Effects of continuous positive airway pressure on cognitition and neuroimaging data in sleep apnea

The relationship between positive airway pressure tolerance and adherence: defining a new metric

STUDY OBJECTIVES

Positive airway pressure (PAP) therapy adherence rates range from 30% to 60%, yet adherent patients may still express dissatisfaction with treatment. The identification of factors affecting PAP tolerance could provide insight into its impact on adherence.

METHODS

Patients with obstructive sleep apnea presenting for first follow-up visit after newly initiating PAP therapy were given a 10-question PAP tolerance survey encompassing domains of psychosocial perception, practical issues, and side effects, utilizing 10-point visual analog scales. Relationships between adherence data, tolerance scores, and patient variables (demographics, sleep-related factors, comorbidities, usage data) were explored via 2-tailed t tests, multivariable regression analysis, and recursive partitioning regression trees with a significance level of P ≤ .05.

RESULTS

For 105 patients, tolerance scores were higher in patients considered adherent to therapy (P = .033), as were scores for individual survey questions addressing the ability to fall asleep (P = .013) and sleep through the night (P = .020). Depression positively (P = .006) and insomnia medication use negatively (P = .010) predicted tolerance score. Data-driven tolerance score cutoffs were identified to correlate with PAP adherence, with higher tolerance scores correlating with greater adherence rates.

CONCLUSIONS

PAP tolerance may play an important role in therapy adherence. Tolerance can be statistically defined and categorized based on prior adherence data. Its utility as a predictive tool in assessing future adherence is warranted.

CITATION

Tekumalla S, Plawecki A, Kaffenberger T, et al. The relationship between positive airway pressure tolerance and adherence: defining a new metric. J Clin Sleep Med. 2024;20(7):1033-1038.

Boosting obstructive sleep apnea therapy by non-pharmacological approaches: A network meta-analysis

INTRODUCTION

Obstructive sleep apnea (OSA) is the most common breathing-related sleep disorder with a considerable economic burden, low diagnosis and treatment rates. Continuous positive airway pressure (CPAP/PAP) is the principal therapy for OSA treatment; nevertheless, effectiveness is often limited by suboptimal adherence. The present network meta-analysis aims to systematically summarize and quantify different interventions' effects on CPAP/PAP adherence (such as mean usage CPAP or PAP in hours per night) in OSA patients, comparing Behavioral, Educational, Supportive and Mixed interventions in Randomized Control Trials (RCT).

METHODS

We conducted a computer-based search using the electronic databases of Pubmed, Psycinfo, Scopus, Embase, Chinal and Medline until August 2022, selecting 50 RCT.

RESULTS

By means of a random effect model network meta-analysis, results suggested that the most effective treatment in improving CPAP/PAP adherence was the Supportive approach followed by Behavioral Therapy focused on OSA treatment adherence.

CONCLUSION

This network meta-analysis might encourage the most experienced clinicians and researchers in the field to collaborate and implement treatments for improving CPAP/PAP treatment adherence. Moreover, these results support the importance of multidisciplinary approaches for OSA treatment, which should be framed within a biopsychological model.

Clinical features of sleep apnea syndrome and cognitive impairment in multiple sclerosis

BACKGROUND

Complications of obstructive sleep apnea (OSA) have been reported in patients with multiple sclerosis (MS). Patients with sleep apnea syndrome (SAS) due to OSA also show cognitive decline, with similar clinical characteristics to that manifested in MS. SAS due to OSA is a treatable condition, and the associated cognitive decline is expected to improve. This study investigates clinical features of SAS in people living with MS and contribute to improve cognitive dysfunction of MS.

METHODS

A case-control study was conducted. Cognitive functions were evaluated by the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test 2 (PASAT-2) and 3 (PASAT-3). The Respiratory Event Index (REI) was measured using Out of Center Sleep Testing (OCST). We defined subjects with REI ≥ 5 as OSA and divided participants into two groups with or without SAS due to OSA. Cognitive and respiratory characteristics were statistically compared between patients with MS and healthy controls.

RESULTS

We enrolled 67 people living with MS and 31 age- and sex-matched controls. OCST detected OSA in people living with MS and controls, and the prevalence rates were 28.4 % and 25.8 %, respectively. REI values (5.2 ± 7.9 vs 3.9 ± 5.2, p = 0.509) and number of participants with REI ≥ 5 (19 vs 8, p = 0.793) were similar between the MS and control group. The SDMT, PASAT-2, and PASAT-3 scores were significantly lower in the MS group than the control group (p < 0.001, p = 0.001, and p < 0.001, respectively). The interaction effect of MS and SAS on cognitive function was not significant in the SDMT (p = 0.078), but in the PASAT-2 (p = 0.043) and PASAT-3 (p = 0.020).

CONCLUSION

This study revealed the prevalence rates of SAS in Japanese people living with MS and the usefulness of OCST for detection of SAS. This study also revealed that concomitant SAS can facilitate cognitive decline in people living with MS. These findings suggest that an appropriate intervention for OSA can be beneficial for people living with MS with cognitive decline.

Mentation Tracks Severity but not Oxygenation in Obstructive Sleep Apnea

There is a rough consensus, after decades of research, that obstructive sleep apnea (OSA) is associated with mild cognitive impairments, especially in areas of executive functioning (EF), attention/working memory (A/WM), episodic memory (EM), and speed of speed of information processing (SIP). However, there is less consensus as to whether apnea severity matters for these impairments, which sleep variables matter most to which cognitive domains, whether common OSA comorbidities contribute to these determinations, or whether the apparent associations are really artifacts of these comorbidities. In this study, 40 participants with OSA submitted to polysomnography and to neuropsychological assessment with an expanded Halstead-Reitan Test Battery. Aggregates of tests to cover the four cognitive domains mentioned above were linearly regressed on the apnea-hypopnea index (AHI), the nadir of oxygen saturation (NOS), and hypertension and diabetes mellitus (scored present or absent). The AHI predicted both EF (p = .015; sr2 = .13) and A/WM (p = .023; sr2 = 11) in the primary analyses, and EM (p = .027; sr2 = .10) in the secondary analyses. Thus, AHI may affect EF, A/WM and perhaps EM beyond NOS and beyond two of OSA's most common comorbidities. Implications of these findings are discussed here.

Positive Airway Pressure and Cognitive Disorders in Adults With Obstructive Sleep Apnea: A Systematic Review of the Literature

BACKGROUND AND OBJECTIVES

Alzheimer disease (AD) and other forms of dementia represent a rising global public health crisis. Because effective treatments to prevent, cure, or slow progression of dementia are unavailable, identification of treatable risk factors that increase dementia risk such as obstructive sleep apnea (OSA) could offer promising means to modify dementia occurrence or severity. Here, we systematically reviewed the impact of positive airway pressure (PAP) therapy on the incidence of cognitive disorders and cognitive decline among middle-aged and older adults with OSA.

