Connections Between Insomnia and Cognitive Aging

Structural connectivity of dopaminergic pathways in major depressive disorder: An ultra-high resolution 7-Tesla diffusion MRI study

Accumulating evidence points to imbalanced dopamine (DA) signaling and circulating levels in the pathophysiology of major depressive disorder (MDD). However, the use of conventional MRI scanners and acquisition techniques has prevented a thorough examination of DA neural pathways in MDD. We uniquely employed ultra-high field diffusion MRI at 7.0 Tesla to map the white matter architecture and integrity of several DA pathways in MDD patients. Fifty-three MDD patients and 12 healthy controls (HCs) were enrolled in the final analysis. Images were acquired using a 7.0 Tesla MRI scanner. FreeSurfer was used to segment components of DA pathways, and MRtrix was used to perform preprocessing and tractography of mesolimbic, mesocortical, nigrostriatal, and unconventional DA pathways. Bayesian analyses assessed the impact of MDD and clinical features on DA tracts. MDD was associated with perturbed white matter microstructural properties of the nigrostriatal pathway, while several MDD features (severity of depression/age of onset/insomnia) related to connectivity changes within mesocortical, nigrostriatal, and unconventional pathways. MDD is associated with microstructural differences in the nigrostriatal pathway. The findings provide insight into the structural architecture and integrity of several DA pathways in MDD, and implicate their involvement in the clinical manifestation of MDD.

The association between insomnia and cognitive decline: A scoping review

OBJECTIVE

This study aimed to investigate the association between insomnia and cognitive decline to provide insights for clinical interventions and future research.

METHODS

The PubMed, Embase, Web of Science, Scopus, Cochrane Library, and ProQuest databases were systematically searched to identify studies on the association between insomnia and cognitive decline published within the last decade. The quality of the included studies was evaluated, followed by data extraction and summary analysis.

RESULTS

A total of 36 studies were included in the review. Both subjective and objective measures were utilized across 12 indices to assess sleep status, while cognitive function was evaluated using 5 scales and 34 tests. The results revealed a significantly increased risk of cognitive decline or Alzheimer's disease among patients with insomnia, alongside notable impairments in attention, memory, visuospatial abilities, executive function, and verbal memory. Comprehensive assessments of cognitive domains were more sensitive in detecting group differences compared to assessments of specific cognitive sub-functions. Furthermore, MRI analyses showed reduced gray matter volumes in regions such as the prefrontal cortex, cingulate gyrus, temporal lobe, and hippocampus, together with reduced integrity of the white matter in patients with insomnia.

CONCLUSIONS

The findings indicate a potentially bidirectional relationship between insomnia and cognitive decline, suggesting that each may influence and exacerbate the other. Insomnia may increase the risk of cognitive decline and appears to be associated with reduced gray matter volume and compromised white matter integrity in the brain, which could potentially lead to declines in attention, memory, visuospatial abilities, executive function, and verbal memory. Conversely, cognitive decline may contribute to the onset of insomnia, further deteriorating sleep quality. However, further research is necessary to fully comprehend this intricate relationship.

Senegenin regulates the mechanism of insomnia through the Keap1/Nrf2/PINK1/Parkin pathway mediated by GAD67

GAD67 impacts insomnia as a key enzyme catalysing the conversion of glutamate (Glu) to gamma-aminobutyric acid (GABA). Senegenin enhances neuroprotection and is used widely to treat insomnia and other neurological diseases. This study aimed to investigate how senegenin regulates insomnia through a GAD67-mediated signalling pathway. We measured GAD67 expression levels in insomnia patients and evaluated the expression levels of GAD67 and Keap1/Nrf2/Parkin/PINK1-related cytokines following GAD67 lentiviral transfection in PC12 cells and in rat models. We also assessed cellular reactive oxygen species (ROS) and mitochondrial membrane potential levels. Additionally, EEG/EMG was used to analyse the sleep phases of rats and to assess memory and exploration functions. Pathological changes and the expression of GAD67 and sleep-related proteins in the hippocampus were examined. The results showed that GAD67 expression was increased in insomnia patients, ROS levels were elevated, and the mitochondrial membrane potential was decreased in the GAD67-KD group. Insomnia rats exhibited changes in sleep rhythm, learning, and exploration dysfunction, pathological changes in the CA1 region of the hippocampus, and differential expression of GAD67 and sleep-related factors. Inhibitory neurofactor expression levels were decreased in insomnia rats, showing a positive correlation in the GAD67-KD group and a negative correlation in the GAD67-OE group. Conversely, excitatory factor expression levels were increased in insomnia rats, showing a positive correlation in the GAD67-KD group and a negative correlation in the GAD67-OE group. Senegenin intervention modulated cytokine expression levels. In conclusion, GAD67 negatively regulates insomnia, and senegenin can regulate insomnia by mediating the expression of cytokines in the GAD67-regulated Keap1/Nrf2/Parkin/PINK1 pathway.

Lectin YKL-40 Level and Telomere Length are Indicators of Insomnia Disorder

OBJECTIVE

To explore the relationship between YKL-40 level, telomere length, and different subtypes of insomnia disorder.

METHODS

A total of 145 individuals suffering from insomnia were enrolled and divided into four groups according to the insomniac subtypes: difficulty initiating sleep, early morning awakening, difficulty maintaining sleep, and mixed symptoms. Eighty healthy controls were also collected at the same time. Peripheral leukocyte genomic DNA was extracted, relative telomere lengths were measured using the real-time quantitative polymerase chain reaction method, and YKL-40 levels were determined using enzyme-linked immunoassay. Logistic regression modeling was used to analyze the correlation between different insomnia subtypes, YKL-40 level, and telomere length.

RESULTS

People with telomere lengths in the lowest tertile were more likely to have trouble falling asleep (odds ratio (OR) 2.13, 95% confidence interval (CI) 1.22-3.63; p = 0.03) and had a higher frequency of mixed symptoms (OR 1.49, 95% CI 1.30-2.81; p = 0.04). People in the highest tertile of YKL-40 level had an increased chance of waking up early (OR 2.98, 95% CI 1.54-5.33; p = 0.01) and more mixed symptoms (OR 1.47, 95% CI 1.22-2.79; p = 0.02). Furthermore, using receiver operating characteristic curve analysis, the area under the curve of YKL-40 level and telomere length was 0.806 and 0.746, respectively.

CONCLUSIONS

Telomere length in patients with difficulty initiating sleep and mixed symptoms was significantly shortened and the level of YKL-40 in people who have early morning awakening and mixed symptoms was significantly increased. Our findings provide the first evidence that leukocyte telomere length and YKL-40 level are individually linked to mixed symptoms.

