The Link between Obstructive Sleep Apnea and Neurocognitive Impairment: An Official American Thoracic Society Workshop Report

Cognitive Function, Sleep, and Neuroinflammatory Markers in Mice Exposed to Very Long-Term Intermittent Hypoxia

Chronic intermittent hypoxia (IH) is one of the hallmark features of obstructive sleep apnea (OSA) and adversely affects neurocognitive and behavioral functioning. However, how the duration of IH correlates with its deleterious effects remains unexplored. We aimed to assess the effects of IH over a prolonged period of time mimicking untreated OSA. Male C57Bl/6J mice were exposed to IH for 96 weeks. Sleep activity was acquired using a piezoelectric system. Novel object recognition (NOR) and the elevated plus maze test (EPMT) were conducted as measures of cognitive function and anxiety, respectively. Brain inflammation was evaluated by a panel of inflammation marker assays. All tests were performed after 16 and 96 weeks of IH exposure. After 96 weeks, sleep percentages during the dark phase decreased in both IH and room air (RA) compared to 16-week exposure (RA: p = 0.0214; IH: p = 0.0188). In addition to age-dependent declines in NOR performance, the mice after 96 weeks of IH exposure had lower NOR preference scores than RA controls (p = 0.0070). The time spent in open arms of the EPMT was reduced in mice exposed to IH compared to RA. Inflammatory marker expression increased in IH-exposed mice. Thus, aging and IH induce similar alterations in sleep, cognition, and neuroinflammation. However, the effects of aging are exacerbated by concurrent IH, suggesting that OSA is a disease associated with an acceleration in biological aging.

Development and Validation of a Screening Equation for Obstructive Sleep Apnea

Background: The high prevalence of obstructive sleep apnea (OSA), about 30% of people worldwide over 30 years old, underscores the crucial need for early screening. This study aimed to identify key predictive factors for OSA; use these factors to develop a screening equation for a population at high risk for OSA; and prospectively validate this equation's application. Methods: The study included two phases: a retrospective phase examining anthropometric data, the Epworth sleepiness scale (ESS), and the home sleep apnea test (HSAT) from 200 patients referred to the Respiratory Sleep Disorder Center at Policlinico Umberto I, Rome, Italy (January 2020-January 2023) to create a predictive equation for OSA using multivariate analysis (with the most predictive data according to scientific literature). A prospective phase testing this equation on 53 patients from May 2023 to September 2024. Results: In the retrospective phase, the most predictive variables for the apnea-hypopnea index (AHI) identified were neck circumference (NC) and the Epworth sleepiness scale (ESS). The predictive equation derived from the multivariate analysis was as follows: AHIp = [-70.498 + (2.196 × NC) + (0.809 × ESS)]. In the prospective phase of the study, we compared the AHI predicted by the equation (AHIp) with the AHI measured via the HSAT (AHIm) in 53 patients recruited. The results showed that AHIp had a sensitivity of 95%, a specificity of 28%, a positive predictive value (PPV) of 46%, and a negative predictive value (NPV) of 90%. Conclusions: This study identified NC and ESS as key predictors of OSA, forming a predictive equation. This equation, showing high sensitivity and high NPV, may be useful as a screening method to rule out OSA.

Obstructive sleep apnea syndrome (OSAS) in women: A forgotten cardiovascular risk factor

Sleep-disordered breathing is a highly prevalent disorder with negative impact on healthcare systems worldwide. This condition has detrimental effects on cardiovascular health and quality of life, and is frequently associated with a variety of comorbidities, including cardiovascular disease, heart failure, diabetes and atrial fibrillation. Nevertheless, it remains frequently undiagnosed and undertreated, especially in specific populations. Studies on sleep-disordered breathing have been conducted mainly on male patients, and the prevalence and severity of this disorder in women are underestimated. Recently, some clinical and laboratory evidence has highlighted the epidemiological and pathophysiological differences between men and women with sleep-disordered breathing. In this review, we discuss sex-related mechanisms of sleep-disordered breathing in frequently associated disorders, to improve clinical understanding of this condition and to simplify the practical application of targeted interventions. The aim is to improve prognosis among female patients and guarantee a better quality of life and a reduction in healthcare costs.

Arousal threshold modifies the effect of CPAP on executive function among individuals with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) is associated with neurocognitive dysfunction. However, randomised trials evaluating the effects of continuous positive airway pressure (CPAP) on neurocognition in those without dementia do not show a benefit. We thus aimed to assess whether arousal threshold (ArTH) modifies the effect of CPAP on neurocognitive function.

METHODS

We performed a secondary analysis of a randomised, sham-controlled trial (Apnea Positive Pressure Long-term Efficacy Study (APPLES); ClinicalTrials.gov: NCT00051363). ArTH was estimated from polysomnography using a translatable method. Neurocognitive outcomes included the Sustained Working Memory Test-Overall Mid-Day (SWMT-OMD) score (executive function, primary outcome), with the Pathfinder Number Test total time (attention) and Buschke Selective Reminding Test sum recall (learning and memory) as secondary outcomes. Generalised linear modelling assessed whether the effect of CPAP was modified by baseline ArTH (treatment×ArTH interaction). 833 participants with OSA (apnoea-hypopnoea index ≥10 events·h-1), available ArTH and outcomes were analysed (active CPAP n=437 and sham CPAP n=396).

RESULTS

For executive function, the effect of CPAP treatment was modified by ArTH (pinteraction=0.042). Specifically, for every 1sd increase in ArTH, the SWMT-OMD score improved by 0.091 (95% CI 0.003-0.178) in active compared to sham CPAP at 6 months; at ArTH 1sd above the mean, SWMT-OMD improvements were nearly three times that in those with average ArTH (0.139 (95% CI 0.018-0.261) versus 0.053 (95% CI -0.034-0.140), respectively). No effect modification was observed for attention (p=0.311) or learning and memory (p=0.744).

CONCLUSION

In OSA, a higher ArTH is associated with greater improvements in executive function following CPAP therapy.

Exploring the link between comorbid insomnia and sleep apnea (COMISA) and erectile dysfunction: implications for male sexual health

INTRODUCTION

This review explores the interplay between comorbid insomnia and sleep apnea (COMISA) and erectile dysfunction (ED), 2 conditions that significantly impact men's health. COMISA, a recently recognized condition characterized by the coexistence of insomnia and obstructive sleep apnea, has been shown to disrupt sleep architecture and cause intermittent hypoxia. These disturbances are increasingly linked to the exacerbation of ED, a prevalent issue among men. Understanding the connection between COMISA and ED is crucial for developing integrated treatment approaches that address both sleep and sexual health.

OBJECTIVES

We aim to explore the epidemiological, physiological, and potential therapeutic intersections of COMISA and ED. This review sets out to develop a better understanding of the relationship between these conditions and to emphasize the need for an integrated diagnostic and therapeutic approach that addresses both sleep and sexual health.

METHODS

Through a comprehensive analysis, including a detailed examination of extant studies, we address the hormonal imbalances and alterations in neural pathways that collectively contribute to the complex pathophysiology of ED and how these are particularly susceptible to the concurrent presence of COMISA.

