The potential link between obstructive sleep apnea and postoperative neurocognitive disorders: current knowledge and possible mechanisms.

PURPOSE: This narrative review examines the current evidence on whether obstructive sleep apnea (OSA) is associated with postoperative delirium (POD) and postoperative cognitive dysfunction (POCD). The mechanisms that could predispose OSA patients to these disorders are also explored. SOURCE: Relevant literature was identified by searching for pertinent terms in Medline®, Pubmed, ScopusTM, and Google scholar databases. Case reports, abstracts, review articles, original research articles, and meta-analyses were reviewed. The bibliographies of retrieved sources were also searched to identify relevant papers. PRINCIPAL FINDINGS: Seven studies have investigated the association between OSA and POD, with mixed results. No studies have examined the potential link between OSA and POCD. If these relationships exist, they could be mediated by several mechanisms, including increased neuroinflammation, blood-brain barrier breakdown, cerebrovascular disease, Alzheimer's disease neuropathology, disrupted cerebral autoregulation, sleep disruption, sympathovagal imbalance, and/or disrupted brain bioenergetics. CONCLUSION: There is very limited evidence that OSA plays a role in postoperative neurocognitive disorders because few studies have been conducted in the perioperative setting. Additional perioperative prospective observational cohort studies and randomized controlled trials of sleep apnea treatment are needed. These investigations should also assess potential underlying mechanisms that could predispose patients with OSA to postoperative neurocognitive disorders. This review highlights the need for more research to improve postoperative neurocognitive outcomes for patients with OSA.

RéSUMé: OBJECTIF: Ce compte rendu narratif examine les données probantes actuelles quant à l'association entre l'apnée obstructive du sommeil (AOS) et le syndrome confusionnel postopératoire (SCPO) ainsi que le dysfonctionnement cognitif postopératoire (DCPO). Les mécanismes qui pourraient prédisposer les patients atteints d'AOS à ces troubles sont également explorés. SOURCES: La littérature concordante a été identifiée en recherchant des termes pertinents dans les bases de données Medline®, Pubmed, ScopusTM et Google Scholar. Les présentations de cas, résumés, articles de synthèse, articles de recherche originaux et méta-analyses ont été examinés. Les bibliographies des sources récupérées ont également été recherchées pour identifier les articles pertinents. CONSTATATIONS PRINCIPALES: Sept études ont examiné l'association entre l'AOS et le SCPO, avec des résultats mitigés. Aucune étude n'a exploré le lien potentiel entre l'AOS et le DCPO. Si ces relations existent, elles pourraient être médiées par plusieurs mécanismes, notamment une neuroinflammation accrue, une dégradation de la barrière hémato-encéphalique, une maladie cérébrovasculaire, une neuropathologie de la maladie d'Alzheimer, une autorégulation cérébrale perturbée, une perturbation du sommeil, un déséquilibre sympathovagal et / ou une bioénergétique cérébrale perturbée. CONCLUSION: Il existe très peu de données probantes soutenant que l'AOS joue un rôle dans les troubles neurocognitifs postopératoires parce que peu d'études ont été menées dans le contexte périopératoire. D'autres études de cohorte observationnelles prospectives périopératoires et des études randomisées contrôlées sur le traitement de l'apnée du sommeil sont nécessaires. Ces études devraient également évaluer les mécanismes sous-jacents potentiels qui pourraient prédisposer les patients atteints d'AOS à des troubles neurocognitifs postopératoires. Ce compte rendu souligne la nécessité de recherches supplémentaires pour améliorer les devenirs neurocognitifs postopératoires des patients atteints d'AOS.

Predictors of moderate to severe obstructive sleep apnea: identification of sex differences.