Chronic Sleep Deprivation Impairs Visual Functions via Oxidative Damage in Mice

Sleep deprivation (SD) is a global public health burden, and has a detrimental role in the nervous system. Retina is an important part of the central nervous system; however, whether SD affects retinal structures and functions remains largely unknown. Herein, chronic SD mouse model indicated that loss of sleep for 4 months could result in reductions in the visual functions, but without obvious morphologic changes of the retina. Ultrastructural analysis by transmission electron microscope revealed the deterioration of mitochondria, which was accompanied with the decrease of multiple mitochondrial proteins in the retina. Mechanistically, oxidative stress was provoked by chronic SD, which could be ameliorated after rest, and thus restore retinal homeostasis. Moreover, the supplementation of two antioxidants, α-lipoic acid and N-acetyl-l-cysteine, could reduce retinal reactive oxygen species, repair damaged mitochondria, and, as a result, improve the retinal functions. Overall, this work demonstrated the essential roles of sleep in maintaining the integrity and health of the retina. More importantly, it points towards supplementation of antioxidants as an effective intervention strategy for people experiencing sleep shortages.

Daytime Sleepiness, Apnea, Neuroimaging Correlates and Cortisol Dysregulation in a Memory Clinic Cohort

BACKGROUND

Sleep disturbances as well as cortisol hypersecretion are increasingly acknowledged as risk factors for Alzheimer's disease (AD). However, the mechanisms underlying the association, and the interplay with cortisol abnormalities, remain unclear.

OBJECTIVES

This study aims to identify how self-reported sleep disturbances are associated with structural brain measures and diurnal cortisol dysregulation among memory clinic patients.

DESIGN

A cross-sectional study performed at Karolinska University Hospital Memory Clinic, Sweden.

PARTICIPANTS

The study was based on 146 memory clinic patients diagnosed with either subjective cognitive impairment or mild cognitive impairment.

MEASUREMENTS

Self-reported sleep was measured using the Karolinska Sleep Questionnaire. MRI or CT was used to quantify structural brain measures using four visual rating scales (Scheltens, Pasquier, Koedam, and Fazekas scales), and salivary cortisol was sampled to measure diurnal cortisol patterns through measures of cortisol immediately after awakening, cortisol awakening response, bedtime cortisol, total cortisol from awakening to bedtime, and the AM/PM cortisol ratio.

RESULTS

Increased sleep apnea index (OR=1.20, 95% CI=1.04:1.39, p=0.015) was associated with greater odds of posterior brain atrophy, measured by the Koedam visual rating scale, and reduced awakening cortisol (β=-0.03, 95% CI=-0.07:0.00, p=0.045). Increased daytime sleepiness was associated with both reduced awakening cortisol (β=-0.03, 95% CI=-0.06:0.00, p=0.025) and a reduced AM/PM cortisol ratio (β=-0.04, CI=-0.08:-0.01, p= 0.021).

CONCLUSION

In a memory clinic cohort self-reported sleep disturbances are associated with both worse structural brain tissue integrity and altered diurnal cortisol profiles. These findings may add insights into possible mechanisms behind sleep disturbances in aging with subjective and cognitive impairment.

Linking Adverse Childhood Experiences and Other Risk Factors to Subjective Cognitive Decline in an Aging Population

Introduction

The Centers for Disease Control and Prevention's Healthy Brain Initiative (HBI) encourages an interdisciplinary approach to addressing the burden of subjective cognitive decline (SCD) among the aging US population as that population continues to increase. Our study is one of the first to evaluate associations between SCD and adverse childhood experiences (ACEs) and other modifiable risk factors to support implementation of the initiative.

Methods

We used multivariate logistic regression to assess data from the 2020 Behavioral Risk Factor Surveillance System survey to evaluate associations between SCD and ACEs scores and sociodemographic, behavioral, and clinical risk factors. Models were weighted to account for the complex survey design.

Results

Approximately 8.1% of survey respondents reported experiencing SCD within the past 12 months. Adjusted regression analysis showed that conditions such as depression (AOR, 2.85; 95% CI, 2.29-3.55), arthritis (AOR, 1.30; 95% CI, 1.05-1.60), and diabetes (AOR, 1.33; 95% CI, 1.05-1.68) were significantly associated with SCD. SCD was also associated with experiencing more than 3 falls per year (AOR, 2.95; 95% CI, 2.13-4.09), sleeping more than 9 hours per night (AOR, 2.06; 95% CI, 1.37-3.09), and physical inactivity (AOR, 1.32; 95% CI, 1.03-1.68). Two or more ACEs also significantly increased the odds of SCD (AOR, 1.69; 95% CI, 1.36-2.10).

Conclusion

Findings from our study can be used to inform policy, environment, and systems change efforts aimed at addressing modifiable risk factors to support healthy aging. The role of ACEs as determinants of brain health across the life course should also be considered in the design of clinical and community-based interventions.

Protocol for a randomized controlled trial exploring the brain mechanism and therapeutic effect of electroacupuncture on cognitive function and sleep quality in chronic insomnia

BACKGROUND

Insomnia is a prevalent sleep disorder that affects up to 15% of the population worldwide and is the second most common mental health issue. There is increasing interest in the effects of long-term insomnia on cognitive function. Electroacupuncture can effectively improve cognitive function and sleep quality, yet the underlying brain network mechanisms remain unclear. This study aims to explore the network regulatory mechanisms associated with enhanced cognitive function and sleep quality, providing theoretical support for the use of electroacupuncture in the clinical treatment of chronic insomnia.

METHODS

This study is divided into two parts. Sixteen individuals with chronic insomnia and 16 healthy controls of similar age and gender will be recruited in Study 1 to examine the brain network topology of individuals with chronic insomnia. Study 2 will be a randomized controlled trial with 120 chronic insomnia patients divided into three groups: Group A (electroacupuncture plus placebo drug), Group B (drug plus placebo electroacupuncture), and Group C (placebo electroacupuncture plus placebo drug). Participants will be exposed to 24 treatments over an 8-week period (3 times per week) and monitored for 12 additional weeks. The primary outcome measure will be changes in brainwave data from before to after the treatment. In addition, the Wisconsin Card Sorting Test and the Pittsburgh Sleep Quality Index will be utilized as secondary outcomes to measure from before to after treatment and during the follow-up. A correlation analysis will be conducted to explore links among modifications in brainwave patterns, Wisconsin Card Sorting Test scores, and Pittsburgh Sleep Quality Index scores. Additionally, any adverse events will be strictly monitored.

DISCUSSION

Electroacupuncture may represent an alternative treatment for chronic insomnia, and this trial is expected to reveal the brain mechanism by which electroacupuncture improves cognitive function and sleep quality in chronic insomnia patients.

TRIAL REGISTRATION

ChiCTR2200060150 (Chinese Clinical Trial Registry, http://www.chictr.org.cn , registered on 20 May 2022).

Short sleeping duration is associated with a higher risk of asymmetric handgrip strength among older Chinese males: a cross-sectional study evidence from the China health and retirement longitudinal study

Objective

This study aimed to explore the potential correlation between sleeping duration and the risk of handgrip strength (HGS) asymmetry in older Chinese adults.