RESULTS

Our analysis indicates that disruptions in sleep architecture and intermittent hypoxia associated with COMISA can exacerbate ED. Hormonal imbalances, endothelial dysfunction, autonomic imbalance, and increased inflammation and oxidative stress are key mechanisms through which COMISA influences ED. These factors collectively impair vascular health, reduce testosterone levels, disrupt neural control of erections, and contribute to the severity of ED.

CONCLUSIONS

This review underscores the necessity for an integrated approach to diagnosis and therapy that considers both sleep and sexual health to improve overall outcomes. These insights should foster a deeper understanding of the relationship between COMISA and ED, encourage further research in this area, and potentially lead to the development of innovative treatment strategies to manage these closely intertwined health concerns.

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.

Screening for obstructive sleep apnea in the memory clinic: A comparison of questionnaires, pulse oximetry, and polysomnography

BACKGROUND

Obstructive sleep apnea (OSA) is highly prevalent among older adults and has been associated with cognitive decline and dementia risk. The suitability of screening tools for detecting OSA in memory clinic settings is unclear.

OBJECTIVE

To evaluate the utility and validity of the STOP-Bang questionnaire (SBQ) and pulse oximeter as a screening tool, compared to gold-standard polysomnography (PSG) in older adults attending a memory clinic.

METHODS

Participants aged over 50 with new onset cognitive/mood concerns attended a memory clinic, then completed the SBQ, oximetry, and PSG. The SBQ and oximetry's accuracy in detecting moderate-severe and severe OSA was evaluated using receiver operating curves. Intraclass correlation and Bland-Altman plots compared the oximeter's adjusted oxygen desaturation index (ODI-Ox) and PSG's apnea-hypopnea index (AHI-PSG).

RESULTS

Of 194 participants (mean age = 65.6, 64 males) who completed PSG, 184 completed the SBQ, and 138 completed oximetry. SBQ demonstrated limited performance for moderate-severe OSA (sensitivity = 52%, specificity = 62%, AUC = 0.600) and severe OSA (sensitivity = 18%, specificity = 87%, AUC = 0.577). Oximetry was satisfactory for moderate-severe OSA (sensitivity = 67%, specificity = 73%, AUC = 0.769) and severe OSA (sensitivity = 50%, specificity = 88%, AUC = 0.730). The diagnostic performance was improved with new cut-offs at ODI-Ox ≥ 11 for AHI-PSG ≥ 15 and ODI-Ox ≥ 20 for AHI-PSG ≥ 30. Bland-Altman plots and intraclass correlation indicated acceptable agreement for oximetry.

CONCLUSIONS

The findings suggest that while the SBQ may be unsuitable to detect moderate or severe OSA for older adults with cognitive impairment, oximetry may be a viable screening tool. Given OSA treatment can optimize sleep and may slow cognitive decline, routine screening for OSA should be part of memory clinic assessments.

Association between sleep microarchitecture and cognition in obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) increases the risk of cognitive impairment. Measures of sleep microarchitecture from EEG may help identify patients at risk of this complication.

METHODS

Participants with suspected OSA (n = 1142) underwent in-laboratory polysomnography and completed sleep and medical history questionnaires, and tests of global cognition (Montreal Cognitive Assessment, MoCA), memory (Rey Auditory Verbal Learning Test, RAVLT) and information processing speed (Digit-Symbol Coding, DSC). Associations between cognitive scores and stage 2 non-rapid eye movement (NREM) sleep spindle density, power, frequency and %-fast (12-16Hz), odds-ratio product (ORP), normalized EEG power (EEGNP), and the delta:alpha ratio were assessed using multivariable linear regression (MLR) adjusted for age, sex, education, and total sleep time. Mediation analyses were performed to determine if sleep microarchitecture indices mediate the negative effect of OSA on cognition.

RESULTS

All spindle characteristics were lower in participants with moderate and severe OSA (p ≤ .001, vs. no/mild OSA) and positively associated with MoCA, RAVLT, and DSC scores (false discovery rate corrected p-value, q ≤ 0.026), except spindle power which was not associated with RAVLT (q = 0.185). ORP during NREM sleep (ORPNREM) was highest in severe OSA participants (p ≤ .001) but neither ORPNREM (q ≥ 0.230) nor the delta:alpha ratio were associated with cognitive scores in MLR analyses (q ≥ 0.166). In mediation analyses, spindle density and EEGNP (p ≥ .048) mediated moderate-to-severe OSA's negative effect on MoCA scores while ORPNREM, spindle power, and %-fast spindles mediated OSA's negative effect on DSC scores (p ≤ .018).

CONCLUSIONS

Altered spindle activity, ORP and normalized EEG power may be important contributors to cognitive deficits in patients with OSA.

Pitolisant 40 mg for excessive daytime sleepiness in obstructive sleep apnea patients treated or not by CPAP: Randomised phase 3 study

Obstructive sleep apnea (OSA) syndrome commonly leads to excessive daytime sleepiness (EDS). Pitolisant, a selective histamine-3 receptor antagonist, is efficacious at doses up to 20 mg once daily in OSA treated or not with continuous positive airway pressure (CPAP). We assessed the efficacy and safety of pitolisant at doses up to 40 mg once daily in patients with moderate to severe OSA treated or not with CPAP therapy. In this phase 3, multicentre, randomised, double-blind, placebo-controlled clinical trial, patients with OSA were assigned 2:1 to receive pitolisant (according to an individual up-titration scheme, 10, 20 or 40 mg once daily) or placebo for 12 weeks. The primary endpoint was a change in the Epworth Sleepiness Scale (ESS) score from baseline to week 12. Secondary endpoints included a change in reaction time using the Oxford Sleep Resistance test (OSleR), Clinical Global Impression of Change (CGI-C), and Patient's Global Opinion of the Effect (PGOE) of study treatment. Overall, 361 patients (mean age 52.4 years, 77.3% male; mean apnea-hypopnea index [AHI] 27.0 events/h) were randomised to receive pitolisant (n = 242; 50% received CPAP) or placebo (n = 119; 48.7% CPAP). After the dose-adjustment phase (week 3), 88.8% of patients received pitolisant 40 mg. Compared with placebo, pitolisant produced a significant reduction in the ESS score at week 12 (least square mean difference -2.6 (95% CI: -3.4; -1.8; p < 0.001)) irrespective of CPAP use; and improved the reaction time on OSleR, CGI-C, and PGOE at week 12. Pitolisant was well tolerated; no new safety signals were identified. In conclusion, pitolisant up to 40 mg once daily was an effective treatment for EDS in patients with moderate to severe OSA irrespective of CPAP use.

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.