METHODS

We performed a systematic search of MEDLINE, EMBASE, Scopus, and CINAHL before May 2021 to identify articles that focused on associations between PAP therapy use and cognitive disorders. We included studies that examined the effects of PAP treatment on (1) the incidence of cognitive disorders among individuals ≥40 years of age diagnosed with OSA and (2) the progression of cognitive decline among people with preexisting cognitive disorders and OSA.

RESULTS

We identified 11 studies (3 clinical trials and 8 observational studies). In these studies, 96% participants had OSA (n = 60,840) and 9% had baseline cognitive impairment (mild cognitive impairment [MCI] or AD) (n=5,826). Of all study participants, 43,970 obtained PAP therapy, and 16,400 were untreated or in a placebo group. Nine out of 11 studies reported a protective effect of PAP therapy on MCI and AD incidence, e.g., delayed age at MCI onset, reduced MCI or AD incidence, slower cognitive decline, or progression to AD.

DISCUSSION

These findings suggest a role for OSA as a modifiable risk factor for cognitive decline. Identification of modifiable risk factors is imperative for alleviating the impact of cognitive disorders on aging adults and their family members. Future research should build on this review and focus on PAP interventions as a potential means to alleviate the incidence of cognitive disorders and cognitive decline, particularly among ethnoracial groups who have been underrepresented and underinvestigated in the extant literature.

Post-Operative Patients’ Satisfaction and Quality of Life Assessment in Adult Patients with Obstructive Sleep Apnea Syndrome (OSAS)

Background: The treatment for severe OSAS includes maxillomandibular advancement surgical option in selected cases. The aim of this study was to evaluate the post-operative impact of bimaxillary surgery on satisfaction and consequently the quality of life of these patients. Methods: This study included 18 patients with severe OSAS who received maxillomandibular advancement surgery. Patients were divided into Group A (operated by CAD/CAM) and Group B (conventional surgery). The impact of bimaxillary surgery on satisfaction and quality of life of these patients was evaluated by utilizing post-operative life quality and Rustemeyer’s patient-satisfaction-based survey. Results: A total of 18 adult OSAS patients (Group A: 11 patients, Group B: 7 patients) with a mean age of 44.39 years (SD ± 9.43) were included. Mean follow-up period was 32.64 months (SD ± 21.91). No intra-operative complications were seen in any patients. Post-operative complication was seen in one patient and the mandible did not integrate. According to the results, overall post-operative satisfaction score was 79.72% (SD ± 9.96). There was no significant difference among those in Group A and Group B. Conclusion: Maxillomandibular advancement surgery seems to be beneficial in terms of patients’ satisfaction in severe adult OSAS patients and can be considered as a valuable option in selected cases.

Obstructive Sleep Apnea Among Army Aircrew

INTRODUCTION: Obstructive sleep apnea (OSA) is a condition characterized by disrupted sleep and excessive daytime fatigue. Associated cognitive and psychomotor decrements pose a threat to aviators' performance and flight safety. Additionally, the longer term health effects associated with the disease can jeopardize an aviator's career and negatively impact operational outputs. This study reviews OSA prevalence, related comorbid conditions in Army aviators, and analyzes the aeromedical dispositions of affected individuals.METHODS: The U.S. Army Aeromedical Electronic Resource Office (AERO) database was interrogated for all cases of OSA from June 2005 through June 2015 using ICD-9 code 327.23. Prevalence rates for OSA and other comorbid conditions were then calculated using the total number of aviators in the AERO database.RESULTS: A total of 663 unique instances of OSA were found among the aviator population (N = 24,568), giving a point prevalence of 2.69%. Four cases affected women. Mean age of initial presentation was 42.62 yr and mean Body Mass Index was 28.69. The top five most prevalent comorbid conditions were hypertension, lumbago, degeneration of a lumbar or lumbosacral intervertebral disc, PTSD, and testicular hypofunction.DISCUSSION: Prevalence of OSA among aviators is lower than the general population but is not uncommon. A positive diagnosis requires a waiver or can result in suspension if not managed effectively, potentially leading to a reduction in aviator numbers. Aggressive health promotion and robust medical surveillance and aeromedical disposition management by the aeromedical community is essential to reduce OSA numbers, maintain aviator health, and maximize flight safety.Goldie C, Stork B, Bernhardt K, Gaydos SJ, Kelley AM. Obstructive sleep apnea among army aircrew. Aerosp Med Hum Perform. 2022; 93(5):415-420.

Neurological effects of respiratory dysfunction

The respiratory and the nervous systems are closely interconnected and are maintained in a fine balance. Central mechanisms maintain strict control of ventilation due to the high metabolic demands of brain which depends on a continuous supply of oxygenated blood along with glucose. Moreover, brain perfusion is highly sensitive to changes in the partial pressures of carbon dioxide and oxygen in blood, which in turn depend on respiratory function. Ventilatory control is strictly monitored and regulated by the central nervous system through central and peripheral chemoreceptors, baroreceptors, the cardiovascular system, and the autonomic nervous system. Disruption in this delicate control of respiratory function can have subtle to devastating neurological effects as a result of ensuing hypoxia or hypercapnia. In addition, pulmonary circulation receives entire cardiac output and this may act as a conduit to transmit infections and also for metastasis of malignancies to brain resulting in neurological dysfunction. Furthermore, many neurological paraneoplastic syndromes can have underlying lung malignancies resulting in respiratory dysfunction. It is essential to understand the underlying mechanisms and the resulting manifestations in order to prevent and effectively manage the many neurological effects of respiratory dysfunction. This chapter explores the various neurological effects of respiratory dysfunction with focus on their pathophysiology, etiologies, clinical features and long-term neurological sequelae.

Sleep in disorders of consciousness: diagnostic, prognostic, and therapeutic considerations

PURPOSE OF REVIEW

Sleep is important in the evaluation of patients with disorders of consciousness (DOC). However, it remains unclear whether reconstitution of sleep could enable consciousness or vice versa. Here we synthesize recent evidence on natural recovery of sleep in DOC, and sleep-promoting therapeutic interventions for recovery of consciousness.

RECENT FINDINGS

In subacute DOC, physiological sleep--wake cycles and complex sleep patterns are related to better outcomes. Moreover, structured rapid-eye-movement (REM), non-REM (NREM) stages, and presence of sleep spindles correlate with full or partial recovery. In chronic DOC, sleep organization may reflect both integrity of consciousness-supporting brain networks and engagement of those networks during wakefulness. Therapeutic strategies have integrated improvement of sleep and sleep--wake cycles in DOC patients; use of bright light stimulation or drugs enhancing sleep and/or vigilance, treatment of sleep apneas, and neuromodulatory stimulations are promising tools to promote healthy sleep architecture and wakeful recovery.

