Obstructive sleep apnea, cognition and Alzheimer's disease: A systematic review integrating three decades of multidisciplinary research

Sleep Disordered Breathing and Subsequent Neuroimaging Markers of Brain Health in Hispanic/Latino Adults

BACKGROUND AND OBJECTIVES

Sleep disordered breathing (SDB) is a risk factor of stroke and Alzheimer disease and related dementias (ADRDs). Hispanic/Latino adults have higher risk of SDB and ADRDs, which emphasizes the need to better understand the association between SDB and brain health. Furthermore, results on SDB and brain aging are mixed, and there are limited data for Hispanic/Latino adults. The main goal of this study is to assess the association between SDB and brain MRI measures in a diverse Hispanic/Latino population.

METHODS

The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a community-based prospective cohort multisite (Bronx, Chicago, Miami, San Diego) study of diverse Hispanic/Latino adults in the United States. Participants underwent 1 night of unsupervised home testing with a sleep apnea test device at baseline. The SOL-Investigation of Neurocognitive Aging MRI, an ancillary study, recruited 2,667 HCHS/SOL participants (35-85 years) who underwent neuroimaging approximately 10 years after baseline sleep assessment. The main exposure was the respiratory event index (REI, 3% desaturation). Secondary exposures encompassed measures of oxygen saturation. Main outcomes included total brain, gray matter, white matter hyperintensity (WMH), and hippocampal volumes. Survey linear regression models were used to determine associations between SDB and brain MRI measures.

RESULTS

The mean age was 67.6 years, with a body mass index of 29.7, and 58.3% were female. We found that increased REI was associated with larger hippocampal volumes (bhippocampus = 0.006 [0.001-0.012]). These results were consistent with oxygen levels (minimum SpO2%) during sleep (bhippocampus = -0.013 [-0.021 to -0.004]). Lower oxygen levels (mean SpO2) during sleep were associated with enlarged WMH volumes (bWMH = -0.095 [-0.164 to -0.025]).

DISCUSSION

We found that SDB and worse oxygenation during sleep were linked to larger hippocampal volumes. These results underscore the complex relationships between sleep health and brain aging and warrant longitudinal follow-up, starting in middle age or earlier.

Engagement in moderate-intensity physical activity supports overnight memory retention in older adults

Preserving the ability to vividly recall emotionally rich experiences contributes to quality of life in older adulthood. While prior works suggest that moderate-intensity physical activity (MPA) may bolster memory, it is unclear whether this extends to emotionally salient memories consolidated during sleep. In the current study, older adults (mean age = 72.3 ± 5.8) completed an overnight polysomnography assessment with emotional memory tested before and after sleep and a self-report questionnaire assessing habitual PA. Results show that better negative emotional memory consolidation was associated with the frequency and duration of MPA. Statistically replacing 30 min of lower-intensity activity with MPA was associated with better negative emotional memory consolidation. MPA may enhance sleep-dependent consolidation of negative memories in older adults, with modest increases in MPA yielding significant consolidation benefits. Findings may guide interventions and inform public health recommendations by demonstrating that substituting even short durations of low-intensity activity for MPA could produce significant cognitive gains in older adulthood.

Review on pathogenesis and treatment of Alzheimer's disease

The rising incidence of Alzheimer's disease (AD) and the associated economic impacts has prompted a global focus in the field. In recent years, there has been a growing understanding of the pathogenic mechanisms of AD, including the aggregation of β-amyloid, hyperphosphorylated tau, and neuroinflammation. These processes collectively lead to neurodegeneration and cognitive decline, which ultimately results in the loss of autonomy in patients. Currently, there are three main types of AD treatments: clinical tools, pharmacological treatment, and material interventions. This review provides a comprehensive analysis of the underlying etiology and pathogenesis of AD, as well as an overview of the current prevalence of AD treatments. We believe this article can help deepen our understanding of the AD mechanism, and facilitate the clinical translation of scientific research or therapies, to address this global problem of AD.

Changes in sleep-disordered breathing severity and post-stroke outcomes in the first year after stroke

BACKGROUND

Sleep-disordered breathing (SDB) is common among stroke survivors and is associated with worse functional, cognitive, and neurologic outcomes after stroke. Little is known about the association between changes in SDB and changes in these outcomes over time.

METHODS

Ischemic stroke (IS) patients identified through the Brain Attack Surveillance in Corpus Christi project were offered SDB testing with a portable respiratory monitor (ApneaLink Plus) shortly after stroke, and at 3-, 6-, and 12-months post-stroke. SDB was quantified using the respiratory event index (REI; apneas plus hypopneas per hour of recording). At 3-, 6-, and 12-months post-stroke, functional outcomes, cognitive outcomes, and neurologic outcomes were measured. Linear mixed models were fitted to obtain random slopes reflecting individual changes in REI and each of outcome over time, adjusted for multiple covariates. Associations between the resulting individual slopes for REI and each outcome were then evaluated using linear regression models.

RESULTS

Of 482 IS patients with at least one REI measurement, in fully adjusted models, faster reduction in REI was not associated with faster improvement in functional (β = -0.06; 95 % CI: -0.15, 0.03, p = 0.16), cognitive (β = -0.03; 95 % CI: -0.12, 0.06, p = 0.51), or neurologic outcomes (β = -0.04; 95 % CI: -0.13, 0.05, p = 0.41).

CONCLUSIONS

In this observational study of stroke survivors, there was no clear association between the rate of improvement in SDB and improvement in functional, cognitive, or neurologic outcomes. It remains to be seen whether treatment of SDB might lead to improved outcomes among stroke survivors.

Clinical correlates of obstructive sleep apnoea in idiopathic normal pressure hydrocephalus

BACKGROUND AND PURPOSE

The pathogenesis of idiopathic normal pressure hydrocephalus (iNPH) remains controversial. Limited studies have indicated a high prevalence of obstructive sleep apnoea (OSA) amongst iNPH patients. The aim was to investigate the clinical correlates of OSA in iNPH patients.

METHODS

In this cross-sectional observational study, consecutive iNPH patients were prospectively enrolled. Evaluations included the iNPH Rating Scale, the Movement Disorder Society Unified Parkinson's Disease Rating Scale part III, the time and number of steps to walk 10 m, the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index, a complete neuropsychological evaluation, 3-T brain MRI, full-night video-polysomnography, tap test and cerebrospinal fluid (CSF) neurodegeneration biomarkers.

RESULTS

Fifty-one patients were screened, of whom 38 met the inclusion criteria. Amongst the recruited patients, 19/38 (50%) exhibited OSA, with 12/19 (63.2%) presenting moderate to severe disorder. OSA+ iNPH patients required more time (p = 0.02) and more steps (p = 0.04) to complete the 10-m walking test, had lower scores on the gait subitem of the iNPH Rating Scale (p = 0.04) and demonstrated poorer performance on specific neuropsychological tests (Rey Auditory Verbal Learning Test immediate recall, p = 0.03, and Rey-Osterrieth Complex Figure, p = 0.01). Additionally, OSA+ iNPH patients had higher levels of total tau (p = 0.02) and phospho-tau (p = 0.03) in their CSF but no statistically significant differences in beta-amyloid (1-42) levels compared to OSA- iNPH patients.

CONCLUSION

Obstructive sleep apnoea is highly prevalent in iNPH patients, particularly at moderate to severe levels. OSA is associated with worse motor and cognitive performance in iNPH. The CSF neurodegeneration biomarker profile observed in OSA+ iNPH patients may reflect OSA-induced impairment of cerebral fluid dynamics.

Associations between quantitative susceptibility mapping with male obstructive sleep apnea clinical and imaging markers

PURPOSE

To quantitatively measure and compare whole-brain iron deposition between OSA patients and a healthy control group, we initially utilized QSM and evaluated its correlation with PSG results and cognitive function.

MATERIALS AND METHODS

A total of 28 OSA patients and 22 healthy control subjects matched in age, education level, and BMI were enrolled in our study. Each participant underwent scanning with 3D T1 and multi-echo GRE sequences. Additionally, PSG results were collected from OSA patients, and they underwent simple cognitive assessments. Finally, we analyzed the relationship between iron content in different brain regions, PSG results, and cognitive ability.

RESULTS

In OSA patients, iron content increased in the left temporal-pole-sup and right putamen, while it decreased in the left fusiform gyrus, left middle temporal gyrus, right inferior occipital gyrus, and right superior temporal gyrus. The correlation analysis between brain iron content and PSG results/cognitive scales is as follows: left fusiform gyrus and MMSE (r = -0.416, p = 0.028); right superior temporal gyrus and MMSE (r = 0.422, p = 0.025); left middle temporal gyrus and average oxygen saturation (r = -0.418, p = 0.027); left temporal-pole-sup and REM stage (rs = 0.466, p = 0.012); the right putamen and N1 stage (rs = 0.393. p = 0.039). Moreover, both MoCA (r = 0.598, p = 0.001) and MMSE (r = 0.456, p = 0.015) show a positive correlation with average oxygen saturation.

CONCLUSION

This study is the first to use QSM technology to show abnormal brain iron levels in OSA. Correlations between brain iron content, PSG, and cognition in OSA may reveal neuropathological mechanisms, aiding OSA diagnosis.

The association between small vessel disease and obstructive sleep apnea: a peak width of skeletonized mean diffusivity-based study

PURPOSE

Peak width of skeletonized mean diffusivity (PSMD) is a novel marker of small vessel disease in the brain. This study aimed to investigate the association between small vessel disease and obstructive sleep apnea (OSA) using PSMD.

METHODS

We enrolled patients with OSA and age- and sex-matched healthy controls, and performed diffusion tensor imaging (DTI) using a 3-tesla MRI scanner in them. We calculated the PSMD based on DTI in several steps, including preprocessing, skeletonization, application of a custom mask, and histogram analysis using the FSL program. We compared the PSMD between patients with OSA and healthy controls and investigated the correlation between PSMD and clinical factors.

RESULTS

Thirty-nine patients with OSA (apnea-hypopnea index > 5; mean = 20.5) and 48 healthy controls were enrolled. The PSMD was significantly higher in patients with OSA than that in the healthy controls (2.521 vs. 2.320 × 10- 4 mm2/s, p = 0.013). In addition, PSMD positively correlated with age (r = 0.512, p < 0.001) and body mass index (r = 0.472, p = 0.002). However, PSMD was not associated with polysomnographic measurements.