Effects of obstructive sleep apnea treatment on neurodegenerative biomarker neurofilament light chain and cognitive performance

Obstructive sleep apnea is associated with cognitive impairment and increased risk for neurodegenerative diseases. Obstructive sleep apnea treatment with positive airway pressure therapy helps to improve cognitive symptoms and reduces long-term dementia risk. To test whether these treatment effects are due to a reduction in neuronal damage, we examined longitudinal changes in the neurodegenerative serum neurofilament light chain and cognitive performance of patients with obstructive sleep apnea. In this study, 17 patients with obstructive sleep apnea completed baseline and follow-up (9 month after starting PAP treatment) investigation of sleep, daytime symptoms, cognitive testing and serum neurofilament light chain measurements. Depending on treatment adherence and efficacy, participants were assigned either to the effective treatment (n = 10) or non-effective treatment group (n = 7). As results at baseline lower mean oxygen saturation during sleep was associated with higher serum neurofilament light chain. Patients in the non-effective treatment group showed a significant increase of age-adjusted percentile of serum neurofilament light chain levels at follow-up, whereas serum neurofilament light chain values remained constant in the effective treatment group. At a functional level, effective treatment leads to an improvement in processing speed, which was not the case in the non-effective treatment group. Longitudinal changes of age-adjusted serum neurofilament light chain levels were associated with changes in cognitive performance. To conclude, this longitudinal observational study showed that effective obstructive sleep apnea treatment positively affects the amount of neuronal damage as well as working memory performance. As cognitive symptoms might not only be attributed to obstructive sleep apnea-related sleep deficiency, but also neurodegeneration, our results underline the importance of treatment adherence and efficacy for the prevention of neuronal damage and cognitive consequences.

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.

Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and obstructive sleep apnea: a cross-sectional study from NHANES

BACKGROUND

Obstructive Sleep Apnea (OSA) is a widespread sleep disturbance linked to metabolic and cardiovascular conditions. The Non-High-Density Lipoprotein Cholesterol to High-Density Lipoprotein Cholesterol Ratios (NHHR) has been proposed as being a potential biomarker to gauge cardiovascular risk. However, its relationship with OSA remains unclear.

METHODS

This survey investigated the link NHHR to OSA in American citizens aged 20 and older using information collected via the National Health and Nutrition Examination Survey (NHANES) during the years 2017 to 2020. Logistic regression models with multivariable adjustments were employed to assess this relationship. Nonlinear associations were explored using smooth curve fitting, with a two-part linear regression model identifying a threshold effect. Subgroup analyses were conducted to evaluate population-specific differences.

RESULTS

The survey encompassed 6763 participants, with an average age of 50.75 ± 17.32. The average NHHR stood at 2.74, accompanied by a standard deviation of 1.34, while the average frequency of OSA was 49.93%. Upon adjusting for covariates, each unit increase in NHHR may be associated with a 9% rise in OSA incidence. (95% confidence intervals 1.04-1.14; P < 0.0001). Notably, a U-shaped curve depicted the NHHR-OSA relationship, with an inflection point at 4.12. Subgroup analyses revealed consistent associations, with educational attainment and diabetes status modifying the NHHR-OSA relationship.

CONCLUSION

The study highlights NHHR as a potential tool for OSA prediction, presenting avenues for advanced risk evaluation, tailored interventions, personalized treatment approaches, and preventive healthcare.

The Crosstalk Between Amyloid-β, Retina, and Sleep for the Early Diagnosis of Alzheimer's Disease: A Narrative Review

Alzheimer's disease (AD) is the most common type of dementia, which is characterised by progressive memory loss and accumulation of hallmark markers amyloid-β (Aβ) and neurofibrillary tangles in the diseased brain. The current gold standard diagnostic methods have limitations of being invasive, costly, and not easily accessible. Thus, there is a need for new avenues, such as imaging the retina for early AD diagnosis. Sleep disruption is symptomatically frequent across preclinical and AD subjects. As circadian activity, such as the sleep-wake cycle, is linked to the retina, analysis of their association may be useful additions for achieving predictive AD diagnosis. In this narrative review, we provide an overview of human retina studies concerning the deposition of Aβ, the role of the retina in sleep-wake cycle, the disruption of sleep in AD, and to gather evidence for the associations between Aβ, the retina, and sleep. Understanding the mechanisms behind the associations between Aβ, retina, and sleep could assist in the interpretation of retinal changes accurately in AD.

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.

Obstructive Sleep Apnea and Sarcoidosis Interactions

Obstructive sleep apnea (OSA) is very prevalent in sarcoidosis patients. Sarcoidosis of the upper respiratory tract may affect upper airway patency and increase the risk of OSA. Weight gain due to steroid use, upper airway myopathy due to steroids and sarcoidosis itself, and interstitial lung disease with decreased upper airway patency are other reasons for the higher OSA prevalence seen in sarcoidosis. Several clinical manifestations such as fatigue, hypersomnolence, cognitive deficits, and pulmonary hypertension are common to both OSA and sarcoidosis. Therefore, early screening and treatment for OSA can improve symptoms and overall patient quality of life.

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.

The Role of Oxygen Homeostasis and the HIF-1 Factor in the Development of Neurodegeneration

Understanding the molecular underpinnings of neurodegeneration processes is a pressing challenge for medicine and neurobiology. Alzheimer's disease (AD) and Parkinson's disease (PD) represent the most prevalent forms of neurodegeneration. To date, a substantial body of experimental evidence has strongly implicated hypoxia in the pathogenesis of numerous neurological disorders, including AD, PD, and other age-related neurodegenerative conditions. Hypoxia-inducible factor (HIF) is a transcription factor that triggers a cell survival program in conditions of oxygen deprivation. The involvement of HIF-1α in neurodegenerative processes presents a complex and sometimes contradictory picture. This review aims to elucidate the current understanding of the interplay between hypoxia and the development of AD and PD, assess the involvement of HIF-1 in their pathogenesis, and summarize promising therapeutic approaches centered on modulating the activity of the HIF-1 complex.

Senolytic-facilitated Reversal of End-Organ Dysfunction in a Murine Model of Obstructive Sleep Apnea

Rationale: Obstructive sleep apnea (OSA) is a highly prevalent condition that is associated with accelerated biological aging and multiple end-organ morbidities. Current treatments, such as continuous positive airway pressure (CPAP), have shown limited cognitive, metabolic, and cardiovascular beneficial outcomes despite adherence. Thus, adjunct therapies aiming to reduce OSA burden, such as senolytics, could improve OSA outcomes.Objectives: To assess if targeting senescence in addition to partial normoxia mimicking "good" CPAP adherence can improve physiological outcomes in mice exposed to chronic intermittent hypoxia.Methods: We compared the effects of 6 weeks of therapy with either partial normoxic recovery alone or combined with the senolytic navitoclax after 16 weeks of intermittent hypoxia exposures, a hallmark of OSA, on multiphenotypic cardiometabolic and neurocognitive parameters.Measurements and Main Results: Our findings indicate that only when combined with navitoclax, partial normoxic recovery significantly improved sleepiness (sleep in the dark phase: 34% ± 4% vs. 26% ± 3%; P < 0.01), cognition (preference score: 51% ± 19% vs. 70% ± 11%; P = 0.048), coronary artery function (response to acetylcholine [vasodilation]: 56% ± 13% vs. 72% ± 10%; P < 0.001), glucose, and lipid metabolism and reduced intestinal permeability and senescence in multiple organs.Conclusions: These findings indicate that the reversibility of end-organ morbidities induced by OSA is not only contingent on restoration of normal oxygenation patterns but can be further enhanced by targeting other OSA-mediated detrimental cellular processes, such as accelerated senescence.