SUMMARY

Sleep features and sleep--wake cycles are important prognostic markers in subacute DOC and can provide insight into covert recovery in chronic DOC. Although large-scale studies are needed, preliminary studies in limited patients suggest that therapeutic options restoring sleep and/or sleep--wake cycles may improve cognitive function and outcomes in DOC.

High-flow nasal cannula compared with continuous positive airway pressure in the treatment of obstructive sleep apnea

PURPOSE

Continuous positive airway pressure (CPAP) is a standard treatment for obstructive sleep apnea (OSA). However, CPAP has limitations. High-flow nasal cannula (HFNC) is already in use for various types of respiratory diseases. As HFNC generates positive airway pressure, it may be a potential candidate for OSA treatment. This prospective study compared the therapeutic effects of HFNC to CPAP in patients with OSA.

METHODS

Patients whose apnea-hypopnea index (AHI) was > 5 events/h were enrolled in this study. All participants were randomly divided into two groups. The first group underwent CPAP the first night and HFNC the second night. Conversely, the second group received HFNC the first night and CPAP the second night. Their respiratory events and sleep quality were compared using baseline polysomnography, CPAP, and HFNC.

RESULTS

In total, 28 participants completed this study. Median [interquartile range] AHI (35.0 [20.0-48.6] vs. 10.8 [5.5-20.6] events/h; p < 0.001) was significantly improved by the HFNC. However, sleep quality was not improved. When CPAP was compared directly with HFNC, CPAP demonstrated a more favorable effect for respiratory events (AHI 5.0 [2.0-7.0] vs. 10.8 [5.5-20.6] events/h; p < 0.001) and sleep efficiency (88.1 [79.9-92.5] vs. 77.9 [69.2-86.6] %; p = 0.001).

CONCLUSION

The efficacy of CPAP was superior to HFNC for both respiratory events and sleep quality.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03843372; URL: www.clinicaltrials.gov ; Date of registration: November 2, 2019.

Longitudinal changes in regional cerebral blood flow in late middle-aged and older adults with treated and untreated obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with abnormal cerebral perfusion at wakefulness, but whether these anomalies evolve over time is unknown. Here, we examined longitudinal changes in regional cerebral blood flow (rCBF) distribution in late middle‐aged and older adults with treated or untreated OSA. Twelve controls (64.8 ± 8.0 years) and 23 participants with newly diagnosed OSA (67.8 ± 6.2 years) were evaluated with polysomnography and cerebral ^99mTc‐HMPAO single‐photon emission computed tomography during wakeful rest. OSA participants were referred to a sleep apnea clinic and 13 of them decided to start continuous positive airway pressure (CPAP). Participants were tested again after 18 months. Voxel‐based analysis and extracted relative rCBF values were used to assess longitudinal changes. Untreated OSA participants showed decreased relative rCBF in the left hippocampus and the right parahippocampal gyrus over time, while treated participants showed trends for increased relative rCBF in the left hippocampus and the right parahippocampal gyrus. No changes were found over time in controls. Untreated OSA is associated with worsening relative rCBF in specific brain areas over time, while treated OSA shows the opposite. Considering that OSA possibly accelerates cognitive decline in older adults, CPAP treatment could help reduce risk for cognitive impairment.

Frequency‑Specific Regional Homogeneity Alterations and Cognitive Function in Obstructive Sleep Apnea Before and After Short-Term Continuous Positive Airway Pressure Treatment

PURPOSE

Previous studies have demonstrated abnormal local spontaneous brain activity in the conventional frequency bands (0.01-0.08 Hz) in obstructive sleep apnea (OSA). However, it is not clear whether these abnormalities are associated with the specific frequency band of low-frequency oscillations or whether it can be improved with a continuous positive airway pressure (CPAP) treatment. This study aimed to investigate the regional homogeneity (ReHo) in specific frequency at baseline (pre-CPAP) and after one month of CPAP adherence treatment (post-CPAP) in OSA patients.

METHODS

Twenty-one patients with moderate-to-severe OSA and 21 age- and sex-matched healthy controls (HCs) were included in the final analysis. ReHo was calculated in three different frequency bands (typical frequency band: 0.01-0.1 Hz; slow-5 band: 0.01-0.027 Hz; slow-4 band: 0.027-0.073 Hz), respectively. A partial correlational analysis was performed to assess the relationship between altered ReHo and clinical evaluation.

RESULTS

OSA patients revealed increased ReHo in the brainstem, bilateral inferior temporal gyrus (ITG)/fusiform, and right-cerebellum posterior lobe (CPL), and decreased ReHo in the bilateral inferior parietal lobule (IPL), right superior temporal gyrus (STG), and left precentral gyrus (PG) compared to HC groups in different frequency bands. Significantly changed ReHo in the bilateral middle temporal gyrus (MTG), PG, medial frontal gyrus (MFG), supplementary motor area (SMA), CPL, IPL, left superior frontal gyrus (SFG), ITG, MTG, and right STG were observed between post-CPAP and pre-CPAP OSA patients, which was associated with specific frequency bands. The altered ReHo in specific frequency bands was correlated with Montreal cognitive assessment score, Epworth sleepiness scale, and apnea hypopnea index in pre-CPAP OSA patients.

CONCLUSION

These findings indicate that OSA has frequency-related abnormalities of spontaneous neural activity before and after short-term CPAP treatment, which might contribute to a better understanding of local neural psychopathology and may serve as potential biomarkers for clinical CPAP treatment.

Cognitive Impairment and Depressive Symptoms in a Patient With Obstructive Sleep Apnea: Full Recovery After CPAP Treatment

Obstructive sleep apnea syndrome (OSA) is associated with neuropsychiatric symptoms, including cognitive impairment and depression. It is important to be aware of this association since these comorbid symptoms may be misdiagnosed as a primary psychiatric condition. We report a case of a 60-year-old man with depressive symptoms and cognitive impairment, with important deficits in memory and great functional impairment. There was no response to many antidepressant trials and, later, he underwent polysomnography and was diagnosed with severe OSA. The patient started treatment with continuous positive airway pressure (CPAP) and showed progressive improvement in depressive and cognitive symptoms. During one year of follow-up, there was no recurrence of psychiatric symptoms and the patient was able to stop antidepressants and to recover his functionality. This case highlights the importance of searching for OSA signals when assessing patients with depressive and cognitive symptoms, since they may improve with OSA adequate treatment.

