder evaluations were less likely to own and use smartphones than individuals referred for other reasons. Care partners reported using their smartphones more frequently than control group adults, with 55% of care partners endorsing utilising their device in caring for the patient. Building upon existing smartphone use habits to increase the use of cognitive aid features may be a feasible intervention for some patients, and including care partners in such interventions is encouraged.

The Effects of an Afternoon Nap on Episodic Memory in Young and Older Adults

Study Objectives

In young adults, napping is hypothesized to benefit episodic memory retention (eg, via consolidation). Whether this relationship is present in older adults has not been adequately tested but is an important question because older adults display marked changes in sleep and memory.

Design

Between-subjects design.

Setting

Sleep laboratory at Emory University School of Medicine.

Participants

Fifty healthy young adults (18-29) and 45 community-dwelling older adults (58-83).

Intervention

Participants were randomly assigned to a 90-minute nap opportunity or an equal interval of quiet wakefulness.

Measurements and Results

Participants underwent an item-wise directed forgetting learning procedure in which they studied words that were individually followed by the instruction to "remember" or "forget." Following a 90-minute retention interval filled with quiet wakefulness or a nap opportunity, they were asked to free recall and recognize those words. Young adults retained significantly more words following a nap interval than a quiet wakefulness interval on both free recall and recognition tests. There was modest evidence for greater nap-related retention of "remember" items relative to "forget" items for free recall but not recognition. Older adults' memory retention did not differ across nap and quiet wakefulness conditions, although they demonstrated greater fragmentation, lower N3, and lower rapid eye movement duration than the young adults.

Conclusions

In young adults, an afternoon nap benefits episodic memory retention, but such benefits decrease with advancing age.

The effects of bedtime writing on difficulty falling asleep: A polysomnographic study comparing to-do lists and completed activity lists

Bedtime worry, including worrying about incomplete future tasks, is a significant contributor to difficulty falling asleep. Previous research showed that writing about one's worries can help individuals fall asleep. We investigated whether the temporal focus of bedtime writing-writing a to-do list versus journaling about completed activities-affected sleep onset latency. Fifty-seven healthy young adults (18-30) completed a writing assignment for 5 min prior to overnight polysomnography recording in a controlled sleep laboratory. They were randomly assigned to write about tasks that they needed to remember to complete the next few days (to-do list) or about tasks they had completed the previous few days (completed list). Participants in the to-do list condition fell asleep significantly faster than those in the completed-list condition. The more specifically participants wrote their to-do list, the faster they subsequently fell asleep, whereas the opposite trend was observed when participants wrote about completed activities. Therefore, to facilitate falling asleep, individuals may derive benefit from writing a very specific to-do list for 5 min at bedtime rather than journaling about completed activities. (PsycINFO Database Record

Do Older Adults Need Sleep? A Review of Neuroimaging, Sleep, and Aging Studies

PURPOSE OF REVIEW

Sleep habits, sleep physiology, and sleep disorders change with increasing age. However, there is a longstanding debate regarding whether older adults need sleep to maintain health and daily functioning (reduced-sleep-need view). An alternative possibility is that all older adults need sleep, but that many older adults have lost the ability to obtain restorative sleep (reduced-sleep-ability view). Prior research using behavioral and polysomnography outcomes has not definitively disentangled the reduced-sleep-need and reduced-sleep-ability views. Therefore, this review examines the neuroimaging literature to determine whether age-related changes in sleep cause-or are caused by-age-related changes in brain structure, function, and pathology.

RECENT FINDINGS

In middle-aged and older adults, poorer sleep quality, greater nighttime hypoxia, and shorter sleep duration related to cortical thinning in frontal regions implicated in slow wave generation, in frontoparietal networks implicated in cognitive control, and in hippocampal regions implicated in memory consolidation. Furthermore, poor sleep quality was associated with higher amyloid burden and decreased connectivity in the default mode network, a network that is disrupted in the pathway to Alzheimer's disease.