PURPOSE: Home sleep apnea tests are recommended only for patients at high risk of moderate to severe obstructive sleep apnea (OSA, apnea-hypopnea index [AHI] ≥ 15/h). We evaluated 14 factors known to be associated with OSA and identified sex differences in predictors of moderate to severe OSA. METHODS: Retrospective analysis was done on 545 subjects who completed sleep questionnaires and underwent diagnostic polysomnogram at a tertiary sleep center. Univariate and multivariate analysis was conducted separately in males and females to determine which variables were independent predictors of moderate to severe OSA. RESULTS: Overall, physical traits were stronger predictors in both males and females. For each sex, only 3 variables were found to be independently predictive of moderate to severe OSA. In order of predictive strength, this included body mass index (BMI) ≥ 38 kg/m2 (aOR 5.80, p < 0.001), neck circumference (NC) ≥ 17 in. (aOR 2.52, p = 0.002), and Epworth sleepiness scale (ESS) ≥ 13 (aOR 2.22, p = 0.015) for males and age ≥ 50 years (aOR 4.19, p < 0.001), NC ≥ 14.5 in. (aOR 3.13, p = 0.003), and report of morning headaches (aOR 2.00, p = 0.039) for females. Applying the Bonferroni correction, BMI and NC remained significant for males, and age and NC remained significant for females. CONCLUSIONS: In a subject population referred for sleep evaluation at a tertiary care center only a few variables are independently predictive of moderate to severe OSA, and these variables differed between males and females. Only BMI, NC, and a high ESS were independently predictive of moderate to severe OSA in males, whereas age, NC, and morning headaches were independently predictive in females.

Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement.

The period of the year from spring to fall, when clocks in most parts of the United States are set one hour ahead of standard time, is called daylight saving time, and its beginning and ending dates and times are set by federal law. The human biological clock is regulated by the timing of light and darkness, which then dictates sleep and wake rhythms. In daily life, the timing of exposure to light is generally linked to the social clock. When the solar clock is misaligned with the social clock, desynchronization occurs between the internal circadian rhythm and the social clock. The yearly change between standard time and daylight saving time introduces this misalignment, which has been associated with risks to physical and mental health and safety, as well as risks to public health. In 2020, the American Academy of Sleep Medicine (AASM) published a position statement advocating for the elimination of seasonal time changes, suggesting that evidence best supports the adoption of year-round standard time. This updated statement cites new evidence and support for permanent standard time. It is the position of the AASM that the United States should eliminate seasonal time changes in favor of permanent standard time, which aligns best with human circadian biology. Evidence supports the distinct benefits of standard time for health and safety, while also underscoring the potential harms that result from seasonal time changes to and from daylight saving time. CITATION: Rishi MA, Cheng JY, Strang AR, et al. Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2024;20(1):121-125.

Non-REM Sleep Parasomnias.

OBJECTIVE: Non-rapid eye movement (non-REM) parasomnias are common across the lifespan. This article describes the manifestations, diagnosis, and management of non-REM parasomnias in adults and discusses the social implications of these conditions. LATEST DEVELOPMENTS: Non-REM parasomnias represent a hybrid state of wakefulness and sleep, often triggered by events that increase the frequency of arousals or make it more difficult to fully arouse from sleep. Sleep deprivation, certain medications, and untreated obstructive sleep apnea are known to provoke parasomnias, particularly in those who are genetically predisposed. Non-REM parasomnias include disorders of arousal (ie, sleepwalking, sleep terrors, and confusional arousals), sleep-related eating disorder, and exploding head syndrome. Clinical overlap exists between sleep-related eating disorder and disorders of arousal, suggesting that sleep-related eating disorder may be a fourth disorder of arousal or a manifestation of sleepwalking. Exploding head syndrome is a unique parasomnia of uncertain etiology. ESSENTIAL POINTS: Non-REM parasomnias can range from minor nuisances to severe, life-altering events. While some patients with non-REM parasomnia experience significant consequences during sleep, wakefulness, or both, non-REM parasomnias do not pose a major risk to most patients. For all patients with non-REM parasomnias, safety should be explicitly discussed and addressed. Nonpharmacologic treatment should be prioritized, as increasing total sleep time, avoiding triggering substances, and treating comorbid sleep disorders is often sufficient for the management of non-REM parasomnias. If symptoms persist despite these interventions, treatment with clonazepam or other medications can be considered.