Sleep-disordered breathing and the risk of Alzheimer's disease

Sleep-disordered breathing is highly prevalent in the elderly population. Obstructive sleep apnea (OSA) represents the most common sleep disorder among the adult and elderly population. Recently, OSA diagnosis has been associated with an increased risk of developing cognitive decline and dementia, including vascular dementia and Alzheimer's disease (AD). Subsequently, there have been studies on AD biomarkers investigating cerebrospinal fluid, blood, neuroimaging, and nuclear medicine biomarkers in patients with OSA. Furthermore, studies have attempted to assess the possible effects of continuous positive airway pressure (CPAP) treatment on the cognitive trajectory and AD biomarkers in patients with OSA. This review summarizes the findings of studies on each AD biomarker (cognitive, biofluid, neuroimaging, and nuclear medicine imaging) in patients with OSA, also accounting for the related effects of CPAP treatment. In addition, the hypothetical model connecting OSA to AD in a bi-directional interplay is analyzed. Finally, the sex-based differences in prevalence and clinical symptoms of OSA between men and women have been investigated in relation to AD risk. Further studies investigating AD biomarkers changes in patients with OSA and the effect of CPAP treatment should be auspicated in future for identifying strategies to prevent the development of AD.

Impact of obstructive sleep apnoea on cognitive function in multiple sclerosis: A longitudinal study

Cognitive impairment (CI) and fatigue are common in people with multiple sclerosis (MS), with well-known profound effects on quality of life. Sleep disorders, including obstructive sleep apnoea (OSA), are also common in MS patients. The presence of CI has previously been shown to strongly correlate with OSA diagnosed using polysomnography in MS. Treatment of OSA has not previously been investigated as a potential modality to improve cognition in MS patients. Therefore, we sought to investigate the potential effects of OSA treatment on both cognitive function and fatigue in MS patients. Twenty-three participants with MS reporting significant fatigue were enrolled. CI was assessed by the Brief International Cognitive Assessment in MS and the 3-second Paced Auditory Serial Addition Test. All participants underwent overnight polysomnography to assess for possible OSA. Cognitive and fatigue measures were repeated in those subsequently treated for OSA and in a comparative untreated sample. Seven participants (30%) had a diagnosis of OSA based on an apnoea-hypopnea index greater than 5 per hour, with no correlation between the presence of CI and OSA. Verbal learning at follow-up assessment was seen to improve significantly in those treated for OSA, compared with those who were not treated for a sleep disorder. This small study demonstrates the potential for OSA treatment to improve verbal learning in people with MS, larger studies are indicated to further investigate the potential for cognitive and fatigue improvement in people with MS through treatment of comorbid OSA.

Therapeutic Approaches for the Management of Sleep Disorders in Geriatric Population

OBJECTIVE

Aging is a natural biological phenomenon that occurs in human beings. With increasing of age, there is an appearance of deleterious changes related to progression onto pathological conditions, including hypertension, heart disease, diabetes, hearing and vision impairments, as well as sleep disorders. It is important to recognize that some sleep disturbances reported by aged subjects include insomnia, obstructive sleep apnea, restless legs syndrome, among others. Moreover, accumulating evidence indicates that coexistence of medical issues with sleep disorders constitutes clinical challenges for treatment of comorbidities in elderly. Here, we have attempted to review and summarize the available literature that assesses the sleep disturbances in aging. In addition, we highlight the management of sleep disorders associated with aging. Due to the particular health condition of aged adults, the development of effective pharmacological interventions for sleep disorders treatment in aging is warranted.

METHODS

Review of studies retrieved from the PubMed.

RESULTS

The sleep-wake cycle includes abnormalities classified as sleep disorders. Comorbidity between sleep disturbances and aging-related health issues will represent a public health challenge to be addressed in the near future. Moreover, this scenario will suggest an area that requires further drug investigation and design of new pharmacological and pharmaceutical strategies to treat sleep disorders in the elderly population.

CONCLUSION

The review highlights the sleep disturbances in aging. We focus on current knowledge in medicinal chemistry and further design of new treatments tools for managing sleep disturbances in the aged population.

The prevalence of obstructive sleep apnea in mild cognitive impairment: a systematic review

Background

Previous studies have shown that obstructive sleep apnea (OSA) is associated with a higher risk of cognitive impairment or dementia in the elderly, leading to deleterious health effects and decreasing quality of life. This systematic review aims to determine the prevalence of OSA in patients with mild cognitive impairment (MCI) and examine whether an association between OSA and MCI exists.

Methods

We searched Medline, PubMed, Embase, Cochrane Central, Cochrane Database of Systematic Reviews, PsychINFO, Scopus, the Web of Science, ClinicalTrials.gov and the International Clinical Trials Registry Platform for published and unpublished studies. We included studies in adults with a diagnosis of MCI that reported on the prevalence of OSA. Two independent reviewers performed the abstract and full-text screening, data extraction and the study quality critical appraisal.

Results

Five studies were included in the systematic review. Overall, OSA prevalence rates in patients with MCI varied between 11 and 71% and were influenced by OSA diagnostic methods and patient recruitment locations (community or clinic based). Among studies using the following OSA diagnostic measures– self-report, Home Sleep Apnea Testing, Berlin Questionnaire and polysomnography– the OSA prevalence rates in MCI were 11, 27, 59 and 71%, respectively. In a community-based sample, the prevalence of OSA in patients with and without MCI was 27 and 26%, respectively.

Conclusions

Based on limited evidence, the prevalence of OSA in patients with MCI is 27% and varies based upon OSA diagnostic methods and patient recruitment locations. Our findings provide an important framework for future studies to prospectively investigate the association between OSA and MCI among larger community-based cohorts and implement a standardized approach to diagnose OSA in memory clinics.

PROSPERO registration

CRD42018096577.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1422-3) contains supplementary material, which is available to authorized users.

Is Maxillomandibular Advancement Associated With Comorbidity Reduction in Patients With Obstructive Sleep Apnea?

PURPOSE

This study investigated whether patients with documented obstructive sleep apnea (OSA) who have a decrease in apnea-hypopnea index (AHI) score and self-reported symptoms after maxillomandibular advancement (MMA) with genial tubercle advancement (GTA) also have a change in their medical comorbidity profile a minimum of 2 years postoperatively. Changes in the quantity of medical diagnoses, quantity of prescription medications, and average weight and body mass index (BMI) were assessed.

PATIENTS AND METHODS

This is a retrospective cohort study of patients with a diagnosis of OSA (AHI score >5 on polysomnogram [PSG]) treated at the Massachusetts General Hospital (Boston, MA) with MMA and GTA from 2001 through 2015. Patients were identified through the oral and maxillofacial surgery patient data registry. Inclusion criteria were the availability of complete clinical records and requisite follow-up time. The primary predictor variable was operative status (preoperative or postoperative). The primary outcome variables were comorbidities reported to be associated with OSA and identified in the authors' previous study (J Oral Maxillofac Surg 76:1999.e1, 2018). Two-tailed paired t tests were used for continuous variables and χ² or Fisher exact tests were used for categorical variables.

