Task switching in older adults with and without insomnia

A non-pharmacological multi-modal therapy to improve sleep and cognition and reduce mild cognitive impairment risk: Design and methodology of a randomized clinical trial

Aging populations are at increased risk of sleep deficiencies (e.g., insomnia) that are associated with a variety of chronic health risks, including Alzheimer's disease and related dementias (ADRD). Insomnia medications carry additional risk, including increased drowsiness and falls, as well as polypharmacy risks. The recommended first-line treatment for insomnia is cognitive behavioral therapy for insomnia (CBTi), but access is limited. Telehealth is one way to increase access, particularly for older adults, but to date telehealth has been typically limited to simple videoconferencing portals. While these portals have been shown to be non-inferior to in-person treatment, it is plausible that telehealth could be significantly improved. This work describes a protocol designed to evaluate whether a clinician-patient dashboard inclusive of several user-friendly features (e.g., patterns of sleep data from ambulatory devices, guided relaxation resources, and reminders to complete in-home CBTi practice) could improve CBTi outcomes for middle- to older-aged adults (N = 100). Participants were randomly assigned to one of three telehealth interventions delivered through 6-weekly sessions: (1) CBTi augmented with a clinician-patient dashboard, smartphone application, and integrated smart devices; (2) standard CBTi (i.e., active comparator); or (3) sleep hygiene education (i.e., active control). All participants were assessed at screening, pre-study evaluation, baseline, throughout treatment, and at 1-week post-treatment. The primary outcome is the Insomnia Severity Index. Secondary and exploratory outcomes span sleep diary, actiwatch and Apple watch assessed sleep parameters (e.g., efficiency, duration, timing, variability), psychosocial correlates (e.g., fatigue, depression, stress), cognitive performance, treatment adherence, and neurodegenerative and systemic inflammatory biomarkers.

FISHERMAN: A Serious Game for Executive Function Assessment of Older Adults

Executive functions (EFs) are essential for daily living activities but decline with age. Convenient assessment and timely intervention have particular significance for older adults. However, the traditional laboratory tasks of EFs are typically monotonous and inconvenient. The current study aimed to develop an interesting and convenient supplementary tool to assess EFs for older adults. According to the theory of EFs, we developed a serious game, FISHERMAN, to assess EFs. The game includes three subgames, Cautious Fisherman, Agile Fisherman, and Wise Fisherman, targeting core components of inhibition, shifting, and working memory, respectively. The current study aims to verify the reliability and validity of the game. One hundred and eight healthy older adults participated in this study and were tested through the FISHERMAN game and a battery of cognitive tests. The results show that the FISHERMAN game has high internal consistency reliability and good construct validity as well as criterion-related validity, suggesting that the game design is valid and can be used in EFs assessment for older adults. Future studies are warranted to establish the norm of the FISHERMAN game in older adults and investigate whether the FISHERMAN game can be generalized to other populations.

Objective Measures of Cognitive Performance in Sleep Disorder Research

Neurocognitive tests offer objective and reliable assessment of patients' status and progress. However, there is no consensus on how to use neurocognitive assessment in sleep disorder research. An effective use of neurocognitive assessment must be based on standardized practices and have a firm theoretic basis. The aim of this review is to offer an overview of how different tests have been used in the field, mapping each test onto a corresponding cognitive domain and propose how to move forward with a suggested cognitive battery of tests covering all major cognitive domains.

Age-related alterations in the cerebrovasculature affect neurovascular coupling and BOLD fMRI responses: Insights from animal models of aging

The present and future research efforts in cognitive neuroscience and psychophysiology rely on the measurement, understanding, and interpretation of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to effectively investigate brain function. Aging and age-associated pathophysiological processes change the structural and functional integrity of the cerebrovasculature which can significantly alter how the BOLD signal is recorded and interpreted. In order to gain an improved understanding of the benefits, drawbacks, and methodological implications for BOLD fMRI in the context of cognitive neuroscience, it is crucial to understand the cellular and molecular mechanism of age-related vascular pathologies. This review discusses the multifaceted effects of aging and the contributions of age-related pathologies on structural and functional integrity of the cerebral microcirculation as they has been investigated in animal models of aging, including age-related alterations in neurovascular coupling responses, cellular and molecular mechanisms involved in microvascular damage, vascular rarefaction, blood-brain barrier disruption, senescence, humoral deficiencies as they relate to, and potentially introduce confounding factors in the interpretation of BOLD fMRI.

