Systematic review of the literature regarding the diagnosis of sleep apnea

Nocturnal Urinary Symptoms as Screening Tools for Obstructive Sleep Apnea

IMPORTANCE

Nocturnal lower urinary tract symptoms are part of obstructive sleep apnea (OSA), and urogynecology clinics may serve as OSA screening sites.

OBJECTIVE

This study's aim was to determine the accuracy of nocturia and nocturnal enuresis (NE) as screening tools for OSA in new patients at a urogynecology clinic.

STUDY DESIGN

Using a retrospective study design, we gathered information regarding diagnostic OSA testing, continuous positive airflow pressure use, and lower urinary tract symptoms improvement from women in a urogynecology clinic who were previously screened for OSA using validated questionnaires. Nocturia and NE were tested for sensitivity and specificity using positive OSA diagnosis by polysomnography as the gold standard.

RESULTS

Nocturia with a cutoff of ≥2 episodes per night had the best test characteristics-86.4% sensitivity (95% confidence interval [CI], 65.1-97.1) and 58.5% specificity (95% CI, 44.1-71.9) for an overall accuracy of 78.4% (95% CI, 67.0-89.8). Nocturnal enuresis with a cutoff of ≥1 episode per week had the best NE characteristics with 31.8% sensitivity (95% CI, 13.9-54.9) and 79.3% specificity (95% CI, 65.9-89.2) for an overall accuracy of 56.1% (95% CI, 41.2-71).

CONCLUSIONS

Lower urinary tract symptoms such as nocturia and NE are routinely assessed in urogynecology clinics, making them useful for OSA screening and referral. The present study found nocturia symptoms with ≥2 episodes per night to retain acceptable test characteristics in screening for OSA, whereas NE was found to have less acceptable test characteristics for OSA screening. Urogynecology clinics may utilize nocturia symptoms in clinical decision making for OSA referral.

NoSAS score predicts cardiovascular disease in patients with obstructive sleep apnea

PURPOSE

The Lausanne NoSAS (Neck circumference, Obesity, Snoring, Age, Sex) score is a new tool for the identification of high-risk patients for obstructive sleep apnea (OSA). Up to now, no study has attempted to determine the role of NoSAS score in cardiovascular morbidity of patients with OSA. We aimed to investigate the relationships between NoSAS scores and CVD and also between severity of OSA, polysomnographic parameters, and NoSAS scores in patients with OSA.

METHODS

Patients with diagnosis of OSA by full-night polysomnography were recruited in the study. Based on apnea-hypopnea index (AHI) scores, the patients were categorized as OSA-negative (AHI < 5), mild OSA (5 ≤ AHI < 15), moderate OSA (15 ≤ AHI < 30), and severe OSA (AHI ≥ 30). The definition of cardiovascular diseases (CVD) included the presence of any of the diseases such as hypertension, coronary artery disease, heart failure, or arrhythmia.

RESULTS

A total of 1514 patients including cases with 199 OSA-negative, 391 mild, 342 moderate, and 582 severe OSA were enrolled in the study. NoSAS scores were significantly different between mild, moderate, and severe OSA groups. NoSAS scores were negatively correlated with minimum oxygen saturation values and positively with AHI and ODI (oxygen desaturation index) values (P < 0.001). NoSAS scores were significantly higher in patients with CVD, diabetes mellitus, and cerebrovascular disease compared with those without (P < 0.005). NoSAS cut-off values for hypertension (14), congestive heart failure (8.5), coronary artery disease (9), cerebrovascular event (11), and diabetes mellitus (10) were also determined.

CONCLUSION

NoSAS scores are associated with CVD and the severity of OSA. NoSAS scores may be useful to predict CVD in patients with OSA.

OSA and Subsequent Risk of Hospitalization With Pneumonia, Respiratory Infection, and Total Infection: The Atherosclerosis Risk in Communities Study

BACKGROUND

OSA has been linked to microaspiration, systemic inflammation, and suboptimal immune function.

RESEARCH QUESTION

Is OSA prospectively associated with risk of hospitalization for pneumonia, respiratory, and total infections?

STUDY DESIGN AND METHODS

Prospective cohort. Participants in the Atherosclerosis Risk in Communities (ARIC) study (N = 1,586) underwent polysomnography in 1996-1998 and were followed up through 2018 for infection-related hospitalizations. The apnea-hypopnea index (AHI; events/h) was used to categorize participants as having severe OSA (≥ 30), moderate OSA (15-29), mild OSA (5-14), or a normal breathing pattern (< 5). Cox regression was used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

ARIC participants were on average 62.7 (SD = 5.5) years of age, and 52.8% were female. Severe OSA was present in 6.0%, moderate OSA in 12.7%, mild OSA in 30.0%, and normal breathing in 51.3%. A total of 253 hospitalizations with pneumonia occurred over a median 20.4 (max, 22.9) years' follow-up. Participants with severe OSA were at 1.87 times (95% CI, 1.19-2.95) higher risk of hospitalization with pneumonia compared with those with a normal breathing pattern after adjustment for demographics and lifestyle behaviors. Results were attenuated modestly after adjustment for BMI (1.62 [0.99-2.63]), and prevalent asthma and COPD (1.62 [0.99-2.63]). A similar pattern existed for hospitalization with respiratory infection and composite infection (demographic and behavior-adjusted HRs: 1.47 [0.96-2.25] and 1.48 [1.07-2.04], respectively).

INTERPRETATION

Severe OSA was associated with increased risk of hospitalizations with pneumonia in this community-based cohort. OSA patients may benefit from more aggressive efforts to prevent pneumonia and other infectious conditions.

The association between obstructive sleep apnea and lung nodule, carcinoembryonic antigen

PURPOSE

The association between obstructive sleep apnea (OSA) and cancer risks gaining more and more attention. Data on the association between OSA and lung cancer risk are limited. This study is to investigate whether a link exists between low-dose computed tomography (LDCT) scanning of the chest findings, carcinoembryonic antigen (CEA) and OSA in patients suspected of OSA.

METHODS

The cross-sectional study included patients aged 18 years or older who underwent continuous nocturnal polysomnography at our sleep center between February 2019 and November 2020. All subjects underwent chest LDCT and CEA. Patients with an apnea-hypopnea index (AHI) of ≥ 15/h were classified as clinically significant OSA group, whereas patients with an AHI < 15/h were classified as control group.

RESULTS

A total of 277 patients were enrolled in the study. 176 patients were categorized into the OSA group, while 101 patients were categorized into the control group. There is no relationship between any OSA-related parameter and presence of lung nodule or presence of ≥ 6 mm lung nodule in the binary logistic regression analysis. OSA group demonstrated a significant higher value of CEA than control group. Stepwise multiple linear regression analysis showed that lowest O₂ saturation (β = - 0.256, p < 0.001), smoking status (β = 0.156, p = 0.007) and age (β = 0.153, p = 0.008) were independent predictors of elevated CEA.