A Concise Review of Polysomnography and Obstructive Sleep Apnea for the Neurophysiologist.

SUMMARY: Sleep as an electrical phenomenon in the brain was first recorded in 1875. Over the next 100 years, recordings of sleep evolved into modern-day polysomnography, which includes not only electroencephalography but also combinations of electro-oculography, electromyography, nasal pressure transducers, oronasal airflow monitors, thermistors, respiratory inductance plethysmography, and oximetry. The most common usage of polysomnography is to identify obstructive sleep apnea (OSA). Research has demonstrated that subjects with OSA have distinctive patterns detected by EEG. The evidence indicates that increased slow activity is seen in both sleep and wake for subjects with OSA and that these changes are reversible with treatment. This article reviews normal sleep, changes in sleep that result from OSA, and the effect that treatment of OSA via continuous positive airway pressure therapy has on normalizing the EEG. A review of alternative OSA treatment options is included, although their effects on EEG in OSA patients have not been studied.

A sleep clinician's guide to runny noses: evaluation and management of chronic rhinosinusitis to improve sleep apnea care in adults.

STUDY OBJECTIVES: The treatment of obstructive sleep apnea is often impeded by intolerance of positive airway pressure therapy, which is frequently attributed to the inability to breathe through the nose. Providers caring for patients with sleep apnea need a working knowledge of nasal passage disease and available treatments to better manage this common comorbidity. METHODS: This review examines the literature connecting rhinosinusitis to adverse sleep and sleep apnea outcomes. It explores the different types of nasal and sinus diseases a sleep apnea provider might encounter, focusing on the medications used to treat them and indications for referral to otolaryngology. RESULTS: Chronic rhinosinusitis can be either allergic or nonallergic. Both types can interfere with sleep and sleep apnea therapy. The successful management of chronic rhinosinusitis can improve positive airway pressure tolerance and adherence. A wide range of over-the-counter and prescription pharmacotherapy is available, with data supporting intranasal over oral treatment. Surgical treatment for chronic rhinosinusitis in obstructive sleep apnea addresses nasal obstruction, often with inferior turbinate reduction and septoplasty. CONCLUSIONS: Sleep specialists should have a working knowledge of the available options to treat chronic rhinosinusitis. These options are often safe, effective, and readily accessible. Otolaryngologists and allergists/immunologists provide additional treatment options for more complicated patients. Providing treatment for chronic rhinosinusitis should be included as part of comprehensive sleep apnea care. CITATION: Ali MM, Ellison M, Iweala OI, Spector AR. A sleep clinician's guide to runny noses: evaluation and management of chronic rhinosinusitis to improve sleep apnea care in adults. J Clin Sleep Med. 2023;19(8):1545-1552.

Anatomy of disturbed sleep in pallido-ponto-nigral degeneration.

OBJECTIVE: Pallido-ponto-nigral degeneration (PPND), caused by an N279K mutation of the MAPT gene, is 1 of a family of disorders collectively referred to as frontotemporal dementia and parkinsonism linked to chromosome 17. This study aims to characterize the nature of the sleep disturbance in PPND and compare these findings to those in other progressive neurological illnesses. Pathological findings are also provided. METHODS: Ten subjects were recruited from the PPND kindred; 5 affected and 5 unaffected. The subjects underwent clinical assessment, polysomnography, and wrist actigraphy. Available sleep-relevant areas (pedunculopontine/laterodorsal tegmentum, nucleus basalis of Meynert, thalamus, and locus ceruleus) of affected subjects were analyzed postmortem. RESULTS: The affected group's total sleep time was an average of 130.8 minutes compared to 403.6 minutes in the control group (p < 0.01). Initial sleep latency was significantly longer in affected subjects (range, 58-260 minutes vs 3-34 minutes). Affected subjects also had an increase in stage I sleep (8.5% vs 1%), and less stage III/IV sleep (8.5% vs 17%). At the time of autopsy, all cases had severe neuronal tau pathology in wake-promoting nuclei, as well as decreases in thalamic cholinergic innervations. There was no difference in orexinergic fiber density in nucleus basalis of Meynert or locus ceruleus compared to controls. INTERPRETATION: The PPND kindred showed severe sleep disturbance. Sleep abnormalities are common in neurodegenerative illnesses, but this is the first study of sleep disorders in PPND. Unlike most neurodegenerative conditions, PPND is characterized by decreased total sleep time, increased sleep latency, and decreased sleep efficiency, without daytime hypersomnolence.

