Predicting the clinical trajectory of feeding and swallowing abilities in CHARGE syndrome

To date, the feeding and oral-motor abilities of patients with CHARGE syndrome (CS) have not been longitudinally assessed. This study aims to investigate the level of these abilities at different ages and evaluate how they evolve during growth. We retrospectively analysed oral-motor features of 16 patients with molecularly confirmed CS (age range 4-21 years old; mean 11 years; SD 6 years; median 10 years). Nearly 100% of CS new-borns had weak sucking at birth, and half of them demonstrated poor coordination between breathing and swallowing. Over time, the percentages of children with tube feeding dependence (60% at birth) faced a slow but steady decrease (from 33% at 6 months, 25% at 12 months, to 13% at school age) in tandem with the decreasing risk of aspiration. The ability of eating foods requiring chewing was achieved at school age, after the acquisition of an adequate oral sensory processing. A mature chewing pattern with a variety of food textures was not achieved by more than half of patients, including those requiring artificial enteral nutrition. Most patients started prolonged oral-motor treatments with speech language therapists in early childhood.

CONCLUSIONS

Although feeding and swallowing disorders are constant features in CS patients, a slow and gradual development of feeding abilities occurs in most cases. Rehabilitation plays a key role in overcoming structural and functional difficulties and attaining appropriate eating skills.

WHAT IS KNOWN

• Feeding problems and swallowing dysfunction have been noted in CHARGE syndrome. • The involvement of multiple factors, including structural problems in the mouth, throat, or esophagus, and neurological impairment, make feeding a complicated task in CHARGE individuals.

WHAT IS NEW

• Dysphagia gradually improves in most CHARGE children over time, though with a wide interindividual variability. • The percentages of children with tube feeding dependence decrease over time from 60% at birth to 33% at 6 months and 13% at school age.

Drooling outcome measures in paediatric disability: a systematic review

Drooling, or sialorrhea, is a common condition in patients with cerebral palsy, rare diseases, and neurodevelopmental disorders. The goal of this review was to identify the different properties of sialorrhea outcome measures in children. Four databases were analysed in search of sialorrhea measurement tools, and the review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. The COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist was used for quality appraisal of the outcome measures. The initial search yielded 891 articles, 430 of which were duplicates. Thus, 461 full-text articles were evaluated. Among these, 21 met the inclusion criteria, reporting 19 different outcome measures that encompassed both quantitative measures and parent/proxy questionnaires.   Conclusions: Among the outcome measures found through this review, the 5-min Drooling Quotient can objectively discriminate sialorrhea frequency in patients with developmental disabilities. The Drooling Impact Scale can be used to evaluate changes after treatment. The modified drooling questionnaire can measure sialorrhea severity and its social acceptability. To date, the tests proposed in this review are the only tools displaying adequate measurement properties. The acquisition of new data about reliability, validity, and responsiveness of these tests will confirm our findings. What is Known: • Although sialorrhea is a recognized problem in children with disabilities, especially those with cerebral palsy (CP), there is a lack of confidence among physicians in measuring sialorrhea. What is New: • Few sialorrhea measures are available for clinicians that may guide decision-making and at the same time have strong evidence to provide confidence in the results. • A combination of both quantitative measures and parent/proxy questionnaires might provide an adequate measurement of sialorrhea in children.

Internight Variability of Apnea-Hypopnea Index in Obstructive Sleep Apnea Using Ambulatory Polysomnography

Rationale: Patients with obstructive sleep apnea (OSA) experience respiratory events with greater frequency and severity while in the supine sleeping position. Postural preference (associated with the sleep monitoring device) and "first night effect" could explain a night-to-night variability in OSA severity. Objectives: We evaluated the variability of internight polysomnography (PSG) in a large group of OSA patients and explored factors explaining this variability. Methods: 188 patients referred for probable OSA (aged 54.9 ± 11.8 y) underwent two consecutive nights of at-home PSG. The effect of age, gender, obesity, neck circumference, sleep position and sleep parameters were considered to explain changes in respiratory parameters. Main Results: The mean apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were respectively, 36.3 ± 27.5 and 22.0 ± 22.7 in the first night, with a tendency to decrease during the second night. While in mild cases (5 ≤ AHI < 15) there was a significant increase in AHI related to an increase in dorsal position time during the second night, there were no changes in moderate cases (15 ≤ AHI < 30); and in severe cases (AHI ≥ 30) there was a significant decrease in both AHI and ODI during the second night independent of sleep position. Conclusion: The internight variability in AHI and ODI was related to changes in sleep structure with a contribution of indices of sleep fragmentation and dorsal position. Since the changes were greater in mild OSA cases, a second night could be routinely proposed in cases with relevant clinical uncertainty.