RESULTS

Forty-six patients (39 men, 7 women) met the inclusion criteria. Average weight (206.7 ± 42.4 lb preoperatively; 213.8 ± 41.7 lb postoperatively; P = .014) and average BMI (30.0 ± 5.7 kg/m² preoperatively; 30.9 ± 5.3 kg/m² postoperatively; P = .041) significantly increased in patients postoperatively. No meaningful changes in the number of medical diagnoses or number of prescription medications were noted. Stratification of patients by BMI showed significant increases in weight (188.6 ± 21.5 lb preoperatively; 200.1 ± 27.9 lb postoperatively; P = .0085) and BMI (27.1 ± 1.44 kg/m² preoperatively; 28.9 ± 3.52 kg/m² postoperatively; P = .013) only in "overweight" patients. No other parameters were found to be relevant.

CONCLUSIONS

Subjective improvement in OSA symptoms was reported by all patients and objective PSG improvement was reported for 71% of those evaluated. However, no relevant changes in comorbidity profile were found, suggesting that the medical conditions commonly observed with OSA are likely of multifocal etiology.

A Policy Analysis of Mandatory Obstructive Sleep Apnea Screening in the Trucking Industry

Obstructive sleep apnea (OSA) is a chronic condition characterized by occlusion of the upper airway during sleep resulting in daytime sleepiness. Drivers with OSA are at a two- to sevenfold increase in risk of motor vehicle crashes (MVCs). Approximately, 13% to 28% of commercial motor vehicle drivers (CMVDs) are thought to have OSA. Obstructive sleep apnea is a significant issue in the transportation industry. Currently, The Federal Motor Carrier Safety Association (FMCSA) does not mandate OSA screening. Federal regulations only specify that CMVDs be free of "respiratory dysfunction" that would impair driving. Untreated OSA is a public safety concern. The purpose of this article is to use Bardach's eightfold policy analysis approach to examine policy options related to OSA screening in the trucking industry.

Challenges and perspectives in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a major challenge for physicians and healthcare systems throughout the world. The high prevalence and the impact on daily life of OSA oblige clinicians to offer effective and acceptable treatment options. However, recent evidence has raised questions about the benefits of positive airway pressure therapy in ameliorating comorbidities.

An international expert group considered the current state of knowledge based on the most relevant publications in the previous 5 years, discussed the current challenges in the field, and proposed topics for future research on epidemiology, phenotyping, underlying mechanisms, prognostic implications and optimal treatment of patients with OSA.

The group concluded that a revision to the diagnostic criteria for OSA is required to include factors that reflect different clinical and pathophysiological phenotypes and relevant comorbidities (e.g.nondipping nocturnal blood pressure). Furthermore, current severity thresholds require revision to reflect factors such as the disparity in the apnoea–hypopnoea index (AHI) between polysomnography and sleep studies that do not include sleep stage measurements, in addition to the poor correlation between AHI and daytime symptoms such as sleepiness. Management decisions should be linked to the underlying phenotype and consider outcomes beyond AHI.

Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study

Study aim

Severe obstructive sleep apnoea (OSA) can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP) on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients.

Material and methods

In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m^-2, apnoea-hypopnoea index = 46.3±11.7 events·h^-1) and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment.

Results

Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5%) and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment.

Conclusion

Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences.

Effects of CPAP therapy on cognitive and psychomotor performances in patients with severe obstructive sleep apnea: a prospective 1-year study

STUDY OBJECTIVES

We prospectively investigated the effects of continuous positive airway pressure (CPAP) on long-term cognitive and psychomotor performances, and excessive daytime sleepiness in severe obstructive sleep apnea (OSA) patients.

METHODS

A total of 40 patients were recruited and 23 patients with severe OSA fully completed the study protocol to investigate the effects of CPAP therapy on psychomotor performance at 1, 3, and 6 months and 1 year following initiation of the therapy. Psychomotor CRD-series tests measuring reaction times of light stimulus perception, solving simple arithmetic operations, and complex psychomotor limb coordination, were used in this study. The data collected following CPAP therapy were compared to baseline values prior to the CPAP treatment for each patient.

RESULTS

All of the measured variables improved following CPAP treatment. However, the most pronounced effect was observed in improvement of reaction times to complex psychomotor limb coordination test (p < 0.05). Self-reported evaluation of excessive daytime sleepiness measured by Epworth Sleepiness Scale (ESS) showed significant decrease from 10.0 ± 1.1 before to 3.5 ± 0.5 (p < 0.001), after 1 year on CPAP therapy.

CONCLUSIONS

The CPAP therapy improved cognitive and psychomotor performance on CRD-series tests with the most significant improvement observed in complex psychomotor limb coordination of severe OSA patients.

Does the Medical Comorbidity Profile of Obstructive Sleep Apnea Patients Treated With Maxillomandibular Advancement Differ From That of Obstructive Sleep Apnea Patients Managed Nonsurgically?

PURPOSE

Obstructive sleep apnea (OSA) patients with retrognathia and measurable anatomic airway determinants may represent a subset of OSA patients and have distinct comorbidity profiles. Our aim was to compare the medical comorbidities of OSA patients managed surgically with maxillomandibular advancement with those of nonsurgical patients.

PATIENTS AND METHODS

In this cross-sectional retrospective study, patients for both cohorts were identified through the Massachusetts General Hospital oral and maxillofacial surgery data registry and the Massachusetts General Hospital Research Patient Data Registry. The inclusion criteria consisted of clinical records documenting body mass index (BMI), apnea-hypopnea index, respiratory disturbance index, and/or oxygen nadir. The primary predictor variable was the treatment modality chosen: surgical (maxillomandibular advancement) or nonsurgical. Demographic information and OSA parameters were evaluated. The primary outcome variable was the number of documented comorbidities in each group. Two-sample t tests were used for continuous variables, whereas χ² or Fisher exact tests were used for categorical variables.

RESULTS

The nonsurgical cohort consisted of 71 patients (67.6% men), and the surgical cohort consisted of 51 patients (84.3% men). Comparison of descriptive characteristics showed that the nonsurgical cohort had a higher average age (49 ± 9.4 years) than the surgical cohort (41 ± 10.7 years, P < .001). In addition, a higher average BMI was present in the nonsurgical group (42.3 ± 11.9 in nonsurgical group vs 29.7 ± 5.5 in surgical group, P < .001). Polysomnogram parameters were comparable with the exception of a higher Epworth Sleepiness Scale score in the surgical cohort (15.5 ± 5.30 in surgical group vs 9.90 ± 6.80 in nonsurgical group, P = .005). The nonsurgical cohort had a higher total number of comorbidities (7 ± 4 in nonsurgical group vs 4 ± 3 in surgical group, P < .001). Hypertension, cardiovascular disease, hyperlipidemia, pulmonary hypertension, obstructive pulmonary disease, and type 2 diabetes mellitus had higher prevalences within the nonsurgical group.