Neurological interest and career exploration among black medical students: Perceptions and solutions for the pipeline.

PURPOSE: The goal of this study was to identify factors that influence the selection of Neurology as a career choice for Black medical students. METHODS: Survey data was collected from attendees at a national educational conference and at a large academic medical school. Two proportion z-tests were used to assess responses among students of different racial/ethnic backgrounds. RESULTS: 199 students participated in the survey. Compared to their Asian and White counterparts, Black students were significantly less likely to choose or consider a career in Neurology. In addition, we found that these students relied more heavily on their pre-clinical experiences to make this determination, citing preference for another specialty, lack of exposure, a preference for a different patient population, and a lack of racial/ethnic diversity as key reasons to not choose a career in Neurology. CONCLUSIONS: Neurological disorders are important contributors to morbidity and mortality. It is imperative that the field attract medical students toward careers in Neurology, particularly those students from traditionally and persistently underrepresented backgrounds. Our findings suggest that Black medical students consider Neurology as a specialty choice less frequently than their counterparts do, and this decision may be made prior to training. We conclude that a multifaceted approach is best to improve the racial/ethnic diversity within the neurological workforce, which should include targeted interventions prior to and after matriculation to medical school.

Developing the Neurology Diversity Officer: A Roadmap for Academic Neurology Departments.

Academic Neurology Departments must confront the challenges of developing a diverse workforce, reducing inequity and discrimination within academia, and providing neurologic care for an increasingly diverse society. A neurology diversity officer should have a specific role and associated title within a neurology department as well as a mandate to focus their efforts on issues of equity, diversity and inclusion that affect staff, trainees and faculty. This role is expansive and works across departmental missions but it has many challenges related to structural intolerance and cultural gaps. In this review, we describe the many challenges that diversity officers face and how they might confront them. We delineate the role and duties of the neurology diversity officer and provide a guide to departmental leaders on how to assess qualifications and evaluate progress. Finally, we describe the elements necessary for success. A neurology diversity officer should have the financial, administrative and emotional support of leadership in order for them to carry out their mission and to truly have a positive influence.

Obstructive sleep apnea in late-onset Pompe disease treated by enzyme replacement therapy.

Obstructive sleep apnea is a common complication of Pompe disease. Treatment for obstructive sleep apnea in patients with Pompe disease is similar to treatment in the general population, typically involving positive airway pressure therapy. We present a case in which a patient with late-onset Pompe disease was able to discontinue positive airway pressure therapy after treatment with enzyme replacement therapy for his Pompe disease. It is likely that an improvement in muscle tone from the enzyme replacement therapy was sufficient to eliminate his obstructive sleep apnea. Pharmacological therapies for obstructive sleep apnea are lacking but could apply to certain populations, such as Pompe disease.

Qualifying Patients for Noninvasive Positive Pressure Ventilation Devices on Hospital Discharge.

