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  • 1
    Language: English
    In: Sensors (Basel, Switzerland), 2020-01-04, Vol.20 (1), p.286
    Description: Sleep apnea (SA) is a prevalent disorder diagnosed by polysomnography (PSG) based on the number of apnea-hypopnea events per hour of sleep (apnea-hypopnea index, AHI). PSG is expensive and technically complex; therefore, its use is rather limited to the initial diagnostic phase and simpler devices are required for long-term follow-up. The validity of single-parameter wearable devices for the assessment of sleep apnea severity is still debated. In this context, a wearable electrocardiogram (ECG) acquisition system (ECG belt) was developed and its suitability for the classification of sleep apnea severity was investigated using heart rate variability analysis with or without data pre-filtering. Several classification algorithms were compared and support vector machine was preferred due to its simplicity and overall performance. Whole-night ECG signals from 241 patients with a suspicion of sleep apnea were recorded using both the ECG belt and patched ECG during PSG recordings. 65% of patients had an obstructive sleep apnea and the median AHI was 21 [IQR: 7-40] h - 1 . The classification accuracy obtained from the ECG belt (accuracy: 72%, sensitivity: 70%, specificity: 74%) was comparable to the patched ECG (accuracy: 74%, sensitivity: 88%, specificity: 61%). The highest classification accuracy was obtained for the discrimination between individuals with no or mild SA vs. moderate to severe SA. In conclusion, the ECG belt provided signals comparable to patched ECG and could be used for the assessment of sleep apnea severity, especially during follow-up.
    Subject(s): classification algorithms ; ecg signal ; heart rate variability analysis ; sleep apnea ; support vector machine ; wearable acquisition device
    ISSN: 1424-8220
    E-ISSN: 1424-8220
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: Alma/SFX Local Collection
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  • 2
    Language: English
    In: Sensors (Basel, Switzerland), 2019-08-01, Vol.19 (15), p.3367
    Description: Sleep monitoring in an unattended home setting provides important information complementing and extending the clinical polysomnography findings. The validity of a wearable textile electrocardiography (ECG)-belt has been proven in a clinical setting. For evaluation in a home setting, ECG signals and features were acquired from 12 patients (10 males and 2 females, showing an interquartile range for age of 48-59 years and for body mass indexes (BMIs) of 28.0-35.5) over 28 nights. The signal quality was assessed by artefacts detection, signal-to-noise ratio, and Poincare plots. To assess the validity, the data were compared to previously reported data from the clinical setting. It was found that the artefact percentage was slightly reduced for the ECG-belt from 9.7% +/- 14.7% in the clinical setting, to 7.5% +/- 10.8% in the home setting. The signal-to-noise ratio was improved in the home setting and reached similar values to the gel electrodes in the clinical setting. Finally, it was found that for artefact percentages above 3%, Poincare plots are instrumental to evaluate the origin of artefacts. In conclusion, the application of the ECG-belt in a home setting did not result in a reduction in signal quality compared to the ECG-belt used in the clinical setting, and thus provides new opportunities for patient pre-screening or follow-up.
    Subject(s): Body Mass Index ; Chemistry ; Chemistry, Analytical ; ECG signal ; Electrocardiography - methods ; Engineering ; Engineering, Electrical & Electronic ; Female ; home monitoring ; Humans ; Instruments & Instrumentation ; long-term electrocardiogram ; Male ; Middle Aged ; Monitoring, Physiologic ; Physical Sciences ; Poincaré plot ; Polysomnography - methods ; Science & Technology ; Signal Processing, Computer-Assisted ; signal quality ; Signal-To-Noise Ratio ; Sleep - physiology ; Sleep Apnea Syndromes - diagnosis ; Sleep Apnea Syndromes - physiopathology ; Technology ; textile electrodes ; Textiles ; validation ; Wearable Electronic Devices
    ISSN: 1424-8220
    E-ISSN: 1424-8220
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
    Source: Alma/SFX Local Collection
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  • 3
    Language: English
    In: Sensors (Basel, Switzerland), 2019-06-01, Vol.19 (11), p.2436
    Description: Even for 1-lead electrocardiography (ECG), single-use gel conductive electrodes are employed in a clinical setting. However, gel electrodes show limited applicability for long-term monitoring due to skin irritation and detachment. In the present study, we investigated the validity of a textile ECG-belt suitable for long-term measurements in clinical use. In order to assess the signal quality and validity of the ECG-belt during sleep, 242 patients (186 males and 56 females, age 52 (interquartile range 42-60) years, body mass index 29 (interquartile range 26-33) kgm(-2)) with suspected sleep apnoea underwent overnight polysomnography including standard 1-lead ECG recording. The single intervals between R-peaks (RR-intervals) were calculated from the ECG-signals. We found a mean difference for average RR-intervals of -2.9 ms, a standard error of estimate of 0.39%, as well as a Pearson r of 0.91. Furthermore, we found that the validity of the ECG-belt decreases when lying on the side, which was potentially due to the fitting of the belt. In conclusion, the validity of RR-interval measurements using the ECG-belt is high and it may be further improved for future applications by optimizing wear fitting.