Mononucleosis: A Possible Cause of Idiopathic Hypersomnia

Idiopathic hypersomnia (IH) is a rare central hypersomnia of unknown physiopathology. In this study, we determine if the presence of infectious mononucleosis evaluated by serological markers of Epstein Barr virus infection plays a role in this hypersomnia. Ten patients with a suspicion of IH underwent to clinical assessment, 24 h polysomnography, and serologic testing for mononucleosis including Viral Capside Antigen (VCA) IgG, the VCA IgM, and the EBV nuclear antigen (EBNA). None of the patients reported neurological inflammatory disease and viral infection prior the onset of the disease. Compared to the laboratory serological reference values, all patients had high levels of VCA IgG and EBNA with lower level of VCA IgM, overall indicating past infection. This study shows that prior infectious mononucleosis may predispose some subjects to idiopathic hypersomnia suggesting the role of inflammatory and immunological processes in this sleep disorder.

Obstructive Sleep Apnea in Cardiac Rehabilitation Patients

STUDY OBJECTIVES

Although regular physical activity improves obstructive sleep apnea (OSA) in the general population, this finding has not been assessed in postmyocardial infarction (MI) patients in a rehabilitation setting (coronary artery disease, CAD). We aimed to determine whether cardiac rehabilitation may benefit post-MI patients in terms of OSA disease and associated autonomic nervous system (ANS) activity.

METHODS

Consecutive post-MI patients participating in the ambulatory cardiac rehabilitation program of St-Etienne University Hospital were included in this study. The apnea-hypopnea index calculated from electrocardiogram (ECG)-derived respiration (AHIEDR) was obtained through nocturnal Holter ECG recordings. According to AHIEDR, patients were classified as normal, mild, moderate, or severe OSA (< 5, 5-14, 15-29, ≥ 30, respectively). Physiological performance (peak VO2) was established via cardiopulmonary exercise testing. ANS activity was evaluated through spontaneous baroreflex sensibility as well as heart rate variability analysis.

RESULTS

Of the 105 patients with CAD and OSA included (95 men, 55.2 ± 12.4 years), 100 had at least 1 cardiovascular risk factor (98%) and 52 patients (50%) had an ANS dysfunction. Surprisingly, 68 of these patients with OSA (65%) were free of classical diurnal symptoms usually associated with sleep apnea. In response to cardiac rehabilitation, AHIEDR decreased significantly (-9.3 ± 9.5, P < .0001) only in patients with severe OSA, and the decrease was even greater when peak VO2 and baroreflex sensibility improved beyond 20% compared to basal values (-11.6 ± 9.1, P < .001).

CONCLUSIONS

Severe OSA in patients with CAD is significantly improved after 2 months of cardiopulmonary rehabilitation. Reviving ANS activity through physical activity might be a target for complementary therapy of OSA in patients with CAD.

Long-lasting active lifestyle and successful cognitive aging in a healthy elderly population: The PROOF cohort

OBJECTIVES

The aim of this study was to determine whether cognitive reserve in the elderly affects the evolution of cognitive performance and what its relationship is with active lifestyles in later life.

METHODS

Cognitive performance was evaluated at baseline and 8 years later in 543 participants of the PROOF cohort, initially aged 67 years. Subjects were categorized as Cognitively Elite (CE), Cognitively Normal (CN) or Cognitively Impaired (CI) at each evaluation. At follow-up, demographic data and lifestyle, including social, intellectual and physical behaviors, were collected by questionnaires.

RESULTS

As much as 69% (n=375) remained unchanged, while 25.5% (n=138) decreased and 5.5% (n=30) improved. When present, the reduction in cognitive status was most often limited to one level, but was dependent on the initial level, affecting up to 73% of the initially CN, but only 58% of the initially CE. Cognitive stability was significantly associated with the degree of social engagement at follow-up (CE: P=0.009; CN: P=0.025).