SUMMARY

All adults need sleep, but cortical thinning and amyloidal deposition with advancing age may weaken the brain's ability to produce restorative sleep. Therefore, sleep in older adults may not always support identical functions for physical, mental, and cognitive health as in young adults.

The Cognitive Attentional Syndrome is Associated With Sleep Difficulties in a Community Sample

We examined whether a process common to anxiety, labeled the cognitive attentional syndrome (CAS), is also associated with sleep disturbances. The CAS represents the sustained use of self-regulating strategies, such as rumination and worry, and beliefs individuals hold about such strategies. Using a sample of community adults located in the United States (N = 226), we found that the CAS was positively associated with sleep difficulties. The association remained intact after controlling for demographic variables, physical health, and negative affect. We further found that self-regulating strategies may be the component of the CAS that is most important to sleep disturbances. Future experimental studies are needed to elucidate whether there exists a causal, and potentially bidirectional, link between the CAS and sleep difficulties.

The Dynamic Interplay Between Bottom-Up and Top-Down Processes Supporting Prospective Remembering

Like many dual process theories in the psychological sciences, existing models of prospective memory (i.e., remembering to execute future intentions) emphasize the role of singular top-down or bottom-up processes that act in isolation. We argue that top-down and bottom-up processes are interconnected and dynamically interact to support prospective memory. We elaborate on this dynamic multiprocess framework by focusing on recent behavioral, neuroimaging, and eye-tracking research that demonstrated the dynamic nature of monitoring (top-down) and spontaneous retrieval (bottom-up) processes in relation to contextual factors, metacognition, and individual differences. We conclude that identifying how dual processes interact with environmental and individual difference factors is crucial for advancing understanding of cognition and behavior.

Improving Prospective Memory in Healthy Older Adults and Individuals with Very Mild Alzheimer's Disease

OBJECTIVES

To test the utility of a memory-encoding strategy for improving prospective memory (PM), the ability to remember to execute future goals (e.g., remembering to take medications), which plays an important role in independent living in healthy older adults and those with very mild Alzheimer's disease (AD).

DESIGN

Participants were randomly assigned to an encoding strategy condition or a standard encoding condition.

SETTING

A longitudinal study conducted at an Alzheimer's disease research center. Testing took place at the center and in a university testing room.

PARTICIPANTS

Healthy older adults (Clinical Dementia Rating (CDR) = 0.0, n = 38) and those classified as being in the very mild stage of AD (CDR = 0.5, n = 34).

INTERVENTION

A simple strategy ("If I see Cue X, then I will perform Intention Y") was used to strengthen PM encoding and reduce the probability of forgetting to execute one's future plans.

MEASUREMENTS

PM was assessed using Virtual Week, a laboratory task that requires the simulation of common PM tasks (the types of tasks performed in everyday life), such as taking one's medication at breakfast.

RESULTS

The encoding strategy significantly reduced PM failures in healthy older adults and those with very mild AD and was effective regardless of the individual's episodic memory ability.

CONCLUSION

This encoding strategy was successful in reducing PM errors in healthy older adults and those with mild AD with a range of memory abilities.

Affective Correlates of Psychosis in Parkinson's Disease

OBJECTIVE

To examine the nature of the association between affective disorders and psychosis in Parkinson's disease (PD).

BACKGROUND

In PD, psychosis and affective disorders are common and independently impact quality of life and mortality. Both depression and psychosis are correlated with the occurrence of cognitive dysfunction, suggesting that they may share neurobiological substrates. Anxiety has not been examined as a correlate of psychosis.

METHODS

144 PD subjects were evaluated with the Schedule for Assessment of Positive Symptoms to assess psychotic features, while depression and anxiety were examined by the Structured Clinical Interview for DSM-IV-TR (SCID) and self-assessment scales Beck Depression Inventory II (BDI-II) and Beck Anxiety Inventory (BAI). Correlational analyses assessed associations between hallucinations and delusions with depression and anxiety.