    Subject(s): Chemistry ; Chemistry, Analytical ; clinical applicability ; ECG-belt ; Engineering ; Engineering, Electrical & Electronic ; Instruments & Instrumentation ; long-term electrocardiogram ; Physical Sciences ; polysomnography ; Science & Technology ; Technology ; textile electrodes ; validation
    ISSN: 1424-8220
    E-ISSN: 1424-8220
    Source: Academic Search Ultimate
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: PubMed Central
    Source: Alma/SFX Local Collection
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  • 4
    Language: English
    In: Journal of Applied Physiology, 2009-02-01, Vol.106 (2), p.454-460
    Description: Little is known about the ocular and cerebral blood flow during exposure to increasingly hypoxic conditions at high altitudes. There is evidence that an increase in cerebral blood flow resulting from altered autoregulation constitutes a risk factor for acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) by leading to capillary overperfusion and vasogenic cerebral edema. The retina represents the only part of the central nervous system where capillary blood flow is visible and can be measured by noninvasive means. In this study we aimed to gain insights into retinal and choroidal autoregulatory properties during hypoxia and to correlate circulatory changes to symptoms of AMS and clinical signs of HACE. This observational study was performed within the scope of a high-altitude medical research expedition to Mount Muztagh Ata (7,546 m). Twenty seven participants underwent general and ophthalmic examinations up to a maximal height of 6,800 m. Examinations included fundus photography and measurements of retinal and choroidal blood flow, as well as measurement of arterial oxygen saturation and hematocrit. The initial increase in retinal blood velocity was followed by a decrease despite further ascent, whereas choroidal flow increase occurred later, at even higher altitudes. The sum of all adaptational mechanisms resulted in a stable oxygen delivery to the retina and the choroid. Parameters reflecting the retinal circulation and optic disc swelling correlated well with the occurrence of AMS-related symptoms. We demonstrate that sojourns at high altitudes trigger distinct behavior of retinal and choroidal blood flow. Increase in retinal but not in choroidal blood flow correlated with the occurrence of AMS-related symptoms.
    Subject(s): Acclimatization ; Adaptation, Physiological ; Adult ; Altitude ; Altitude Sickness - physiopathology ; Biological and medical sciences ; Blood Flow Velocity ; Blood Pressure ; Cerebrovascular Circulation ; Choroid - blood supply ; Female ; Fluorescein Angiography ; Fundamental and applied biological sciences. Psychology ; Hematocrit ; Homeostasis ; Humans ; Hypoxia - physiopathology ; Intraocular Pressure ; Laser-Doppler Flowmetry ; Logistic Models ; Male ; Middle Aged ; Odds Ratio ; Oxygen - blood ; Prospective Studies ; Regional Blood Flow ; Retinal Vessels - diagnostic imaging ; Retinal Vessels - physiopathology ; Risk Assessment ; Switzerland ; Time Factors ; Ultrasonography ; Visual Acuity
    ISSN: 8750-7587
    E-ISSN: 1522-1601
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: Vascular health and risk management, 2016, Vol.12, p.85-103
    Description: Obstructive sleep apnea (OSA) is associated with cardiovascular risk factors, cardiovascular diseases, and increased mortality. Epidemiological studies have established these associations, and there are now numerous experimental and clinical studies which have provided information on the possible underlying mechanisms. Mechanistic proof-of-concept studies with surrogate endpoints have been performed to demonstrate that treatment of OSA by continuous positive airway pressure (CPAP) has the potential to reverse or at least to attenuate not only OSA but also the adverse cardiovascular effects associated with OSA. However, no randomized studies have been performed to demonstrate that treatment of OSA by CPAP improves clinical outcomes in patients with cardiovascular risk factors and/or established cardiovascular disease and concomitant OSA. In the present review, we summarize the current knowledge on the role of OSA as a potential cardiovascular risk factor, the impact of OSA on cardiac function, the role of OSA as a modifier of the course of cardiovascular diseases such as coronary artery disease, atrial fibrillation, and heart failure, and the insights from studies evaluating the impact of CPAP therapy on the cardiovascular features associated with OSA.