CONCLUSIONS

OSA was independently related to the elevated of serum CEA level, but not with presence of pulmonary nodule or ≥ 6 mm pulmonary nodule in LDCT. Further well-designed longitudinal studies with pathology available are needed to identify the association between OSA and risk of lung cancer.

Experimental study of the negative effects of raised bedroom temperature and reduced ventilation on the sleep quality of elderly subjects

This study investigated the effects of air temperature and ventilation on the sleep quality of elderly subjects and elucidated the mechanisms involved. Sixteen subjects aged over 65 years old were exposed to four conditions in a 2 × 2 design: air temperatures of 27°C and 30°C (with a ceiling fan in operation at 30°C) and two ventilation conditions (with and without mechanical ventilation) in experimental bedrooms. Their electroencephalogram, electrooculogram, chin electromyogram, electrocardiogram, respiration, oxygen saturation, and wrist skin temperature were measured continuously during sleep. Saliva samples were collected, and blood pressure was measured both before and after sleep. The results showed that at the temperature of 30°C, the total sleep time, sleep efficiency, and duration of REM sleep of the elderly decreased by 26.3 min, 5.5%, and 5.3 min, respectively, and time awake increased by 27.0 min, in comparison with 27°C, indicating that the sleep quality of the elderly is very vulnerable to heat exposure. Even a small heat load led to an overactive sympathetic nervous system and increased wrist skin temperature, which reduced sleep quality. Improving the ventilation increased the duration of deep sleep and REM sleep by 10.3 min and 3.7 min, respectively. Higher pollutant concentrations affected the respiration and autonomous nervous systems to reduce sleep quality. The benefits of improved thermal environment and ventilation on sleep quality were found to be additive. Good ventilation and the avoidance of raised temperatures in the bedroom are thus both important for the sleep quality of the elderly.

Diagnostic accuracy of screening questionnaires for obstructive sleep apnoea in adults in different clinical cohorts: a systematic review and meta-analysis

PURPOSE

The majority of individuals with clinically significant obstructive sleep apnoea (OSA) are undiagnosed and untreated. A simple screening tool may support risk stratification, identification, and appropriate management of at-risk patients. Therefore, this systematic review and meta-analysis evaluated and compared the accuracy and clinical utility of existing screening questionnaires for identifying OSA in different clinical cohorts.

METHODS

We conducted a systematic review and meta-analysis of observational studies assessing the diagnostic value of OSA screening questionnaires. We identified prospective studies, validated against polysomnography, and published to December 2020 from online databases. To pool the results, we used random effects bivariate binomial meta-analysis.

RESULTS

We included 38 studies across three clinical cohorts in the meta-analysis. In the sleep clinic cohort, the Berlin questionnaire's pooled sensitivity for apnoea-hypopnoea index (AHI) ≥ 5, ≥ 15, and ≥ 30 was 85%, 84%, and 89%, and pooled specificity was 43%, 30%, and 33%, respectively. The STOP questionnaire's pooled sensitivity for AHI ≥ 5, ≥ 15, and ≥ 30 was 90%, 90%, and 95%, and pooled specificity was 31%, 29%, and 21%. The pooled sensitivity of the STOP-Bang questionnaire for AHI ≥ 5, ≥ 15, and ≥ 30 was 92%, 95%, and 96%, and pooled specificity was 35%, 27%, and 28%. In the surgical cohort (AHI ≥ 15), the Berlin and STOP-Bang questionnaires' pooled sensitivity were 76% and 90% and pooled specificity 47% and 27%.

CONCLUSION

Among the identified questionnaires, the STOP-Bang questionnaire had the highest sensitivity to detect OSA but lacked specificity. Subgroup analysis considering other at-risk populations was not possible. Our observations are limited by the low certainty level in available data.

Development and validation of a model for diagnosis of obstructive sleep apnoea in primary care

BACKGROUND AND OBJECTIVE

Use of in-laboratory polysomnography (PSG) to diagnose obstructive sleep apnoea (OSA) is cost and resource intensive. Questionnaires, physical measurements and home monitors have been studied as potential simpler alternatives. This study aimed to develop a diagnostic model for OSA for use in primary care.

METHODS

Primary care practitioners were trained to recognize symptoms of sleep apnoea and recruited patients based on the clinical need to investigate OSA. Assessment was by symptom questionnaires, anthropomorphic measurements, digital facial photography, and a single-channel nasal flow monitor (Flow Wizard©, DiagnoseIT, Sydney, Australia) worn at home for 3 nights. The in-laboratory PSG was the reference test, with OSA defined as apnoea-hypopnoea index (AHI) ≥10 events/h.

RESULTS

In the model development phase, 25 primary care practitioners studied 315 patients in whom they suspected OSA, of which 57% had AHI≥10 and 22% had AHI≥30. Published OSA questionnaires provided low to moderate prediction of OSA (area under the curve [AUC] 0.53-0.73). The nasal flow monitor alone yielded high accuracy for predicting OSA with AUC of 0.87. Sensitivity was 0.87 and specificity 0.77 at a threshold respiratory event index (REI) of 18 events/h. A model adding age, gender, symptoms and BMI to the nasal flow monitor REI only modestly improved OSA prediction (AUC 0.89), with similar AUC (0.88) confirmed in the validation population of 114 patients.

CONCLUSION

Sleep apnoea can be diagnosed in the primary care setting with a combination of clinical judgement and portable monitor test outcomes.

Explainable fuzzy neural network with easy-to-obtain physiological features for screening obstructive sleep apnea-hypopnea syndrome

OBJECTIVE/BACKGROUND

Recently, several tools for screening obstructive sleep apnea-hypopnea syndrome (OSAHS) have been devised with varied shortcomings. To overcome these drawbacks, we aimed to propose a self-estimation method using an explainable prediction model with easy-to-obtain variables and evaluate its performance for predicting OSAHS.

PATIENTS/METHODS

This retrospective, cross-sectional study selected significant easy-to-obtain variables from patients, suspected of having OSAHS by regression analysis, and fed these variables into the proposed explainable fuzzy neural network (EFNN), a back propagation neural network (BPNN) and a stepwise regression model to compare the screening performance for OSAHS.

RESULTS

Of the 300 participants, three easily available features, such as waist circumference, mean blood pressure (BP) at the end of polysomnography and the difference in systolic BP between the end and start of polysomnography, were obtained from regression analysis with a five-fold cross-validation scheme. Feeding these three variables into the prediction models showed that the average prediction differences for apnea-hypopnea index (AHI) when using the EFNN, BPNN, and regression model were respectively 1.5 ± 18.2, 3.5 ± 19.1 and 0.1 ± 19.3, indicating none of the tested methods had good efficacy to predict the AHI values. The performance as determined by the sensitivity + specificity-1 value for screening moderate-to-severe OSAHS of the EFNN, BPNN and regression model were respectively 0.440, 0.414 and 0.380.