Methods

The data of participants (65+ years of age) were obtained from the first Wave 1 (2011) of the China Health and Retirement Longitudinal Study (CHARLS). Information on sleeping duration during the previous month was collected from self-reports and was divided into three groups: long (>8 h), normal (6-8 h), and short (< 6 h). HGS was computed as the average of two tests per hand and asymmetric HGS was diagnosed when the ratio of average non-dominant to average dominant HGS was greater than 1.1 or less than 0.9. Logistic regression analyses were employed to gauge the relationship between sleeping duration and asymmetric HGS risk.

Results

In total, 3,174 participants were enrolled in this analysis, of whom 51.54% (1,636/3,174) were male. The proportions of asymmetric HGS were 42.18% in males and 41.87% in females. The sleeping duration (hours) in the asymmetric and non-asymmetric HGS groups were 6 h (5,8) and 7 h (5,8) in males with a significant difference between them (p = 0.015), and 6 h (5,8) and 6 h (5,8) in females with no significant difference (p = 0.415). Compared with non-asymmetric HGS individuals, the proportions of normal, short, and long sleeping duration were 40.4, 47.3, and 37.7% in males with a significant difference (p = 0.023), and 42.4, 40.3, and 43.8% in females with no significant differences (p = 0.685). An adjusted logistic regression analysis model confirmed that short sleeping duration was significantly associated with asymmetric HGS risk among older males (p = 0.048, OR = 1.252, 95%CI:1.002-1.565).

Conclusion

The results demonstrated that short sleeping duration (<6 h) was a risk factor for increased HGS asymmetry among older Chinese males.

Outdoor artificial light at night and risk of early-onset dementia: A case-control study in the Modena population, Northern Italy

Background

Dementia is a neurological syndrome characterized by severe cognitive impairment with functional impact on everyday life. It can be classified as young onset dementia (EOD) in case of symptom onset before 65, and late onset dementia (LOD). The purpose of this study is to assess the risk of dementia due to light pollution, and specifically outdoor artificial light at night (LAN).

Methods

Using a case-control design, we enrolled dementia patients newly-diagnosed in the province of Modena in the period 2017-2019 and a referent population from their caregivers. We geo-referenced the address of residence on the date of recruitment, provided it was stable for the previous five years. We assessed LAN exposure through 2015 nighttime luminance satellite images from the Visible Infrared Imaging Radiometer Suite (VIIRS). Using a logistic regression model adjusted for age, sex, and education, we calculated the risk of dementia associated with increasing LAN exposure, namely using <10 nW/cm²/sr as reference and considering ≥10-<40 nW/cm²/sr intermediate and ≥40 nW/cm²/sr high exposure, respectively We also implemented non-linear assessment using a spline regression model.

Results

We recruited 58 EOD cases, 34 LOD cases and 54 controls. Average LAN exposure levels overlapped for EOD cases and controls, while LOD cases showed higher levels. Compared with the lowest exposure, the risk of EOD associated with LAN was higher in the intermediate exposure (OR = 1.36, 95% CI 0.54-3.39), but not in the high exposure category (OR = 1.04, 95% CI 0.32-3.34). In contrast, the risk of LOD was positively associated with LAN exposure, with ORs of 2.58 (95% CI 0.26-25.97) and 3.50 (95% CI 0.32-38.87) in the intermediate and high exposure categories, respectively. The spline regression analysis showed substantial lack of association between LAN and EOD, while almost linear although highly imprecise association emerged for LOD.

Conclusions

Although the precision of the estimates was affected by the limited sample size and the study design did not allow us to exclude the presence of residual confounding, these results suggest a possible role of LAN in the etiology of dementia, particularly of its late-onset form.

The Relationship Between Cognitive Impairments and Sleep Quality Measures in Persistent Insomnia Disorder

Study Objectives

Persistent insomnia disorder (pID) is linked to neurocognitive decline and increased risk of Alzheimer's Disease (AD) in later life. However, research in this field often utilizes self-reported sleep quality data - which may be biased by sleep misperception - or uses extensive neurocognitive test batteries - which are often not feasible in clinical settings. This study therefore aims to assess whether a simple screening tool could uncover a specific pattern of cognitive changes in pID patients, and whether these relate to objective aspect(s) of sleep quality.

Methods

Neurocognitive performance (Montreal Cognitive Assessment; MoCA), anxiety/depression severity, and subjective sleep quality (Pittsburgh Sleep Quality Index: PSQI; Insomnia Severity Index: ISI) data were collected from 22 middle-aged pID patients and 22 good-sleepers. Patients underwent overnight polysomnography.

Results

Compared to good-sleepers, patients had lower overall cognitive performance (average: 24.6 versus 26.3 points, Mann-Whitney U = 136.5, p = <0.006), with deficits in clock drawing and verbal abstraction. In patients, poorer overall cognitive performance correlated with reduced subjective sleep quality (PSQI: r(42) = -0.47, p = 0.001; and ISI: r(42) = -0.43, p = 0.004), reduced objective sleep quality (lower sleep efficiency: r(20) = 0.59, p = 0.004 and less REM-sleep: r(20) = 0.52, p = 0.013; and increased sleep latency: r(20) = -0.57, p = 0.005 and time awake: r(20) = -0.59, p = 0.004). Cognitive performance was not related to anxiety/depression scores.

Conclusion

Using a simple neurocognitive screening tool, we found that pID patients showed cognitive deficiencies that related to both subjective/self-reported and objective/polysomnographic measures of sleep quality. Furthermore, these cognitive changes resembled those seen in preclinical non-amnestic AD, and thus could indicate incumbent neurodegenerative processes in pID. Interestingly, increased REM-sleep was correlated with better cognitive performance. However, whether REM-sleep is protective against neurodegeneration requires further investigation.

Detection of Insomnia and Its Relationship with Cognitive Impairment, Depression, and Quality of Life in Older Community-Dwelling Mexicans

Sleep disturbances are one of the most frequent health problems in old age, among which insomnia stands out. It is characterized by difficulty falling asleep, staying asleep, frequent awakenings, or waking up too early and not having restful sleep, which may be a risk factor for cognitive impairment and depression, affecting functionality and quality of life. Insomnia is a very complex multifactorial problem that requires a multi- and interdisciplinary approach. However, it is frequently not diagnosed in older community-dwelling people, increasing the risk of psychological, cognitive, and quality of life alterations. The aim was to detect insomnia and its relationship with cognitive impairment, depression, and quality of life in older community-dwelling Mexicans. An analytical cross-sectional study was carried out in 107 older adults from Mexico City. The following screening instruments were applied: Athens Insomnia Scale, Mini-Mental State Examination, Geriatric Depression Scale, WHO Quality of Life Questionnaire WHOQoL-Bref, Pittsburgh Sleep Quality Inventory. The frequency of insomnia detected was 57% and its relationship with cognitive impairment, depression, and low quality of life was 31% (OR = 2.5, 95% CI, 1.1-6.6. p < 0.05), 41% (OR = 7.3, 95% CI, 2.3-22.9, p < 0.001), and 59% (OR = 2.5, 95% CI, 1.1-5.4, p < 0.05), respectively. Our findings suggest that insomnia is a frequent clinical disorder that is not diagnosed and a significant risk factor for cognitive decline, depression, and poor quality of life.