CONCLUSIONS

The mean PSMD is higher in patients with OSA than that in healthy controls, indicating a white matter injury due to small-vessel disease in patients with OSA. Our study highlights the importance of actively diagnosing and treating OSA. In addition, PSMD can be used to determine the relationship between sleep disorders and small vessel disease.

Sex-specific dementia risk in known or suspected obstructive sleep apnea: a 10-year longitudinal population-based study

Study Objectives

To evaluate sex-specific associations between known or suspected obstructive sleep apnea (OSA) and dementia risk over 10 years among older women and men.

Methods

This study included 18 815 women and men age 50+ years (dementia-free at baseline) who participated in the Health and Retirement Study (HRS), a nationally representative cohort of US adults. Presence of OSA was defined by self-reported diagnosis or key HRS items that correspond to elements of a validated OSA screening tool (STOP-Bang). Incident dementia cases were identified using a validated, HRS-based algorithm derived from objective cognitive assessments. Survey-weighted regression models based on pseudo-values were utilized to estimate sex- and age-specific differences in cumulative incidence of dementia by OSA status.

Results

Data from 18 815 adults were analyzed, of which 9% of women and 8% of men (weighted proportions) met criteria for incident dementia. Known/suspected OSA was more prevalent in men than in women (weighted proportions 68% vs. 31%). Unadjusted sex-stratified analyses showed that known/suspected OSA was associated with higher cumulative incidence of dementia across ages 60-84 years for women and men. By age 80, relative to adults without known/suspected OSA, the cumulative incidence of dementia was 4.7% higher (CI 2.8%, 6.7%) for women with known/suspected OSA, and 2.5% (CI 0.5%, 4.5%) for men with known/suspected OSA, respectively. Adjusted associations between age-specific OSA and cumulative incidence of dementia attenuated for both women and men but remained statistically significant.

Conclusions

OSA contributes to dementia risk in older adults, particularly women. This study illuminates the impact of a potentially modifiable yet frequently overlooked risk factor for dementia onset.

Mediating role of obstructive sleep apnea in altering slow-wave activity and elevating Alzheimer's disease risk: Pilot study from a northern Taiwan cohort

OBJECTIVES

Obstructive sleep apnea is associated with alterations in slow-wave activity during sleep, potentially increasing the risk of Alzheimer's disease. This study investigated the associations between obstructive sleep apnea manifestations such as respiratory events, hypoxia, arousal, slow-wave patterns, and neurochemical biomarker levels.

METHODS

Individuals with suspected obstructive sleep apnea underwent polysomnography. Sleep disorder indices, oxygen metrics, and slow-wave activity data were obtained from the polysomnography, and blood samples were taken the following morning to determine the plasma levels of total tau (T-Tau) and amyloid beta-peptide 42 (Aβ42) by using an ultrasensitive immunomagnetic reduction assay. Subsequently, the participants were categorized into groups with low and high Alzheimer's disease risk on the basis of their computed product Aβ42 × T-Tau. Intergroup differences and the associations and mediation effects between sleep-related parameters and neurochemical biomarkers were analyzed.

RESULTS

Forty-two participants were enrolled, with 21 assigned to each of the low- and high-risk groups. High-risk individuals had a higher apnea-hypopnea index, oxygen desaturation index (≥3%, ODI-3%), fraction of total sleep time with oxygen desaturation (SpO2-90% TST), and arousal index and greater peak-to-peak amplitude and slope in slow-wave activity, with a correspondingly shorter duration, than did low-risk individuals. Furthermore, indices such as the apnea-hypopnea index, ODI-3% and SpO2-90% TST were found to indirectly affect slow-wave activity, thereby raising the Aβ42 × T-Tau level.

CONCLUSIONS

Obstructive sleep apnea manifestations, such as respiratory events and hypoxia, may influence slow-wave sleep activity (functioning as intermediaries) and may be linked to elevated neurochemical biomarker levels. However, a longitudinal study is necessary to determine causal relationships among these factors.

STATEMENT OF SIGNIFICANCE

This research aims to bridge gaps in understanding how obstructive sleep apnea is associated with an elevated risk of Alzheimer's disease, providing valuable knowledge for sleep and cognitive health.

Louis EK, McCarter SJ, Bukartyk J, Przybelski SA, Kamykowski MG, Spychalla AJ, Machulda MM, Boeve BF, Petersen RC, Jack CR, Lowe VJ, Graff-Radford J, Worrell GA, Somers VK, Varga AW, Vemuri P. Non-rapid eye movement sleep slow-wave activity features are associated with amyloid accumulation in older adults with obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is associated with an increased risk for cognitive impairment and dementia, which likely involves Alzheimer's disease pathology. Non-rapid eye movement slow-wave activity (SWA) has been implicated in amyloid clearance, but it has not been studied in the context of longitudinal amyloid accumulation in OSA. This longitudinal retrospective study aims to investigate the relationship between polysomnographic and electrophysiological SWA features and amyloid accumulation. From the Mayo Clinic Study of Aging cohort, we identified 71 participants ≥60 years old with OSA (mean baseline age = 72.9 ± 7.5 years, 60.6% male, 93% cognitively unimpaired) who had at least 2 consecutive Amyloid Pittsburgh Compound B (PiB)-PET scans and a polysomnographic study within 5 years of the baseline scan and before the second scan. Annualized PiB-PET accumulation [global ΔPiB(log)/year] was estimated by the difference between the second and first log-transformed global PiB-PET uptake estimations divided by the interval between scans (years). Sixty-four participants were included in SWA analysis. SWA was characterized by the mean relative spectral power density (%) in slow oscillation (SO: 0.5-0.9 Hz) and delta (1-3.9 Hz) frequency bands and by their downslopes (SO-slope and delta-slope, respectively) during the diagnostic portion of polysomnography. We fit linear regression models to test for associations among global ΔPiB(log)/year, SWA features (mean SO% and delta% or mean SO-slope and delta-slope), and OSA severity markers, after adjusting for age at baseline PiB-PET, APOE ɛ4 and baseline amyloid positivity. For 1 SD increase in SO% and SO-slope, global ΔPiB(log)/year increased by 0.0033 (95% CI: 0.0001; 0.0064, P = 0.042) and 0.0069 (95% CI: 0.0009; 0.0129, P = 0.026), which were comparable to 32% and 59% of the effect size associated with baseline amyloid positivity, respectively. Delta-slope was associated with a reduction in global ΔPiB(log)/year by -0.0082 (95% CI: -0.0143; -0.0021, P = 0.009). Sleep apnoea severity was not associated with amyloid accumulation. Regional associations were stronger in the pre-frontal region. Both slow-wave slopes had more significant and widespread regional associations. Annualized PiB-PET accumulation was positively associated with SO and SO-slope, which may reflect altered sleep homeostasis due to increased homeostatic pressure in the setting of unmet sleep needs, increased synaptic strength, and/or hyper-excitability in OSA. Delta-slope was inversely associated with PiB-PET accumulation, suggesting it may represent residual physiological activity. Further investigation of SWA dynamics in the presence of sleep disorders before and after treatment is necessary for understanding the relationship between amyloid accumulation and SWA physiology.

Sleep apnea evokes right hemisphere dominance and psychological disorders: An exploratory study

BACKGROUND

Obstructive sleep apnea (OSA) is considered one of the major causes of sleep disorders and psychological disorders in individuals. Brain asymmetry (BA) demonstrates individual hemispheric activity and psychological disorders. This study aimed to explore the characteristics of BA and psychology in OSA.

METHODS

Enrolment of patients for sleep assessment at the Sleep Medicine Center. Clinical characteristics, handedness, and psychological scales were prospectively collected from subjects. Subsequently, EEG power in alpha, beta, and theta bilaterally was calculated for the rest and sleep phases.

RESULTS

A total of 152 OSA and 21 non-OSA subjects were included in the study. In the frontal, central and occipital regions, OSA exhibited increased interhemispheric asymmetry with increasing apnea-hypopnea index (AHI) during rest and sleep. Simultaneously, the results showed that greater activity in the right hemisphere was positively associated with anxiety and extraversion, while inversely with positive and lie scale. In addition, the results show that OSA contributes to abnormal BA fluctuations during sleep.

CONCLUSIONS

Our results suggest that sleep disorders associated with apnea-hypopnea and arousal may contribute to increased BA during sleep. Such changes may persist into wakefulness with psychological traits.

Microstructural brain abnormalities and associated neurocognitive dysfunction in obstructive sleep apnea: a pilot study with diffusion kurtosis imaging

STUDY OBJECTIVES

We assessed possible brain abnormalities in adult patients with moderate and severe obstructive sleep apnea using the mean kurtosis (MK) from diffusion kurtosis imaging and analyzed the correlation between MK and cognitive function.

METHODS

A total of 30 patients with moderate or severe obstructive sleep apnea and 30 healthy controls evaluated by the Montreal Cognitive Assessment scale were enrolled. All participants underwent diffusion kurtosis imaging and 3-dimensional T1-weighted imaging on a 3.0T magnetic resonance scanner. The MK values of gray and white matter brain regions were compared. Partial correlation analysis was used to analyze the correlation between respiratory sleep parameters/cognitive score and MK values in different brain regions.

RESULTS

Compared with the healthy controls, the MK of 20 brain regions (13 after false discovery rate correction) and cognitive scores in the obstructive sleep apnea group were significantly lower. In the obstructive sleep apnea group, apnea-hypopnea index was negatively correlated with the MK in the white matter of the right occipital lobe; lowest oxygen saturation was positively correlated with the MK in the bilateral parietal, precentral, and right postcentral cortex; total score on the Montreal Cognitive Assessment scale was positively correlated with MK in the left hippocampus; language function was positively correlated with MK in the white matter of the left parietal lobe; and delayed recall was positively correlated with the MK in right insula cortex and bilateral cingulate. After false discovery rate correction, only the correlations of lowest oxygen saturation with right precentral gyrus cortex and bilateral parietal cortex were significant.

CONCLUSIONS

MK values of diffusion kurtosis imaging may provide valuable information in assessing the neurological impacts of obstructive sleep apnea.