CONCLUSIONS

When fed with easy-to-obtain physiological features, the understandable EFNN should be the preferred method to predict moderate-to-severe OSAHS.

Revisiting level II sleep studies in the era of COVID-19: a theoretical economic decision model in patients with suspected obstructive sleep apnea

Background

The recent pandemic has made it more challenging to assess patients with suspected obstructive sleep apnea (OSA) with in laboratory polysomnography (PSG) due to concerns of patient and staff safety. The purpose of this study was to assess how Level II sleep studies (LII, full PSG in the home) might be utilized in diagnostic algorithms of suspected OSA using a theoretical decision model.

Methods

We examined four diagnostic algorithms for suspected OSA: an initial PSG approach, an initial LII approach, an initial Level III approach (LIII, limited channel home sleep study) followed by PSG if needed, and an initial LIII approach followed by LII if needed. Costs per patient assessed was calculated as a function of pretest OSA probability and a variety of other variables (e.g. costs of tests, failure rate of LIII/LII, sensitivity/specificity of LIII). The situation in British Columbia was used as a case study.

Results

The variation in cost per test was calculated for each algorithm as a function of the above variables. For British Columbia, initial LII was the least costly across a broad range of pretest OSA probabilities (< 0.80) while initial LIII followed by LII as needed was least costly at very high pretest probability (> 0.8). In patients with a pretest OSA probability of 0.5, costs per patient for initial PSG, initial LII, initial LIII followed by PSG, and initial LIII followed by LII were: $588, $417, $607, and $481 respectively.

Conclusions

Using a theoretical decision model, we developed a preliminary cost framework to assess the potential role of LII studies in OSA assessment. Across a broad range of patient pretest probabilities, initial LII studies may provide substantial cost advantages. LII studies might be especially useful during pandemics as they combine the extensive physiologic information characteristic of PSG with the ability to avoid in-laboratory stays. More empiric studies need to be done to test these different algorithms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41606-021-00063-5.

Diagnostic accuracy and suitability of instruments that screen for obstructive sleep apnoea, insomnia and sleep quality in cardiac patients: a meta-analysis

BACKGROUND

A number of clinical guidelines recommend that all cardiac rehabilitation patients should be screened for potential sleep disorders with a validated screening instrument. There is currently no consensus on what specific tools should be used.

OBJECTIVE

To identify tools that are practical to use in the clinical environment and have high diagnostic accuracy.

METHODS

We systematically searched online databases to identify patient reported outcome instruments that have been used in published research studies to assess the likelihood of obstructive sleep apnoea (OSA) in cardiac patients. In studies that provided diagnostic data, these data were extracted and verified via an evidence-based diagnostic calculator. Where sufficient numbers of studies were available, a meta-analysis was conducted to determine pooled estimates of specificity, sensitivity and diagnostic odds ratios. Selected papers were qualitatively assessed using the Standards for Reporting Diagnostic accuracy studies (STARD).

RESULTS

Of the 21 instruments identified, six detected likelihood of OSA, two assessed daytime sleepiness, five assessed insomnia and eight examined sleep quality. A meta-analysis of 14 studies that assessed diagnostic accuracy of moderate OSA, revealed moderate sensitivity for the Berlin Questionnaire, Sens = 0.49 (95% CI 0.45-0.52) and good sensitivity for the Stop-BANG, Sens = 0.93 (95% CI 0.87-0.96) but poor specificity at standard cut-off criteria.

CONCLUSION

There are promising practical tools available to screen patients with OSA and other sleep disorders in cardiac rehabilitation settings, but specificity could be improved. Additional assessment of sleep quality may enhance prognostic ability with both OSA and insomnia screening.

Polysomnographic and neuropsychological characteristics of rapid eye movement sleep behavior disorder patients

OBJECTIVES

To compare the sleep characteristics and cognition between rapid eye movement sleep behavior disorder (RBD) patients and non-RBD (nRBD) healthy control subjects and to determine the correlation between sleep and cognition in RBD patients.

METHODS

Polysomnography (PSG) was performed to confirm and exclude RBD. Fifteen iRBD patients, 12 PD with RBD patients, and 23 matched nRBD healthy control subjects were enrolled. Subjective sleep and neuropsychological evaluations were performed.

RESULTS

No differences were found in the subjective sleep among the three groups. Compared to the nRBD subjects, iRBD patients showed higher PLMI, the PD with RBD patients showed an increased proportion of N1 sleep, a decreased proportion of N2 and N3 sleep, and an increased periodic leg movement index. The iRBD patients performed worse on RCFT time than the nRBD subjects, the PD with RBD patients performed worse than the nRBD subjects on the following evaluations: the Mini-Mental State Examination; auditory verbal learning test (AVLT); Rey Complex Figure Test (RCFT) time, Clock drawing test (CDT); delay memory score of RCFT; Symbol digit modalities test (SDMT); Trail Making Test (TMT); and Stroop Test B and C, all significant changes (all p < 0.05). Furthermore, in RBD patients, lower sleep efficiency was correlated with decreased SDMT scores (r = 0.694, p < 0.01), longer time on the TMT A (r = -0.589, p < 0.01), and lower city fluency test scores(r = 0.556, p < 0.01). Less total sleep time was correlated with lower RCFT scores (r = 0.392, p = 0.043), longer time on the TMT A (r = -0.417, p = 0.031), and lower city fluency test scores (r = 0.405, p = 0.036).

CONCLUSIONS

PD with RBD patients suffered from abnormal sleep architecture and extensive cognition dysfunction. Decreased total sleep time and sleep efficiency may contribute to cognitive deterioration in RBD patients.

Diagnostic accuracy of a two-stage model for detecting obstructive sleep apnoea in chronic tetraplegia

BACKGROUND

Obstructive sleep apnoea (OSA) is highly prevalent in people with spinal cord injury (SCI). Polysomnography (PSG) is the gold-standard diagnostic test for OSA, however PSG is expensive and frequently inaccessible, especially in SCI. A two-stage model, incorporating a questionnaire followed by oximetry, has been found to accurately detect moderate to severe OSA (MS-OSA) in a non-disabled primary care population. This study investigated the accuracy of the two-stage model in chronic tetraplegia using both the original model and a modified version for tetraplegia.

METHODS

An existing data set of 78 people with tetraplegia was used to modify the original two-stage model. Multivariable analysis identified significant risk factors for inclusion in a new tetraplegia-specific questionnaire. Receiver operating characteristic (ROC) curve analyses of the questionnaires and oximetry established thresholds for diagnosing MS-OSA. The accuracy of both models in diagnosing MS-OSA was prospectively evaluated in 100 participants with chronic tetraplegia across four international SCI units.

RESULTS

Injury completeness, sleepiness, self-reported snoring and apnoeas were included in the modified questionnaire, which was highly predictive of MS-OSA (ROC area under the curve 0.87 (95% CI 0.79 to 0.95)). The 3% oxygen desaturation index was also highly predictive (0.93 (0.87-0.98)). The two-stage model with modified questionnaire had a sensitivity and specificity of 83% (66-93) and 88% (75-94) in the development group, and 77% (65-87) and 81% (68-90) in the validation group. Similar results were demonstrated with the original model.