Study on the Mechanism of Jiaotai Pill Intervention on Insomnia Animal Model Based on Gut Microbiome and Metabolomics

Background

With the continuous advancement of clinical application and experimental research of JTP, the application prospect of JTP in nervous system diseases and metabolic diseases is becoming increasingly clear. Jiaotai Pill (JTP) is a traditional Chinese medicine formula for insomnia, consisting of Coptidis rhizoma and Cinnamomi cortex, which dates back to Han Shi Yi Tong in the Ming Dynasty of China.

Objective

Based on the brain-gut axis theory, this paper aims to explore the potential mechanism of JTP in the intervention of insomnia by using intestinal microbiome and metabolomics technology, taking the animal model of insomnia as the research object, so as to provide experimental basis for its further application and research.

Methods

The insomnia mouse model was induced by intraperitoneal injection of para-chlorophenylalanine (PCPA). The clinical equivalent dose of JTP was administered by gavage for one week. The efficacy of JTP was evaluated by behavioral tests, serum biochemical detection, and brain histomorphological observation. The contents of cecum were analyzed by microbiomics and metabolomics.

Results

The results show that insomnia caused by PCPA led to daytime dysfunction, higher HPA axis hormone levels, and morphologically impaired hippocampus. JTP reversed these anomalies. Omics research indicates that JTP significantly reduced gut α diversity; at the phylum level, JTP reduced the relative abundance of Firmicutes, Deferribacterota, Cyanobacteria, and Actinobacteriota and increased the relative abundance of Verrucomicrobiota, Proteobacteria, and Desulfobacterota. At the genus level, JTP reduced the relative abundance of Muribaculaceae, Lachnospiraceae_NK4A136_group, Alistipes, Colidextribacter, Muribaculum, and Mucispirillum and increased the relative abundance of Bacteroides and Akkermansia. JTP also reversed the activation of the linoleic acid metabolism pathway induced by insomnia. The combined analysis of omics suggests that JTP may play a role by regulating the inflammatory state of the body. Further gene expression analysis of brain tissue confirmed this.

Conclusions

We hypothesize that JTP may achieve insomnia relief by eliminating inflammation-causing bacteria in the gut and reducing inflammation levels through the brain-gut axis, pointing to potential targets and pathways for future research on JTP.

Depression circuit adaptation in post-stroke depression

BACKGROUND

Lesion locations of post-stroke depression (PSD) mapped to a depression circuit which centered by the left dorsolateral prefrontal cortex (DLPFC). However, it remains unknown whether the compensatory adaptations that may occur in this depression circuit due to the lesions in PSD.

METHODS

Rs-fMRI data were collected from 82 non-depressed stroke patients (Stroke), 39 PSD patients and 74 healthy controls (HC). We tested the existence of depression circuit, examined PSD-related alterations of DLPFC-seeded connectivity and their associations with depression severity, and analyzed the connectivity between each repetitive transcranial magnetic stimulation (rTMS) target and DLPFC to find the best treatment target for PSD.

RESULTS

We found that: 1) the left DLPFC showed significantly stronger connectivity to lesions of PSD than Stroke group; 2) in comparison to both Stroke and HC groups, PSD exhibited increased connectivity with DLPFC in bilateral lingual gyrus, contralesional superior frontal gyrus, precuneus, and middle frontal gyrus (MFG); 3) the connectivity between DLPFC and the contralesional lingual gyrus positively correlated with depression severity; 4) the rTMS target in center of MFG showed largest between-group difference in connectivity with DLPFC, and also reported the highest predicted clinical efficacy.

LIMITATIONS

Longitudinal studies are required to explore the alterations of depression circuit in PSD as the disease progress.

CONCLUSION

PSD underwent specific alterations in depression circuit, which may help to establish objective imaging markers for early diagnosis and interventions of the disease.

Effectiveness of non-pharmacological interventions for sleep disturbances in people living with dementia: A systematic review and meta-analysis

We summarize the evidence on non-pharmacological interventions for sleep disturbances in people living with dementia(PlwD). A literature search was performed using PubMed, Embase, Cochrane library, Web of Science, PsycINFO, CINAHL, and clinicaltrials.gov. Up to August 20, 2022. Six studies met our eligibility criteria. Light therapy, the therapeutic pet-type robotic seal(PRAO), and slow-stroke back massage(SSBM) are non-pharmacological interventions for sleep disturbances in PlwD.PARO increased night-time sleep duration (p < 0.05). The benefit of SSBM for sleep disturbances in PlwD is unclear (p > 0.05). Although there is a lack of evidence for the effect of light therapy on sleep disturbances in PlwD (p > 0.05), light therapy reduced sleep disturbance (SMD = -0.38; 95% CI:1.25, 0.48), increased sleep efficiency (MD = 3.77; 95% CI:-0.23, 7.78), and also reduced depression (MD = -2.49; 95% CI: -2.92, -2.06). More large-scale randomized controlled trials are needed and consider combining multiple non-pharmacological measures for sleep interventions in PlwD.

Mental and physical health pathways linking insomnia symptoms to cognitive performance 14 years later

STUDY OBJECTIVES

Insomnia may be a modifiable risk factor for later-life cognitive impairment. We investigated: (1) which insomnia symptoms are associated with subsequent cognitive functioning across domains; (2) whether insomnia-cognition associations are mediated by mental and physical health; and (3) whether these associations are modified by gender.

METHODS

Participants included 2595 adults ages 51-88 at baseline (Mage=64.00 ± 6.66, 64.5% women) in the Health and Retirement Study. The frequency of insomnia symptoms (difficulty initiating sleep, night time awakenings, early awakenings, and feeling unrested upon awakening) at baseline (2002) were quantified using a modified Jenkins Sleep Questionnaire. Cognition was assessed in 2016 via the Harmonized Cognitive Assessment Protocol and operationalized with factor scores corresponding to five domains. Depressive symptoms and vascular conditions in 2014 were assessed via self-report. Structural equation models estimated total, indirect, and direct effects of insomnia symptoms on subsequent cognition through depressive symptoms and vascular diseases, controlling for baseline sociodemographic and global cognition.

RESULTS

Frequent difficulty initiating sleep was associated with poorer episodic memory, executive function, language, visuoconstruction, and processing speed 14 years later (-0.06 ≤ β ≤ -0.04; equivalent to 2.2-3.4 years of aging). Depressive symptoms explained 12.3%-19.5% of these associations and vascular disease explained 6.3%-14.6% of non-memory associations. No other insomnia symptoms were associated with cognition, and no associations were modified by gender.