CITATION

Zhang N, Peng K, Guo J-X, Liu Q, Xiao A-L, Jing H. Microstructural brain abnormalities and associated neurocognitive dysfunction in obstructive sleep apnea: a pilot study with diffusion kurtosis imaging. J Clin Sleep Med. 2024;20(10):1571-1578.

Impact of excessive daytime sleepiness on attention impairment in obstructive sleep apnea: a cross-sectional observational study

PURPOSE

This study aims to examine the relationship between excessive daytime sleepiness (EDS) and attention impairment in Chinese individuals with obstructive sleep apnea (OSA).

METHODS

A total of 1996 OSA patients with an apnea-hypopnea index (AHI) of ≥ 5 events per hour were included in this study. EDS was measured using the Epworth Sleepiness Scale (ESS), while cognitive function was assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA).

RESULTS

OSA patients with EDS demonstrated higher body mass index (BMI), comorbidities of hypertension and diabetes, decreased N3 sleep, increased AHI and ODI, as well as lower minimum oxygen saturation. Despite no significant differences in total cognitive scores assessed by MMSE and MoCA, individuals with comorbid sleepiness exhibited more evident attention deficits in the subdomains of MoCA. Stratified analysis indicated that regardless of age, educational level was the primary factor influencing attention in the AHI < =20 group. In the AHI > 20 group, attention impairment in patients younger than 40 remained significantly associated with education level, whereas for individuals aged 40 and above, attention deficits were associated with education level, age, and daytime sleepiness. The interaction analysis indicated that OSA severity modulated the impact of sleepiness on attention in patients aged 40 and above.

CONCLUSION

A significant correlation was observed between EDS and attention deficits in Chinese individuals diagnosed with OSA, with a particular emphasis on patients aged 40 and above. The severity of OSA modulates the impact of sleepiness on attention in patients aged 40 and above.

Cortical activation during the verbal fluency task for obstructive sleep apnea patients with depressive symptoms: A multi-channel fNIRS study

STUDY OBJECTIVE

The aim of our study was to elucidate differences in brain activity patterns among obstructive sleep apnea (OSA) patients, OSA patients with depressive symptoms, and healthy controls (HCs). We also investigated the relationship between brain function and depression in OSA patients.

METHODS

A total of 95 subjects were included in the study, including 34 OSA patients without depressive symptoms, 31 OSA patients with depressive symptoms, and 30 HCs. The 53-channel functional near-infrared spectroscopy (fNIRS) was used to monitor the concentration of oxy-hemoglobin (Oxy-Hb) in the brain, whereas the participants performed the verbal fluency task, and the degree of depression was scored using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Hierarchical regression models were conducted to analyze the association of fNIRS features with depressive symptom.

RESULTS

The Oxy-Hb changes of the three groups were significantly different in Channels 25 (H = 9.878, p = .007) and 43 (H = 6.957, p = .031). Inter-group comparisons showed that the Oxy-Hb change of Channel 25 (located in the dorsolateral prefrontal cortex [DLPFC]) in OSA group was less than that in HC group (p = .006), and the Oxy-Hb change of Channel 43 (located in the right frontal polar region) in OSA group with depression was less than that in OSA group (p = .025). Spearman's test showed that there was a significant negative correlation between HAMD-17 scores and mean Oxy-Hb changes in Channel 43 (r = -.319, p < .05) in the OSA patients. Using hierarchical regression, Oxy-Hb changes in Channel 43 accounted for a significant proportion of the variation in outcome variables, even when accounting for other polysomnography features.

CONCLUSIONS

Changes in the hemodynamic response of DLPFC may be a potential mechanism of executive dysfunction in OSA patients. And the right frontal polar region may be significant in assessing depressive symptoms in patients with OSA.

Health outcomes of former division I college athletes

BACKGROUND

Former professional collision sport (CS) athletes, particularly American football players, are at risk of developing chronic health conditions; however, little is known about the health outcomes of amateur athletes.

METHODS

A 60-item health survey examined self-reported symptoms and diagnoses among former Division 1 Collegiate CS athletes and non- or limited-contact sport (non-CS) athletes. Binary logistic regressions tested the association between playing CS and health outcomes.

RESULTS

Five hundred and two (6.2%) participants completed the survey: 160 CS athletes (mean age: 59.2, SD = 16.0) and 303 non-CS athletes (mean age: 54.0, SD = 16.9). CS athletes had increased odds of reported cognitive complaints and neuropsychiatric symptoms including memory (Padj < 0.01), attention/concentration (Padj = 0.01), problem solving/multi-tasking (Padj = 0.05), language (Padj = 0.02), anxiety (Padj = 0.04), impulsivity (Padj = 0.02), short-fuse/rage/explosivity (Padj < 0.001), and violence/aggression (Padj = 0.02). CS athletes also reported higher rates of sleep apnea (Padj = 0.02). There were no group differences in cardiovascular and physical health outcomes.

CONCLUSIONS

Former CS athletes reported more cognitive and neuropsychiatric complaints. The low response rate is a limitation of this study; however, over 500,000 athletes play college sports each year, thus research on long-term health outcomes in this population is critical.

Sleep apnea in schizophrenia: Estimating prevalence and impact on cognition

Undertreated medical illnesses can compound the disabling cognitive deficits of schizophrenia. Obstructive sleep apnea (OSA) impairs cognitive domains also affected by schizophrenia, is common, and is treatable. The effects of sleep apnea on cognition in schizophrenia, however, are not well understood. We estimated the prevalence of OSA in a previously characterized sample of 3942 Veterans with schizophrenia by self-report and with a predictive model to identify individuals at high risk for OSA. We then compared neuropsychological and functional capacity assessment results between those who reported OSA versus those who did not, and between those predicted to have OSA versus predicted to not have OSA. We expected that many Veterans not reporting sleep apnea would be predicted to have it, and that both reported and predicted sleep apnea would be associated with lower cognitive and functional performance. The reported prevalence of OSA in the sample was 14%, whereas 72% were predicted to be at high risk of OSA. Interestingly, participants who reported having OSA had better cognitive and functional capacity performance (p's < 0.001) compared to those who did not report OSA, particularly on speed of processing assessments (p < 0.001). Predicted OSA, by contrast, was associated with lower speed of processing, verbal learning and working memory test scores (p's < 0.001). One possible interpretation of these results is that people with higher cognitive capacity may be more likely to seek medical care, while those with cognitive impairments are at greater risk for having untreated co-occurring medical conditions that further compromise cognition.

Evaluating practice effects across learning trials - ceiling effects or something more?

BACKGROUND

Practice effects (PE) are traditionally considered improvements in performance observed resulting from repeated exposure to test materials across multiple testing sessions. While PE are commonly observed for memory tests, this effect has only been considered in summary total scores. The current objective was to consider PE in summary total scores, individual learning trials, and learning slopes.

METHOD

One-week PE for individual trial and learning slope performance was examined on the BVMT-R and HVLT-R in 151 cognitively intact participants and 131 participants with Mild Cognitive Impairment (MCI) aged 65 years and older.

RESULTS

One-week PE were observed across all trials and summary total scores for both memory measures and diagnostic classifications, despite the potential for ceiling effects to limit improvement on retesting. PE were largest on the first trial relative to subsequent learning trials. This effect was diminished - but not eliminated - in participants with MCI. Conversely, no PE were observed for learning slope scores, which was counter to expectations and likely confounded by ceiling effects.

CONCLUSIONS

PE were present across learning trials but not learning slopes, and the initial learning trial at follow-up tended to benefit most from PE relative to subsequent learning trials. Ceiling effects appeared to influence PE for learning slopes more than learning trials. These results highlight the potential diagnostic utility of PE across individual learning trials and inform how they are distributed at follow-up, while also suggesting that learning slopes may be generally stable during longitudinal assessment.

Amyloid profile is associated with sleep quality in preclinical but not in prodromal Alzheimer's disease older adults

BACKGROUND

Few studies have assessed whether neuropathological markers of AD in the preclinical and prodromal stages are associated with polysomnographic changes and obstructive sleep apnea (OSA).

METHODS

This was a cross-sectional, case-control study of older adults (≥60 years) without relevant clinical and psychiatric comorbidities selected randomly from a cohort of individuals without dementia in a tertiary university hospital in São Paulo, Brazil. They underwent neuropsychological evaluation for clinical diagnosis and were allocated into two samples: cognitively unimpaired (CU) and mild cognitive impairment (MCI). Also, they underwent PET-PiB to determine the amyloid profile and all-night in-lab polysomnography. For each sample, we compared polysomnographic parameters according to the amyloid profile (A+ vs A-).

RESULTS

We allocated 67 participants (mean age 73 years, SD 10,1), 70 % females, 14 ± 5 years of education, into two samples: CU (n = 28, 42.4 %) and MCI (n = 39, 57.6 %). In the CU sample, the group A+ (n = 9) showed worse sleep parameters than A- (n = 19) (lower total sleep time (p = 0.007), and sleep efficiency (p = 0.005); higher sleep onset latency (p = 0.025), wake time after sleep onset (p = 0.011), and arousal index (AI) (p = 0.007)), and changes in sleep structure: higher %N1 (p = 0.005), and lower %REM (p = 0.006). In the MCI sample, MCI A-had higher AI (p = 0.013), respiratory disturbance index (p = 0.025, controlled for age), and higher rates of severe OSA than A+.

DISCUSSION

The amyloid profile was associated with polysomnographic markers of worse sleep quality in individuals with preclinical AD but not with prodromal AD, probably due to the higher frequencies of severe OSA.

Development of a diagnostic model for detecting mild cognitive impairment in young and middle-aged patients with obstructive sleep apnea: a prospective observational study

Objectives

Obstructive sleep apnea (OSA) is a common sleep-disordered breathing condition linked to the accelerated onset of mild cognitive impairment (MCI). However, the prevalence of undiagnosed MCI among OSA patients is high and attributable to the complexity and specialized nature of MCI diagnosis. Timely identification and intervention for MCI can potentially prevent or delay the onset of dementia. This study aimed to develop screening models for MCI in OSA patients that will be suitable for healthcare professionals in diverse settings and can be effectively utilized without specialized neurological training.