CONCLUSION

Implementation of this simple alternative to full PSG could substantially increase the detection of OSA in patients with tetraplegia and improve access to treatments.

TRIAL REGISTRATION NUMBER

Results, ACTRN12615000896572 (The Australian and New Zealand Clinical Trials Registry) and pre-results, NCT02176928 (clinicaltrials.gov).

Obstructive sleep apnea is associated with increased QT corrected interval dispersion: the effects of continuous positive airway pressure

Introduction

Severe obstructive sleep apnea is associated with increased QT corrected interval dispersion and continuous positive airway pressure is thought to improve this arrhythmogenic marker.

Objective

The aim of the study was to determine the decrease of ratio of cardiovascular risk in patients with obstructive sleep apnea.

Methods

The study included 65 patients with severe obstructive sleep apnea who had an apnea-hypopnea index score of >30. Each patient underwent 12-channel electrocardiogram monitoring and polysomnography. Patients with an apnea-hypopnea index score of <5 were used as the control group. The control group also underwent electrocardiogram monitoring and polysomnography testing. The QT corrected interval dispersion levels of both groups were calculated. Three months after continuous positive airway pressure treatment, electrocardiogram recordings were obtained from the 65 patients with severe obstructive sleep apnea again, and their QT corrected interval dispersion values were calculated.

Results

There were 44 male and 21 female patients with severe obstructive sleep apnea syndrome. The age, gender, body mass index, initial saturation, minimum saturation, average saturation, and desaturation index were determined in both groups. The QT corrected intervals of the obstructive sleep apnea patients (62.48 ± 16.29 ms) were significantly higher (p = 0.001) than those of the control group (29.72 ± 6.30 ms). There were statistically significant differences between the QT corrected values before and after the continuous positive airway pressure treatment, with pretreatment QT corrected intervals of 62.48 ± 16.29 ms and 3-month post-treatment values of 41.42 ± 16.96 ms (p = 0.001). There was a positive and significant correlation between QT corrected interval dispersion periods and the apnea-hypopnea index and hypopnea index in obstructive sleep apnea patients (p = 0.001; r = 0.71; p = 0.001; r = 0.679, respectively).

Conclusion

Continuous positive airway pressure treatment reduced the QT corrected interval dispersion in patients with severe obstructive sleep apnea. In addition, shortening the QT corrected interval dispersion periods in patients with severe obstructive sleep apnea may reduce their risk of arrhythmias and cardiovascular disease.

The association between asthma and obstructive sleep apnea (OSA): A systematic review

OBJECTIVE

Bronchial asthma and obstructive sleep apnoea (OSA) are common respiratory disorders that can co-exist. The strength of this association, and also the impact of OSA on asthma-related clinical outcomes remain unclear.

DATA SOURCES

Literature review was performed in EMBASE and MEDLINE databases. Studies up to and including 2016 were selected.

STUDY SELECTION

Studies were included if they contained; 1) a population with asthma AND 2) a prevalence of OSA reported using either polysomnography or validated questionnaires such as the Sleep Apnoea Scale of the Sleep Disorders Questionnaire (SA-SDQ), STOP BANG or the Berlin questionnaire.

RESULTS

Nineteen studies were identified. Thirteen questionnaire-based studies met the inclusion/exclusion criteria and twelve of these demonstrated a prevalence of OSA in asthma of 8-52.6%, with one study showing no association between the two conditions. Six studies using polysomnography demonstrated a high prevalence of 19.2-60%; which was higher at 50-95% in severe asthma. Two polysomnography and four questionnaire studies found worse asthma-related clinical outcomes with co-existing OSA. One polysomnography and two questionnaire studies showed no difference.

CONCLUSION

This systematic review suggests that there is a high prevalence of OSA in asthma, particularly within severe asthma populations and that co-diagnosis of OSA in asthma patients is associated with worse clinical outcomes. However this outcome was not uniform and the number of studies using polysomnography to confirm OSA was small. This weakens the conclusions that can be drawn and prompts the need for adequately powered and well-designed studies to confirm or refute these findings.

Evaluación del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) mediante instrumentos de medición como escalas y fórmulas matemáticas

La psicometría del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) se puede proporcionar con el uso de variados métodos de evaluación como entrevistas clínicas, escalas, cuestionarios de sueño, autoregistros y registros psicofisiológicos. La prueba de oro para el diagnóstico de esta enfermedad sigue siendo la polisomnografía, la cual puede llegar a tener altos costos y dificultades para acceder al estudio. Debido a la alta morbimortalidad asociada a este síndrome, se requieren instrumentos que permitan la identificación rápida de individuos que puedan estar en riesgo de padecerlo. Por tales motivos, se han desarrollado herramientas que permiten detectar los pacientes en riesgo de presentar SAHOS, tales como el Cuestionario de Berlín, el STOP-Bang y la Escala de Somnolencia de Epworth. Es importante tener en cuenta los alcances y limitaciones de estas herramientas para escoger el instrumento indicado según lo que se desee evaluar.

Exploring the Phenotype in Mild Cognitive Impairment to Aid the Prediction of Those at Risk of Transitioning to Parkinson Disease and Dementia With Lewy Bodies

To date, only limited research has concurrently investigated the presence of rapid eye movement sleep behavior disorder (RBD) and other features associated with Parkinson disease (PD) and dementia with Lewy bodies (DLB) in people presenting with mild cognitive impairment (MCI). As a first step towards a longitudinal research project, the present study explored the relationships between MCI, RBD, and depression in 108 older adults who presented with subjective memory complaints but were not known to have a neurodegenerative condition. The present study found that RBD was a frequent feature in individuals with MCI (35%). Furthermore, MCI patients with RBD were more likely to exhibit nonamnestic MCI (89%) rather than an amnestic MCI phenotype (χ² = 4.99, P = .025). Specifically, nonamnestic MCI patients with RBD had selective deficits in executive function and verbal memory, as well as a higher level of depressive symptoms. This cognitive and psychiatric profile is aligned with PD and DLB patients at their time of initial diagnosis and suggests that targeting nonamnestic MCI patients who report RBD with additional biomarker testing including smell, color vision, and neuroimaging (eg, dopamine transporters scan and transcranial ultrasonography) may aid in early diagnosis and prediction of these α-synucleinopathies.

Pre-operative screening for obstructive sleep apnoea

Sleep disordered breathing, especially obstructive sleep apnoea (OSA), has a high and increasing prevalence. Depending on the apnoea and hypopnoea scoring criteria used, and depending on the sex and age of the subjects investigated, prevalence varies between 3% and 49% of the general population. These varying prevalences need to be reflected when considering screening for OSA. OSA is a cardiovascular risk factor and patients are at risk when undergoing medical interventions such as surgery. Screening for OSA before anaesthesia and surgical interventions is increasingly considered. Therefore, methods for screening and the rationale for screening for OSA are reviewed in this study.