CONCLUSION

In the healthy elderly, high cognitive ability predicts both cognitive ability and social involvement in later life. Cognitive decline by only one level may also extend the time to reach impairment, underlining the importance of the so-called cognitive reserve.

Restless Genital Syndrome: Differential Diagnosis and Treatment With Pramipexole

ABSTRACT

Restless genital syndrome refers to excessive and persistent sensations of genital and clitoral arousal with the absence of conscious feeling of sexual desire. These sensations have been linked to symptoms of restless legs syndrome (RLS) or an overactive bladder. Restless genital syndrome may be related to small fiber sensory neuropathy of the dorsal nerve of the clitoris, so it more frequently occurs in women. The association with RLS suggests a possible dopaminergic mechanism. We report a case of a 74-year-old woman who presented restless genital symptoms every night in association with RLS symptoms. During polysomnography she reported 3 awakenings from rapid eye movement sleep with associated genital symptoms followed by a period of insomnia with RLS symptoms and sexual activity. The frequency and the intensity of the symptoms were responsive to treatment by pramipexole after 1 week of treatment and the efficacy was maintained at follow-up.

A 7-year follow-up study of obstructive sleep apnoea in healthy elderly: The PROOF cohort study

BACKGROUND AND OBJECTIVE

Clinical and epidemiological cohort studies have shown that obstructive sleep apnoea (OSA) is a common but largely undiagnosed disorder in senior subjects, where progressive deterioration of the pathology would be expected as a consequence of the ageing processes. Our study examines the longitudinal progression of OSA over a 7-year period in a community-based sample of healthy subjects.

METHODS

The sample consisted of 284 volunteers, aged >65 years (52% women, 48% men) accepting clinical and instrumental follow-up at 7 years. OSA was defined as an apnoea-hypopnoea index (AHI) of ≥15.

RESULTS

Between evaluations in the total sample, AHI slightly decreased from 17.8 ± 14 to 16.7 ± 11 with a decrease affecting more the hypopnoea index (P < 0.001) and associated with significant changes (P < 0.001) in all indices of hypoxaemia. While in the non-OSA group there was a slight but significant increase of AHI, a significant AHI decrease was noted in mild-moderate patients (P < 0.01) and a significant rise of nocturnal hypoxaemia in severe OSA patients (P < 0.001). The AHI decrease was not associated with clinical, weight, metabolic and blood pressure changes between the two evaluations; the baseline AHI value being the only factor correlated to the degree of AHI decline.

CONCLUSIONS

In elderlies, the severity and prevalence of OSA decrease progressively with ageing without effect of factors commonly influencing OSA severity. This trend may support the hypothesis that in healthy elderly, OSA is a phenomenon related to ageing.

Does Subjective Sleep Affect Bone Mineral Density in Older People with Minimal Health Disorders? The PROOF Cohort

STUDY OBJECTIVES

Clinical and epidemiological studies suggest a relation between bone mineral density (BMD) and self-assessment of sleep with an effect on bone formation and osteoporosis (OS) risk in short and long sleepers. This study explores this association in a large sample of older subjects.

METHODS

We examined 500 participants without insomnia complaints aged 65.7 ± 0.8 y. Each participant had a full evaluation including anthropometric measurement, clinical examination and measurements of BMD at the lumbar spine and femoral sites by dual-energy X-ray absorptiometry. The daily energy expenditure (DEE) was measured by the Population Physical Activity Questionnaire. Sleep duration and quality were evaluated by the Pittsburgh Sleep Quality Index. The subjects were stratified into three groups according to sleep duration, i.e., short (< 6 h), normal (6-8 h), and long (≥ 8 h) sleepers.

RESULTS

Osteopenia was found in 40% of the subjects at the femoral level and 43% at the vertebral level. The prevalence of OS was lower both at femoral (8%) and vertebral (12%) levels. Short, normal, and long sleepers accounted for 29%, 40%, and 31% of subjects, respectively. After adjustments for metabolic, anthropometric, and DEE, multinomial logistic regression analysis indicated that long sleepers were more likely to have femoral neck OS with a slight effect of DEE at vertebral spine.