When and how do I qualify inpatients with acute on chronic hypercapnic respiratory failure for home noninvasive positive-pressure ventilation at the time of discharge? A 44-year-old woman with morbid obesity (BMI, 48) was brought to the hospital by her boyfriend for 1 day of confusion and reduced alertness. She had a history of chronic dyspnea on exertion and 10-pack-years of smoking. She also had history of well-treated diabetes and hypertension. In the ER, she was found to be somnolent but arousable and following commands appropriately. Her oxygen saturation was 86% on room air, and arterial blood gases indicated a pH of 7.16 with a Paco2 of 87 mm Hg, a Pao2 of 60 mm Hg, and a bicarbonate of 42 mEq/L. Chest radiograph showed mild pulmonary vascular congestion. She was started on continuous bilevel positive airway pressure and medical therapy, with clinical improvement.

The stroke that struck back: an unusual alien hand presentation.

Alien hand syndrome is a rare condition that can result from neurodegenerative disorders, tumors, or strokes. We encountered an acute presentation of alien hand syndrome from a right parietal ischemic stroke. The condition was not recognized by the emergency department, delaying diagnosis and appropriate treatment. Early recognition of unusual manifestations of stroke, such as an acute alien hand syndrome, can lead to timely diagnosis and therapy.

Reducing Reliance on Test Scores Reduces Racial Bias in Neurology Residency Recruitment.

PURPOSE: We sought to correct a low interview rate for racial groups underrepresented in medicine (URM) by analyzing our interview selection process, identifying sources of unintended bias, and developing a new process that would provide a more racially diverse interview pool. METHODS: We analyzed our review process to determine at which point we were eliminating URM candidates at a higher rate than those who are not from an underrepresented group. A point system was created incorporating clinical grades, extracurricular activities, research, letters of recommendation, board exam scores, and life experiences. We compared the rate at which interviews were offered to URM candidates and compared those rates to historical data. We then analyzed the new process by comparing groups who were offered interviews to those who were not. RESULTS: In 2016, 56% of URM applicants were screened out by a mandatory minimum United States Medical Licensing Examination (USMLE) test score, whereas only 39% of all other groups were disqualified by test scores. This led to 20% of the URM applicants receiving interview offers. By comparison, 30.6% of other groups were offered interviews. After removing the required minimum test score for application review and modifying the screening process to a more holistic one the following application cycle, 24.5% of URMs were offered interviews in 2017 compared to 28.1% of others. CONCLUSIONS: A comprehensive review of applications that minimizes emphasis on USMLE step 1 scores substantially reduced the difference between the percentages of URMs and those of other racial backgrounds who were offered interviews for a Neurology residency.

The Clinical Significance of Apneas Versus Hypopneas: Is There Really a Difference?

Introduction Obstructive sleep apnea is diagnosed by identifying obstructive apneas and hypopneas, but no study has shown that it is necessary to distinguish these events from each other. Our goal was to analyze results from polysomnograms to determine if adverse health outcomes were more likely in patients with higher apnea indices relative to their hypopnea indices. Our hypothesis was that scoring apneas separately from hypopneas has no predictive value. Methods A retrospective case series was performed for consecutive diagnostic and split-night polysomnograms with apnea-hypopnea indices greater than five per hour. Clinical data reviewed included the presence of cardiovascular diseases, hypertension, depression, and migraine. Both univariate and multivariate analyses were performed to look for correlations between polysomnographic indices and the comorbidities. Results Three hundred fifty-one records were included. Univariate analysis showed no significant difference between the apnea index (AI) and hypopnea index (HI) based on the presence of any of the comorbidities. Multivariate logistic regression also indicated no significant association between indices and comorbidities, aside from one statistically significant correlation between a higher HI and depression. Conclusions Clinical comorbidities are no more likely in patients with higher apnea indices than hypopnea indices. While apneas are considered a more severe form of obstruction, this distinction does not have any known clinically predictive value. This finding raises the question as to whether scoring hypopneas and apneas as different events on polysomnograms is necessary or helpful. Scoring apneas and hypopneas as "obstructions" could save resources and increase inter-scorer reliability.