A community-based study of risk factors for probable rapid eye movement sleep behavior disorder

OBJECTIVES

To cross-sectionally explore the potential risk factors for rapid eye movement (REM) sleep behavior disorder (RBD) in a community cohort in Shanghai.

METHODS

Based on the validated RBD screening questionnaire (RBDSQ), we identified individuals with probable RBD (pRBD) in 3635 community-dwelling residents (≥50 years old) from an urban community of Shanghai. Potential risk factors of pRBD, including age, sex, smoking, socioeconomic status, obesity, consumption of tea (surrogate for caffeine intake) and alcohol, medications and chronic disease status, were assessed via questionnaire. We used logistic regression to investigate the associations between these studied factors and pRBD after adjusting for age, sex and other studied factors.

RESULTS

Based on the RBDSQ score ≥5, 2.70% (3.28% in men and 2.41% in women) participants were considered as pRBD. We found that lower education, presence of head injury, atrial fibrillation, hyperlipidemia, constipation, olfactory disturbance, and imbalance, use of alcoholic beverage, selective serotonin reuptake inhibitor, and benzodiazepine were associated with higher likelihood of having pRBD (P < 0.05 for all). In contrast, male sex, use of coffee or tea, smoking and other factors were not significantly association with altered risk of having pRBD. We did not find significant interaction between sex, age and these factors, in relation to pRBD risk.

CONCLUSIONS

In this community-based study of older adults, we identified several potential risk factors for concurrent pRBD, including environmental factors and vascular risk factors.

Apnea-hypopnea index prediction through an assessment of autonomic influence on heart rate in wakefulness

With the high prevalence of obstructive sleep apnea, the issue of developing a practical tool for obstructive sleep apnea screening has been raised. Conventional obstructive sleep apnea screening tools are limited in their ability to help clinicians make rational decisions due to their inability to predict the apnea-hypopnea index. Our study aimed to develop a new prediction model that can provide a reliable apnea-hypopnea index value during wakefulness. We hypothesized that patients with more severe obstructive sleep apnea would exhibit more attenuated waking vagal tone, which may result in lower effectiveness in decreasing heart rate as a response to deep inspiration breath-holding. Prior to conducting nocturnal in-laboratory polysomnography, 30 non-obstructive sleep apnea (apnea-hypopnea index<5events/h) subjects and 246 patients with obstructive sleep apnea participated in a 75-second experiment that consisted of a 60-second baseline measurement and consecutive 15-second deep inspiration breath-hold sessions. Two apnea-hypopnea index predictors were devised by considering the vagal activities reflected in the electrocardiographic recordings acquired during the experiment. Using the predictors obtained from 184 individuals, regression analyses and k-fold cross-validation tests were performed to develop an apnea-hypopnea index prediction model. For the remaining 92 individuals, the developed model provided an absolute error (mean±SD) of 3.53±2.67events/h and a Pearson's correlation coefficient of 0.99 (P<0.01) between the apnea-hypopnea index predictive values and the reference values reported by polysomnography. Our study is the first to achieve reliable and time-efficient prediction of the apnea-hypopnea index during wakefulness.

Pramipexole in the treatment of REM sleep behaviour disorder: A critical review

While widely accepted as a first-line treatment for rapid eye movement sleep (REM) behaviour disorder, clonazepam (CNZP) has side effects that limit its applicability. Pramipexole is a possible alternative, but limited literature on its effectiveness exists. This review aims to summarize the available data on the use of pramipexole in REM sleep behaviour disorder. A systematic search of major databases was conducted to look for published and on-going trials. This search yielded a total of five articles, all of which are observational in nature. Factors associated with effectiveness include low doses (less than 1.5mg/day) and idiopathic rapid eye movement sleep behaviour disorder/absence of neurodegenerative disease. Overall, the evidence is inconclusive. This is due to the lack of randomised controlled trials and the challenges in interpreting polysomgraphy findings in rapid eye movement sleep behaviour disorder. Suggestions are given on how future trials evaluating pramipexole treatment in rapid eye movement sleep behaviour disorder could overcome current methodological issues in extant literature.

Caring burden of REM sleep behavior disorder - spouses' health and marital relationship

OBJECTIVES

Idiopathic REM sleep behavior disorder (iRBD) is noxious due to the high prevalence of sleep-related injuries to patients and their bed-partners. In this study, we aimed to investigate the impact of patients' RBD symptoms on their spouses, in terms of the quality of sleep, and physical, mental and marital aspects.

METHOD

A cross-sectional study comparing spouses of iRBD patients to the spouses of the age-and-sex-matched OSAS patients.

RESULTS

40 iRBD patients and their spouses (patients' age 66.6 ± 9.1, male 90%; spouses' age 62.9 ± 7.5), and 35 OSAS patients and their spouses (patients' age 67.8 ± 8.7 years old, male 80%; spouses' age 64.1 ± 9.1) were recruited. Almost all iRBD spouses (90%) reported disturbances by the nocturnal RBD behavioral symptoms of their bedpartners. About two-thirds (62.5%, N = 25) of the iRBD spouses reported a history of being injured during sleep. Spouses of both iRBD and OSAS patients reported a comparably high prevalence of insomnia, anxiety and depressive symptoms. Spouses of iRBD patients, however, reported more impaired quality of life and marital relationship. Nearly two-thirds of RBD couples continued co-sleeping, despite the risk of sleep-related injuries and nocturnal disturbances.

CONCLUSIONS

Both iRBD and OSAS spouses exhibited a high prevalence of insomnia and mood problems. In particular, iRBD significantly and negatively affect the spouses' quality of life and the marital relationship. Optimization of iRBD treatment, proper diagnosis, and management of sleep and mental health aspects of spouses may help to lessen the caring burden.

Idiopathic rapid eye movement sleep behaviour disorder: diagnosis, management, and the need for neuroprotective interventions

Idiopathic rapid eye movement (REM) sleep behaviour disorder (IRBD) manifests as unpleasant dreams and vigorous behaviours during REM sleep that can result in injuries. Patients with IRBD have no known neurological diseases or motor or cognitive complaints; however, this sleep disorder is not harmless. In most cases, IRBD is the prelude of the synucleinopathies Parkinson's disease, dementia with Lewy bodies, or, less frequently, multiple system atrophy. Patients can show abnormalities that are characteristic of the synucleinopathies, and longitudinal follow-up shows that most patients develop parkinsonism and cognitive impairments with time. Thus, diagnosis of IRBD needs to be accurate and involves informing the patient of the risk of developing a neurodegenerative disease. It is extraordinary for a sleep disorder to precede the full expression of a neurodegenerative disease, which renders IRBD of particular interest in studies of the prodromal stage of the synucleinopathies, and in the development of neuroprotective interventions to stop or slow neurodegenerative deterioration before motor and cognitive symptomatology emerges. Such therapeutics do not currently exist, and thus represent an unmet need in IRBD.

