Rapid-eye-movement-specific sleep-disordered breathing: a possible cause of excessive daytime sleepiness.
ABSTRACT Some patients referred for polysomnography with complaints of excessive daytime sleepiness (EDS) and clinically suspected obstructive sleep apnea (OSA) have a respiratory disturbance index (RDI) < 10. Many would consider these patients not to have OSA. We reviewed 34 such patients to determine whether respiratory disturbances confined primarily to rapid eye movement (REM) sleep correlated with an objective criterion for EDS: a mean sleep latency (MSL) < 10 min. REM-specific events were quantified with indices calculated for REM sleep alone. Univariate linear regression showed that a REM-specific respiratory disturbance index (REM-RDI) and the transient arousal index (TAI) computed for REM sleep (REM-TAI) were associated with a low MSL (R2 = -0.35, p = 0.001; and R2 = -0.27, p = 0.01, respectively). In our subjectively sleepy patients with an overall RDI < 10, a REM-RDI > or = 15 had the highest predictive accuracy (82%) for an MSL < 10 min. Seventeen of the 34 study patients had a REM-RDI > or = 15. Their mean MSL was 8.3 +/- 0.8 min. We conclude that within a group of patients with daytime sleepiness, suspected OSA, and a normal RDI, there may be a subset who have clinically significant REM-specific sleep-disordered breathing.
SourceAvailable from: Ganesh K Kumar[Show abstract] [Hide abstract]
ABSTRACT: Apnea, the cessation of breathing, is a common physiological and pathophysiological phenomenon with many basic scientific and clinical implications. Among the different forms of apnea, obstructive sleep apnea (OSA) is clinically the most prominent manifestation. OSA is characterized by repetitive airway occlusions that are typically associated with peripheral airway obstructions. However, it would be a gross oversimplification to conclude that OSA is caused by peripheral obstructions. OSA is the result of a dynamic interplay between chemo- and mechanosensory reflexes, neuromodulation, behavioral state and the differential activation of the central respiratory network and its motor outputs. This interplay has numerous neuronal and cardiovascular consequences that are initially adaptive but in the long-term become major contributors to the morbidity and mortality associated with OSA. However, not only OSA, but all forms of apnea have multiple, and partly overlapping mechanisms. In all cases the underlying mechanisms are neither "exclusively peripheral" nor "exclusively central" in origin. While the emphasis has long been on the role of peripheral reflex pathways in the case of OSA, and central mechanisms in the case of central apneas, we are learning that such a separation is inconsistent with the integration of these mechanisms in all cases of apneas. This review discusses the complex interplay of peripheral and central nervous components that characterizes the cessation of breathing.Respiratory Physiology & Neurobiology 06/2013; 189(2). DOI:10.1016/j.resp.2013.06.004 · 1.97 Impact Factor
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ABSTRACT: Adolescents and young adults with Down syndrome (DS) sometimes experience new-onset mood disorder and decline in adaptive skills. The clinical phenomenon is poorly characterized and its pathogenesis is not understood. The possible contribution of obstructive sleep apnea syndrome (OSAS) to this phenomenon has not been studied. Subjects were ascertained as a convenience sample through our clinic for persons with DS and medical or mental health concerns between 2004 and 2009. When mood symptoms were present an axis I diagnosis was made using DSM-IV-R criteria. Subjects without an axis I diagnosis served as controls. The Reiss scales for children's dual diagnosis and the aberrant behavior checklist (ABC) were completed by caretakers. Twenty-eight cases meeting criteria for major depressive episode (MDE) and nine controls without psychopathology were referred for overnight polysomnography (PSG). Functional decline was reported in 19 (68%) of cases with MDE, but none of the controls. Twenty-four (86%) cases had OSAS compared with only 4 (44%) of controls. Moderate-severe OSAS was present in 15 (54%) of cases compared to only 1 (11%) of controls. Intermittent sleep-associated hypoxia and REM sleep deficits were also more frequent in cases. Across all subjects, prior tonsillectomy was not related to the presence or absence of OSAS. Our findings suggest that OSAS may be a common co-morbidity in adolescents and younger adults with DS and depression. Recognition of this association maybe critical to understanding the pathogenesis and management of mood-related disorders, and functional decline in affected individuals. © 2013 Wiley Periodicals, Inc.American Journal of Medical Genetics Part A 09/2013; 161(9). DOI:10.1002/ajmg.a.36052 · 2.05 Impact Factor
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ABSTRACT: We aimed to investigate if different childhood obstructive sleep apnea (OSA) subtypes, namely rapid eye movement (REM)-related, nonrapid eye movement (NREM)-related and stage-independent OSA would exert different effects on ambulatory blood pressure (ABP). Data from our previous school-based cross-sectional study were reanalyzed. Subjects who had an obstructive apnea-hypopnea index (OAHI) between 1 and 10 events per hour and a total REM sleep duration of >30min were included in our analysis. REM-related and NREM-related OSA were defined as a ratio of OAHI in REM sleep (OAHIREM) to OAHI in NREM sleep (OAHINREM) of >2 and <0.5, respectively. The others were classified as stage-independent OSA. A total of 162 subjects were included in the analysis. In the mild OSA (OAHI, 1-5events/h) subgroup, no significant differences in any ABP parameters were found between OSA subtypes. On the other hand, in subjects with moderate OSA (OAHI, 5-10events/h), the REM-related OSA subtype had a significantly lower daytime systolic blood pressure (SBP) z score (-0.13±0.90 cf 1.15±0.67; P=.012) and nighttime SBP z score (0.29±1.06 cf 1.48±0.88, P=.039) than the stage-independent OSA subtype. Linear regression analyses revealed that OAHINREM but not OAHIREM was significantly associated with both daytime (P=.008) and nighttime SBP (P=.042) after controlling for age, gender, and body size. Children with obstructive events mainly in REM sleep may have less cardiovascular complications than those with stage-independent OSA.Sleep Medicine 10/2013; 14(12). DOI:10.1016/j.sleep.2013.09.017 · 3.10 Impact Factor