CONCLUSIONS

In a sample of older subjects, self-reported long sleep was the best predictor of OS risk at the femoral level. This finding suggests an association between OS and self-reported sleep duration in older subjects.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

Is there an association between altered baroreceptor sensitivity and obstructive sleep apnoea in the healthy elderly?

Obstructive sleep apnoea (OSA) is associated with a rise in cardiovascular risk in which increased sympathetic activity and depressed baroreceptor reflex sensitivity (BRS) have been proposed. We examined this association in a sample of healthy elderly subjects with unrecognised OSA. 801 healthy elderly (aged ≥65 years) subjects undergoing clinical, respiratory polygraphy and vascular assessment were examined. According to the apnoea-hypopnoea index (AHI), the subjects were stratified into no OSA, mild-moderate OSA and severe OSA cases. OSA was present in 62% of the sample, 62% being mild-moderate and 38% severe. No differences were found for BRS value according to sex and OSA severity. 54% of the group had normal BRS value, 36% mild impairment and 10% severe dysfunction. BRS was negatively associated with body mass index (p=0.006), 24-h systolic (p=0.001) and diastolic pressure (p=0.001), and oxygen desaturation index (ODI) (p=0.03). Regression analyses revealed that subjects with lower BRS were those with hypertension (OR 0.41, 95% CI 0.24-0.81; p=0.002) and overweight (OR 0.42, 95% CI 0.25-0.81; p=0.008), without the effect of AHI and ODI. In the healthy elderly, the presence of a severe BRS dysfunction affects a small amount of severe cases without effect on snorers and mild OSA. Hypertension and obesity seem to play a great role in BRS impairment.

Diurnal and nocturnal cardiovascular variability and heart rate arousal response in idiopathic hypersomnia

OBJECTIVES

Autonomic nervous system dysfunction has been described in narcolepsy with cataplexy affecting sympathetic functions. In this study we analyzed whether altered diurnal and nocturnal cardiovascular control is present in idiopathic hypersomnia (IH).

METHODS

Fourteen drug-free patients aged 26.2 ± 7 years and 14 age-matched controls were examined. Clinical data, 24-h polysomnography, heart rate (HR) variability, and the HR response to spontaneous arousal were available.

RESULTS

Sleep macrostructure was comparable between controls and patients, with the latter having significantly longer sleep time, a higher number of sleep cycles (p < 0.0001), and low sleep efficiency (p < 0.01). The HR variability indices did not differ between groups, except for the rise of high frequency (HF) and HFnu in patients (p < 0.05) associated with blunted sympathetic indices (p < 0.01). These parasympathetic alterations were present for light, slow wave, and rapid eye-movement sleep and persisted for all sleep cycles. Compared to controls, the HR arousal response was significantly higher (p < 0.01) in patients starting before the arousal onset and persisting into the post-arousal period.

CONCLUSIONS

In IH patients a dysfunction of the parasympathetic activity during awake and sleep and an altered autonomic response to arousals are present. These findings suggest an impaired parasympathetic function that may explain some vegetative symptoms present in this type of central hypersomnia.

Chronic intermittent hypoxia and obstructive sleep apnea: an experimental and clinical approach

Obstructive sleep apnea (OSA) is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH) inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity. Overall, these mechanisms have an effect on vessel permeability and are considered to be important factors for explaining vascular, metabolic, and cognitive OSA-related consequences. The present review attempts to examine together the research paradigms and clinical studies on the effect of acute and chronic IH and the potential link with OSA. We firstly describe the literature data on the mechanisms activated by acute and chronic IH at the experimental level, which are very helpful and beneficial to explaining OSA consequences. Then, we describe in detail the effect of IH in patients with OSA that we can consider "the human model" of chronic IH. In this way, we can better understand the specific pathophysiological mechanisms proposed to explain the consequences of IH in OSA.

Echocardiographic Findings in Healthy Elderly People with Unrecognized Sleep Disordered Breathing

OBJECTIVE

Sleep disordered breathing (SDB) is associated with cardiovascular disease such as hypertension and left ventricular hypertrophy in middle-aged patients; however, this association is not well described in the elderly. The aim of this study was to evaluate the impact of unrecognized SDB on cardiac function and remodeling in a population-based sample of healthy elderly without cardiac disease.