    Subject(s): Age ; Airway management ; atrial fibrillation ; Beta blockers ; Cardiac arrhythmia ; cardiovascular ; Cardiovascular disease ; Cardiovascular diseases ; Cardiovascular Diseases - diagnosis ; Cardiovascular Diseases - epidemiology ; Cardiovascular Diseases - physiopathology ; Cardiovascular Diseases - prevention & control ; Complications and side effects ; Continuous Positive Airway Pressure ; Coronary vessels ; Health risk assessment ; Heart failure ; Hemodynamics ; Humans ; Hypertension ; Hypoxia ; obstructive sleep apnea ; Prevalence ; Review ; risk ; Risk Assessment ; Risk Factors ; Sleep apnea ; Sleep apnea syndromes ; Sleep Apnea, Obstructive - diagnosis ; Sleep Apnea, Obstructive - epidemiology ; Sleep Apnea, Obstructive - physiopathology ; Sleep Apnea, Obstructive - therapy ; Sleep disorders ; Treatment Outcome ; Ventricular Function ; Weight control ; Womens health
    ISSN: 1178-2048
    ISSN: 1176-6344
    E-ISSN: 1178-2048
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 6
    Language: English
    In: European journal of applied physiology, 2013-04-06, Vol.113 (8), p.2025-2037
    Description: Impairment of cognitive performance during and after high-altitude climbing has been described in numerous studies and has mostly been attributed to cerebral hypoxia and resulting functional and structural cerebral alterations. To investigate the hypothesis that high-altitude climbing leads to cognitive impairment, we used of neuropsychological tests and measurements of eye movement (EM) performance during different stimulus conditions. The study was conducted in 32 mountaineers participating in an expedition to Muztagh Ata (7,546 m). Neuropsychological tests comprised figural fluency, line bisection, letter and number cancellation, and a modified pegboard task. Saccadic performance was evaluated under three stimulus conditions with varying degrees of cortical involvement: visually guided pro- and anti-saccades, and visuo-visual interaction. Typical saccade parameters (latency, mean sequence, post-saccadic stability, and error rate) were computed off-line. Measurements were taken at a baseline level of 440 m and at altitudes of 4,497, 5,533, 6,265, and again at 440 m. All subjects reached 5,533 m, and 28 reached 6,265 m. The neuropsychological test results did not reveal any cognitive impairment. Complete eye movement recordings for all stimulus conditions were obtained in 24 subjects at baseline and at least two altitudes and in 10 subjects at baseline and all altitudes. Measurements of saccade performances showed no dependence on any altitude-related parameter and were well within normal limits. Our data indicates that acclimatized climbers do not seem to suffer from significant cognitive deficits during or after climbs to altitudes above 7,500 m. We demonstrated that investigation of EMs is feasible during high-altitude expeditions.