CONCLUSIONS

Difficulty initiating sleep in later life may predict future cognitive impairment through multiple pathways. Future research with longitudinal assessments of insomnia, insomnia treatments, and cognition is needed to evaluate insomnia as a potential intervention target to optimize cognitive aging.

Sex differences in the effects of sleep disorders on cognitive dysfunction

Sleep is an essential physiological function that sustains human life. Sleep disorders involve problems with the quality, duration, and abnormal behaviour of sleep. Insomnia is the most common sleep disorder, followed by sleep-disordered breathing (SDB). Sleep disorders often occur along with medical conditions or other mental health conditions. Of particular interest to researchers is the role of sleep disorders in cognitive dysfunction. Sleep disorder is a risk factor for cognitive dysfunction, yet the exact pathogenesis is still far from agreement. Little is known about how sex differences influence the changes in cognitive functions caused by sleep disorders. This narrative review examines how sleep disorders might affect cognitive impairment, and then explores the sex-specific consequences of sleep disorders as a risk factor for dementia and the potential underlying mechanisms. Some insights on the direction of further research are also presented.

P2X7 receptor-activated microglia in cortex is critical for sleep disorder under neuropathic pain

Neuropathic pain (NP) is associated with sleep disturbances, which may substantially influence the quality of life. Clinical and animal studies demonstrated that neurotransmitter is one of the main contributors to cause sleep disturbances induced by NP. Recently, it was reported that P2X7 receptors (P2X7R) are widely expressed in microglia, which serves crucial role in neuronal activity in the pain and sleep-awake cycle. In this study, we adopted the chronic constriction injury (CCI) model to establish the progress of chronic pain and investigated whether P2X7R of microglia in cortex played a critical role in sleep disturbance induced by NP. At electroencephalogram (EEG) level, sleep disturbance was observed in mice treated with CCI as they exhibited mechanical and thermal hypersensitivity, and inhibition of P2X7R ameliorated these changes. We showed a dramatic high level of P2X7R and Iba-1 co-expression in the cortical region, and the inhibition of P2X7R also adversely affected it. Furthermore, the power of LFPs in ventral posterior nucleus (VP) and primary somatosensory cortex (S1) which changed in the CCI group was adverse after the inhibition of P2X7R. Furthermore, inhibition of P2X7R also decreased the VP-S1 coherence which increased in CCI group. Nuclear magnetic resonance demonstrated inhibition of P2X7R decreased glutamate (Glu) levels in thalamic and cortical regions which were significantly increased in the CCI mice. Our findings provide evidence that NP has a critical effect on neuronal activity linked to sleep and may built up a new target for the development of sleep disturbances under chronic pain conditions.

A bibliometric analysis of the application of imaging in sleep in neurodegenerative disease

Objective

The purpose of this study was to examine the current state of the application of imaging in sleep research in degenerative disease, as well as hotspots and trends.

Materials and methods

A search was conducted on the Web of Science Core Collection (WoSCC) between 1 September 2012, and 31 August 2022 for literature related to sleep imaging. This study analyzed 7,679 articles published in this field over the past 10 years, using CiteSpace to analyze tendencies, countries, institutions, authors, and hotspots.

Results

There were 7,679 articles on the application of imaging to sleep research published by 566 institutions located in 135 countries in 1,428 journals; the number of articles was increasing on a yearly basis. According to keyword analysis, the research direction of the application of imaging in sleep research focused on the effects of degenerative diseases on sleep, such as Parkinson's disease, Alzheimer's disease, and small vessel disease. A literature evaluation found that Parkinson's disease, insomnia, sleep quality, and rapid eye movement sleep behavior disorder were the top research trends in this field.

Conclusion

A growing body of research has focused on sleep disorders caused by degenerative diseases. In the application of imaging to sleep research, magnetic resonance functional brain imaging represents a reliable research method. In the future, more aging-related diseases may be the subject of sleep-related research, and imaging could provide convenient and reliable evidence in this respect.

The Impact of the Six Pillars of Lifestyle Medicine on Brain Health

Dementia is growing exponentially worldwide. Unfortunately, the treatment available does not reverse any type of cognitive impairment. As a result, healthcare professionals are focusing on other evidence-based options, such as lifestyle medicine (LM). Current evidence demonstrates improvement in neurocognitive decline by applying the six pillars of LM, which include plant-based nutrition, physical activity, stress management, avoidance of risky substances, restorative sleep, and social connections. Plant-based nutrition has a positive impact on cognition by decreasing the risk for Alzheimer's disease (AD) with high adherence to the Mediterranean-Dietary Approach to Systolic Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND). Physical activity also might prevent neurocognitive decline by increasing fibronectin type III domain-containing protein 5 (FNDC5) and Irisin in the hippocampus, which increases energy expenditure and prolongs endurance. Additionally, higher perceived stress in adulthood and the use of risky substances such as alcohol, nicotine, and opioids are significantly associated with developing mild cognitive impairment and all-cause dementia. Furthermore, there is a positive correlation between poor sleep and social isolation with a rapid progression in cognitive decline. Lifestyle changes have a substantial impact on brain health. Therefore, the focus should always be on prevention as the primary treatment tool.

Insomnia and risk of dementia in a large population-based study with 11-year follow-up: The HUNT study

Despite evidence suggesting that insomnia is associated with the risk of dementia and cognitive dysfunction, studies have shown mixed results. Dementia has a long prodromal phase, and studies with long follow-up are required to avoid reverse causality. In our 11-year follow-up study, we assessed whether probable insomnia disorder (PID) based on diagnostic criteria, and insomnia symptoms were associated with risk of all-cause dementia, Alzheimer's disease (AD) and cognition, measured with the Montreal Cognitive Assessment scale. We also examined if Apolipoprotein E genotype modified any associations with dementia through interaction. We analysed data from 7492 participants in the Norwegian Trøndelag Health Study. PID was not associated with all-cause dementia (odds ratio = 1.03, 95% confidence interval = 0.74-1.43), AD (odds ratio = 1.07, 95% confidence interval = 0.71-1.60) or Montreal Cognitive Assessment score (regression coefficient = 0.37, 95% confidence interval = -0.06 to 0.80). The insomnia symptom "difficulties maintaining sleep" was associated with a lower risk of all-cause dementia (odds ratio = 0.81, 95% confidence interval = 0.67-0.98), AD (odds ratio = 0.73, 95% confidence interval = 0.57-0.93), and better Montreal Cognitive Assessment score, mean 0.40 units (95% confidence interval = 0.15-0.64). No interaction with Apolipoprotein E genotype was found. PID and insomnia symptoms did not increase the risk of dementia in our study. More research with longer follow-up is needed, and future studies should explore if the associations to dementia risk vary across insomnia subtypes.