Chronic intermittent hypoxia attenuates noradrenergic innervation of hypoglossal motor nucleus

The state-dependent noradrenergic activation of hypoglossal motoneurons plays an important role in the maintenance of upper airway patency and pathophysiology of obstructive sleep apnea (OSA). Chronic intermittent hypoxia (CIH), a major pathogenic factor of OSA, contributes to the risk for developing neurodegenerative disorders in OSA patients. Using anterograde tracer, channelrhodopsin-2, we mapped axonal projections from noradrenergic A7 and SubCoeruleus neurons to hypoglossal nucleus in DBH-cre mice and assessed the effect of CIH on these projections. We found that CIH significantly reduced the number of axonal projections from SubCoeruleus neurons to both dorsal (by 68%) and to ventral (by73%) subregions of the hypoglossal motor nucleus compared to sham-treated animals. The animals' body weight was also negatively affected by CIH. Both effects, the decrease in axonal projections and body weight, were more pronounced in male than female mice, which was likely caused by less sensitivity of female mice to CIH as compared to males. The A7 neurons appeared to have limited projections to the hypoglossal nucleus. Our findings suggest that CIH-induced reduction of noradrenergic innervation of hypoglossal motoneurons may exacerbate progression of OSA, especially in men.

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.

A systematic review on adherence to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnoea (OSA) in individuals with mild cognitive impairment and Alzheimer's disease dementia

Obstructive sleep apnoea (OSA) is highly prevalent in mild cognitive impairment (MCI) and Alzheimer's disease (AD). The gold standard treatment for OSA is continuous positive airway pressure (CPAP). Long-term, well-powered efficacy trials are required to understand whether CPAP could slow cognitive decline in individuals with MCI/AD, but its tolerability in this group remains uncertain. The present review investigates CPAP adherence among individuals with OSA and MCI/AD. Electronic searches were performed on 8 databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Six independent studies and four secondary analyses included 278 unique participants (mean age = 72.1 years). In five of the retained studies, around half of participants (45% N = 85 MCI, 56% N = 22 AD) were adherent to CPAP, where ≥4 h use per night was considered adherent. Three of the retained studies also reported average CPAP use to range between 3.2 and 6.3 h/night. CPAP adherence in individuals with MCI and AD is low, albeit similar to the general elderly population. Reporting adherence in future studies as both average duration as well as using a binary cut-off would improve our understanding of the optimum CPAP use in dementia clinical trials and care.

REducing Sleep Apnoea for the PrEvention of Dementia (REShAPED): Protocol for a multi-site feasibility randomised controlled trial

There is accumulating evidence that has linked OSA with increased risk of cognitive decline and dementia. Here we present the protocol for an Australian, multi-site randomised controlled, parallel open-label trial which will evaluate the feasibility for a full-scale trial investigating the effects of treating OSA on cognitive decline in older adults at risk of dementia within memory clinic settings. We will randomise 180 older adults to either the treatment intervention group or control group for 2 years. Inclusion criteria include: 50-85 years; mild-severe OSA (defined average ODI ≥ 10 with 3% oxygen desaturation determined by wrist oximetry over two nights); and subjective cognitive complaints or mild cognitive impairment. The treatment intervention arm aims to achieve an optimal treatment response based on reducing hypoxic burden with either CPAP, mandibular advancement splint, positional therapy, or oxygen therapy. Furthermore, participants will receive up to 8 sessions which involve motivational interviewing, collaborative goal setting, and behavioural sleep management. The control arm will not receive OSA treatment as part of this trial, however there will be no OSA treatment restrictions, and any treatment will be documented. Primary outcomes are 1) acceptability based upon willingness of participants to be randomised; 2) alleviating hypoxic burden by reducing OSA severity; 3) tolerability of the trial burden based upon collection of outcomes over the 2-year follow-up. Secondary outcomes include safety and cognitive function. Outcomes will be collected at 0, 6 and 24-months. This feasibility study aims to will provide the basis for a larger longer-term trial of dementia prevention.

The role of lncRNAs in intermittent hypoxia and sleep Apnea: A review of experimental and clinical evidence

In this narrative review, we present a comprehensive assessment on the putative roles of long non-coding RNAs (lncRNAs) in intermittent hypoxia (IH) and sleep apnea. Collectively, the evidence from cell culture, animal, and clinical research studies points to the functional involvement of lncRNAs in the pathogenesis, diagnosis, and potential treatment strategies for this highly prevalent disorder. Further research is clearly warranted to uncover the mechanistic pathways and to exploit the therapeutic potential of lncRNAs, thereby improving the management and outcomes of patients suffering from sleep apnea.

Predicting neurodegeneration from sleep related biofluid changes

Sleep-wake disturbances are common in neurodegenerative diseases and may occur years before the clinical diagnosis, potentially either representing an early stage of the disease itself or acting as a pathophysiological driver. Therefore, discovering biomarkers that identify individuals with sleep-wake disturbances who are at risk of developing neurodegenerative diseases will allow early diagnosis and intervention. Given the association between sleep and neurodegeneration, the most frequently analyzed fluid biomarkers in people with sleep-wake disturbances to date include those directly associated with neurodegeneration itself, such as neurofilament light chain, phosphorylated tau, amyloid-beta and alpha-synuclein. Abnormalities in these biomarkers in patients with sleep-wake disturbances are considered as evidence of an underlying neurodegenerative process. Levels of hormonal sleep-related biomarkers such as melatonin, cortisol and orexin are often abnormal in patients with clinical neurodegenerative diseases, but their relationships with the more standard neurodegenerative biomarkers remain unclear. Similarly, it is unclear whether other chronobiological/circadian biomarkers, such as disrupted clock gene expression, are causal factors or a consequence of neurodegeneration. Current data would suggest that a combination of fluid biomarkers may identify sleep-wake disturbances that are most predictive for the risk of developing neurodegenerative disease with more optimal sensitivity and specificity.

Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary

This multisociety commentary critically examines the Agency for Healthcare Research and Quality (AHRQ) final report and systematic review on long-term health outcomes in obstructive sleep apnea. The AHRQ report was commissioned by the Centers for Medicare & Medicaid Services and particularly focused on the long-term patient-centered outcomes of continuous positive airway pressure, the variability of sleep-disordered breathing metrics, and the validity of these metrics as surrogate outcomes. This commentary raises concerns regarding the AHRQ report conclusions and their potential implications for policy decisions. A major concern expressed in this commentary is that the AHRQ report inadequately acknowledges the benefits of continuous positive airway pressure for several established, long-term clinically important outcomes including excessive sleepiness, motor vehicle accidents, and blood pressure. While acknowledging the limited evidence for the long-term benefits of continuous positive airway pressure treatment, especially cardiovascular outcomes, as summarized by the AHRQ report, this commentary reviews the limitations of recent randomized controlled trials and nonrandomized controlled studies and the challenges of conducting future randomized controlled trials. A research agenda to address these challenges is proposed including study designs that may include both high quality randomized controlled trials and nonrandomized controlled studies. This commentary concludes by highlighting implications for the safety and quality of life for the millions of people living with obstructive sleep apnea if the AHRQ report alone was used by payers to limit coverage for the treatment of obstructive sleep apnea while not considering the totality of available evidence.