Methods

A prospective observational study was conducted at a specialized sleep medicine center from April 2021 to September 2022. Three hundred and fifty consecutive patients (age: 18-60 years) suspected OSA, underwent the Montreal Cognitive Assessment (MoCA) and polysomnography overnight. Demographic and clinical data, including polysomnographic sleep parameters and additional cognitive function assessments were collected from OSA patients. The data were divided into training (70%) and validation (30%) sets, and predictors of MCI were identified using univariate and multivariate logistic regression analyses. Models were evaluated for predictive accuracy and calibration, with nomograms for application.

Results

Two hundred and thirty-three patients with newly diagnosed OSA were enrolled. The proportion of patients with MCI was 38.2%. Three diagnostic models, each with an accompanying nomogram, were developed. Model 1 utilized body mass index (BMI) and years of education as predictors. Model 2 incorporated N1 and the score of backward task of the digital span test (DST_B) into the base of Model 1. Model 3 expanded upon Model 1 by including the total score of digital span test (DST). Each of these models exhibited robust discriminatory power and calibration. The C-statistics for Model 1, 2, and 3 were 0.803 [95% confidence interval (CI): 0.735-0.872], 0.849 (95% CI: 0.788-0.910), and 0.83 (95% CI: 0.763-0.896), respectively.

Conclusion

Three straightforward diagnostic models, each requiring only two to four easily accessible parameters, were developed that demonstrated high efficacy. These models offer a convenient diagnostic tool for healthcare professionals in diverse healthcare settings, facilitating timely and necessary further evaluation and intervention for OSA patients at an increased risk of MCI.

Tet1-mediated 5hmC regulates hippocampal neuroinflammation via wnt signaling as a novel mechanism in obstructive sleep apnoea leads to cognitive deficit

BACKGROUND

Obstructive sleep apnoea (OSA) is a sleep-disordered breathing characterized by intermittent hypoxia (IH) that may cause cognitive dysfunction. However, the impact of IH on molecular processes involved in cognitive function remains unclear.

METHODS

C57BL / 6 J mice were exposed to either normoxia (control) or IH for 6 weeks. DNA hydroxymethylation was quantified by hydroxymethylated DNA immunoprecipitation (hMeDIP) sequencing. ten-eleven translocation 1 (Tet1) was knocked down by lentivirus. Specifically, cognitive function was assessed by behavioral experiments, pathological features were assessed by HE staining, the hippocampal DNA hydroxymethylation was examined by DNA dot blot and immunohistochemical staining, while the Wnt signaling pathway and its downstream effects were studied using qRT-PCR, immunofluorescence staining, and Luminex liquid suspension chip analysis.

RESULTS

IH mice showed pathological changes and cognitive dysfunction in the hippocampus. Compared with the control group, IH mice exhibited global DNA hydroxylmethylation in the hippocampus, and the expression of three hydroxylmethylases increased significantly. The Wnt signaling pathway was activated, and the mRNA and 5hmC levels of Wnt3a, Ccnd2, and Prickle2 were significantly up-regulated. Further caused downstream neurogenesis abnormalities and neuroinflammatory activation, manifested as increased expression of IBA1 (a marker of microglia), GFAP (a marker of astrocytes), and DCX (a marker of immature neurons), as well as a range of inflammatory cytokines (e.g. TNFa, IL3, IL9, and IL17A). After Tet1 knocked down, the above indicators return to normal.

CONCLUSION

Activation of Wnt signaling pathway by hippocampal Tet1 is associated with cognitive dysfunction induced by IH.

Sex differences in the association of sleep spindle density and cognitive performance among community-dwelling middle-aged and older adults with obstructive sleep apnea

Recent studies have found associations between obstructive sleep apnea and cognitive decline. The underlying mechanisms are still unclear. Here, we investigate the associations between changes in micro-architecture, specifically sleep spindles, and cognitive function in community-dwelling middle-aged and older adults, some with obstructive sleep apnea, with a focus on sex differences. A total of 125 voluntary participants (mean age 66.0 ± 6.4 years, 64 females) from a larger cohort (participants of the Brain in Motion Studies I and II) underwent 1 night of in-home polysomnography and a neuropsychological battery (sleep and cognitive testing were conducted within 2 weeks of each other). A semi-automatic computerized algorithm was used to score polysomnography data and detect spindle characteristics in non-rapid eye movement Stages 2 and 3 in both frontal and central electrodes. Based on their apnea-hypopnea index, participants were divided into those with no obstructive sleep apnea (apnea-hypopnea index < 5 per hr, n = 21), mild obstructive sleep apnea (5 ≥ apnea-hypopnea index < 15, n = 47), moderate obstructive sleep apnea (15 ≥ apnea-hypopnea index < 30, n = 34) and severe obstructive sleep apnea (apnea-hypopnea index ≥ 30, n = 23). There were no significant differences in spindle characteristics between the four obstructive sleep apnea severity groups. Spindle density and percentage of fast spindles were positively associated with some verbal fluency measures on the cognitive testing. Sex might be linked with these associations. Biological sex could play a role in the associations between spindle characteristics and some verbal fluency measures. Obstructive sleep apnea severity was not found to be a contributing factor in this non-clinical community-dwelling cohort.

Biomarkers of sleep-wake disturbance as predictors of cognitive decline and accelerated disease progression

INTRODUCTION

In older adults, where sleep disturbances and cognitive impairment are common, mounting evidence suggests a potential connection between sleep and cognitive function, highlighting the significance of utilizing sleep as a biomarker for early detection of cognitive impairment to improve clinical outcomes in a noninvasive, cost-effective manner.

AREAS COVERED

This review describes the relationship between sleep and cognitive function in older adults, encompassing both subjective and objective measures of sleep quality, duration, architecture, and sleep-disordered breathing. The authors consider the directionality of the associations observed in prospective and cross-sectional studies, exploring whether sleep disturbances precede cognitive decline or vice versa. Furthermore, they discuss the potential bidirectional relationships between sleep and Alzheimer's disease (AD) risks in older adults while also examining the neurodegenerative pathways of this relationship.

EXPERT OPINION

Routine sleep monitoring in primary care settings has the potential to bolster early detection and treatment of sleep disturbance, and by extension, reduce the risk of dementia. Improving sleep assessment tools, such as wearables, provide scalable alternatives to traditional methods like polysomnography, potentially enabling widespread monitoring of sleep characteristics. Standardized measurement and inclusive participant recruitment are needed to enhance generalizability, while longitudinal studies are essential to understand the interaction between sleep and AD pathology.

Rural-Urban mild cognitive impairment comparison in West Michigan through EHR

INTRODUCTION

Mild cognitive impairment (MCI) is a significant public health concern and a potential precursor to Alzheimer's disease (AD). This study leverages electronic health record (EHR) data to explore rural-urban differences in MCI incidence, risk factors, and healthcare navigation in West Michigan.

METHODS

Analysis was conducted on 1,528,464 patients from Corewell Health West, using face-to-face encounters between 1/1/2015 and 7/31/2022. MCI cases were identified using International Classification of Diseases (ICD) codes, focusing on patients aged 45+ without prior MCI, dementia, or AD diagnoses. Incidence rates, cumulative incidences, primary care physicians (PCPs), and neuropsychology referral outcomes were examined across rural and urban areas. Risk factors were evaluated through univariate and multivariate Cox regression analyses. The geographic distribution of patient counts, hospital locations, and neurology department referrals were examined.

RESULTS

Among 423,592 patients, a higher MCI incidence rate was observed in urban settings compared to rural settings (3.83 vs. 3.22 per 1,000 person-years). However, sensitivity analysis revealed higher incidence rates in rural areas when including patients who progressed directly to dementia. Urban patients demonstrated higher rates of referrals to and completion of neurological services. While the risk factors for MCI were largely similar across urban and rural populations, urban-specific factors for incident MCI are hearing loss, inflammatory bowel disease, obstructive sleep apnea, insomnia, being African American, and being underweight. Common risk factors include diabetes, intracranial injury, cerebrovascular disease, coronary artery disease, stroke, Parkinson's disease, epilepsy, chronic obstructive pulmonary disease, depression, and increased age. Lower risk was associated with being female, having a higher body mass index, and having a higher diastolic blood pressure.

DISCUSSION

This study highlights rural-urban differences in MCI incidence and access to care, suggesting potential underdiagnosis in rural areas likely due to reduced access to specialists. Future research should explore socioeconomic, environmental, and lifestyle determinants of MCI to refine prevention and management strategies across geographic settings.

Highlights

Leveraged EHRs to explore rural-urban differences in MCI in West Michigan.Revealed a significant underdiagnosis of MCI, especially in rural areas.Observed lower rates of neurological referrals and completions for rural patients.Identified risk factors specific to rural and urban populations.

Sex and APOE genotype influence respiratory function under hypoxic and hypoxic-hypercapnic conditions

The apolipoprotein E (APOE) gene has been studied due to its influence on Alzheimer's disease (AD) development and work in an APOE mouse model recently demonstrated impaired respiratory motor plasticity following spinal cord injury (SCI). Individuals with AD often copresent with obstructive sleep apnea (OSA) characterized by cessations in breathing during sleep. Despite the prominence of APOE genotype and sex as factors in AD progression, little is known about the impact of these variables on respiratory control. Ventilation is tightly regulated across many systems, with respiratory rhythm formation occurring in the brainstem but modulated in response to chemoreception. Alterations within these modulatory systems may result in disruptions of appropriate respiratory control and ultimately, disease. Using mice expressing two different humanized APOE alleles, we characterized how sex and the presence of APOE3 or APOE4 influences ventilation during baseline breathing (normoxia) and during respiratory challenges. We show that sex and APOE genotype influence breathing during hypoxic challenge, which may have clinical implications in the context of AD and OSA. In addition, female mice, while responding robustly to hypoxia, were unable to recover to baseline respiratory levels, emphasizing sex differences in disordered breathing.NEW & NOTEWORTHY This study is the first to use whole body plethysmography (WBP) to measure the impact of APOE alleles on breathing under normoxia and during adverse respiratory challenges in a targeted replacement Alzheimer's model. Both sex and genotype were shown to affect breathing under normoxia, hypoxic challenge, and hypoxic-hypercapnic challenge. This work has important implications regarding the impact of genetics on respiratory control as well as applications pertaining to conditions of disordered breathing including sleep apnea and neurotrauma.