Impact of obstructive sleep apnea on lung volumes and mechanical properties of the respiratory system in overweight and obese individuals

BACKGROUND

Even through narrowing of the upper-airway plays an important role in the generation of obstructive sleep apnea (OSA), the peripheral airways is implicated in pre-obese and obese OSA patients, as a result of decreased lung volume and increased lung elastic recoil pressure, which, in turn, may aggravate upper-airway collapsibility.

METHODS

A total of 263 male (n = 193) and female (n = 70) subjects who were obese to various degrees without a history of lung diseases and an expiratory flow limitation, but troubled with snoring or suspicion of OSA were included in this cross-sectional study. According to nocturnal-polysomnography the subjects were distributed into OSA and non-OSA groups, and were further sub-grouped by gender because of differences between males and females, in term of, lung volume size, airway resistance, and the prevalence of OSA among genders. Lung volume and respiratory mechanical properties at different-frequencies were evaluated by plethysmograph and an impulse oscillation system, respectively.

RESULTS

Functional residual capacity (FRC) and expiratory reserve volume were significantly decreased in the OSA group compared to the non-OSA group among males and females. As weight and BMI in males in the OSA group were greater than in the non-OSA group (90 ± 14.8 kg vs. 82 ± 10.4 kg, p < 0.001; 30.5 ± 4.2 kg/m(2) vs. 28.0 ± 3.0 kg/m(2), p < 0.001), multiple regression analysis was required to adjust for BMI or weight and demonstrated that these lung volumes decreases were independent from BMI and associated with the severity of OSA. This result was further confirmed by the female cohort. Significant increases in total respiratory resistance and decreases in respiratory conductance (Grs) were observed with increasing severity of OSA, as defined by the apnea-hypopnea index (AHI) in both genders. The specific Grs (sGrs) stayed relatively constant between the two groups in woman, and there was only a weak association between AHI and sGrs among man. Multiple-stepwise-regression showed that reactance at 5 Hz was highly correlated with AHI in males and females or hypopnea index in females, independently-highly correlated with peripheral-airway resistance and significantly associated with decreasing FRC.

CONCLUSIONS

Total respiratory resistance and peripheral airway resistance significantly increase, and its inverse Grs decrease, in obese patients with OSA in comparison with those without OSA, and are independently associated with OSA severity. These results might be attributed to the abnormally increased lung elasticity recoil pressure on exhalation, due to increase in lung elasticity and decreased lung volume in obese OSA.

Validation of a Portuguese version of the STOP-Bang questionnaire as a screening tool for obstructive sleep apnea: Analysis in a sleep clinic

INTRODUCTION

Screening methods have become increasingly important owing to the growing number of patients suspected of obstructive sleep apnea (OSA) being referred for sleep consultation. The STOP-Bang questionnaire has been validated as a screening tool for OSA in surgical patients.

OBJECTIVES

To evaluate the performance of a Portuguese version of the STOP-Bang questionnaire for the diagnosis of OSA in a sleep clinic.

METHODS

Prospectively, for 2 months, all patients referred to our clinic for clinical evaluation completed a translated version of the STOP-Bang questionnaire in Portuguese and underwent a sleep study.

RESULTS

We observed 216 patients and 215 (99.5%) were included. Age was 53.63±13.10 years, 63.3% were male patients, neck circumference was 40.4±44.11 cm and BMI was 29.41 [26.85; 33.06] kg/m(2). OSA was present in 78% of the patients, of whom, 33% had moderate and 37% had severe OSA. A STOP-Bang score ≥3 had a sensitivity and positive predictive value (PPV) for OSA of 93.4% and 86.6%, respectively. Each increase in the STOP-Bang score was associated with an increase in the probability of OSA and severe OSA; reaching a 95% OSA probability, for a score of 6, and a 73% severe OSA probability, for a score of 8. A score of 3 and 2 had a negative predictive value for moderate/severe OSA of 85.3% and 91.7%, respectively.

CONCLUSIONS

The STOP-Bang questionnaire showed high sensitivity and PPV for OSA with the probability of severe OSA steadily increasing, the higher the scores. Furthermore, a low score showed high predictive value for the exclusion of moderate/severe OSA. The STOP-Bang questionnaire can be a powerful tool for stratifying patients in the diagnosis of OSA.

WITHDRAWN: Validation of a Portuguese version of the STOP-Bang questionnaire as a screening tool for obstructive sleep apnea: Analysis in a sleep clinic

This article has been withdrawn for editorial reasons because the journal will be published only in English. In order to avoid duplicated records, this article can be found at http://dx.doi.org/10.1016/j.rppnen.2014.04.009. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Reliability of SleepStrip as a screening test in obstructive sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder and related to multiple conditions that cause mortality in adults. In the present study, reliability of SleepStrip, a disposable screening device for detection of OSAS, is tested. In this prospective, nonrandomized double-blinded single cohort study at an academic health center, the performance of the SleepStrip in detecting respiratory events and establishing an SleepStrip score (Sscore) in domestic use were compared to the apnea-hypopnea index (AHI) obtained by the standard polysomnography (PSG) recordings in the sleep laboratory. Forty-one patients who have the PSG results participated the study and wore the SleepStrips at home. Test efficiency rate was 75% and there was a positive correlation between PSG-AHI scores and Sscores (r = 0.71, p < 0.001). However, diagnostic accuracy analysis showed that the correlation between Sscores and PSG-AHI scores were significant only at AHI > 30 levels. The SleepStrip has 100% specificity and positive predictive values, but it also has low negative predictive and sensitivity values. The SleepStrip is not a reliable screening test in differential diagnosis among simple snorers, mild, moderate and severe OSAS patients. However, high Sscores highly indicate the presence of moderate-severe OSAS. We can safely send these patients to split-night PSG and continuous, automatic, bi-level positive airway pressure (CPAP/BPAP/APAP) titration at the same night. The SleepStrip may increase the effective use of the sleep laboratories.

Criterion validity of the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale for the diagnosis of sleep disorders

OBJECTIVES

(1) To examine criterion validity of the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) using obstructive sleep apnea (OSA), periodic limb movement disorder (PLMD), rapid eye movement sleep behavior disorder (RBD), and narcolepsy as criterion standard. (2) To summarize the evidence for criterion validity of the ESS for the diagnosis of OSA by a meta-analysis that combines the current and previous studies. (3) To investigate the determinants of the PSQI and ESS scores.

METHODS

The PSQI and ESS as well as the Hospital Anxiety and Depression Scale (HADS), which measures anxiety and depression levels, were administered to 367 patients consecutively referred to a sleep clinic. They underwent overnight polysomnography (PSG) and the multiple sleep latency test if narcolepsy was suspected.