CITATION

Patil SP, Billings ME, Bourjeily G, et al. Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary. J Clin Sleep Med. 2024;20(1):135-149.

Multilayer network analysis of dynamic network reconfiguration in patients with moderate-to-severe obstructive sleep apnea and its association with neurocognitive function

BACKGROUND

Brain functional network disruption and neurocognitive dysfunction have been reported in obstructive sleep apnea (OSA) patients. Nevertheless, most research studies static networks, while brain evolution continues dynamically.

PURPOSE

To investigate the characteristics of dynamical networks in moderate-to-severe OSA patients using multilayer network analysis of dynamic networks and compare their association with neurocognitive function.

METHODS

Twenty-seven moderate-to-severe OSA patients and twenty-five matched healthy controls (HCs) who completed the examination of the Epworth sleepiness scale (ESS), neurocognitive function, polysomnography, and functional magnetic resonance imaging (fMRI) were prospectively included. The dynamic variations of resting-state functional networks in both groups were described via network switching rate. Switching rates and their correlation with clinical parameters were analyzed.

RESULTS

At the global level, network switching rates were notably lower in the OSA group than in the HCs group (p = 0.002). More specifically, the differences include the default mode network (DMN), auditory network, and ventral attention network at the subnetwork level, and the right rolandic operculum, left middle temporal gyrus, and right precentral gyrus at the nodal level. Furthermore, these altered switching rates have a close correlation with ESS, sleep parameters, and neurocognitive function.

CONCLUSION

Patients with moderate-to-severe OSA showed lower network switching rates, especially in the DMN, auditory network, and ventral attention network. The disruption of dynamic functional networks may be a potentially crucial mechanism of neurocognitive dysfunction in moderate-to-severe OSA patients.

Recovery Mimicking "Ideal" CPAP Adherence Does Not Improve Wakefulness or Cognition in Chronic Murine Models of OSA: Effect of Wake-Promoting Agents

INTRODUCTION

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH) and sleep fragmentation (SF). OSA can induce excessive daytime sleepiness (EDS) and is associated with impaired cognition and anxiety. Solriamfetol (SOL) and modafinil (MOD) are widely used wake-promoting agents in OSA patients with EDS.

METHODS

Male C57Bl/6J mice were exposed to SF along with sleep controls (SC) or to IH and room air (RA) controls during the light (inactive) phase for 4 and 16 weeks, respectively. Both IH and SF exposures were then discontinued to mimic "ideal" continuous positive airway pressure (CPAP) adherence. All groups were then randomly assigned to receive once daily intraperitoneal injections of SOL, MOD, or vehicle (VEH) for 6 days. Sleep/wake activity was assessed along with tests of explicit memory, anxiety and depression were performed before and after treatments.

RESULTS

IH and SF exposures increased sleep percentage in the dark phase and reduced wake bouts lengths (i.e., EDS), and induced cognitive deficits and impulsivity in mice. Both SOL and MOD treatments effectively mitigated EDS when combined with recovery, while recovery alone did not improve EDS over the 6-day period. Furthermore, improvements explicit memory emerged only after SOL.

CONCLUSION

Chronic IH and SF induce EDS in young adult mice that is not ameliorated by recovery except when combined with either SOL or MOD. SOL, but not MOD, significantly improves IH-induced cognitive deficits. Thus, SOL emerges as a viable adjuvant medication for residual EDS in OSA along with its positive impact on cognition.

History of obstructive sleep apnea associated with incident cognitive impairment in white but not black individuals in a US national cohort study

BACKGROUND

We sought to determine if risk for obstructive sleep apnea (OSA), a history of OSA, and/or treatment of OSA has a different association with incident cognitive impairment or cognitive decline in Black individuals and White individuals.

METHODS

To determine whether the risk for OSA, a history of OSA, and/or treatment of OSA has a different association with incident cognitive impairment or cognitive decline in Black individuals and White individuals; data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) was used. Participants that completed the sleep questionnaire module, had baseline cognitive assessment, and at least one cognitive assessment during follow-up were included. Risk of OSA was determined based on Berlin Sleep Questionnaire. History of sleep apnea was determined based on structured interview questions. Optimally treated OSA was defined as treated sleep apnea as at least 4 h of continuous positive airway pressure use per night for ≥5 nights per week.

RESULTS

In 19,017 participants stratified by race, White participants with history of OSA were 1.62 times more likely to have incident cognitive impairment compared to White participants without history of OSA after adjusting for demographic characteristics, history, and lifestyle factors (OR = 1.62, 95% CI = 1.05-2.50, p-value = 0.03). This relationship was not seen in Black participants (OR = 0.92, 95% CI = 0.60-1.43, p-value = 0.72).

DISCUSSION

A previous diagnosis of OSA is associated with incident cognitive impairment in White Americans but not Black Americans. Further investigations are required to determine the mechanism for this difference.

Predictors of Adherence to Continuous Positive Airway Pressure in Older Adults With Apnea and Amnestic Mild Cognitive Impairment

BACKGROUND

Almost 60% of adults with amnestic mild cognitive impairment (aMCI) have obstructive sleep apnea (OSA). Treatment with continuous positive airway pressure (CPAP) may delay cognitive decline, but CPAP adherence is often suboptimal. In this study, we report predictors of CPAP adherence in older adults with aMCI who have increased odds of progressing to dementia, particularly due to Alzheimer's disease.

METHODS

The data are from Memories 2, "Changing the Trajectory of Mild Cognitive Impairment with CPAP Treatment of Obstructive Sleep Apnea." Participants had moderate to severe OSA, were CPAP naïve, and received a telehealth CPAP adherence intervention. Linear and logistic regression models examined predictors.

RESULTS

The 174 participants (mean age 67.08 years, 80 female, 38 Black persons) had a mean apnea-hypopnea index of 34.78, and 73.6% were adherent, defined as an average of ≥4 hours of CPAP use per night. Only 18 (47.4%) Black persons were CPAP adherent. In linear models, White race, moderate OSA, and participation in the tailored CPAP adherence intervention were significantly associated with higher CPAP use at 3 months. In logistic models, White persons had 9.94 times the odds of adhering to CPAP compared to Black persons. Age, sex, ethnicity, education, body mass index, nighttime sleep duration, daytime sleepiness, and cognitive status were not significant predictors.

CONCLUSIONS

Older patients with aMCI have high CPAP adherence, suggesting that age and cognitive impairment should not be a barrier to prescribing CPAP. Research is needed to improve adherence in Black patients, perhaps through culturally tailored interventions.

Obstructive sleep apnea and cognition: insights gleaned from bibliometric analysis

Objective

Obstructive sleep apnea (OSA) is associated with cognitive impairment. However, the broad trends of the research publications on OSA and cognition are unclear. This study aimed to investigate patterns of research on the relationship between OSA and cognitive function using bibliometric analysis and to identify future research directions by analyzing research trends and emerging hotspots in the field.