Emergency Neurology Oral Cases for Trainee Assessment and Education.

OBJECTIVES: Neurological emergencies comprise much of neurology residency, but there may be a lack of clinical experience. For our program, oral examinations have been used to assess resident readiness for additional clinical independence. In this study, we examined the perceptions of learners and examiners of oral case examinations. METHODS: Six attending physicians administered case-based oral examinations to 8 trainees. Each case involved a chief complaint and progressed through a clinical encounter. Following the examination, each attending physician and trainee completed an online 5-point Likert scale survey of content and educational value. Statistical analysis of point assignment based on Likert scale responses was performed. RESULTS: Six attendings (100% response) and 7 trainees (87.5% response) completed the assessment. The trainees assessed all 6 cases. Residents had negative responses for 3 cases with specific concern in "feedback" and "learning experience." Residents responded with less positive response than attendings for "The case is easy to understand and progressed in a logical fashion" (3.90 for residents vs. 4.83 attendings; P=0.015) and "The case complexity is appropriate for level of training" (4.14 vs. 4.83; P=0.033). Attendings noted better understanding of trainees thought processes following oral examinations. Trainees noted feedback as the most useful component of case-based assessments. CONCLUSIONS: Case-based assessment in neurology training allows for rapid evaluation of trainees' abilities to critically think. There is general agreement from attendings and trainees that case-based assessment is a useful and positive learning tool. The responses from this survey are being used to modify the cases for future examinations.

Phrenic Nerve Stimulation for the Treatment of Central Sleep Apnea: A Pooled Cohort Analysis.

STUDY OBJECTIVES: Early evidence with transvenous phrenic nerve stimulation (PNS) demonstrates improved disease severity and quality of life (QOL) in patients with central sleep apnea (CSA). The goal of this analysis is to evaluate the complete prospective experience with PNS in order to better characterize its efficacy and safety, including in patients with concomitant heart failure (HF). METHODS: Using pooled individual data from the pilot (n = 57) and pivotal (n = 151) studies of the remede System in patients with predominant moderate to severe CSA, we evaluated 12-month safety and 6- and 12-month effectiveness based on polysomnography data, QOL, and cardiac function. RESULTS: Among 208 combined patients (June 2010 to May 2015), a remede device implant was successful in 197 patients (95%), 50/57 pilot study patients (88%) and 147/151 pivotal trial patients (97%). The pooled cohort included patients with CSA of various etiologies, and 141 (68%) had concomitant HF. PNS reduced apnea-hypopnea index (AHI) at 6 months by a median of -22.6 episodes/h (25th and 75th percentile; -38.6 and -8.4, respectively) (median 58% reduction from baseline, P < .001). Improvement in sleep variables was maintained through 12 months of follow-up. In patients with HF and ejection fraction ≤ 45%, PNS was associated with improvement in systolic function from 27.0% (23.3, 36.0) to 31.1% (24.0, 41.5) at 12 months (P = .003). In the entire cohort, improvement in QOL was concordant with amelioration of sleep measures. CONCLUSIONS: Transvenous PNS significantly improves CSA severity, sleep quality, ventricular function, and QOL regardless of HF status. Improvements, which are independent of patient compliance, are sustained at 1 year and are associated with acceptable safety.

Treatment of Trigeminal Neuralgia with Anti-viral Therapy for Zoster: A Case Report.

Varicella zoster virus can infect the trigeminal ganglion, but viral infection is not frequently considered as a cause of trigeminal neuralgia. This is a case of a woman whose trigeminal neuralgia remitted after being treated with valacyclovir for a thoracic zoster rash and later resolved entirely following administration of the zoster vaccine. Successful treatment of trigeminal neuralgia with anti-viral therapies has not previously been reported. Zoster vaccination is currently recommended for adults over age 60, so patients with trigeminal neuralgia, especially those over the age of 60, should be encouraged to receive the varicella zoster vaccine.