Worldwide prevalence of sleep problems in community-dwelling older adults: A systematic review and meta-analysis

The understanding of the prevalence of sleep problems in older adults can provide a broad and reliable perspective into the occurrence of such issues among older adults. This systematic review and meta-analysis aimed to estimate the worldwide prevalence of sleep problems in community-dwelling older adults. Studies that provide information on the prevalence of sleep problems in community-dwelling older adults (≥60 years) were screened between December 2022 and March 2023. A total of 20,379 studies were identified in database searches, from which 252 were included in this review. These studies covered the last 35 years (from 1988 to 2023) and pooled a sample of 995,544 participants from 36 countries. The most frequent sleep problem worldwide was obstructive sleep apnea (46.0%), followed by poor sleep quality (40.0%), other sleep problems (37.0%), insomnia (29.0%), and excessive daytime sleepiness (19.0%). No significant difference in the prevalence estimates of all sleep problems was observed between the sexes. This systematic review and meta-analysis showed a high prevalence of some sleep problems, mainly obstructive sleep apnea, poor sleep quality, and other sleep problems. Our estimates can be useful for managers and policymakers in planning healthcare strategies for sleep problems aimed at the older population.

Mitochondrial dysfunction is associated with cognitive impairment in adults with OSA without dementia

STUDY OBJECTIVES

Increased reactive oxygen species associated with loss of mitochondrial function affect synaptic activity, which is an important mechanism underlying cognitive decline. This study assesses the role of mitochondrial proteins in neuron-derived exosomes (NDEs) on cognitive impairment in patients with obstructive sleep apnea (OSA) without dementia.

METHODS

Analyses were conducted in 268 study participants with complete polysomnography data, cognitive tests, and important clinical data available. NDEs were isolated immunochemically for enzyme-linked immunosorbent assay quantification of mitochondrial proteins, i.e., humanin and mitochondrial open reading frame of the 12S rRNA-c (MOTS-c), and synaptic protein, i.e., neurogranin (NRGN). A mediation analysis of the relationship between sleep parameters and cognition was performed using humanin, MOTS-c, and NRGN values as a mediating factor. Twenty-two patients with moderate to severe OSA who received CPAP therapy were followed up, and humanin, MOTS-c and NRGN levels were reassessed after 1 year of treatment.

RESULTS

All participants were divided into the OSA + MCI group (n = 91), OSA-MCI group (n = 89), MCI group (MCI without OSA) (n = 38) and control group (normal cognitive state without OSA) (n = 50). The mean CD63-normalized NDE levels of humanin, MOTS-c, and NRGN in the OSA + MCI group were higher than those in the OSA-MCI and control groups. The NDE levels of humanin, MOTS-c, and NRGN in the MCI group were lower than those in controls. The odds of cognitive impairment in patients with OSA were higher with higher NDE levels of humanin, MOTS-c, and NRGN (odds ratio (OR): 2.100, 95 % confidence interval (CI): 1.646-2.679, P < 0.001; OR: 5.453, 95 % CI: 3.112-9.556, P < 0.001; OR: 3.115, 95 % CI: 2.163-4.484, P < 0.001). The impaired cognitive performance was associated with higher NDE levels of humanin (β: 0.505, SE: 0.048, P < 0.001), MOTS-c (β: 0.580, SE: 0.001, P < 0.001), and NRGN (β: 0.585, SE: 0.553, P < 0.001). The relationship between sleep parameters (mean SaO2 and T90) and MoCA scores was mediated by the NDE levels of humanin, MOTS-c, and NRGN with the proportion of mediation varying from 35.33 % to 149.07 %. Receiver operating characteristic curve revealed an area under the curve of 0.905 for humanin, 0.873 for MOTS-c, and 0.934 for NRGN to predict MCI in OSA patients without dementia. Increased humanin, MOTS-c, and NRGN levels significantly decreased after CPAP treatment.

CONCLUSIONS

Mitochondrial dysfunction is implicated in cognitive impairment in OSA patients without dementia, and mainly mediates the association between intermittent hypoxia and cognitive impairment in adults with OSA without dementia. Mitochondrial dysfunction can be partially reversible by CPAP treatment. Mitochondrial proteins can be used as markers of cognitive impairment in patients with OSA.

Could an increased risk of obstructive sleep apnoea be one of the determinants associated with disability in individuals with cardiovascular and cerebrovascular diseases?

PURPOSE

To investigate a possible association between the risk of obstructive sleep apnoea (OSA) and disability in individuals with cardiovascular or cerebrovascular diseases.

METHODS

Cross-sectional study was conducted with 373 individuals (313 with cardiovascular or cerebrovascular diseases and 60 healthy). Disability was assessed by the 12-item World Health Organization Disability Assessment Schedule (WHODAS), and the risk of OSA was assessed by STOP-BANG. Anxiety and depression symptoms, daytime sleepiness, and cognition were assessed by the Hospital Anxiety and Depression Scale (HADS), Epworth Sleepiness Scale (ESS), and Mini Mental State Examination (MMSE).

RESULTS

Greater disability was found in individuals with intermediate or high risk of OSA, considering healthy individuals (p=0.03), or individuals diagnosed with arrhythmia (p<0.01) or coronary artery disease (p=0.04). A high risk of OSA and higher WHODAS scores was significant among women as well as between OSA risk categories (p<0.01). Cognitive deficit and level of education also showed differences between OSA risk categories. Age, depression, and sleepiness were also associated with the subjects' disability (p<0.01). Gamma regression model showed higher WHODAS scores in female, in those with intermediate and high risk of OSA, and in those with depressive symptoms and cognitive deficit. Age also showed a correlation with higher WHODAS scores. The presence of all investigated cardio and cerebrovascular diseases showed an increase in the WHODAS score, implying a greater disability compared to healthy individuals.

CONCLUSION

Moderate and high risk of OSA is associated with disability, as well as gender, age, depressive symptoms, cognitive deficit, and cardiovascular diseases.

Altered cerebral white matter network topology and cognition in children with obstructive sleep apnea

OBJECTIVES

The study aimed to explore the underlying mechanisms of OSA-related cognitive impairment by investigating the altered topology of brain white matter networks in children with OSA.

METHODS

Graph theory was used to examine white matter networks' network topological properties in 46 OSA and 31 non-OSA children. All participants underwent MRI, polysomnography, and cognitive testing. The effects of the obstructive apnea-hypopnea index (OAHI) on topological properties of white matter networks and network properties on cognition were studied using hierarchical linear regression. Mediation analyses were used to explore whether white matter network properties mediated the effects of OAHI on cognition.

RESULTS

Children with OSA had significantly higher assortativity than non-OSA children. Furthermore, OAHI was associated with the nodal properties of several brain regions, primarily in the frontal and temporal lobes. The relationship between OAHI and verbal comprehension index was mediated through clustering coefficients in the right temporal pole of the superior temporal gyrus.

CONCLUSIONS

OSA affects the development of white matter networks in children's brains. Besides, the mediating role of white matter network properties between the OAHI and the verbal comprehension index provided neuroimaging evidence of impaired cognitive function in children with OSA.

Bioinformatics-based identification of key candidate genes and signaling pathways in patients with Parkinson's disease and obstructive sleep apnea

OBJECTIVES

Existing evidence exhibits that obstructive sleep apnea (OSA) is a potential consequence of Parkinson's disease (PD) or a contributor to PD progression. This investigation aimed to detect potential critical genes and molecular mechanisms underlying interactions between PD and OSA through bioinformatics analyses.

METHODS

The Gene Expression Omnibus (GEO) database was employed to obtain the expression profiles GSE20163 and GSE135917. The identification of common genes connected to PD and OSA was performed utilizing weighted gene co-expression network analysis and the R 4.0.4 program. The Cytoscape program was utilized to generate a network of protein-protein interactions (PPI), and the CytoHubba plugin was utilized to detect hub genes. Subsequently, functional enrichment analyses of the hub genes were conducted. Markers with increased diagnostic values for PD and OSA were confirmed using the GEO datasets GSE8397 and GSE38792.

RESULTS

Typically, 57 genes that are common were identified in PD and OSA. Among these common genes, the top 10 hub genes in the PPI network were chosen. The verified datasets confirmed the presence of three important genes: CADPS, CHGA, and SCG3. Functional enrichment analysis revealed that these hub genes mostly participate in GABAergic synapses.

CONCLUSION

Our findings suggest that CADPS, CHGA, and SCG3 are key genes involved in molecular mechanisms underlying interactions between OSA and PD. Functional enrichment of hub genes indicated a link between GABAergic synapses and the shared pathogenesis of PD and OSA. These candidate genes and corresponding pathways offer novel insights regarding biological targets that underlie the transcriptional connection between OSA and PD.

Continuous positive airway pressure compliance in patients with mild cognitive impairment

PURPOSE

Sleep apnoea (SA) is associated with accelerated cognitive decline in patients with mild cognitive impairment (MCI). Treatment of SA by continuous positive airway pressure (CPAP) may slow this decline if patients comply with the treatment. The aim of this study was to assess the rate of CPAP compliance in this population.

METHODS

In this single-centre retrospective study conducted in a tertiary care institution, patients with a diagnosis of MCI and SA initiating CPAP between January 2015 and August 2021 were included. Data from the initial sleep recording, the 3-month follow-up and compliance with at least 12 months of CPAP were analysed. Compliance was defined as an average CPAP use of at least 4 h per night.

RESULTS

55 patients were included (49% women, age 70.7 ± 8.9 years, body mass index 28.9 ± 6.5 kg/m2). Aetiology of MCI was vascular (45.5%), psychiatric (12.7%) and related to Alzheimer's disease (7.3%), with 47.3% of amnesic disorders and 45.5% of dysexecutive disorders. The MiniMentalState score was 26.7 ± 3.1. SA was mostly obstructive (81.8%) with a mean apnoea-hypopnoea index of 41.1 ± 16.4/h. At 3 months, 38 patients were compliant (69%) with a CPAP median use of 5.9 h per night and 83% of nights. Self-reported tolerance was better in compliant patients (75.7% vs 38.5% p = 0.017). Thirty-four patients remained compliant at 12 months (62%).

CONCLUSION

Our results suggest a high rate of CPAP compliance in patients suffering from MCI. Compliance was related to the device tolerance, emphasizing the need to closely monitor and improve this factor.

The study of the relationship between moderate to severe sleep obstructive apnea and cognitive impairment, anxiety, and depression

Objective

The present study endeavored to investigate the interconnection between obstructive sleep apnea (OSA) and cognitive function, alongside the manifestations of depression and anxiety. Simultaneously, an analysis was conducted to discern the factors exerting influence upon cognitive function.