RESULTS

A diagnosis of anxiety (SCID) was significantly (p=.015) associated with hallucinations (OR=4.81, CI=1.36-16.99). Severity of anxiety (BAI) significantly predicted (p=.03) the presence of hallucinations (OR=1.08, CI=1.01-1.15) and delusions (OR=1.09, CR=1.01-1.17). Current depression (SCID) was significantly (p=.001) associated with the presence of hallucinations (OR=6.12, CI=2.04-18.39) and delusions (OR=7.14, CI=2.23-22.93). Multiple linear regressions revealed that severity of anxiety remained an independent predictor (p<.05) of both the number of types of hallucinations (t=3.06, p=.003) and delusions (t=2.87, p=.005). Severity of depression was a significant predictor of the total number of delusions (t=2.28, p=.024).

CONCLUSIONS

This study demonstrates an association between depression and psychosis and, for the first time, an association between anxiety and psychosis. These associations may have implications on pathophysiology and treatment of psychosis in PD.

An implementation intention strategy can improve prospective memory in older adults with very mild Alzheimer's disease

OBJECTIVES

This study tested whether (1) very mild Alzheimer's disease (AD) is associated with impaired prospective memory (PM) for tasks that are supported by either spontaneous retrieval (focal PM) or strategic monitoring (non-focal PM) and (2) implementation intention (II) encoding could improve PM performance in very mild AD.

DESIGN

Thirty-eight healthy older adults and 34 with very mild AD were randomly assigned to perform two PM tasks in either the standard or the II encoding condition.

METHOD

All participants performed blocks of category decision in which they were asked to respond to a focal PM target (e.g., the word 'orange') and a non-focal PM target (e.g., words that begin with the letter 'o'). Half of the participants encoded PM instructions in the standard manner, while the other half had a stronger encoding by forming IIs. PM accuracy and category decision accuracy and reaction times were measured.

RESULTS

Participants with very mild AD showed deficits in both focal and non-focal PM performance compared to the healthy controls, reflecting deficits in both spontaneous retrieval and strategic monitoring. Participants with very mild AD in the II encoding condition showed better focal PM performance relative to those in the standard encoding condition.

CONCLUSIONS

Deficits in both focal and non-focal PM are associated with very mild AD and IIs may be a helpful behavioural intervention for the focal PM deficits.

PRACTITIONER POINTS

Multiple deficits in PM are observable in very mild AD. Implementation intentions may enhance focal PM in very mild AD. Future research using larger samples is needed to better understand the effect of II on non-focal PM tasks in healthy older adults and those with very mild AD. The use of simple laboratory PM tasks may limit the generality of our findings. Future research is needed to investigate whether IIs improve PM over a range of more realistic tasks.

Sleep correlates of trait executive function and memory in Parkinson's disease

BACKGROUND

Sleep disturbance and cognitive impairment are correlated in non-diseased populations, but their association in Parkinson's disease (PD) is uncertain. Prior studies examining measures of cognition in relation to sleep have used either self-report or actigraphically measured sleep and have produced conflicting findings.

OBJECTIVE

In this descriptive study, we correlated measurements of sleep in PD patients derived from the gold-standard measurement, in-lab polysomnography, with an extensive battery of cognitive measures. We hypothesized that poorer sleep would be related to relatively more impaired cognition.

METHODS

Idiopathic PD patients (n = 34) completed a cognitive battery encompassing three broad domains (executive function, immediate memory and delayed memory), and underwent PSG for two nights. Scores for each domain from individual cognitive measures were converted to z-scores and then averaged to produce a composite score. We used second night PSG data and quantified measures of sleep architecture, sleep continuity, sleep apnea and nocturnal movement (periodic leg movements, PLMS).

RESULTS

Lower executive function was associated with higher PLMS after controlling for chronological age, mini-mental state examination scores, and UPDRS motor subscale scores. These results were independent from psychomotor speed. There was a marginally significant positive correlation between the proportion of time spent in REM and immediate recall ability. Measures of sleep continuity and sleep apnea were unrelated to cognition in these patients.

CONCLUSIONS

PLMS, known to be a frequent feature of PSG-measured sleep in PD, may be an important correlate of impaired executive function in PD. Whether treating this disorder of sleep results in improvement in cognition remains to be determined.