Methods

We searched Web of Science for relevant publications from 2003 to 2022 and conducted a bibliometric analysis of OSA and cognitive research using CiteSpace, R, and VOSviewer.

Results

A total of 1995 articles met the eligibility criteria for the analysis of OSA and cognition research. There was a notable increase in publications over time, with significant contributions from the United States, particularly Harvard University, leading to substantial academic impact. Gozal D emerged as the most prolific author (59 articles) and influential researcher (3,612 citations) in this field. Hotspot analysis revealed that investigating the pathological physiology and mechanisms of OSA-associated cognitive dysfunction is a recent area of focus, while burst detection analysis identified sleep quality and mild cognitive impairment as top investigation topics. The study by Canessa N published in the American Journal of Respiratory and Critical Care Medicine received the highest number of 77 citations.

Conclusion

Researchers are increasingly focusing on OSA and cognition. Currently, the majority of studies on OSA-related cognitive dysfunction are focused on correctable aspects of the condition. Future investigations into the pathology of OSA-induced cognitive impairment will facilitate more precise therapeutic interventions.

Progressive tauopathy disrupts breathing stability and chemoreflexes during presumptive sleep in mice

Rationale: Although sleep apnea occurs in over 50% of individuals with Alzheimer's Disease (AD) or related tauopathies, little is known concerning the potential role of tauopathy in the pathogenesis of sleep apnea. Here, we tested the hypotheses that, during presumptive sleep, a murine model of tauopathy (rTg4510) exhibits: 1) increased breathing instability; 2) impaired chemoreflex function; and 3) exacerbation of these effects with tauopathy progression. Methods: rTg4510 mice initially develop robust tauopathy in the hippocampus and cortex, and eventually progresses to the brainstem. Type I and II post-sigh apnea, Type III (spontaneous) apnea, sigh, and hypopnea incidence were measured in young adult (5-6 months; n = 10-14/group) and aged (13-15 months; n = 22-24/group) non-transgenic (nTg), monogenic control tetracycline transactivator, and bigenic rTg4510 mice using whole-body plethysmography during presumptive sleep (i.e., eyes closed, curled/laying posture, stable breathing for >200 breaths) while breathing room air (21% O2). Peripheral and central chemoreceptor sensitivity were assessed with transient exposures (5 min) to hyperoxia (100% O2) or hypercapnia (3% and 5% CO2 in 21% O2), respectively. Results: We report significant increases in Type I, II, and III apneas (all p < 0.001), sighs (p = 0.002) and hypopneas (p < 0.001) in aged rTg4510 mice, but only Type III apneas in young adult rTg4510 mice (p < 0.001) versus age-matched nTg controls. Aged rTg4510 mice exhibited profound chemoreflex impairment versus age matched nTg and tTA mice. In rTg4510 mice, breathing frequency, tidal volume and minute ventilation were not affected by hyperoxic or hypercapnic challenges, in striking contrast to controls. Histological examination revealed hyperphosphorylated tau in brainstem regions involved in the control of breathing (e.g., pons, medullary respiratory column, retrotrapezoid nucleus) in aged rTg4510 mice. Neither breathing instability nor hyperphosphorylated tau in brainstem tissues were observed in young adult rTg4510 mice. Conclusion: Older rTg4510 mice exhibit profound impairment in the neural control of breathing, with greater breathing instability and near absence of oxygen and carbon-dioxide chemoreflexes. Breathing impairments paralleled tauopathy progression into brainstem regions that control breathing. These findings are consistent with the idea that tauopathy per se undermines chemoreflexes and promotes breathing instability during sleep.

Impact of PTSD and Obstructive Sleep Apnea on Cognition in Older Adult Veterans

Background: Posttraumatic stress disorder (PTSD) and obstructive sleep apnea (OSA) are highly prevalent and comorbid among older adult male veterans. Both PTSD and OSA are independently associated with cognitive deficits in older adults, but little research regarding the impact of comorbid PTSD and OSA among older adults exists. Purpose: The current study aimed to examine the independent and interactive effects of PTSD and OSA on cognitive functioning in older adult veterans. Study Sample: Older adult male veterans with (n = 106) and without PTSD (n = 69), ranging in age from 55 to 89 (M = 63.35). Data Collection: Participants underwent polysomnography evaluation to assess severity of OSA symptoms and comprehensive neuropsychological evaluation to assess cognitive functioning in 3 domains: attention and processing speed, learning and memory, and executive functioning. Results: Multiple regression analyses showed that the interaction between PTSD and OSA did not predict cognitive performance. However, PTSD significantly predicted poorer attention and processing speed, and increased OSA severity predicted poorer learning and memory. Conclusions: While PTSD and OSA did not have a synergistic detrimental impact on cognition, each independently predicted poorer cognitive functioning within certain domains, suggesting that older adults with these comorbid conditions may experience a wider array of cognitive difficulties.

Creating an Optimal Approach for Diagnosing Sleep Apnea

Sleep apnea is nowadays recognized as a treatable chronic disease and awareness of it has increased, leading to an upsurge in demand for diagnostic testing. Conventionally, diagnosis depends on overnight polysomnography in a sleep clinic, which is highly human-resource intensive and ignores the night-to-night variability in classical sleep apnea markers, such as the apnea-hypopnea index. In this review, the authors summarize the main improvements that could be made in the sleep apnea diagnosis strategy; how technological innovations and multi-night home testing could be used to simplify, increase access, and reduce costs of diagnostic testing while avoiding misclassification of severity.

Solriamfetol enhances wakefulness and improves cognition and anxiety in a murine model of OSA

BACKGROUND

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH). Excessive daytime sleepiness (EDS) is a common consequence of OSA and is associated with cognitive deficits and anxiety. Modafinil (MOD) and Solriamfetol (SOL) are potent wake-promoting agents clinically used to improve wakefulness in OSA patients with EDS.

METHODS

Male C57Bl/6J mice were exposed to either IH or room air (RA) controls during the light phase for 16 weeks. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg) or vehicle (VEH) for 9 days while continuing IH exposures. Sleep/wake activity was assessed during the dark (active) phase. Novel object recognition (NOR), elevated-plus maze test (EPMT), and forced swim test (FST) were performed before and after drug treatment.

RESULTS

IH exposure increased dark phase sleep percentage and reduced wake bouts lengths and induced cognitive deficits and anxiogenic effects. Both SOL and MOD treatments decreased sleep propensity under IH conditions, but only SOL promoted improvements in NOR performance (explicit memory) and reduced anxiety-like behaviors.

CONCLUSION

Chronic IH, a hallmark feature of OSA, induces EDS in young adult mice that is ameliorated by both SOL and MOD. SOL, but not MOD, significantly improves IH-induced cognitive deficits and promotes anxiolytic effects. Thus, SOL could potentially benefit OSA patients beyond EDS management.