    Subject(s): Adult ; Altitude ; Biomedical and Life Sciences ; Biomedicine ; Cognition ; Cognitive function ; Female ; High altitude ; Human Physiology ; Humans ; Hypoxia ; Male ; Middle Aged ; Mountaineering - physiology ; Neuropsychological testing ; Neuropsychological Tests ; Occupational Medicine/Industrial Medicine ; Original Article ; Saccades ; Saccadic eye movement ; Sports Medicine
    ISSN: 1439-6319
    E-ISSN: 1439-6327
    Source: Alma/SFX Local Collection
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  • 7
    Language: English
    In: Thorax, 2018-02, Vol.73 (2), p.174-184
    Description: BackgroundThe obstructive sleep apnoea syndrome (OSAS) is conventionally treated by continuous positive airway pressure set at a fixed level (fCPAP). Automatic mask pressure adjustment (autoCPAP) is increasingly used during home therapy. We investigated whether autoCPAP is equivalent to fCPAP in improving sleepiness in patients with OSAS in the long-term.MethodsIn this multicentre equivalence trial, 208 patients with OSAS, with median Epworth sleepiness score (ESS) 13, apnoea/hypopnoea index 48.4/hour, were randomised to treatment with autoCPAP (5–15 mbar) or fCPAP (pressure set at the 90th percentile applied by autoCPAP during 2–4 weeks adaptation). Coprimary outcomes were changes in subjective and objective sleepiness from baseline to 2 years after treatment. Equivalence ranges were ±2 points in ESS and ±3 min sleep resistance time evaluated by recording responses to light signals.ResultsAt 2 years, in the intention to treat analysis, the reduction in sleepiness versus pretreatment baseline was similar in patients using autoCPAP (n=113, mean ESS-change −6.3, 95% CI −7.1 to −5.5; sleep resistance time +8.3 min, +6.9 to +9.7) and fCPAP (n=95, mean ESS-change −6.2, 95% CI −7.0 to −5.3; sleep resistance time +6.3 min, +4.7 to +7.8). The 95% CI of difference in ESS-reduction between autoCPAP and fCPAP was −0.9 to +1.4 and the 95% CI of difference in increase in sleep resistance time was −2.6 to +1.0 min. Blood pressure reduction and OSAS-related costs were similar between groups.ConclusionsAutoCPAP and fCPAP are equivalent within prespecified ranges in improving subjective and objective sleepiness in patients with OSAS over the course of 2 years. Costs of these treatments are similar.Trial registration numberClinicalTrials.gov NCT00280800.
    Subject(s): Blood pressure ; Care and treatment ; Continuous positive airway pressure ; Hypertension ; Patient outcomes ; Patients ; Quality of life ; Questionnaires ; Research ; Sleep apnea ; Sleep apnea syndromes ; Sleep deprivation ; Studies ; Systematic review ; Thorax ; Usage
    ISSN: 0040-6376
    E-ISSN: 1468-3296
    Source: HighWire Press (Free Journals)
    Source: Alma/SFX Local Collection
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  • 8
    Language: English
    In: American journal of respiratory and critical care medicine, 2010, Vol.182 (4), p.562-568
    Description: Quantitative data on ventilation during acclimatization at very high altitude are scant. Therefore, we monitored nocturnal ventilation and oxygen saturation in mountaineers ascending Mt. Muztagh Ata (7,546 m). To investigate whether periodic breathing persists during prolonged stay at very high altitude. A total of 34 mountaineers (median age, 46 yr; 7 women) climbed from 3,750 m within 19-20 days to the summit at 7,546 m. During ascent, repeated nocturnal recordings of calibrated respiratory inductive plethysmography, pulse oximetry, and scores of acute mountain sickness were obtained. Nocturnal oxygen saturation decreased, whereas minute ventilation and the number of periodic breathing cycles increased with increasing altitude. At the highest camp (6,850 m), median nocturnal oxygen saturation, minute ventilation, and the number of periodic breathing cycles were 64%, 11.3 L/min, and 132.3 cycles/h. Repeated recordings within 5-8 days at 4,497 m and 5,533 m, respectively, revealed increased oxygen saturation, but no decrease in periodic breathing. The number of periodic breathing cycles was positively correlated with days of acclimatization, even when controlled for altitude, oxygen saturation, and other potential confounders, whereas symptoms of acute mountain sickness had no independent effect on periodic breathing. Our field study provides novel data on nocturnal oxygen saturation, breathing patterns, and ventilation at very high altitude. It demonstrates that periodic breathing increases during acclimatization over 2 weeks at altitudes greater than 3,730 m, despite improved oxygen saturation consistent with a progressive increase in loop gain of the respiratory control system. Clinical trial registered with www.clinicaltrials.gov (NCT00514826).