Race Differences in the Association Between Sleep Medication Use and Risk of Dementia

BACKGROUND

The effect of sleep medications on cognition in older adults is controversial, possibly dependent upon sleep quality, and may differ by race.

OBJECTIVE

To determine the longitudinal association between sleep medication use and incident dementia over 15 years, and to explore whether the association is independent of nighttime sleep disturbances and if it differs by race.

METHODS

We examined 3,068 community-dwelling older adults (aged 74.1±2.9 years, 41.7% Black, 51.5% female) without dementia. Sleep medication use was recorded three times by asking "Do you take sleeping pills or other medications to help you sleep?" with the response options: "Never (0)", "Rarely (≤1/month)", "Sometimes (2-4/month)", "Often (5-15/month)", or "Almost Always (16-30/month)". Incident dementia was defined using hospitalization records, dementia medication prescription or clinically significant decline in global cognition.

RESULTS

138 (7.71%) of Whites and 34 (2.66%) of Blacks reported taking sleep medications "often or almost always". Whites were almost twice as likely to take all prescription hypnotics. 617 participants developed dementia over the follow-up. After adjustment for all covariates, participants who reported taking sleep medications ≥ 5/month versus ≤1/month were significantly more likely to develop dementia, and the association was only observed among Whites (HR = 1.79,1.21-2.66) but not Blacks (HR = 0.84,0.38-1.83); p for interaction = 0.048. Further adjustment for nighttime sleep did not appreciably alter the results. The association was similar for the cumulative frequency of sleep medication use and remained after introducing a time lag of 3 years.

CONCLUSION

Frequent sleep medication use was associated with an increased risk of dementia in White older adults. Further research is needed to determine underlying mechanisms.

Novel neuroelectrophysiological age index associated with imaging features of brain aging and sleep disorders

Sleep architecture and microstructures alter with aging and sleep disorder-led accelerated aging. We proposed a sleep EEG based brain age prediction model using convolutional neural networks. We then associated the estimated brain age index with brain structural aging features, sleep disorders and various sleep parameters. Our model also showed a higher BAI (predicted brain age minus chronological age) is associated with cortical thinning in various functional areas. We found a higher BAI for sleep disorder groups compared to healthy sleepers, as well as significant differences in the spectral pattern of EEG among different sleep disorders (lower power in slow and ϑ waves for sleep apnea vs. higher power in β and σ for insomnia), suggesting sleep disorder-dependent pathomechanisms of aging. Our results demonstrate that the new EEG-BAI can be a biomarker reflecting brain health in normal and various sleep disorder subjects, and may be used to assess treatment efficacy.

Epidemiology and Risk Factors for Dementia

In this article, the authors discuss primarily what is known about the epidemiology of all-cause dementia. Dementia is caused by a complex interplay of genetics, comorbidities, and lifestyle factors, and drug development has been challenging. However, evidence from large, prospective, observational studies has identified a variety of factors that may prevent or delay the onset of dementia. Several of these factors are modifiable and lend themselves to well to treatments currently available. The authors discuss the state of current evidence on dementia risk factors, the most promising avenues, and future directions for dementia prevention and management.

How Would You Manage This Patient With Chronic Insomnia? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Insomnia, which is characterized by persistent sleep difficulties in association with daytime dysfunction, is a common concern in clinical practice. Chronic insomnia disorder is defined as symptoms that occur at least 3 times per week and persist for at least 3 months. The American Academy of Sleep Medicine (AASM) published recent guidelines on behavioral and psychological treatment as well as pharmacologic therapy for chronic insomnia disorder. Regarding behavioral and psychological approaches, the only intervention strongly recommended was multicomponent cognitive behavioral therapy for insomnia. Regarding pharmacologic treatment, the AASM, based on weak evidence, suggested a limited number of medications that might be useful and others that probably are not. Here, 2 clinicians with expertise in sleep disorders-one a clinical psychologist and the other a physician-debate the management of a patient with chronic insomnia who has been treated with medications. They discuss the role of behavioral and psychological interventions and pharmacologic therapy for chronic insomnia and how the primary care practitioner should approach such a patient.

Hippocampal atrophy in neurofunctional subfields in insomnia individuals

Objective

The aim of this study was to investigate the pattern of volume changes in neurofunctional hippocampal subfields in patients with insomnia and their associations with risk of development of insomnia.

Methods

A total of 120 patients with insomnia (78 females, 42 males; mean age ± standard deviation, 43.74 ± 13.02 years) and 120 good sleepers (67 females, 53 males; mean age, 42.69 ± 12.24 years) were recruited. The left hippocampus was segmented into anterior (L1), middle (L2), and posterior (L3) subregions. The right hippocampus was segmented into top anterior (R1), second top anterior (R2), middle (R3), posterior (R4), and last posterior (R5) subregions. Multivariate logistic regression was used to evaluate the associations of hippocampal volume (HV) of each subfield with the risk of the development of insomnia. Mediation analyses were performed to evaluate mediated associations among post-insomnia negative emotion, insomnia severity, and HV atrophy. A visual easy-to-deploy risk nomogram was used for individual prediction of risk of development of insomnia.

Results

Hippocampal volume atrophy was identified in the L1, R1, and R2 subregions. L1 and R2 volume atrophy each predisposed to an ~3-fold higher risk of insomnia (L1, odds ratio: 2.90, 95% confidence intervals: [1.24, 6.76], p = 0.014; R2, 2.72 [1.19, 6.20], p = 0.018). Anxiety fully mediates the causal path of insomnia severity leading to R1 volume atrophy with a positive effect. We developed a practical and visual competing risk-nomogram tool for individual prediction of insomnia risk, which stratifies individuals into different levels of insomnia risk with the highest prediction accuracy of 97.4% and an average C-statistic of 0.83.

Conclusion

Hippocampal atrophy in specific neurofunctional subfields was not only found to be associated with insomnia but also a significant risk factor predicting development of insomnia.

Mindfulness-based Cognitive Therapy to Improve Sleep Quality in Older Adults with Insomnia

There is a high prevalence of insomnia in older adults, which has negative consequences for their well-being and quality of life. The recommendation for first-line treatments is to administer non-pharmacological interventions. The objective of this research was to verify the effectiveness of Mindfulness-Based Cognitive Therapy in older adults with subclinical and moderate insomnia, studying its impact on sleep quality. One hundred and six older adults participated and were assigned to the subclinical insomnia (n = 50) or moderate insomnia (n = 56) groups; subsequently, they were randomly assigned to the control and intervention groups. Subjects were evaluated at two times with the Insomnia Severity Index and the Pittsburgh Sleep Quality Index. Significant results were obtained on both scales, with a reduction in insomnia symptoms in the subclinical and moderate intervention groups. The administration of a treatment that combines mindfulness and cognitive therapy is effective for treating insomnia in older adults.