CONCLUSIONS

The results of this study suggest that nonsurgically managed OSA patients tend to have more complex medical comorbidity profiles than those managed surgically. Obesity (BMI >30) was more prevalent in the nonsurgical cohort, which may be contributory. The additive contribution of OSA needs to be further elucidated.

Continuous positive airway pressure therapy in obstuctive sleep apnea: benefits and alternatives

INTRODUCTION

Obstructive sleep apnea (OSA) is a highly prevalent condition affecting persons of all age with an increasing public health burden. It is implicated in cardiovascular disease, metabolic syndrome, neurocognitive impairment, reductions in quality of life, and increased motor vehicle accidents. The goals of OSA treatment are to improve sleep and daytime symptoms, and minimize cardiovascular risks.Areas covered: Continuous positive airway pressure (CPAP) is considered the gold standard therapy that delivers pressurized air into the upper airway to relieve obstruction during sleep. Although CPAP is an effective modality of treatment for OSA, adherence to therapy is highly variable. This article highlights the benefits of CPAP therapy, along with alternative treatment options including oral appliance, implantable and wearable devices, and surgery. Expert commentary: CPAP therapy is the gold standard treatment option and should continue to be offered to those who suffer from OSA. Alternative options are available for those who are unable to adhere to CPAP or choose an alternative treatment modality. The most interesting advances have been incorporating orthodontic procedures in conjunction with myofunctional therapy in prepubertal children, raising the possibility of OSA prevention by initiating treatment early in life.

Reduced cognitive function in patients with Parkinson disease and obstructive sleep apnea

OBJECTIVE

To assess the association between obstructive sleep apnea (OSA) and nonmotor symptoms (NMS), including cognitive dysfunction, in patients with Parkinson disease (PD).

METHODS

Patients with idiopathic PD, recruited from a movement disorder clinic, underwent overnight polysomnography. OSA was defined as an apnea-hypopnea index (AHI) ≥15/h. PD severity was assessed using the Hoehn & Yahr (H&Y) scale and the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). NMS were assessed using the Montreal Cognitive Assessment (MoCA), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale, Apathy Scale, Beck Depression Inventory, Hospital Depression and Anxiety Scale, and PD sleep Scale.

RESULTS

Sixty-seven patients (61.2% male), mean age 64.4 (SD 9.9) years and motor MDS-UPDRS 21.9 (12.6) using levodopa equivalent dose (LED) 752.4 (714.6) mg/d, were studied. OSA occurred in 47 patients (61.6%, mean AHI 27.1/h, SD 20.2/h), and NMS in 57 patients (85%). ESS and MoCA were associated with the AHI (ESS β = 0.0670, p = 0.031; MoCA β = -0.0520, p = 0.043, adjusted for age, sex, body mass index, LED, and H&Y). ESS was associated with respiratory arousals (β = 0.1015, p = 0.011) and intermittent hypoxemia (β = 0.1470, p = 0.006). MoCA was negatively associated with respiratory arousals (β = -0.0596, p = 0.049) but not intermittent hypoxemia.

CONCLUSIONS

OSA is associated with sleepiness and cognitive dysfunction in PD, suggesting that OSA may be a reversible contributor to these NMS. Further studies will be required to evaluate whether OSA treatment can improve excessive sleepiness and cognitive dysfunction in PD.

Continuous positive airway pressure treatment impact on memory processes in obstructive sleep apnea patients: a randomized sham-controlled trial

OBJECTIVE

The aim of this study was to investigate the changes in a large panel of memory processes after six weeks of continuous positive airway pressure (CPAP) in obstructive sleep apnea (OSA) patients. This randomized controlled trial compared the influence of effective CPAP to sham CPAP over six weeks on different memory processes in OSA patients.

METHODS

The study took place in a sleep laboratory and outpatient sleep clinic in a French tertiary-care university hospital. A total of 36 patients with OSA were randomized to receive either CPAP (n = 18) or sham CPAP (n = 18) for six weeks. Interventions were either effective CPAP or non-effective sham CPAP, for six weeks. All patients underwent an extensive battery of tasks evaluating three separate memory systems, before and after treatment. Verbal episodic memory was tested after forced encoding, procedural memory was tested using simplified versions of mirror drawing and reading tests, and working memory was examined with validated paradigms based on a theoretical model.

RESULTS

The study subjects were 55 ± 11 years of age and 72.2% were male. The mean body mass index was 29.5 ± 4.1 kg/m² and the apnea-hypopnea index was 37.1 ± 16.3/h. Prior to treatment, memory performances of OSA patients were altered. In an intention-to-treat analysis, memory deficits were not significantly improved after six weeks of effective CPAP compared to sham CPAP treatment. Verbal episodic, procedural, and working memory scores were comparable between both groups.

CONCLUSION

Using cautious methodology in comparing effective CPAP to sham CPAP and a well-defined set of memory assessments, we did not find improvement in memory performance after six weeks of treatment.

Impact of Obstructive Sleep Apnea on Neurocognitive Function and Impact of Continuous Positive Air Pressure

There is evidence that obstructive sleep apnea (OSA) can negatively impact attention, memory, learning, executive function, and overall intellectual function in adults and children. Imaging techniques, including MRI, MR diffusion tensor imaging, MR spectroscopy, and fMRI, have provided additional insight into the anatomic and functional underpinnings of OSA-related cognitive impairment. Both animal and human studies have looked to elucidate the separate effects of oxygen desaturation and sleep fragmentation on independent aspects of cognition. Data from animal models point to neuro-inflammation and oxidative stress as driving factors of cognitive impairment.

Chronic Intermittent Hypoxia Induces Chronic Low-Grade Neuroinflammation in the Dorsal Hippocampus of Mice

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) induces cognitive impairment that involves intermittent hypoxia (IH). Because OSA is recognized as a low-grade systemic inflammatory disease and only some patients develop cognitive deficits, we investigated whether IH-related brain consequences shared similar pathophysiology and required additional factors such as systemic inflammation to develop.