    Subject(s): Abridged Index Medicus ; Acclimatization - physiology ; Adult ; Aged ; Altitude Sickness - complications ; Altitude Sickness - diagnosis ; Altitude Sickness - physiopathology ; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy ; Biological and medical sciences ; China ; Emergency and intensive respiratory care ; Female ; Humans ; Hypoxia - complications ; Hypoxia - diagnosis ; Hypoxia - physiopathology ; Intensive care medicine ; Male ; Medical sciences ; Middle Aged ; Mountaineering - physiology ; Oximetry - methods ; Oxygen Consumption - physiology ; Plethysmography - methods ; Plethysmography - statistics & numerical data ; Polysomnography - methods ; Polysomnography - statistics & numerical data ; Respiration ; Sleep Apnea, Central - complications ; Sleep Apnea, Central - diagnosis ; Sleep Apnea, Central - physiopathology
    ISSN: 1073-449X
    E-ISSN: 1535-4970
    Source: ProQuest Central
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  • 9
    Language: English
    In: Sleep & breathing, 2011-03-30, Vol.16 (2), p.405-412
    Description: Objectives The aim of this study was to assess serum tumor necrosis factor alpha (TNFA) concentrations 8 months of continuous positive airway pressure (CPAP) therapy. Design This study used prospective, observational clinical trial. Patients Sixty-six patients with newly diagnosed sleep apnea syndrome (12 women, 54 men), age 52.3 ± 9.8 (mean ± SD) with a body mass index of 29.7 ± 4.4 and an apnea-hypopnea index of 39.7 ± 26.8, were studied. Intervention CPAP was administered for a mean of 7.8 ± 1.3 months. Measurements and results TNFA concentrations using an ultrasensitive ELISA assay at baseline and follow-up. TNFA decreased in men with high (5.2 ± 1.7 h/night, −0.46 ± 1.1 ng/l, p  = 0.001) and with low (2.5 ± 1.0 h/night −0.63 ± 0.77 ng/l, p  = 0.001) adherence but not in women. Average number of hours of CPAP use correlated positively with delta TNFA ( R 2 0.08, p  = 0.04) Conclusion Long-term CPAP positively affects TNFA even in men with poor adherence to CPAP.
    Subject(s): Abdominal Fat ; Adherence ; Adult ; Biological and medical sciences ; Biomarkers - blood ; Body Composition ; Cerebrospinal fluid. Meninges. Spinal cord ; Continuous Positive Airway Pressure ; CPAP ; Dentistry ; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes ; Enzyme-Linked Immunosorbent Assay ; Female ; Follow-Up Studies ; Fundamental and applied biological sciences. Psychology ; Humans ; Inflammation ; Internal Medicine ; Male ; Medical sciences ; Medicine ; Medicine & Public Health ; Middle Aged ; Nervous system (semeiology, syndromes) ; Neurology ; Obstructive sleep apnea syndrome ; Original Article ; Otorhinolaryngology ; Patient Compliance ; Pediatrics ; Pneumology/Respiratory System ; Polysomnography ; Prospective Studies ; Sex Factors ; Sleep Apnea, Obstructive - blood ; Sleep Apnea, Obstructive - therapy ; Sleep. Vigilance ; Statistics as Topic ; Tumor necrosis factor ; Tumor Necrosis Factor-alpha - blood ; Vertebrates: nervous system and sense organs
    ISSN: 1520-9512
    E-ISSN: 1522-1709
    Source: Alma/SFX Local Collection
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  • 10
    Language: English
    In: Journal of telemedicine and telecare, 2016-06, Vol.22 (4), p.209-214
    Description: Obstructive sleep apnoea syndrome (OSAS) is characterised by repetitive collapse of the upper airway during sleep. Continuous positive airway pressure (CPAP) applied via a mask is the standard treatment for OSAS. CPAP adherence is crucial in therapy to prevent the deleterious consequences of OSAS. We hypothesised that a combination of supervision by telemetry together with targeted telephone support in the first month of CPAP would increase CPAP adherence and treatment success. A total of 113 OSAS patients followed by telemetry-triggered interventions used the device for 5.3 h/night on 28/30 nights, significantly more than the 110 OSAS patients in the control group with 4.6 h/night and 27/30 nights. Telemetry-triggered interventions have a significant impact on adherence rate in early CPAP treatment. These results can be reached with an acceptable additional effort.
    Subject(s): Continuous Positive Airway Pressure - methods ; Female ; Humans ; Male ; Middle Aged ; Patient Compliance ; Pilot Projects ; Sleep Apnea, Obstructive - therapy ; Sleep deprivation ; Telemedicine - methods ; Telemetry ; Telemetry - methods
    ISSN: 1357-633X
    E-ISSN: 1758-1109
    Source: SAGE Complete A-Z List
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