METHODOLOGY

A total of 405 healthy elderly (age ≥ 65 years) were examined by echocardiography and respiratory polygraphy. According to the apnea-hypopnea index (AHI), subjects were stratified in four categories: snorers (AHI < 5), mild (AHI: 5-15), moderate (AHI: 15-30), and severe (AHI > 30) cases.

RESULTS

Comparative analysis between snorers and SDB cases revealed that left atrial (LA) diameter and surface increased according to SDB severity (p < 0.05) without differences in LA mass index. In subjects with an AHI > 30, an increase was found for LV end-diastolic and end-systolic dimension (p < 0.001), as well as for LV mass (p < 0.03) and LV index (p < 0.05). The current study showed a weak but significant correlation between altered LA and LV measurements versus AHI and hypoxemia indices (p < 0.001). In the regression analysis, AHI and hypoxemia had a minimal effect, body mass index and male gender being the most significant predictors.

CONCLUSIONS

In a population of healthy elderly with SDB, slight changes in left atrial and ventricular measurements occur in severe cases (AHI > 30). Irrespective of the lack of a strong association between SDB and cardiac dysfunction, the presence of slight cardiac pathology in severe SDB cases might be considered.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

Association of body fat composition and obstructive sleep apnea in the elderly: A longitudinal study

OBJECTIVE

Obesity and aging are considered risk factors for developing sleep apnea syndrome (OSA). The aim of this study was to determine the association between body fat composition and OSA in healthy elderly subjects examined in a 7-year longitudinal study.

METHODS

A total of 209 elderly with unrecognized OSA aged 68.3 ± 0.8 years underwent a clinical, ambulatory nocturnal respiratory recording, and anthropometric as well as body fat composition assessment by dual-energy X-ray absorptiometry (DEXA) at baseline and follow-up.

RESULTS

At study entry, 50.3% of the population showed an apnea+hypopnea index (AHI) <15 with a mean AHI of 16.8 ± 11. At follow-up, a reduction of OSA cases (42%) was evident with a mean AHI of 14.6 ± 10.2. The DEXA data demonstrated that body mass and total lean mass were reduced at follow-up, while central and peripheral fat mass showed a slight increase. Correlation analysis between the changes in DEXA measurements versus the changes in AHI and the indices of nocturnal hypoxemia showed an absence of a statistical correlation.

CONCLUSIONS

The lack of correlation between the DEXA measurement changes and the changes in the AHI confirm our previous data on the absence of a central fat mass effect on OSA in the elderly.

Prevalence and determinants of subjective sleepiness in healthy elderly with unrecognized obstructive sleep apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is associated with behavioral consequences such as excessive daytime sleepiness (EDS). The aim of this study was to establish the presence of sleepiness in elderly with unrecognized OSA and the factors explaining its occurrence.

METHODOLOGY

A total of 825 healthy elderly (aged ≥65 years) undergoing clinical, respiratory polygraphy, and heart-rate variability analysis were studied. According to the apnea-hypopnea index (AHI), the subjects were stratified in four categories: no-OSA (AHI <5), mild (5 > AHI <15), moderate (15 ≥ AHI <30), and severe OSA (AHI ≥30). Participants with EDS were defined on the basis of the Epworth Sleepiness Scale (ESS) score ≥10.

RESULTS

Overall, the mean ESS score was 5.7 ± 5.6, 14.9% showing EDS with an increasing trend according to OSA severity (p <0.001). Sleepy subjects were more frequently men, having a greater body mass index (BMI), alcohol intake, depression score, and indices of OSA severity (23% of severe OSA cases being sleepy). No differences were present between sleepy and non-sleepy subjects in regard to other clinical, metabolic, and autonomic nervous system measurements. Regression analyses adjusted for age, gender, BMI, hypertension, depression score, autonomic sleep fragmentation, and AHI and/or oxygen desaturation index revealed that gender (p <0.0001), depression score (p <0.0001), and BMI (p = 0.01) were the only significant factors affecting the presence of sleepiness in this population.

CONCLUSIONS

In healthy elderly with OSA, the prevalence of EDS was low, and it affected only severe cases. Despite a weak association between the ESS score and the AHI index, male gender and depression score were the most significant predictors for the occurrence of sleepiness.