DESIGN

Nine-week-old male C57BL/6J mice were exposed to 1 day, 6 or 24 w of IH (alternating 21-5% FiO2 every 30 sec, 8 h/day) or normoxia. Microglial changes were assessed in the functionally distinct dorsal (dH) and ventral (vH) regions of the hippocampus using Iba1 immunolabeling. Then the study concerned dH, as vH only tended to be lately affected. Seven proinflammatory and anti-inflammatory cytokine messenger RNA (mRNA) were assessed at all time points using semiquantitative real-time reverse transcription polymerase chain reaction (RT-PCR). Similar mRNA analysis was performed after 6 w IH or normoxia associated for the past 3 w with repeated intraperitoneal low-dose lipopolysaccharide or saline.

MEASUREMENTS AND RESULTS

Chronic (6, 24 w) but not acute IH induced significant microglial changes in dH only, including increased density and morphological features of microglia priming. In dH, acute but not chronic IH increased IL-1β and RANTES/CCL5 mRNA, whereas the other cytokines remained unchanged. In contrast, chronic IH plus lipopolysaccharide increased interleukin (IL)-6 and IL10 mRNA whereas lipopolysaccharide alone did not affect these cytokines.

CONCLUSION

The obstructive sleep apnea component intermittent hypoxia (IH) causes low-grade neuroinflammation in the dorsal hippocampus of mice, including early but transient cytokine elevations, delayed but long-term microglial changes, and cytokine response alterations to lipopolysaccharide inflammatory challenge. These changes may contribute to IH-induced cognitive impairment and pathological brain aging.

Sleep-disordered breathing in dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common form of dementia, and it is very frequently associated with changes in sleep patterns. To date, the literature has focused mainly on REM sleep behavior as the most prominent sleep disorder in DLB while little is known about the prevalence and the impact of sleep-disordered breathing (SDB) in DLB. Clinicians should be aware that the clinical diagnosis of SDB in DLB is difficult to establish and that the risk of overlooking SDB in patients with DLB is substantial. Polysomnographic sleep investigations may therefore be advisable in patients with DLB in order to objectify their sleep respiratory patterns. The available literature data on this topic, which are very limited and based on small case series, indicate that SDB occurs in 34.8 to 60% of patients with DLB. SDB can be hypothesized to coexist with other sleep-related disorders in an interactive loop: SDB alters sleep continuity, which can in turn facilitate nocturnal and daytime vigilance-dependent phenomena. There is an absolute need for prospective, preferably multi-center, controlled trials to establish whether, and to what extent, SDB might affect neuropsychological performances in patients with DLB and whether its treatment can improve residual daytime functioning in these patients.

Obstructive sleep apnea: acute effects of CPAP on polyssonographic variables

Introduction The use of non-invasive ventilation in the form of continuous positive airway pressure (CPAP) is among the main therapeutic options for patients with obstructive sleep apnea (OSA). Yet the effects of CPAP obtained on the first night of use are underreported. Objective To evaluate the acute effects of CPAP on polysomnographic variables in patients with OSA. Materials and methods This study is a case series with 31 patients (55.8 ± 11.4 years; 22 men) in the initial phase of CPAP treatment. The subjects were evaluated by means of polysomnography with and without CPAP (10.2 ± 3.1 cmH2O) and without CPAP, on different days, by means of the following variables: sleep stages 1, 2 and 3 (N1, N2 and N3), rapid eye movement (REM) sleep, apnea and hypopnea index (AHI), AHI in REM sleep (AHIREM) and the micro-arousal index (MAI). Results The use of CPAP resulted in a reduction of N2 (p < 0.001), AHI (p < 0.001), AHIREM (p < 0.001) and MAI (p = 0.001). There was an increase in N3 (p = 0.006) and REM sleep (p < 0.001) during the night with use of CPAP. Conclusion This study demonstrated that, from the first night of use by patients with OSA, CPAP promotes greater balance between sleep phases, and improves sleep quality. These results should be presented to patients and their families in order to encourage greater adherence in the initial phase of treatment with CPAP.

Desperately seeking grey matter volume changes in sleep apnea: A methodological review of magnetic resonance brain voxel-based morphometry studies

Cognitive impairment related to obstructive sleep apnea might be explained by subtle changes in brain anatomy. This has been mainly investigated using magnetic resonance brain scans coupled with a voxel-based morphometry analysis. However, this approach is prone to several methodological pitfalls that may explain the large discrepancy in the results reported in the literature. We critically reviewed twelve papers addressing grey matter volume modifications in association with obstructive sleep apnea. Finally, based on strict methodological criteria, only three studies reported robust, but conflicting, results. No clear evidence has emerged and exploring brain alteration due to obstructive sleep apnea should thus be considered as an open field. We provide recommendations for designing additional robust voxel-based morphometry studies, notably the use of larger cohorts, which is the only way to solve the underpowered issue and the underestimated role of confounders in neuroimaging studies.

Obstructive sleep apnea and psychiatric disorders: a systematic review

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been associated with psychiatric pathology. Psychiatric comorbidity in OSA may affect patient quality of life and adherence to CPAP. A focused evaluation of OSA in highly selected groups of primarily psychiatric patients may provide further insights into the factors contributing to comorbidity of OSA and psychopathology. The goal of this study is to examine the prevalence and treatment of OSA in psychiatric populations.

METHODS

A systematic review following the PRISMA guidelines was conducted to determine the prevalence of OSA in schizophrenia and other psychotic disorders, mood disorders, and anxiety disorders, and to examine potential interventions. The PubMed, EMBASE, and PsycINFO databases were searched (last search April 26, 2014) using keywords based on the ICD-9-CM coding for OSA and the DSM-IV-TR diagnostic groups.

RESULTS

The search retrieved 47 records concerning studies of OSA in the selected disorders. The prevalence studies indicate that there may be an increased prevalence of OSA in individuals with major depressive disorder (MDD) and posttraumatic stress disorder (PTSD), despite considerable heterogeneity and a high risk of bias. There was insufficient evidence to support increased OSA in schizophrenia and psychotic disorders, bipolar and related disorders, and anxiety disorders other than PTSD. Studies of treatment of OSA indicate an improvement in both OSA and psychiatric symptoms. CPAP adherence was reduced in veterans with PTSD.

CONCLUSIONS

OSA prevalence may be increased in MDD and PTSD. In individuals with OSA and psychiatric illness, treatment of both disorders should be considered for optimal treatment outcomes.

Cognitive dysfunction in type 2 diabetes patients accompanied with obstructive sleep apnea syndrome

OBJECTIVE

To investigate cognitive dysfunction of type 2 diabetes patients accompanied with obstructive sleep apnea syndrome (OSAS), and to analyze its relevant characteristics.

METHODS

Total 115 type 2 diabetes patients were divided into OSAS group (O group, n=83) and non-OSAS group (N group, n=32); Physical examination patients (C1 group, n=64) and OSAS patients without diabetes (C2 group, n=47) served as the control group. Apnea-hypopnea index (AHI), nocturnal lowest saturation of pulse oxygen (LSPO2) and simple mental state examination scale (MMSE) were evaluated.