Does objectively-assessed sleep moderate the association between history of major depressive disorder and task-switching?

BACKGROUND

Executive function and psychomotor speed are consistently impaired in patients with major depressive disorder (MDD). Persistent cognitive impairments after depression remission are thought to reflect "scarring" from the neurotoxic effects of hypothalamic-pituitary-adrenal axis activity during a depressive episode. As sleep also deteriorates with depression and restores daytime executive functions, we examined whether adequate sleep could be protective against task-switching and psychomotor impairments associated with a history of MDD.

METHODS

This cross-sectional study tested task-switching associations with MDD history, sleep, and their interaction to determine whether sleep continuity and sleep duration moderate the relationship between MDD history and task-switching performance.

RESULTS

After adjusting for age, sex, education, current depressive symptoms, and use of anti-depressants, a history of MDD, particularly recurrent MDD, was associated with slower response speed and disproportionately lower accuracy on repetition trials compared to switch trials, reflecting impaired adoption of a task-set. Regardless of MDD history, higher wake after sleep onset and shorter total sleep time were associated with slower response times, but neither sleep measure moderated the association between depression history and task-switching performance.

LIMITATIONS

This cross-sectional study cannot assess the causal direction of associations. One night of sleep in the laboratory was used to assess sleep and a single task-switching paradigm was used to assess executive function.

CONCLUSIONS

These results suggest that longer, more continuous sleep is associated with greater psychomotor speed across healthy controls and those with a history of MDD, but MDD-task-switching associations are not mitigated by longer or more continuous sleep.

Effects of Brief Behavioral Treatment for Insomnia on Daily Associations between Self-Reported Sleep and Objective Cognitive Performance in Older Adults

OBJECTIVE

Behavioral treatments for insomnia improve sleep in older adults, but research documenting their effects on cognitive performance is mixed. We explored whether a brief behavioral treatment for insomnia (BBTi) impacts daily associations between sleep parameters and next day cognition.

METHODS

Sixty-two older adults (M_age = 69.45 years, SD = 7.71) with insomnia completed either 4 weeks of BBTi or self-monitoring control (SMC). At baseline, post-treatment, and 3 month follow-up, participants completed 14 days of diaries measuring sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE), as well as daily cognitive tests measuring processing speed (i.e., symbol digit modalities test, SDMT), and reasoning (i.e., letter series). At each time period, associations between sleep parameters and daily cognition, controlling for age, education, insomnia duration, use of sleep medications, and depression (i.e., Beck Depression Inventory-2^nd Edition scores), were examined through multilevel modeling.

RESULTS

At post-treatment, we observed an interactive fixed effect of treatment condition (i.e., BBTi/SMC) and TST on daily SDMT and letter series performance. For BBTi, longer TST was associated with better letter series performance, and did not predict SDMT performance. For SMC, longer TST was associated with worse SDMT, and was not associated with letter series performance. Greater WASO (regardless of group) was associated with better SDMT performance at post-treatment. Associations were not maintained at follow-up.

CONCLUSIONS

Sleep duration may play an important role in BBTi-related improvements in daily higher order cognition. Maintenance of these associations may be facilitated by booster sessions following post-treatment.

CLINICAL TRIAL IDENTIFIER

NCT02967185.

Insomnia in Older Adults

Purpose of Review

To evaluate and summarize recent research articles pertaining to insomnia in older adults that can guide healthcare providers on factors to consider when assessing and managing insomnia.

Recent Findings

Up to 75% of older adults experience symptoms of insomnia. Insomnia is associated with socioeconomic status, racial and ethnic classification, family relationships, medical and mental health disorders, cognitive function, and dementia. Although one-fifth of older adults are still prescribed sleep medications, cognitive behavioral therapy for insomnia is the first line treatment for insomnia, resulting in short-term and long-term benefits.

Summary

To manage insomnia safely and effectively, healthcare providers need to consistently assess for insomnia during baseline and annual assessments, evaluate medical and social factors associated with insomnia, minimize the use of sleep medications, and provide referrals to and/or collaborate with providers who perform cognitive behavioral therapy for insomnia. Insomnia screening is important as it facilitates early intervention with behavioral management, reduces the potential for pharmacological management, which increases fall risk in older adults, and enables further assessment and early identification of outcomes such as cognitive impairment.