Eight-year parallel change in baroreflex sensitivity and memory function in a sample of healthy older adults

OBJECTIVES

To examine whether changes in the cardiac autonomic nervous system (ANS) over time, as expressed by baroreflex sensitivity (BRS), were associated with long-term changes in cognitive performance in elderly individuals without dementia.

DESIGN

Community-based 8-year longitudinal study.

SETTING

Clinical settings.

PARTICIPANTS

Individuals aged 66.9 ± 0.9 (N = 425).

MEASUREMENTS

At baseline and follow-up, subjects underwent a clinical interview, autonomic and vascular measurements, and a neuropsychological evaluation including attentional, executive, and memory tests using standardized Z-scores. BRS was defined as being normal, moderate, or severe alteration at each evaluation. On the basis of the longitudinal changes subjects were stratified as being stable, moderate or improved.

RESULTS

Mean attentional, executive, and memory change Z-scores were -0.41 ± 0.9, -0.15 ± 0.7, and -0.14 ± 0.8, respectively. BRS of 56% of the subjects remained unchanged, of 20% decreased, and of 24% improved. After regression analysis, the worsened BRS group was 1.88 times as likely to have greater memory change as the group with stable BRS (P = .02). No significant association was found between longitudinal change in BRS and attentional and executive changes.

CONCLUSION

In healthy elderly individuals, BRS decrease was associated with a weak but significant decrease in memory function. The long-term effect of BRS on memory changes may suggest a role of the ANS in cognitive decline.

Sleep breathing disorders and cognitive function in the elderly: an 8-year follow-up study. the proof-synapse cohort

STUDY OBJECTIVES

Sleep breathing disorder (SBD) may be an important factor in age-related cognitive decline. In a cohort of healthy elderly subjects, we performed an 8-y longitudinal study to assess whether changes in cognitive function occur in untreated elderly patients with SBD and without dementia and the factors implicated in these changes.

DESIGN

A population-based longitudinal study.

SETTING

Clinical research settings.

PARTICIPANTS

A total of 559 participants of the PROOF study aged 67 y at the study entry and free from neurological disorders were examined.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Abnormal breathing events were defined by an apnea-hypopnea index (AHI) > 15. The raw cognitive data and averaged Z-scores for the attentional, executive, and memory functions were collected at the baseline and follow-up. At baseline, AHI > 15 was found in 54% of subjects with 18% having an AHI > 30. At follow-up, the presence of abnormal breathing events was associated with a slight but significant decline in the attentional domain (P = 0.01), which was more evident in the subjects with an AHI > 30 (P = 0.004). No significant changes over time were observed in the executive and memory functions. Several indices of chronic hypoxemia, defined either as a cumulative peripheral oxygen saturation (SpO2) < 90% or a minimal SpO2, accounted for portions of the variance in the decline in attention. All observed effects were small, accounting for 4-7% of variance in multivariate models.

CONCLUSION

In healthy elderly subjects, various components of sleep breathing disorder at baseline were associated with small changes in selected cognitive functions specific to the attention domain after controlling for multiple comorbidities, such as sleepiness, hypertension, diabetes, anxiety, and depression.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT 00759304 and NCT 00766584.

Association of self-reported sleep and hypertension in non-insomniac elderly subjects

OBJECTIVES

Sleep duration and sleep quality play important roles in the development of hypertension (HT) in middle-aged subjects, with controversial data in elderly. In this study, we investigated the link between HT and self-reported sleep in non-insomniac elderly subjects.

METHODS

We examined 500 participants without insomnia complaints aged 72 ± 1 years. An extensive instrumental evaluation was carried out, including 24-h blood pressure (BP) monitoring and an assessment of nocturnal BP dipping. Sleep duration and quality were evaluated by the Pittsburgh Sleep Quality Index (PSQI). The subjects were stratified into three groups according to sleep duration: short (< 6 h), normal (> 6h to < 8 h), and long (> 8 h) sleepers. A PSQI < 5 defined good sleepers (GS, n = 252), and a PSQI > 5 (n = 248) defined poor sleepers (PS).