RESULTS

Among diabetes patients, patients with OSAS have lower glycated hemoglobin, platelet count, thrombocytocrit, MMSE score and lowest mean arterial oxygen than non-OSAS patients; cognitive dysfunction state and glycemic control of patients are related to their diabetic duration, and then along with increase of diabetic duration, glycemic control becomes poor, so that cognitive dysfunction becomes more and more obvious.

CONCLUSION

Along with increased diabetic duration in type 2 diabetes accompanied with OSAS, glycemic control becomes poor, so that cognitive dysfunction more easily occurs. Meanwhile, coagulation function of blood system in OSAS patients with diabetes is impacted to some extent.

Cognitive impairment in obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterised by repetitive cessation or reduction of airflow due to upper airway obstructions. These respiratory events lead to chronic sleep fragmentation and intermittent hypoxemia. Several studies have shown that OSA is associated with daytime sleepiness and cognitive dysfunctions, characterized by impairments of attention, episodic memory, working memory, and executive functions. This paper reviews the cognitive profile of adults with OSA and discusses the relative role of altered sleep and hypoxemia in the aetiology of these cognitive deficits. Markers of cognitive dysfunctions such as those measured with waking electroencephalography and neuroimaging are also presented. The effects of continuous positive airway pressure (CPAP) on cognitive functioning and the possibility of permanent brain damage associated with OSA are also discussed. Finally, this paper reviews the evidence suggesting that OSA is a risk factor for developing mild cognitive impairment and dementia in the aging population and stresses the importance of its early diagnosis and treatment.

Occupational health of patients with obstructive sleep apnea syndrome: a systematic review

PURPOSE

The aim of this systematic literature review was to assess the impact of obstructive sleep apnea syndrome (OSAS) on patients' occupational health.

METHODS

We selected 19 studies that dealt with issues related to job performance and productivity, absenteeism, and psychosocial health of patients with OSAS and assessed the risk of bias in their conclusions.

RESULTS

Although methodologically rigorous studies are needed to confirm these findings, the results obtained suggest the existence of multiple relationships between OSAS and work limitations of patients (i.e., difficulties maintaining attention, learning new tasks, or performing monotonous tasks). The studies reviewed reached more scientifically consistent conclusions about such patients' risk of taking more days of sick leave or having work disability, particularly if they reported excessive daytime sleepiness. Very few studies have explored the relationship between OSAS and psychosocial occupational health of patients. Thus, there is a need for research to clarify these aspects of occupational medicine.

CONCLUSIONS

OSAS has numerous effects on patients' occupational health, yet, in general, results should be confirmed by studies with sufficiently large samples in which OSAS is diagnosed with reliable methods and occupational variables are assessed with standardized and validated questionnaires.

The relationship between CPAP usage and corneal thickness

The purpose of this study was to determine whether there is a correlation between CPAP usage and corneal thickness in patients with sleep disordered breathing. Full-night polysomnography (PSG) recordings were collected. Ten patients had undergone PSG recordings with continuous positive airway pressure (CPAP), and seven patients had undergone PSG recordings without CPAP. We measured corneal thickness by ultrasonic pachymeter before sleep and ten minutes after waking. We also measured visual acuity with a routine ophthalmologic eye chart before and after sleep. We asked patients to fill out a post-sleep questionnaire to get their subjective opinions. In the without-CPAP group, corneal thickness increased significantly during sleep in both eyes (left, p = 0.0025; right, p<0.0001). In the with-CPAP group, corneal thickness did not increase significantly (p>0.05 for both left and right cornea). There was no significant difference in visual acuity tests (p>0.05 for both left and right eye) between the two groups. According to our results, there is a significant increase in corneal thickness in the without-CPAP group. Our data show that a low percentage of Rapid Eye Movement (REM) sleep may cause an increase in corneal thickness, which can indicate poor corneal oxygenation. In fact, many sleep-disordered breathing (SDB) patients have low REM. Since a contact lens may cause low corneal oxygenation, SDB patients with contact lenses should be monitored carefully for their corneal thickness.

Executive dysfunction in children affected by obstructive sleep apnea syndrome: an observational study

INTRODUCTION

The role of sleep in cognitive processes can be considered clear and well established. Different reports have disclosed the association between sleep and cognition in adults and in children, as well as the impact of disturbed sleep on various aspects of neuropsychological functioning and behavior in children and adolescents. Behavioral and cognitive dysfunctions can also be considered as related to alterations in the executive functions (EF) system. In particular, the EF concept refers to self-regulatory cognitive processes that are associated with monitoring and controlling both thought and goal directed behaviors. The aim of the present study is to assess the impact of the obstructive sleep apnea syndrome (OSAS) on EF in a large sample of school aged children.

MATERIALS AND METHODS

The study population comprised 79 children (51 males and 28 females) aged 7-12 years (mean 9.14 ± 2.36 years) with OSAS and 92 healthy children (63 males and 29 females, mean age 9.08 ± 2.44 years). To identify the severity of OSAS, an overnight respiratory evaluation was performed. All subjects filled out the Italian version of the Modified Card Sorting Test to screen EFs. Moreover, to check the degree of subjective perceived daytime sleepiness, all subjects were administered the Pediatric Daytime Sleepiness Scale (PDSS).

RESULTS

No significant differences between the two study groups were found for age (P = 0.871), gender (P = 0.704), z-score of body mass index (P = 0.656), total intelligence quotient (P = 0.358), and PDSS scores (P = 0.232). The OSAS children showed a significantly higher rate of total errors (P < 0.001), perseverative errors (P < 0.001), nonperseverative errors (P < 0.001), percentage of total errors (P < 0.001), percentage of perseverative errors (P < 0.001), and percentage of nonperseverative errors (P < 0.001). On the other hand, OSAS children showed a significant reduction in the number of completed categories (P = 0.036), total correct sorts (P = 0.001), and categorizing efficiency (P < 0.001). The Pearson's correlation analysis revealed a significant positive relationship between all error parameters and apnea-hypopnea index, oxygen desaturation index, and percentage of mean desaturation of O2 with a specular negative relationship between the error parameters and the mean oxygen saturation values, such as a significant negative relationship between apnea-hypopnea index, oxygen desaturation index, percent of mean desaturation of O2, and the number of completed categories.

CONCLUSION

Our study identified differences in the executive functioning of children affected by OSAS and is the first to identify a correlation between alteration in respiratory nocturnal parameters and EF that has not yet been reported in developmental age. These findings can be considered as the strength and novelty of the present report in a large pediatric population.