Cognitive Impairments, Neuroinflammation and Blood-Brain Barrier Permeability in Mice Exposed to Chronic Sleep Fragmentation during the Daylight Period

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH) and sleep fragmentation (SF). In murine models, chronic SF can impair endothelial function and induce cognitive declines. These deficits are likely mediated, at least in part, by alterations in Blood-brain barrier (BBB) integrity. Male C57Bl/6J mice were randomly assigned to SF or sleep control (SC) conditions for 4 or 9 weeks and in a subset 2 or 6 weeks of normal sleep recovery. The presence of inflammation and microglia activation were evaluated. Explicit memory function was assessed with the novel object recognition (NOR) test, while BBB permeability was determined by systemic dextran-4kDA-FITC injection and Claudin 5 expression. SF exposures resulted in decreased NOR performance and in increased inflammatory markers and microglial activation, as well as enhanced BBB permeability. Explicit memory and BBB permeability were significantly associated. BBB permeability remained elevated after 2 weeks of sleep recovery (p < 0.01) and returned to baseline values only after 6 weeks. Chronic SF exposures mimicking the fragmentation of sleep that characterizes patients with OSA elicits evidence of inflammation in brain regions and explicit memory impairments in mice. Similarly, SF is also associated with increased BBB permeability, the magnitude of which is closely associated with cognitive functional losses. Despite the normalization of sleep patterns, BBB functional recovery is a protracted process that merits further investigation.

Sleep-related predictors of cognition among adults with chronic insomnia and heart failure enrolled in a randomized controlled trial of cognitive behavioral therapy for insomnia

STUDY OBJECTIVES

Cognitive impairment and insomnia are common in chronic heart failure (HF). We examined the effects of cognitive behavioral therapy for insomnia (CBT-I) and the extent to which demographic, clinical, symptom, and functional characteristics predicted cognition among people with chronic HF and insomnia who participated in a randomized controlled trial of CBT-I.

METHODS

Participants with HF were randomized to group-based CBT-I or an attention control (HF self-management education). Outcomes were measured over 1 year. We measured psychomotor vigilance and self-reported cognitive ability (PROMIS Cognitive Abilities Scale), clinical and demographic characteristics, history of sleep apnea, fatigue, pain, insomnia (Insomnia Severity Index), sleepiness (Epworth Sleepiness Scale), Six Minute Walk, EuroQoL Quality of Life, and wrist actigraphy (sleep characteristics and rest-activity rhythms). We used cosinor analysis to compute rest-activity rhythms and general linear models and general estimating equations to test the effects of predictors over 1 year.

RESULTS

The sample included 175 participants (mean age = 63 SD = 12.9 Years; 43% women). There was a statistically significant group-time effect on self-reported cognitive function and increases in the proportion of participants, with < 3 psychomotor vigilance lapses in the CBT-I group. Controlling for group-time effects and baseline cognition, decreased sleepiness, improved rest-activity rhythms, and 6-minute walk distance predicted a composite measure of cognition (psychomotor vigilance lapses and self-reported cognition).

CONCLUSIONS

CBT-I may improve cognition in adults with chronic HF. A future fully powered randomized controlled trial is needed to confirm the extent to which CBT-I improves multiple dimensions of cognition.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Cognitive Behavioral Therapy for Insomnia: A Self-Management Strategy for Chronic Illness in Heart Failure; URL: https://clinicaltrials.gov/ct2/show/NCT02660385; Identifier: NCT02660385.

CITATION

Redeker NS, Conley S, O'Connell M, Geer JH, Yaggi H, Jeon S. Sleep-related predictors of cognition among adults with chronic insomnia and heart failure enrolled in a randomized controlled trial of cognitive behavioral therapy for insomnia. J Clin Sleep Med. 2023;19(6):1073-1081.

Solriamfetol improves chronic sleep fragmentation-induced increases in sleep propensity and ameliorates explicit memory in male mice

Obstructive sleep apnea (OSA) is a highly prevalent condition characterized by episodes of partial or complete breath cessation during sleep that induces sleep fragmentation (SF). One of the frequent manifestations of OSA is the presence of excessive daytime sleepiness (EDS) associated with cognitive deficits. Solriamfetol (SOL) and modafinil (MOD) are wake-promoting agents commonly prescribed to improve wakefulness in OSA patients with EDS. This study aimed to assess the effects of SOL and MOD in a murine model of OSA characterized by periodic SF. Male C57Bl/6J mice were exposed to either control sleep (SC) or SF (mimicking OSA) during the light period (06:00 h to 18:00 h) for 4 weeks, which consistently induces sustained excessive sleepiness during the dark phase. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg), or vehicle for 1 week while continuing exposures to SF or SC. Sleep/wake activity and sleep propensity were assessed during the dark phase. Novel Object Recognition test, Elevated-Plus Maze Test, and Forced Swim Test were performed before and after treatment. SOL or MOD decreased sleep propensity in SF, but only SOL induced improvements in explicit memory, while MOD exhibited increased anxiety behaviors. Chronic SF, a major hallmark of OSA, induces EDS in young adult mice that is mitigated by both SOL and MOD. SOL, but not MOD, significantly improves SF-induced cognitive deficits. Increased anxiety behaviors are apparent in MOD-treated mice. Further studies aiming to elucidate the beneficial cognitive effects of SOL are warranted.

Obstructive Sleep Apnea - Influence on the Cardiovascular System and Cognition

Kardiovaskuläre und kognitive Erkrankungen sind ebenso wie die obstruktive Schlafapnoe sehr häufige Krankheiten mit einer erheblichen Beeinträchtigung der Lebensqualität und einer deutlichen sozioökonomischen Bedeutung. Die Auswirkungen einer unbehandelten obstruktiven Schlafapnoe (OSA) auf das kardiovaskuläre und kognitive Erkrankungsrisiko und die Therapieeffekte einer OSA sind für die meisten kardiovaskulären und kognitiven Folgeerkrankungen wissenschaftlich nachgewiesen. Für die klinische Praxis besteht ein deutlicher Bedarf nach mehr Interdisziplinarität. Aus schlafmedizinischer Sicht müssen bei der Therapieindikation das individuelle kardiovaskuläre und kognitive Risiko berücksichtigt und kognitive Erkrankungen bei der Beurteilung der Therapieintoleranz und residuellen Symptomatik beachtet werden. Aus internistischer Sicht sollte bei Patienten mit schlecht einstellbarem Hypertonus, Vorhofflimmern, koronarer Herzkrankheit und Schlaganfall die Abklärung einer OSA in die Diagnostik integriert werden. Bei Patienten mit milder kognitiver Beeinträchtigung, Alzheimer-Krankheit und Depression können sich die typischen Symptome wie Fatigue, Tagesmüdigkeit und Reduktion der kognitiven Leistungen mit OSA-Symptomen überschneiden. Die Diagnostik einer OSA sollte in die Abklärung dieser Krankheitsbilder integriert werden, da eine Therapie der OSA die kognitiven Beeinträchtigungen reduzieren und die Lebensqualität verbessern kann.

Severity, comorbidities, and adherence to therapy in Native Hawaiians/Pacific Islanders with obstructive sleep apnea

STUDY OBJECTIVES

Considerable disparities in the prevalence, diagnosis, and management of obstructive sleep apnea (OSA) exist for minority groups in the United States. However, the impact of OSA on Native Hawaiian/Pacific Islanders (NHPIs) has not been evaluated.