RESULTS

PS represented 50% of the subjects, more frequently females. Compared to GS, PS did not differ in terms of HT, BP, baroreflex sensitivity (BRS), and BP dipping. Short, normal, and long sleepers accounted for 28%, 42%, and 30% of subjects, with HT, BP values, BRS, and gender not differing between groups. No relationship was found between nocturnal BP values and self-reported sleep measures. Logistic regression analysis indicated that neither sleep duration nor sleep quality predicts the prevalence of HT, the body mass index being the only factor affecting this association.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT00759304 and NCT00766584.

CONCLUSIONS

In a sample of non-insomniac elderly subjects, neither sleep duration nor sleep quality affected the prevalence of HT. These data argue against a relationship between self-reported sleep duration and quality and HT in elderly without insomnia.

An Identifiable State Model To Describe Light Intensity Influence on Microalgae Growth

Despite the high potential as feedstock for the production of fuels and chemicals, the industrial cultivation of microalgae still exhibits many issues. Yield in microalgae cultivation systems is limited by the solar energy that can be harvested. The availability of reliable models representing key phenomena affecting algae growth may help designing and optimizing effective production systems at an industrial level. In this work the complex influence of different light regimes on seawater alga Nannochloropsis salina growth is represented by first principles models. Experimental data such as in vivo fluorescence measurements are employed to develop the model. The proposed model allows description of all growth curves and fluorescence data in a reliable way. The model structure is assessed and modified in order to guarantee the model identifiability and the estimation of its parametric set in a robust and reliable way.

Baroreflex sensitivity, vascular risk factors, and cognitive function in a healthy elderly population: the PROOF cohort

OBJECTIVES

To assess the role of the cardiac autonomic nervous system (ANS), as measured according to spontaneous cardiac baroreflex sensitivity (BRS), in the type and degree of cognitive performance in healthy young-elderly individuals, taking into account the presence of other vascular risk factors.

DESIGN

Community-based cross-sectional study.

SETTING

In-home and clinical settings.

PARTICIPANTS

A subset of participants, aged 66.9±0.9, from a prospective study that aimed to assess the influence of ANS activity on cardiovascular and cerebrovascular morbidity and mortality (N=916).

MEASUREMENTS

All subjects underwent a clinical interview, neuropsychological testing, and autonomic and vascular measurements. Three cognitive domains were defined: attentional (Trail-Making Test Part A, Stroop code and parts I & II), executive (Trail-Making Test Part B, Stroop part III, verbal fluency and similarity tests), and memory (Benton visual retention test, Grober and Buschké procedure). Subjects were stratified according to their scores into normal, low, and impaired performers.

RESULTS

After adjustments to demographic and vascular data, participants with moderate autonomic dysregulation (3<BRS≤6) were determined to be 1.82 times as likely to have memory impairment (odds ratio (OR)=1.82, 95% confidence interval (CI)=1.13-3.17, P=.02) and those with severe autonomic dysregulation (BRS≤3) to be 2.65 as likely (OR=2.65, 95% CI=1.40-5.59, P=.006) as participants with normal BRS (>6).

CONCLUSION

In older individuals without dementia, autonomic dysregulation seems to have a direct, gradual, and independent effect on memory. Future studies are needed to evaluate the long-term effects of BRS and other markers of the ANS on cognitive decline.

Obstructive sleep apnea is associated with preserved bone mineral density in healthy elderly subjects

STUDY OBJECTIVES

Chronic intermittent hypoxia (IH) acts as a stimulator of mesenchymal stem cell (MSC) mobilization, intensifying osteoblast formation in animal models. The recurrence of apnea and oxygen desaturation in obstructive sleep apnea (OSA) may mimic experimental models of IH. We hypothesized that in elderly with OSA, apnea-related IH may mobilize MSCs and thereby prevent the age-related decline in osteogenesis. This study explored the relationship between OSA and bone mineral density (BMD), and the effect of IH on BMD, in a large sample of elderly subjects.

PARTICIPANTS

There were 833 volunteers age 68.6 ± 0.8 y (59% women).

INTERVENTION

Each participant underwent evaluation of BMD at lumbar spine and femoral sites by dual-energy x-ray absorptiometry (DEXA) as well as clinical and polygraphic examinations. OSA was diagnosed on the basis of an apnea-hypopnea index (AHI) ≥ 15.