Methods

A cohort of 102 patients, who had undergone polysomnography (PSG) at Binhu Hospital, Anhui Medical University, between January 2022 and June 2023, was encompassed in the study. Employing the PSG findings, these individuals were classified into two distinct categories: the grouping consisted of those with either negligible or mild OSA, and the other comprised individuals with moderate to severe OSA. Utilizing the Montreal Cognitive Assessment (MoCA-Beijing), Stroop Color and Word Test (SCWT), Digit Span Test (DST), Self-rating Depression Scale (SDS), and Self-rating Anxiety Scale (SAS), scores were recorded and analysed for each of the respective assessments. Additionally, discrepancies and associations between these groups were also scrutinized.

Results

The group exhibiting moderate to severe OSA demonstrated significantly elevated measurements in parameters such as neck circumference, BMI, completion times for SCWT-A, B, C, Sleep Inefficiency Index (SIE), SAS, and SDS, in comparison to the No or Mild OSA group. Furthermore, the moderate-severe OSA group manifested notably diminished MoCA scores in areas of visual-spatial and executive function, memory, language, abstraction, delayed recall, orientation, total MoCA score, lowest oxygen saturation (LSaO2), average oxygen saturation, Digit Span Test-backward(DST-b), and Digit Span Test-forward(DST-f), as contrasted with the no-mild OSA group. These inter-group disparities exhibited statistical significance (p < 0.05). The MoCA total score portrayed inverse correlations with age, Apnea-Hypopnea Index (AHI), BMI, SIE, SAS, SDS, CT90%, AHT90%, and Hypoxic Apnea Duration (HAD) (ranging from -0.380 to -0.481, p < 0.05). Conversely, it displayed positive correlations with DST-f, DST-b, LSaO2, and average oxygen saturation (ranging from 0.414 to 0.744, p < 0.05). Neck circumference, AHI, and SAS were autonomously linked to MoCA scores (OR = 1.401, 1.028, 1.070, p < 0.05), while AHI exhibited an independent correlation with SDS and SAS scores (OR = 1.001, p = 0.003).

Conclusion

Patients grappling with moderate to severe OSA frequently reveal cognitive impairment and concomitant emotional predicaments encompassing depression and anxiety. These manifestations share an intimate association with AHI, LSaO2, and average oxygen saturation. Notably, anxiety, when coupled with OSA, emerges as an autonomous influential element impinging upon cognitive impairment.

Older adults at greater risk for Alzheimer's disease show stronger associations between sleep apnea severity in REM sleep and verbal memory

BACKGROUND

Obstructive sleep apnea (OSA) increases risk for cognitive decline and Alzheimer's disease (AD). While the underlying mechanisms remain unclear, hypoxemia during OSA has been implicated in cognitive impairment. OSA during rapid eye movement (REM) sleep is usually more severe than in non-rapid eye movement (NREM) sleep, but the relative effect of oxyhemoglobin desaturation during REM versus NREM sleep on memory is not completely characterized. Here, we examined the impact of OSA, as well as the moderating effects of AD risk factors, on verbal memory in a sample of middle-aged and older adults with heightened AD risk.

METHODS

Eighty-one adults (mean age:61.7 ± 6.0 years, 62% females, 32% apolipoprotein E ε4 allele (APOE4) carriers, and 70% with parental history of AD) underwent clinical polysomnography including assessment of OSA. OSA features were derived in total, NREM, and REM sleep. REM-NREM ratios of OSA features were also calculated. Verbal memory was assessed with the Rey Auditory Verbal Learning Test (RAVLT). Multiple regression models evaluated the relationships between OSA features and RAVLT scores while adjusting for sex, age, time between assessments, education years, body mass index (BMI), and APOE4 status or parental history of AD. The significant main effects of OSA features on RAVLT performance and the moderating effects of AD risk factors (i.e., sex, age, APOE4 status, and parental history of AD) were examined.

RESULTS

Apnea-hypopnea index (AHI), respiratory disturbance index (RDI), and oxyhemoglobin desaturation index (ODI) during REM sleep were negatively associated with RAVLT total learning and long-delay recall. Further, greater REM-NREM ratios of AHI, RDI, and ODI (i.e., more events in REM than NREM) were related to worse total learning and recall. We found specifically that the negative association between REM ODI and total learning was driven by adults 60 + years old. In addition, the negative relationships between REM-NREM ODI ratio and total learning, and REM-NREM RDI ratio and long-delay recall were driven by APOE4 carriers.

CONCLUSION

Greater OSA severity, particularly during REM sleep, negatively affects verbal memory, especially for people with greater AD risk. These findings underscore the potential importance of proactive screening and treatment of REM OSA even if overall AHI appears low.

Elucidating the association of obstructive sleep apnea with brain structure and cognitive performance

BACKGROUND

Obstructive sleep apnea (OSA) is a pervasive, chronic sleep-related respiratory condition that causes brain structural alterations and cognitive impairments. However, the causal association of OSA with brain morphology and cognitive performance has not been determined.

METHODS

We conducted a two-sample bidirectional Mendelian randomization (MR) analysis to investigate the causal relationship between OSA and a range of neurocognitive characteristics, including brain cortical structure, brain subcortical structure, brain structural change across the lifespan, and cognitive performance. Summary-level GWAS data for OSA from the FinnGen consortium was used to identify genetically predicted OSA. Data regarding neurocognitive characteristics were obtained from published meta-analysis studies. Linkage disequilibrium score regression analysis was employed to reveal genetic correlations between OSA and related traits.

RESULTS

Our MR study provided evidence that OSA was found to significantly increase the volume of the hippocampus (IVW β (95% CI) = 158.997 (76.768 to 241.227), P = 1.51e-04), with no heterogeneity and pleiotropy detected. Nominally causal effects of OSA on brain structures, such as the thickness of the temporal pole with or without global weighted, amygdala structure change, and cerebellum white matter change covering lifespan, were observed. Bidirectional causal links were also detected between brain cortical structure, brain subcortical, cognitive performance, and OSA risk. LDSC regression analysis showed no significant correlation between OSA and hippocampus volume.

CONCLUSIONS

Overall, we observed a positive association between genetically predicted OSA and hippocampus volume. These findings may provide new insights into the bidirectional links between OSA and neurocognitive features, including brain morphology and cognitive performance.

2024 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including prevalence and incidence, mortality and morbidity, use and costs of care and the ramifications of AD for family caregivers, the dementia workforce and society. The Special Report discusses the larger health care system for older adults with cognitive issues, focusing on the role of caregivers and non-physician health care professionals. An estimated 6.9 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060, barring the development of medical breakthroughs to prevent or cure AD. Official AD death certificates recorded 119,399 deaths from AD in 2021. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death in the United States. Official counts for more recent years are still being compiled. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2021, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 140%. More than 11 million family members and other unpaid caregivers provided an estimated 18.4 billion hours of care to people with Alzheimer's or other dementias in 2023. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $346.6 billion in 2023. Its costs, however, extend to unpaid caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Members of the paid health care and broader community-based workforce are involved in diagnosing, treating and caring for people with dementia. However, the United States faces growing shortages across different segments of the dementia care workforce due to a combination of factors, including the absolute increase in the number of people living with dementia. Therefore, targeted programs and care delivery models will be needed to attract, better train and effectively deploy health care and community-based workers to provide dementia care. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2024 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $360 billion. The Special Report investigates how caregivers of older adults with cognitive issues interact with the health care system and examines the role non-physician health care professionals play in facilitating clinical care and access to community-based services and supports. It includes surveys of caregivers and health care workers, focusing on their experiences, challenges, awareness and perceptions of dementia care navigation.

Respiratory muscle training for obstructive sleep apnea: Systematic review and meta-analysis

Obstructive sleep apnea is the most common sleep disorder. This review aims to evaluate the effectiveness and safety of respiratory muscle training in the treatment of patients with obstructive sleep apnea. The study protocol was registered in Prospero Platform (CRD42018096980). We performed searches in the main databases: Medical Literature Analysis and Retrieval System Online (MEDLINE) via Pubmed; Excerpta Medica dataBASE (Embase) via Elsevier; Cochrane Central Register of Controlled Trials (CENTRAL) via Cochrane Library; Latin American and Caribbean Literature on Health Sciences (LILACS) through the Portal of the Virtual Health Library and Physiotherapy Evidence Database (PEDro) for all randomised-controlled trials published before July 2022. The randomised-controlled trials were assessed for risk of bias and certainty of evidence. Thirteen randomised-controlled trials were included. All studies had an overall high risk of bias. Inspiratory muscle training probably improves systolic blood pressure and sleepiness when compared with sham. However, inspiratory muscle training probably does not improve diastolic blood pressure and maximum expiratory pressure, and may not be superior to sham for apnea-hypopnea index, forced expiratory volume in 1 s, forced vital capacity, sleep quality and quality of life. In addition, it is uncertain whether there is any effect of inspiratory muscle training on maximum inspiratory pressure and physical capacity. Inspiratory muscle training may also improve maximum inspiratory pressure and maximum expiratory pressure compared with oropharyngeal exercises. However, it may not be superior for apnea-hypopnea index, sleep quality, sleepiness, quality of life and functional capacity. When associated with physical exercise, inspiratory muscle training may not be superior to physical exercise alone for maximum inspiratory pressure, maximum expiratory pressure, systolic and diastolic blood pressure, and functional capacity. At the same time, when associated with cardiac rehabilitation exercises, inspiratory muscle training may reduce apnea-hypopnea index, improve inspiratory muscle strength, sleepiness and sleep quality compared with cardiac rehabilitation alone. However, it may not be superior for improving quality of life. Regarding expiratory muscle training, it may improve expiratory muscle strength and sleep quality, but not sleepiness when compared with sham. The evidence on the effects of expiratory muscle training in apnea-hypopnea index is very uncertain.

Association of obstructive sleep apnea and sleep quality with cognitive function: a study of middle-aged and elderly persons in India

INTRODUCTION

Symptoms of obstructive sleep apnea (OSA) and poor sleep quality affect around one in ten people in India. We aimed to determine if OSA symptoms and poor sleep quality are independently associated with cognition in middle-aged and elderly urban Indian populations.