Psychosocial Mediation of Light-Moderate Physical Activity and Cognitive Performance among Adults Aged 60+ in China

Physical activity is a key determinant of healthy ageing; yet, little is known about the varying degrees of benefits by intensity nor the mediating mechanisms that operate through psychosocial health. Leveraging structural mediation analysis using the 2018 China Health and Retirement Longitudinal Study (CHARLS) national survey data, we screened 4371 community-dwelling older adults, and investigated the mediation mechanism of psychosocial health on the link between light-moderate physical activity and cognitive performance. Physical activity intensity, psychosocial health, and cognitive performance were measured by the international physical activity questionnaire (IPAQ), the Center for Epidemiological Studies Depression Scale (CESD), and the mini-mental state examination (MMSE) instruments, respectively. Results show that, while light physical activity (LPA) and moderate physical activity (MPA) both significantly contribute to better cognitive performance, psychosocial health is a significant mediator only for LPA but not for MPA. For direct pathways, both LPA (std. β = 0.062, p < 0.001, 95% confidence interval = 0.032−0.091) and MPA (std. β = 0.049, p = 0.001, 95% CI = 0.019−0.078) have significant influence on cognitive performance. For mediation pathways, results show that there exists only one indirect channel through which psychosocial health mediates the influence of LPA (std. β = 0.024, p < 0.001, 95% CI = 0.016−0.033), which accounts for 27.9% of the total effect linking LPA and cognitive performance. Findings uncover an important indirect psychosocial mediation channel through which LPA affects cognitive performance among older adults.

Insomnia symptom severity and cognitive performance: Moderating role of APOE genotype

INTRODUCTION

We evaluated whether insomnia symptom severity was associated with cognitive function, and whether this relationship was modified by biomarkers associated with Alzheimer's disease risk.

METHODS

We examined insomnia symptoms and neuropsychological performance 3.4 years later in 511 dementia-free Framingham Heart Study participants (62.65 ± 8.7 years, 50.9% male). Additionally, we explored insomnia symptoms combined with self-reported short habitual sleep duration and effect modification by apolipoprotein E (APOE) ε4 allele status.

RESULTS

More severe insomnia symptoms were associated with lower performance on global cognition, and immediate and delayed Logical Memory recall, especially when insomnia symptoms were combined with short sleep duration. The association between insomnia symptoms and poorer memory recall was more pronounced in APOE ε4 allele carriers.

DISCUSSION

Insomnia symptom severity was associated with worse subsequent global cognitive and memory performance, which was especially apparent in APOE ε4 allele carriers, suggesting that poor sleep might be particularly detrimental when the brain is already vulnerable to neurodegeneration.

Changes in telomere length and serum neurofilament light chain levels in female patients with chronic insomnia disorder

STUDY OBJECTIVES

The aims of this study were to explore changes in the telomere length (relative telomere repeat copy/single-copy gene [T/S ratio]) and serum neurofilament light chain (sNfL) levels in female patients with chronic insomnia disorder (CID), examine their relationships with emotional abnormalities and cognitive impairment, and determine whether these 2 indicators were independently associated with sleep quality.

METHODS

The CID group contained 80 patients diagnosed with CID, and 51 individuals constituted a healthy control group. Participants completed sleep, emotion, and cognition assessments. Telomere length was detected through quantitative real-time polymerase chain reaction. Enzyme-linked immunosorbent assay was used to determine sNfL concentrations.

RESULTS

Relative to the healthy control group, the CID group had elevated Pittsburgh Sleep Quality Index, Hamilton Anxiety Scale-14, and Hamilton Depression Rating Scale-17 scores and reduced Montreal Cognitive Assessment scale scores, a decreased T/S ratio, and an increased sNfL concentration. Subgroup analysis according to various CID-associated sleep factors showed that poor sleep performance corresponded to a lower T/S ratio. Higher anxiety levels and more cognitive dysfunction correlated with shorter telomere lengths. The T/S ratio negatively correlated with age, whereas the sNfL concentration positively correlated with age in the CID group. The Pittsburgh Sleep Quality Index score negatively correlated with the T/S ratio but did not correlate with sNfL levels. Multiple linear regression analysis showed that the T/S ratio had a negative and independent effect on Pittsburgh Sleep Quality Index scores.

CONCLUSIONS

The CID group had shorter telomeres and higher sNfL concentrations, and reduced telomere length independently affected sleep quality.

CITATION

Ren C-Y, Liu P-P, Li J, et al. Changes in telomere length and serum neurofilament light chain levels in female patients with chronic insomnia disorder. J Clin Sleep Med. 2022;18(2):383-392.

Current Alzheimer disease research highlights: evidence for novel risk factors

Alzheimer disease (AD) is the most common type of dementia characterized by the progressive cognitive and social decline. Clinical drug targets have heavily focused on the amyloid hypothesis, with amyloid beta (Aβ), and tau proteins as key pathophysiologic markers of AD. However, no effective treatment has been developed so far, which prompts researchers to focus on other aspects of AD beyond Aβ, and tau proteins. Additionally, there is a mounting epidemiologic evidence that various environmental factors influence the development of dementia and that dementia etiology is likely heterogenous. In the past decades, new risk factors or potential etiologies have been widely studied. Here, we review several novel epidemiologic and clinical research developments that focus on sleep, hypoxia, diet, gut microbiota, and hearing impairment and their links to AD published in recent years. At the frontiers of AD research, these findings and updates could be worthy of further attention.

Tea polyphenols protect learning and memory in sleep-deprived mice by promoting AMPA receptor internalization

Chronic sleep loss caused lots of health problems, also including cognition impairment. Tea is one of the most popular drinks when people stay up late. Nevertheless, the effects of tea on sleep deprivation-induced cognition impairment are still unclear. In the present study, we found 24-h sleep deprivation (S-DEP) increased membrane α-amino-3-hydroxy-5-methyl-4-isoxa-zolep-propionate (AMPA) receptor level through a tumor necrosis factor α (TNFα)-dependent pathway in hippocampi. Blocking elevated TNFα level can protect S-DEP mice from impaired learning ability according to behavioral test. Tea polyphenols, major active compounds in green tea, suppressed TNFα production through downregulating TNFα converting enzyme (TACE) level. Meanwhile, tea polyphenols treatment could ameliorate recognition impairment and anxiety-like behaviors in S-DEP mice. The aforementioned results demonstrate cognition protective effects of tea polyphenols in S-DEP mice model, which provide a theoretical basis for the treatments of S-DEP-induced cognition impairment by targeting the TACE/TNFα/AMPA pathway.