RESULTS

The area under the receiver operating characteristic curves for the ESS and PSQI (and its subscale) were <0.9, meaning that these questionnaires were not highly accurate for predicting the four sleep disorders. The meta-analysis found that the ESS had no value in identifying OSA. The variable that most strongly influenced PSQI or ESS scores was the HADS score.

CONCLUSION

The PSQI and ESS should no longer be used as a screening or diagnostic instrument for the four PSG-defined sleep disorders, especially in a low-risk population.

Cognitive dysfunction and REM sleep behavior disorder: key findings in the literature and preliminary longitudinal findings

A considerable proportion of subjects initially diagnosed with idiopathic REM sleep behavior disorder (iRBD) are reported to convert to a neurodegenerative disorder, mainly synucleinopathies. It is unclear whether cognitive deficits in iRBD represent an associated feature or a marker predictive of subsequent development of a synucleinopathy. Cross-sectional studies indicate that a proportion of iRBD patients show cognitive deficits similar to those typically found in patients with synucleinopathies. The available longitudinal data suggest that cognitive dysfunction in iRBD tends to progress over time, with this progression probably being underpinned by a neurodegenerative process. Furthermore, within the framework of Parkinson's disease, RBD has been shown to be a risk factor for progressive cognitive decline even advancing to dementia. This paper addresses the multifaceted issue of cognitive dysfunction in RBD. Taking into account some key literature findings and preliminary longitudinal observations of our own, it shows that cognitive deterioration, mainly involving visuospatial abilities (learning as a stable deficit and copying as an evolving deficit), non-verbal logic, attention and executive functions can be observed in iRBD follow-up, suggesting an underlying evolving degenerative process. Large cohort studies with more prolonged follow-ups and greater methodological uniformity are needed to provide more reliable and robust findings.

Treatment outcomes in REM sleep behavior disorder

OBJECTIVE

REM sleep behavior disorder (RBD) is usually characterized by potentially injurious dream enactment behaviors (DEB). RBD treatment aims to reduce DEBs and prevent injury, but outcomes require further elucidation. We surveyed RBD patients to describe longitudinal treatment outcomes with melatonin and clonazepam.

METHODS

We surveyed and reviewed records of consecutive RBD patients seen at Mayo Clinic between 2008-2010 to describe RBD-related injury frequency-severity as well as RBD visual analog scale (VAS) ratings, medication dosage, and side effects. Statistical analyses were performed with appropriate non-parametric matched pairs tests before and after treatment, and with comparative group analyses for continuous and categorical variables between treatment groups. The primary outcome variables were RBD VAS ratings and injury frequency.

RESULTS

Forty-five (84.9%) of 53 respondent surveys were analyzed. Mean age was 65.8 years and 35 (77.8%) patients were men. Neurodegenerative disorders were seen in 24 (53%) patients and 25 (56%) received antidepressants. Twenty-five patients received melatonin, 18 received clonazepam, and two received both as initial treatment. Before treatment, 27 patients (60%) reported an RBD associated injury. Median dosages were melatonin 6 mg and clonazepam 0.5 mg. RBD VAS ratings were significantly improved following both treatments (p(m) = 0.0001, p(c) = 0.0005). Melatonin-treated patients reported significantly reduced injuries (p(m) = 0.001, p(c) = 0.06) and fewer adverse effects (p = 0.07). Mean durations of treatment were no different between groups (for clonazepam 53.9 ± 29.5 months, and for melatonin 27.4 ± 24 months, p = 0.13) and there were no differences in treatment retention, with 28% of melatonin and 22% of clonazepam-treated patients discontinuing treatment (p = 0.43).

CONCLUSIONS

Melatonin and clonazepam were each reported to reduce RBD behaviors and injuries and appeared comparably effective in our naturalistic practice experience. Melatonin-treated patients reported less frequent adverse effects than those treated with clonazepam. More effective treatments that would eliminate injury potential and evidence-based treatment outcomes from prospective clinical trials for RBD are needed.

Rapid eye movement sleep behavior disorder in adults younger than 50 years of age

Rapid eye movement (REM) sleep behavior disorder (RBD) occurring prior to age 50 is termed early-onset RBD. Early-onset RBD comprises a substantial minority of cases, and demonstrates the differences in demographics, comorbidities, and clinical considerations from previously described typical RBD with onset >50years. The world literature on RBD is reviewed with specific focus on features that distinguish early-onset RBD, including more gender parity, increased proportion of idiopathic cases, increased proportion of cases associated with narcolepsy, parasomnia overlap disorder, antidepressants, and possibly autoimmune disorders, and clinical presentation.

Sleep, blood pressure and obesity in 22,389 New Zealanders

AIM

To determine the relationship of sleep disorders with blood pressure and obesity in a large, relatively healthy, community-based cohort.

METHODS

A cross-sectional study was undertaken using data from 22,389 volunteer blood donors in New Zealand aged 16-84 years. Height, weight, neck circumference and blood pressure were measured directly, and data on sleep and other factors were ascertained using a validated self-administered questionnaire.

RESULTS

Even in a relatively young, non-clinical cohort, lack of sleep (34%), snoring (33%), high blood pressure (20%) and obesity (19%) are common. After adjusting for relevant confounders, participants at high risk of sleep apnoea had double the odds of having high blood pressure but only in participants over 40 years. Very low and high quantities of sleep are also associated with high blood pressure. Even after controlling for neck circumference, self-reported sleep apnoea, sleep dissatisfaction and low amounts of sleep are associated with a higher body mass index.

CONCLUSIONS

Obesity and hypertension have significant associations with a variety of sleep disorders, even in those less than 40 years of age and after adjusting for a wide range of potential confounders.

Sleep and Parkinson's disease: a review of case-control polysomnography studies

The link between Parkinson's disease (PD) and certain primary sleep disorders has yet to be clarified. We performed a systematic review of case-control polysomnography studies to evaluate the relationship between PD and sleep disorders. A PubMed literature search and bibliography review yielded 15 case-control polysomnography studies in patients with PD. Studies differed by recruitment methods, duration of polysomnography monitoring, and sleep parameters measured. Subjective sleepiness was greater in patients than controls (50%-66% vs 2.9%-12%) despite lack of objective increase in daytime sleepiness by mean sleep latency testing. The 4 case-control polysomnography studies investigating rapid eye movement behavior disorder support a higher prevalence in PD (0%-47% vs 0%-1.8% in controls), although differences in diagnostic criteria hamper interpretation. The preponderance of evidence did not support an increased incidence of obstructive sleep apnea (27%-60% vs 13%-65%) or periodic leg movements of sleep in patients compared to controls. Adequately powered, prospective studies with uniform methodology and healthy controls are needed to further address the association and pathophysiological significance between PD and sleep problems.

Does rapid eye movement sleep behavior disorder exist in psychiatric populations? A clinical and polysomnographic case-control study

OBJECTIVES

Rapid eye movement (REM) sleep behavior disorder (RBD) has been increasingly reported in patients with psychiatric disorders (pRBD). Although a close association with the usage of psychotropics has been postulated, it remains elusive whether psychotropics are the only causative factor of RBD symptoms in psychiatric populations. Moreover, there is limited literature documenting and quantifying the clinical and polysomnographic features in this population.