METHODS

We studied the cross-sectional association between OSA symptoms (by Berlin Questionnaire), poor sleep quality (by Pittsburgh Sleep Quality Index), and cognitive function in adults ≥ 50 years. Using a standard neuropsychological battery for cognitive function, a G-factor was derived as the first rotated principal component assessing domains of information processing, memory, and executive function. The associations of exposures with cognitive measures were modeled using linear regression, adjusted for metabolic risk factors, lifestyle factors, and psychosocial problems, followed by stratified analysis by decadal age group.

RESULTS

A total of 7505 adults were enrolled. Excluding those with MMSE < 26 (n 710), of 6795 individuals (49.2% women), mean (SD) age 64.2 (9.0) years, 38.3% had high risk of OSA symptoms, and 15.9% had poor sleep quality. OSA symptoms were negatively associated with cognitive domains of information processing (adjusted beta coefficient of z-score - 0.02, p-value 0.006), memory (- 0.03, 0.014), and G-factor (- 0.11, 0.014) in full-model. Stratified analysis by age group showed significant adverse effects of OSA symptoms on cognition for middle-aged people (50-60 years) (- 0.26, 0.001), but not in later age groups. Poor sleep quality was also associated with lower cognitive scores for G-factor (- 0.48, < 0.001), memory (- 0.08, 0.005), and executive domains (- 0.12, < 0.001), but not with information domain.

CONCLUSION

The findings suggest that both symptoms of OSA and poor sleep quality have a direct adverse impact on cognition in an Indian setting. A modest effect of age on the relationship of OSA and cognition was also observed.

Brainstem impairment in obstructive sleep apnoea and the effect of CPAP treatment: an electrophysiological blink reflex study

PURPOSE

This study aimed to evaluate the functionality of the brainstem structures through the blink reflex (BR) test in patients with obstructive sleep apnoea (OSA) and to assess the effects of continuous positive airway pressure (CPAP) treatment on BR responses.

METHODS

Patients with moderate-severe OSA and controls underwent BR testing. Patients with OSA who were adherent to CPAP therapy repeated BR testing at 6 months follow-up. CPAP adherence was defined as CPAP use for ≥ 4 hour per night on > 5 nights per week with residual apnoea-hypopnea index less than 5 events per hour.

RESULTS

A total of 22 patients with OSA (86% male, mean age 57.8 ± 10.6 years) and 20 controls (60% male, mean age 55.3 ± 9.3 years) were included. Patients with OSA showed longer right and left R1 latency, as well as delayed right ipsilateral and contralateral R2 latencies compared to controls. Patients with OSA who were compliant with CPAP treatment (n = 16; 88% men, mean age 58.8 ± 9.7 years) showed a significant decrease in latency of the right ipsilateral and contralateral R2 responses at 6 months.

CONCLUSION

This study showed an abnormal pattern of BR responses in patients with OSA, consistent with a significant impairment of brainstem functionality in OSA. CPAP treatment partially improved the BR responses, suggesting the importance of treating OSA.

Automatic detection of obstructive sleep apnea based on speech or snoring sounds: a narrative review

Background and Objective

Obstructive sleep apnea (OSA) is a common chronic disorder characterized by repeated breathing pauses during sleep caused by upper airway narrowing or collapse. The gold standard for OSA diagnosis is the polysomnography test, which is time consuming, expensive, and invasive. In recent years, more cost-effective approaches for OSA detection based in predictive value of speech and snoring has emerged. In this paper, we offer a comprehensive summary of current research progress on the applications of speech or snoring sounds for the automatic detection of OSA and discuss the key challenges that need to be overcome for future research into this novel approach.

Methods

PubMed, IEEE Xplore, and Web of Science databases were searched with related keywords. Literature published between 1989 and 2022 examining the potential of using speech or snoring sounds for automated OSA detection was reviewed.

Key Content and Findings

Speech and snoring sounds contain a large amount of information about OSA, and they have been extensively studied in the automatic screening of OSA. By importing features extracted from speech and snoring sounds into artificial intelligence models, clinicians can automatically screen for OSA. Features such as formant, linear prediction cepstral coefficients, mel-frequency cepstral coefficients, and artificial intelligence algorithms including support vector machines, Gaussian mixture model, and hidden Markov models have been extensively studied for the detection of OSA.

Conclusions

Due to the significant advantages of noninvasive, low-cost, and contactless data collection, an automatic approach based on speech or snoring sounds seems to be a promising tool for the detection of OSA.

Predicting Risk of Alzheimer's Diseases and Related Dementias with AI Foundation Model on Electronic Health Records

Early identification of Alzheimer's disease (AD) and AD-related dementias (ADRD) has high clinical significance, both because of the potential to slow decline through initiating FDA-approved therapies and managing modifiable risk factors, and to help persons living with dementia and their families to plan before cognitive loss makes doing so challenging. However, substantial racial and ethnic disparities in early diagnosis currently lead to additional inequities in care, urging accurate and inclusive risk assessment programs. In this study, we trained an artificial intelligence foundation model to represent the electronic health records (EHR) data with a vast cohort of 1.2 million patients within a large health system. Building upon this foundation EHR model, we developed a predictive Transformer model, named TRADE, capable of identifying risks for AD/ADRD and mild cognitive impairment (MCI), by analyzing the past sequential visit records. Amongst individuals 65 and older, our model was able to generate risk predictions for various future timeframes. On the held-out validation set, our model achieved an area under the receiver operating characteristic (AUROC) of 0.772 (95% CI: 0.770, 0.773) for identifying the AD/ADRD/MCI risks in 1 year, and AUROC of 0.735 (95% CI: 0.734, 0.736) in 5 years. The positive predictive values (PPV) in 5 years among individuals with top 1% and 5% highest estimated risks were 39.2% and 27.8%, respectively. These results demonstrate significant improvements upon the current EHR-based AD/ADRD/MCI risk assessment models, paving the way for better prognosis and management of AD/ADRD/MCI at scale.

Implications of depressive mood in OSAHS patients: insights from event-related potential

BACKGROUND

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a chronic breathing disorder characterized by recurrent upper airway obstruction during sleep. Although previous studies have shown a link between OSAHS and depressive mood, the neurobiological mechanisms underlying mood disorders in OSAHS patients remain poorly understood. This study aims to investigate the emotion processing mechanism in OSAHS patients with depressive mood using event-related potentials (ERPs).

METHODS

Seventy-four OSAHS patients were divided into the depressive mood and non-depressive mood groups according to their Self-rating Depression Scale (SDS) scores. Patients underwent overnight polysomnography and completed various cognitive and emotional questionnaires. The patients were shown facial images displaying positive, neutral, and negative emotions and tasked to identify the emotion category, while their visual evoked potential was simultaneously recorded.

RESULTS

The two groups did not differ significantly in age, BMI, and years of education, but showed significant differences in their slow wave sleep ratio (P = 0.039), ESS (P = 0.006), MMSE (P < 0.001), and MOCA scores (P = 0.043). No significant difference was found in accuracy and response time on emotional face recognition between the two groups. N170 latency in the depressive group was significantly longer than the non-depressive group (P = 0.014 and 0.007) at the bilateral parieto-occipital lobe, while no significant difference in N170 amplitude was found. No significant difference in P300 amplitude or latency between the two groups. Furthermore, N170 amplitude at PO7 was positively correlated with the arousal index and negatively with MOCA scores (both P < 0.01).

CONCLUSION

OSAHS patients with depressive mood exhibit increased N170 latency and impaired facial emotion recognition ability. Special attention towards the depressive mood among OSAHS patients is warranted for its implications for patient care.

Altered Functional Connectivity of Temporoparietal Lobe in Obstructive Sleep Apnea: A Resting-State fNIRS Study

Obstructive Sleep Apnea (OSA), a sleep disorder with high prevalence, is normally accompanied by affective, autonomic, and cognitive abnormalities, and is deemed to be linked to functional brain alterations. To investigate alterations in brain functional connectivity properties in patients with OSA, a comparative analysis of global and local topological properties of brain networks was conducted between patients with OSA and healthy controls (HCs), utilizing functional near-infrared spectroscopy (fNIRS) imaging. A total of 148 patients with OSA and 150 healthy individuals were involved. Firstly, quantitative alterations in blood oxygen concentration, changes in functional connectivity, and variations in graph theory-based network topological characteristics were assessed. Then, with Mann-Whitney statistics, this study compared whether there are significant differences in the above characteristics between patients with OSA and HCs. Lastly, the study further examined the correlation between the altered characteristics and the apnea hypopnea index (AHI) using linear regression. Results revealed a higher mean and standard deviation of hemoglobin concentration in the superior temporal gyrus among patients with OSA compared to HCs. Resting-state functional connectivity (RSFC) exhibited a slight increase between the superior temporal gyrus and other specific areas in patients with OSA. Notably, neither patients with OSA nor HCs demonstrated significant small-world network properties. Patients with OSA displayed an elevated clustering coefficient (p < 0.05) and local efficiency (p < 0.05). Additionally, patients with OSA exhibited a tendency towards increased nodal betweenness centrality (p < 0.05) and degree centrality (p < 0.05) in the right supramarginal gyrus, as well as a trend towards higher betweenness centrality (p < 0.05) in the right precentral gyrus. The results of multiple linear regressions indicate that the influence of the AHI on RSFC between the right precentral gyrus and right superior temporal gyrus (p < 0.05), as well as between the right precentral gyrus and right supramarginal gyrus (p < 0.05), are statistically significant. These findings suggest that OSA may compromise functional brain connectivity and network topological properties in affected individuals, serving as a potential neurological mechanism underlying the observed abnormalities in brain function associated with OSA.

Sleep disturbance in people living with dementia or mild cognitive impairment: a realist review of general practice

BACKGROUND

Sleep disturbance is a prevalent condition among people living with dementia (PLwD) or mild cognitive impairment (MCI). Its assessment and management within primary care is complex because of the comorbidities, older age, and cognitive impairment typical of this patient group.

AIM

To explore how primary care clinicians assess, understand, and manage sleep disturbance for PLwD or MCI; if and why such initiatives work; and how people and their carers experience sleep disturbance and its treatment.

DESIGN AND SETTING

A realist review of existing literature conducted in 2022.

METHOD

Six bibliographic databases were searched. Context-mechanism-outcome configurations (CMOCs) were developed and refined.