METHODS

We performed a retrospective review of patient records of NHPIs who underwent sleep apnea testing between 2014 and 2021 at a single center in Utah to characterize the distribution of comorbidities, disease severity, and treatment adherence.

RESULTS

140 of 141 NHPI patients who underwent sleep testing had OSA. High rates of obesity (94%) and other relevant comorbidities were found. OSA was mostly severe (57%), particularly in males with higher obesity. Adherence to continuous positive airway pressure was low (41% using for 4 or more hours on 70% of nights), and medical factors predicted whether adherence targets were met with modest accuracy (area under the curve 0.699).

CONCLUSIONS

NHPIs at a single sleep center had a high prevalence of comorbidities in association with OSA, a skewed distribution toward severe disease suggestive of barriers to care or unique disease characteristics, and low adherence to continuous positive airway pressure. These findings suggest a high burden of OSA in this population, and further work to characterize barriers to identifying and treating OSA in NHPIs can improve chronic disease outcomes in NHPIs.

CITATION

Locke BW, Sundar DJ, Ryujin D. Severity, comorbidities, and adherence to therapy in Native Hawaiians/Pacific Islanders with obstructive sleep apnea. J Clin Sleep Med. 2023;19(5):967-974.

Exploring the combined effects of sleep apnea and APOE-e4 on biomarkers of Alzheimer's disease

Objective

We determined the interactive associations of apolipoprotein e4 (APOE-e4), and obstructive sleep apnea (OSA) on biomarkers of Alzheimer's disease and examined for racial/ethnic differences of this association.

Methods

We used data from the National Alzheimer's Coordinating Center Uniform Dataset (NACC UDS). All participants undergo annual observations, including demographic survey, battery of neuropsychological tests, blood draw (with genotyping), and a clinical evaluation with medical and cognitive/dementia status assessment, while a subset of participants have cerebrospinal fluid (CSF) biomarkers and neuroimaging data. Biomarkers of AD were characterized as the presence of abnormally low amyloid in CSF, via validated Aβ42 cut off protocols, and total segmented hippocampal volume, and volume of white matter hyper intensities (WMH). While clinical markers (to preview cognitive relationships) were characterized via the Montreal Cognitive Assessment (MOCA).

Results

Biomarker and clinical marker data were derived from 1,387 participants at baseline (mean age = 69.73 ± 8.32; 58.6% female; 13.7% Black/African American), 18.4% of the sample had sleep apnea, and 37.9% were APOE-e4 carriers. Our results confirmed previous reports that OSA and APOE-e4 were independently associated with AD through abnormal levels of amyloid (F (1,306) = 4.27; p = 0.040; F (1,285) = 60.88; p < 0.000, respectively), WMH volume (F (1,306) = 4.27; p = 0.040; F (1,285) = 60.88; p < 0.000, respectively), and MOCA scores (F (1,306) = 4.27; p = 0.040; F (1,285) = 60.88; p < 0.000, respectively). No significant interaction between OSA and APOE-e4 relative to amyloid emerged, however, race stratified analyses indicated the interaction of OSA and APOE-e4 and was significantly associated with WMH and hippocampal volume in Black/African American, but not white participants.

Conclusion

OSA and APOE-e4 are interactively associated with WHM in Black/African Americans. This interaction may partially explicate increased levels of risk in this population.

Sleep matters: Neurodegeneration spectrum heterogeneity, combustion and friction ultrafine particles, industrial nanoparticle pollution, and sleep disorders-Denial is not an option

Sustained exposures to ubiquitous outdoor/indoor fine particulate matter (PM_2.5), including combustion and friction ultrafine PM (UFPM) and industrial nanoparticles (NPs) starting in utero, are linked to early pediatric and young adulthood aberrant neural protein accumulation, including hyperphosphorylated tau (p-tau), beta-amyloid (Aβ_{1 - 42}), α-synuclein (α syn) and TAR DNA-binding protein 43 (TDP-43), hallmarks of Alzheimer's (AD), Parkinson's disease (PD), frontotemporal lobar degeneration (FTLD), and amyotrophic lateral sclerosis (ALS). UFPM from anthropogenic and natural sources and NPs enter the brain through the nasal/olfactory pathway, lung, gastrointestinal (GI) tract, skin, and placental barriers. On a global scale, the most important sources of outdoor UFPM are motor traffic emissions. This study focuses on the neuropathology heterogeneity and overlap of AD, PD, FTLD, and ALS in older adults, their similarities with the neuropathology of young, highly exposed urbanites, and their strong link with sleep disorders. Critical information includes how this UFPM and NPs cross all biological barriers, interact with brain soluble proteins and key organelles, and result in the oxidative, endoplasmic reticulum, and mitochondrial stress, neuroinflammation, DNA damage, protein aggregation and misfolding, and faulty complex protein quality control. The brain toxicity of UFPM and NPs makes them powerful candidates for early development and progression of fatal common neurodegenerative diseases, all having sleep disturbances. A detailed residential history, proximity to high-traffic roads, occupational histories, exposures to high-emission sources (i.e., factories, burning pits, forest fires, and airports), indoor PM sources (tobacco, wood burning in winter, cooking fumes, and microplastics in house dust), and consumption of industrial NPs, along with neurocognitive and neuropsychiatric histories, are critical. Environmental pollution is a ubiquitous, early, and cumulative risk factor for neurodegeneration and sleep disorders. Prevention of deadly neurological diseases associated with air pollution should be a public health priority.

Obstructive Sleep Apnea Resolution in Hypopnea-Predominant versus Apnea-Predominant Patients after Maxillomandibular Advancement

This retrospective cohort study aimed: (1) to analyze the influence of apnea-predominant versus hypopnea-predominant obstructive sleep apnea (OSA) on surgical outcome after maxillomandibular advancement (MMA); and (2) to evaluate whether MMA alters the presence of apnea-predominant to hypopnea-predominant OSA more than vice versa. In total 96 consecutive moderate to severe OSA patients, who underwent MMA between 2010 and 2021, were included. The baseline apnea−hypopnea index, apnea index, and oxygen desaturation index were significantly higher in apnea-predominant group, while the hypopnea index was significantly higher in hypopnea-predominant group (p < 0.001). No significant difference was found between apnea-predominant group and hypopnea-predominant group in the degree of advancement of A-point, B-point, and pogonion. Surgical success and cure were significantly higher in the hypopnea-predominant group compared to the apnea-predominant group, 57.4% versus 82.1% (p = 0.021) and 13.2% versus 55.5% (p = 0.012), respectively. Of the 68 (70.8%) apnea-predominant patients, 37 (54.4%) shifted to hypopnea-predominant after MMA. Of the 28 (29.2%) hypopnea-predominant patients, 7 (25%) shifted to apnea-predominant postoperatively. These findings suggest that preoperative hypopnea-predominant OSA patients might be more suitable candidates for MMA compared to preoperative apnea-predominant OSA patients. Additionally, MMA proved to alter the presence of apnea-predominant to hypopnea-predominant OSA to a larger extend than vice versa.