Older Adults' Subjective Cognitive Decline Correlated with Subjective but Not Objective Sleep: A Mediator Role of Depression

This study examined the relationship between older adults' subjective versus objective sleep and subjective cognitive decline (SCD), and explored the role of depression on this association. One hundred and four community-dwelling older adults underwent a week of actigraphic sleep monitoring, and completed a series of neuropsychological screeners. Older adults'SCD score was positively correlated with subjective insomnia, but not with objective sleep parameters. Further mediation modeling revealed that older adults'depression mediated the association between subjective insomnia and SCD. Subjective sleep, rather than objective sleep, may be a more sensitive indicator for older adults' SCD, with depression symptoms appearing to account for most of the variance. These findings extend our perspective on the relationship between sleep disruption and cognitive decline, and highlight the necessity of early targeted interventions on sleep to reduce the risk of cognitive impairment in the elderly with SCD.

Association Between Sleep Duration and Intelligence Quotient in 6-Year-Old Children

BACKGROUND

Sufficient sleep during childhood is important for cognitive functions such as learning and successful school performance. This study aimed to investigate the effects of sleep duration on the intelligence quotient (IQ) of 6-year-old children and aimed to analyze whether these effects differed by sex.

METHODS

The IQ of 538 6-year-old Korean participants from the cohort study, "The Environment and Development of Children," was measured during follow-up using the Korean Educational Developmental Institute's Wechsler Intelligence Scale for Children. The total, verbal, and performance IQ scores were evaluated. The relationship between sleep duration and IQ scores after adjusting for maternal age, maternal educational level, maternal occupation, maternal IQ, exposure to secondhand smoking, gestational age, and monthly age and birth season was also assessed.

RESULTS

Longer sleep duration was significantly associated with improved verbal IQ measures (β 0.55; p value 0.030). After stratifying participants by sex, a significant association was observed between sleep duration and total, verbal, and performance IQ scores in boys (total IQ 2.49, p value 0.012; verbal IQ 0.75, p value: 0.037; performance IQ 0.73, p value 0.048), but not in girls.

CONCLUSIONS

The results indicated that only boys show a significant association between IQ scores and sleep duration. These findings support the hypothesis that sleep duration is associated with IQ, in a sex dependent manner. Future studies are needed for a thorough evaluation of the connection between sleep duration and health outcome in young children.

Sleep Well and Recover Faster with Less Pain-A Narrative Review on Sleep in the Perioperative Period

Sleep disturbance, pain, and having a surgical procedure of some kind are all very likely to occur during the average lifespan. Postoperative pain continues to be a prevalent problem and growing evidence supports the association between pain and sleep disturbances. The bidirectional nature of sleep and pain is widely acknowledged. A decline in sleep quality adds a risk for the onset of pain and also exacerbates existing pain. The risk factors for developing insomnia and experiencing severe pain after surgery are quite similar. The main aim of this narrative review is to discuss why it is important to be aware of sleep disturbances both before and after surgery, to know how sleep disturbances should be assessed and monitored, and to understand how better sleep can be supported by both pharmacological and non-pharmacological interventions.

The effect of insomnia on development of Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia and a neurodegenerative disorder characterized by memory deficits especially forgetting recent information, recall ability impairment, and loss of time tracking, problem-solving, language, and recognition difficulties. AD is also a globally important health issue but despite all scientific efforts, the treatment of AD is still a challenge. Sleep has important roles in learning and memory consolidation. Studies have shown that sleep deprivation (SD) and insomnia are associated with the pathogenesis of Alzheimer's disease and may have an impact on the symptoms and development. Thus, sleep disorders have decisive effects on AD; this association deserves more attention in research, diagnostics, and treatment, and knowing this relation also can help to prevent AD through screening and proper management of sleep disorders. This study aimed to show the potential role of SD and insomnia in the pathogenesis and progression of AD.

The interrelation of sleep and mental and physical health is anchored in grey-matter neuroanatomy and under genetic control

Humans need about seven to nine hours of sleep per night. Sleep habits are heritable, associated with brain function and structure, and intrinsically related to well-being, mental, and physical health. However, the biological basis of the interplay of sleep and health is incompletely understood. Here we show, by combining neuroimaging and behavioral genetic approaches in two independent large-scale datasets (HCP (n = 1106), age range: 22-37, eNKI (n = 783), age range: 12-85), that sleep, mental, and physical health have a shared neurobiological basis in grey matter anatomy; and that these relationships are driven by shared genetic factors. Though local associations between sleep and cortical thickness were inconsistent across samples, we identified two robust latent components, highlighting the multivariate interdigitation of sleep, intelligence, BMI, depression, and macroscale cortical structure. Our observations provide a system-level perspective on the interrelation of sleep, mental, and physical conditions, anchored in grey-matter neuroanatomy.

[Interaction of insomnia in old age and associated diseases : Cognitive, behavioral and neurobiological aspects]

The prevalence of insomnia is particularly high in old age. Sleep disturbances and impaired daytime functioning reflected in mood swings and concentration difficulties are often accompanied by other mental disorders such as depression. The objective of this article is to shed light on the role of insomnia in the context of frequent comorbidities in middle and old age. The focus is on the identification of linkage points between insomnia and associated diseases on a neurobiological level; however, possible distinguishing features are also named and deliberations on cognitive behavioral aspects and integrative theories, such as the hyperarousal theory are discussed. In order to provide an outlook for future research opportunities, the UK Biobank is presented as a promising resource of long-term data. Finally, the contents of the preceding deliberations are critically reflected and practical implications for the treatment of older patients with insomnia are derived.

Test-Retest Reliability of Functional Magnetic Resonance Imaging Activation for a Vergence Eye Movement Task

Vergence eye movements are the inward and outward rotation of the eyes responsible for binocular coordination. While studies have mapped and investigated the neural substrates of vergence, it is not well understood whether vergence eye movements evoke the blood oxygen level-dependent signal reliably in separate experimental visits. The test-retest reliability of stimulus-induced vergence eye movement tasks during a functional magnetic resonance imaging (fMRI) experiment is important for future randomized clinical trials (RCTs). In this study, we established region of interest (ROI) masks for the vergence neural circuit. Twenty-seven binocularly normal young adults participated in two functional imaging sessions measured on different days on the same 3T Siemens scanner. The fMRI experiments used a block design of sustained visual fixation and rest blocks interleaved between task blocks that stimulated eight or four vergence eye movements. The test-retest reliability of task-activation was assessed using the intraclass correlation coefficient (ICC), and that of spatial extent was assessed using the Dice coefficient. Functional activation during the vergence eye movement task of eight movements compared to rest was repeatable within the primary visual cortex (ICC = 0.8), parietal eye fields (ICC = 0.6), supplementary eye field (ICC = 0.5), frontal eye fields (ICC = 0.5), and oculomotor vermis (ICC = 0.6). The results demonstrate significant test-retest reliability in the ROIs of the vergence neural substrates for functional activation magnitude and spatial extent using the stimulus protocol of a task block stimulating eight vergence eye movements compared to sustained fixation. These ROIs can be used in future longitudinal RCTs to study patient populations with vergence dysfunctions.