RESULTS

In total, 60 records were included from 1869 retrieved hits and 19 CMOCs were developed. Low awareness of and confidence in the treatment of sleep disturbance among primary care clinicians and patients, combined with time and resource constraints, meant that identifying sleep disturbance was difficult and not prioritised. Medication was perceived by clinicians and patients as the primary management tool, resulting in inappropriate or long-term prescription. Rigid nursing routines in care homes were reportedly not conducive to good-quality sleep.

CONCLUSION

In primary care, sleep disturbance among PLwD or MCI is not adequately addressed. Over-reliance on medication, underutilisation of non-pharmacological strategies, and inflexible care home routines were reported as a result of low confidence in sleep management and resource constraints. This does not constitute effective and person-centred care. Future work should consider ways to tailor the assessment and management of sleep disturbance to the needs of individuals and their informal carers without overstretching services.

Abnormal prefrontal functional network in adult obstructive sleep apnea: A resting-state fNIRS study

To assess prefrontal brain network abnormality in adults with obstructive sleep apnea (OSA), resting-state functional near infrared spectroscopy (rs-fNIRS) was used to evaluate 52 subjects, including 27 with OSA and 25 healthy controls (HC). The study found that patients with OSA had a decreased connection edge number, particularly in the connection between the right medial frontal cortex (MFG-R) and other right-hemisphere regions. Graph-based analysis also revealed that patients with OSA had a lower global efficiency, local efficiency, and clustering coefficient than the HC group. Additionally, the study found a significant positive correlation between the Montreal Cognitive Assessment (MoCA) score and both the connection edge number and the graph-based indicators in patients with OSA. These preliminary results suggest that prefrontal rs-fNIRS could be a useful tool for objectively and quantitatively assessing cognitive function impairment in patients with OSA.

Dynamic associations between glucose and ecological momentary cognition in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic condition characterized by glucose fluctuations. Laboratory studies suggest that cognition is reduced when glucose is very low (hypoglycemia) and very high (hyperglycemia). Until recently, technological limitations prevented researchers from understanding how naturally-occurring glucose fluctuations impact cognitive fluctuations. This study leveraged advances in continuous glucose monitoring (CGM) and cognitive ecological momentary assessment (EMA) to characterize dynamic, within-person associations between glucose and cognition in naturalistic environments. Using CGM and EMA, we obtained intensive longitudinal measurements of glucose and cognition (processing speed, sustained attention) in 200 adults with T1D. First, we used hierarchical Bayesian modeling to estimate dynamic, within-person associations between glucose and cognition. Consistent with laboratory studies, we hypothesized that cognitive performance would be reduced at low and high glucose, reflecting cognitive vulnerability to glucose fluctuations. Second, we used data-driven lasso regression to identify clinical characteristics that predicted individual differences in cognitive vulnerability to glucose fluctuations. Large glucose fluctuations were associated with slower and less accurate processing speed, although slight glucose elevations (relative to person-level means) were associated with faster processing speed. Glucose fluctuations were not related to sustained attention. Seven clinical characteristics predicted individual differences in cognitive vulnerability to glucose fluctuations: age, time in hypoglycemia, lifetime severe hypoglycemic events, microvascular complications, glucose variability, fatigue, and neck circumference. Results establish the impact of glucose on processing speed in naturalistic environments, suggest that minimizing glucose fluctuations is important for optimizing processing speed, and identify several clinical characteristics that may exacerbate cognitive vulnerability to glucose fluctuations.

Relationship of Sleep Disorder with Neurodegenerative and Psychiatric Diseases: An Updated Review

Sleep disorders affect many people worldwide and can accompany neurodegenerative and psychiatric diseases. Sleep may be altered before the clinical manifestations of some of these diseases appear. Moreover, some sleep disorders affect the physiological organization and function of the brain by influencing gene expression, accelerating the accumulation of abnormal proteins, interfering with the clearance of abnormal proteins, or altering the levels of related hormones and neurotransmitters, which can cause or may be associated with the development of neurodegenerative and psychiatric diseases. However, the detailed mechanisms of these effects are unclear. This review mainly focuses on the relationship between and mechanisms of action of sleep in Alzheimer's disease, depression, and anxiety, as well as the relationships between sleep and Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. This summary of current research hotspots may provide researchers with better clues and ideas to develop treatment solutions for neurodegenerative and psychiatric diseases associated with sleep disorders.

Down Syndrome-Basque Alzheimer Initiative (DS-BAI): Clinic-Biological Cohort

BACKGROUND

Down syndrome (DS) is the most common genetically determined intellectual disability. In recent decades, it has experienced an exponential increase in life expectancy, leading to a rise in age-related diseases, including Alzheimer's disease (AD). Specific health plans for the comprehensive care of the DS community are an unmet need, which is crucial for the early and accurate diagnosis of main medical comorbidities. We present the protocol of a newly created clinical and research cohort and its feasibility in real life.

METHODS

The Down Syndrome-Basque Alzheimer Initiative (DS-BAI) is a population-based, inclusive, multidisciplinary initiative for the clinical-assistance and clinical-biological research approach to aging in DS led by the CITA-Alzheimer Foundation (Donostia, Basque Country). It aims to achieve the following: (1) provide comprehensive care for adults with DS, (2) optimize access to rigorous and quality training for socio-family and healthcare references, and (3) create a valuable multimodal clinical-biological research platform.

RESULTS

During the first year, 114 adults with DS joined the initiative, with 36% of them showing symptoms indicative of AD. Furthermore, adherence to training programs for healthcare professionals and families has been high, and the willingness to collaborate in basic and translational research has been encouraging.

CONCLUSION

Specific health plans for DS and conducting clinical and translational research on the challenges of aging, including AD, are necessary and feasible.

Respiratory Dysfunction in Alzheimer's Disease-Consequence or Underlying Cause? Applying Animal Models to the Study of Respiratory Malfunctions

Alzheimer's disease (AD) is a neurodegenerative brain disease that is the most common cause of dementia among the elderly. In addition to dementia, which is the loss of cognitive function, including thinking, remembering, and reasoning, and behavioral abilities, AD patients also experience respiratory disturbances. The most common respiratory problems observed in AD patients are pneumonia, shortness of breath, respiratory muscle weakness, and obstructive sleep apnea (OSA). The latter is considered an outcome of Alzheimer's disease and is suggested to be a causative factor. While this narrative review addresses the bidirectional relationship between obstructive sleep apnea and Alzheimer's disease and reports on existing studies describing the most common respiratory disorders found in patients with Alzheimer's disease, its main purpose is to review all currently available studies using animal models of Alzheimer's disease to study respiratory impairments. These studies on animal models of AD are few in number but are crucial for establishing mechanisms, causation, implementing potential therapies for respiratory disorders, and ultimately applying these findings to clinical practice. This review summarizes what is already known in the context of research on respiratory disorders in animal models, while pointing out directions for future research.

NLRP3-GSDMD-dependent IL-1β Secretion from Microglia Mediates Learning and Memory Impairment in a Chronic Intermittent Hypoxia-induced Mouse Model

Hypoxia/reoxygenation caused by chronic intermittent hypoxia (CIH) plays an important role in cognitive deficits in patients with obstructive sleep apnea. However, the precise underlying mechanism remains unclear. This study investigated whether the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is involved in CIH-induced spatial learning and memory impairment in mice, and the possible underlying upstream and downstream mechanisms. The C57BL/6 male mice were exposed to CIH (21% O2-6% O2, 4 min/cycle, 8 h/day) for 9 weeks to investigate the role of NLRP3 in CIH-induced spatial learning and memory impairment in mice. BV2 cells were exposed to intermittent hypoxia (21% O2-1% O2, 90 min/cycle) for 48 h to investigate the possible mechanisms in vitro. We found that: 1) inhibition of NLRP3 inflammasome activation improved CIH-induced spatial learning and memory impairment in mice. 2) CIH damaged hippocampal neurons but increased the number of microglia in mice hippocampi; CIH activated microglia-specific NLRP3 inflammasome, leading to upregulation of matured IL-1β and N-GSDMD. 3) intermittent hypoxia activated NLRP3 inflammasome via the ROS-NF-κB signaling pathway to promote the release of matured IL-1β from microglia in a GSDMD-dependent manner without pyroptosis. 4) The IL-1β released from microglia might impair the synaptic plasticity of hippocampal CA3-CA1 synapses by acting on IL-1 receptors in hippocampal neurons. Our findings reveal that ROS-NF-κB-NLRP3 inflammasome-GSDMD dependent IL-1β release from microglia may participate in CIH-induced spatial learning and memory impairment by acting on hippocampal neuronal IL-1 receptor, leading to synaptic plasticity impairment.

The context of COVID-19 affected the long-term sleep quality of older adults more than SARS-CoV-2 infection

Introduction

Sleep problems are one of the most persistent symptoms of post-COVID syndrome in adults. However, most recent research on sleep quality has relied on the impact of the pandemic, with scarcely any data for older adults on the long-term consequences of COVID infection. This study aims to understand whether older individuals present persistently impaired sleep quality after COVID-19 infection and possible moderators for this outcome.

Methods

This is a cross-sectional analysis of a longitudinal cohort study with 70 elders with 6-month-previous SARS-CoV-2 infection and 153 controls. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality; Geriatric Depression Scale and Geriatric Anxiety Inventory for screening depression and anxiety. Demographics and comorbid conditions were collected.

Results

The mean age of participants was 66,97 ± 4,64 years. There were no statistical differences in depression and anxiety between groups. Poor sleep quality was found in 52,9% and 43,8% of the COVID and control groups (p=.208). After controlling for multiple variables, all the following factors resulted in greater chances of poor sleep quality: female gender (OR, 2.12; p=.027), memory complaints (OR, 2.49; p=.074), insomnia (OR, 3.66; p=.032), anxiety (OR, 5.46; p<.001), depression (OR, 7.26; p=.001), joint disease (OR, 1.80; p=.050), glucose intolerance (OR, 2.20; p=.045), psychoactive drugs (OR, 8.36; p<.001), diuretics (OR, 2.46; p=.034), and polypharmacy (OR, 2.84; p=.016).

Conclusion

Psychosocial burden in the context of the COVID-19 pandemic and pre-existing conditions seems to influence the sleep quality of older adults more than SARS-CoV-2 infection.