Slow-Wave Activity Enhancement to Improve Cognition

Slow-wave activity (SWA), and its coupling with other sleep features, reorganizes cortical circuitry, supporting cognition. This raises the question: can cognition be improved through SWA enhancement? SWA enhancement techniques range from behavioral interventions (such as exercise), which have high feasibility but low specificity, to laboratory-based techniques (such as transcranial stimulation), which have high specificity but are less feasible for widespread use. In this review we describe the pathways through which SWA is enhanced. Pathways encompass enhanced neural activity, increased energy metabolism, and endocrine signaling during wakefulness; also direct enhancement during sleep. We evaluate the robustness and practicality of SWA-enhancement techniques, discuss approaches for determining a causal role of SWA on cognition, and present questions to clarify the mechanisms of SWA-dependent cognitive improvements.

Efficacy of brief behavioral treatment for insomnia in older adults: examination of sleep, mood, and cognitive outcomes

OBJECTIVE

The aim of the present study was to examine the effects of a brief behavioral intervention for insomnia (BBTi) on sleep parameters, mood, and cognitive functioning in older adults.

METHODS

Older adults (aged 65 years or more) underwent four weekly sessions of BBTi or self-monitoring control (SMC). Participants completed 14 days of sleep diaries and actigraphy measuring sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), sleep efficiency (SE), and sleep quality ratings at baseline, post-treatment, and three month follow-up. Participants also completed mood scales (Geriatric Depression Scale [GDS]; Beck Depression Inventory-II; and State Trait Anxiety Inventory) and neuropsychological testing (measuring global cognition, language, memory, attention and processing speed, and executive function) at the three timepoints.

RESULTS

Significant condition (BBTi vs. SMC) x time (baseline vs. post-treatment vs. follow-up) interactions revealed that BBTi improved relative to baseline in sleep diary-reported SOL, WASO, SE, and sleep quality, and these improvements were maintained at follow-up. SMC showed no change in these measures. A main effect of time showed that actigraphy-measured WASO improved from baseline for both BBTi and SMC at post-treatment. A main effect of time revealed that both BBTi and SMC patients endorsed fewer GDS symptoms relative to baseline at post-treatment and follow-up. We observed no change in performance on neuropsychological measures.

CONCLUSIONS

A four-week BBTi is an efficacious intervention for reducing insomnia symptoms in older adults. BBTi does not selectively improve mood or cognitive functioning. Future work should examine effects of BBTi on physiological measures of sleep architecture and day-to-day cognition.

CLINICAL TRIAL IDENTIFER

NCT02967185.

Physiological Aging Influence on Brain Hemodynamic Activity during Task-Switching: A fNIRS Study

Task-switching (TS) paradigm is a well-known validated tool useful for exploring the neural substrates of cognitive control, in particular the activity of the lateral and medial prefrontal cortex. This work is aimed at investigating how physiological aging influences hemodynamic response during the execution of a color-shape TS paradigm. A multi-channel near infrared spectroscopy (fNIRS) was used to measure hemodynamic activity in 27 young (30.00 ± 7.90 years) and 11 elderly participants (57.18 ± 9.29 years) healthy volunteers (55% male, age range: (19-69) years) during the execution of a TS paradigm. Two holders were placed symmetrically over the left/right hemispheres to record cortical activity [oxy-(HbO) and deoxy-hemoglobin (HbR) concentration] of the dorso-lateral prefrontal cortex (DLPFC), the dorsal premotor cortex (PMC), and the dorso-medial part of the superior frontal gyrus (sFG). TS paradigm requires participants to repeat the same task over a variable number of trials, and then to switch to a different task during the trial sequence. A two-sample t-test was carried out to detect differences in cortical responses between groups. Multiple linear regression analysis was used to evaluate the impact of age on the prefrontal neural activity. Elderly participants were significantly slower than young participants in both color- (p < 0.01, t = -3.67) and shape-single tasks (p = 0.026, t = -2.54) as well as switching (p = 0.026, t = -2.41) and repetition trials (p = 0.012, t = -2.80). Differences in cortical activation between groups were revealed for HbO mean concentration of switching task in the PMC (p = 0.048, t = 2.94). In the whole group, significant increases of behavioral performance were detected in switching trials, which positively correlated with aging. Multivariate regression analysis revealed that the HbO mean concentration of switching task in the PMC (p = 0.01, β = -0.321) and of shape single-task in the sFG (p = 0.003, β = 0.342) were the best predictors of age effects. Our findings demonstrated that TS might be a reliable instrument to gather a measure of cognitive resources in older people. Moreover, the fNIRS-related brain activity extracted from frontoparietal cortex might become a useful indicator of aging effects.