METHODS

A case-control study comparing the clinical and polysomnographic features of 31 pRBD patients with: (1) Age-, sex-, and psychiatric diagnoses-matched controls; and (2) Typical idiopathic RBD (tRBD) patients.

RESULTS

Despite being prescribed with similar psychotropics, pRBD patients had more dream-enacting behaviors (p<0.01), sleep-related injuries (p<0.01), and nightmares (p<0.01) than the psychiatric controls. pRBD patients were younger with more females, but they had comparable sleep-related injuries to tRBD. Both tRBD and pRBD had more REM-related muscle activity than controls (p<0.01) and the effect remained significant after adjusting for age, gender, and use of antidepressants.

CONCLUSIONS

Our study suggests that pRBD had comparable clinical features and consequences to those of tRBD. The occurrence of RBD symptoms in these patients may be related to a constellation of factors, including individual predisposition, depressive illness, antidepressants, and other clinical factors. Given the association of RBD and neurodegeneration in tRBD, further prospective follow-up of these patients is warranted.

Does idiopathic REM sleep behavior disorder (iRBD) really exist? What are the potential markers of neurodegeneration in iRBD?

REM sleep behavior disorder (RBD) may be idiopathic or associated with other neurologic disorders. A strong association between RBD and α-synucleinopathies has recently been observed, with the parasomnia often heralding the clinical onset of the neurodegenerative disease. The idiopathic form accounts for up to 60% of the cases reported in the three largest series of patients with RBD. Some clinical follow-up studies revealed that a large proportion of these patients will eventually develop a parkinsonian syndrome or a dementia of the Lewy bodies type in the years following the RBD diagnosis. The estimated 10-year risk of neurodegenerative disease for idiopathic RBD is about 40%. Moreover, it has been reported that the median interval between RBD and subsequent neurologic syndrome is 25years. Several studies have looked at neurophysiologic and neuropsychological functions in idiopathic RBD and have found evidence of CNS dysfunction during both wakefulness and sleep in a variable proportion of these patients, challenging the concept of idiopathic RBD. Identifying subjects with a high risk of developing a neurodegenerative process may be crucial to develop early intervention strategies. Prospective studies in idiopathic RBD showed that potential markers of neurodegeneration include: (1) marked EEG slowing on spectral analysis; (2) decreased striatal 123I-FP-CIT binding and substantia nigra hyperechogenicity; (3) impaired olfactory function; (4) impaired color vision.

Secondary ''incidental'' REM sleep behavior disorder: do we ever think of it?

Most secondary forms of REM sleep behavior disorder are associated with neurodegenerative diseases belonging to the α-synucleinopathies or with narcolepsy. However, RBD may also occur in subacute- or acute-onset conditions involving the central nervous system, irrespective of subjects' age and sex, and with or without relapse at follow-up. These conditions include structural brain lesions (vascular, demyelinating, tumoral, iatrogenic, etc.), CNS diseases (encephalitis, Guillain-Barré syndrome, etc.), forms induced by drug consumption or alcohol withdrawal, and possibly post-traumatic stress disorder. This review focuses on these forms of RBD, which are referred to as 'acute' as they occur as incidental phenomena within the context of other subacute- or acute-onset disorders. In these cases, RBD does not appear as a 'classical' clinical feature of the underlying condition, but rather as an intercurrent, somewhat unexpected phenomenon that deserves consideration in routine clinical practice, in order to avoid misdiagnoses and mistreatments.

Sleep-related falling out of bed in Parkinson's disease

BACKGROUND AND PURPOSE

Sleep-related falling out of bed (SFOB), with its potential for significant injury, has not been a strong focus of investigation in Parkinson's disease (PD) to date. We describe the demographic and clinical characteristics of PD patients with and without SFOB.

METHODS

We performed a retrospective analysis of 50 consecutive PD patients, who completed an REM sleep behavior disorder screening questionnaire (RBDSQ), questionnaires to assess for RBD clinical mimickers and questions about SFOB and resulting injuries. Determination of high risk for RBD was based on an RBDSQ score of 5 or greater.

RESULTS

Thirteen patients reported history of SFOB (26%). Visual hallucinations, sleep-related injury, quetiapine and amantadine use were more common in those patients reporting SFOB. Twenty-two patients (44%) fulfilled criteria for high risk for RBD, 12 of which (55%) reported SFOB. Five patients reported injuries related to SFOB. SFOB patients had higher RBDSQ scores than non-SFOB patients (8.2±3.0 vs. 3.3±2.0, p<0.01). For every one unit increase in RBDSQ score, the likelihood of SFOB increased two-fold (OR 2.4, 95% CI 1.3-4.2, p<0.003).

CONCLUSIONS

SFOB may be a clinical marker of RBD in PD and should prompt confirmatory polysomnography and pharmacologic treatment to avoid imminent injury. Larger prospective studies are needed to identify risk factors for initial and recurrent SFOB in PD.

Interrelationships between body mass, oxygen desaturation, and apnea-hypopnea indices in a sleep clinic population

STUDY OBJECTIVES

To investigate the relationship between oxygen desaturation index (ODI), body mass index (BMI), and apnea-hypopnea index (AHI) in a large sleep clinic population.

DESIGN

Retrospective observational.

SETTING

Sleep disorders clinic.

PATIENTS OR PARTICIPANTS

11,448 individuals undergoing diagnostic polysomnography (PSG) at a sleep disorders clinic.

MEASUREMENTS AND RESULTS

Polysomnography were scored using Chicago criteria. ODI at 2%, 3%, and 4% threshold levels were derived. The study population was subdivided into BMI categories in steps of 5 kg/m(2). Mean ODI and the accuracy of ODI for detecting an AHI ≥ 15 (moderate-severe OSA) or ≥ 30 (severe OSA) were examined by BMI category, using the area under the curve (AUC) of receiver operator characteristic (ROC) curves for the 3 ODI thresholds. Based on AUC, ODI-3% performed best overall, achieving a significantly higher AUC than ODI-2% and ODI-4% for the diagnosis of moderate-severe OSA, and a higher AUC than ODI-2% for the diagnosis of severe OSA. When examining the effect of BMI, ODI-3% achieved a significantly higher AUC than ODI-2% in all BMI categories, and ODI-4% in non-obese subjects. The sensitivity of ODI for detecting OSA increased with BMI, while specificity decreased.

CONCLUSIONS

ODI-3% performed best overall, and when combined with appropriate clinical assessment, could be considered as an initial diagnostic test for OSA. OSA is more frequently associated with oxygen desaturation in obese subjects. BMI influences the accuracy of ODI for the diagnosis of OSA, and ODI should not be used in isolation as a test for OSA in subjects with a BMI below 25kg/m(2).