MEASUREMENTS AND RESULTS

There were 55% of the participants who presented with OSA, and these subjects were predominantly male and overweight. Compared with subjects without OSA, those with OSA had a higher femoral and spinal BMD (P < 0.001). Body mass index (BMI), AHI, and oxygen desaturation index (ODI) (P < 0.01) were significantly related to BMD. After adjustment for sex, BMI, metabolic values, and hypertension, multiple regression analysis showed a significant association between femoral and lumbar T scores and both daily energy expenditure (P < 0.001) and ODI (P = 0.007).

CONCLUSIONS

In elderly subjects, the presence of obstructive sleep apnea is associated with higher bone mineral density, with oxygen desaturation index being a significant determinant of bone metabolism. These results suggest that apnea-related intermittent hypoxia may stimulate the bone remodeling process in older population.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

Association between severe obstructive sleep apnea and incident arterial hypertension in the older people population

OBJECTIVES

The impact of sleep-related breathing disorders on the incidence of arterial hypertension (AHT) in the older adults is not well-established. The aim of our study was to test the link between severe obstructive sleep apnea (OSA) and the occurrence of hypertension in older subjects after 3 years.

METHODS

372 normotensive subjects with a mean age of 68.2 years were included in our longitudinal study. All participants had a ventilatory polygraphic recording and an ambulatory blood pressure (BP) monitoring at baseline and after 3 years. Severe OSA was defined by an apnea-hypopnea index (AHI) of ≥ P30 per hour. A new onset of hypertension was defined according to a mean 24-hour value >140mmHg for systolic BP and >85mmHg for diastolic BP or the use of antihypertensive medication.

RESULTS

The baseline factors significantly associated with an increased risk for new-onset hypertension were male gender, obesity, diabetes mellitus (DM), dyslipidemia, and OSA. Multiple logistic regression analyses showed that an AHI ≥30 per hour was independently associated with incident hypertension after 3 years (P=.02; odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-2.8).

CONCLUSIONS

The presence of severe OSA is associated with new-onset AHT in normotensive elderly (mean age, 68.2 y) subjects.

Relation of central fat mass to obstructive sleep apnea in the elderly

STUDY OBJECTIVES

Obesity is a recognized risk factor for obstructive sleep apnea syndrome (OSAS). We evaluated whether total trunk and central fat mass (CFM) is associated with OSAS in elderly subjects.

DESIGN

Cross-sectional.

SETTING

Body composition assessment by dual-energy X-ray absorbsiometry (DEXA).

PARTICIPANTS

749 volunteers aged 67.2 ± 0.8 years (59.4% women).

INTERVENTION

All participants underwent evaluation of their body composition by DEXA in parallel with clinical and polygraphic assessments. The presence of OSAS was defined by an apnea plus hypopnea index (AHI) ≥ 15.

MEASUREMENTS AND RESULTS

A total of 44.8% of the population had an AHI < 15, and 55.2% presented OSAS. OSAS subjects were more frequently overweight and had a higher total trunk fat mass and central fat mass (CFM). Correlation analyses revealed that body mass index (r = 0.27, P < 0.001), neck circumference (r = 0.35, P < 0.001), and CFM (r = 0.23, P < 0.001) were significantly related to AHI. Logistic regression analysis indicated that in mild OSAS cases (> 15AHI < 30), BMI (OR: 1.10; 95% CI: 1.03-1.18; P = 0.008), and male gender (OR: 1.49; 95% CI: 1.05-2.12, P = 0.03) were key factors explaining an AHI between 15 and 30. In severe cases (AHI > 30), male gender (OR: 3.65; 95% CI: 2.40-5.55; P < 0.001) and CFM (OR: 1.10; 95% CI: 1.03-1.19; P = 0.009) were significant independent predictors of OSAS.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

CONCLUSIONS

Although central fat mass plays a role in the occurrence of severe OSAS in men older than 65 years of age, its low discriminative sensitivity in mild OSAS cases does not warrant systematic use of DEXA for the diagnosis of OSAS.

Sleep apnea syndrome and cognition

Obstructive sleep apnea (OSA) is a sleep-related breathing disorder characterized by repetitive episodes of airflow cessation resulting in brief arousals and intermittent hypoxemia. Several studies have documented significant daytime cognitive and behavioral dysfunction that seems to extend beyond that associated with simple sleepiness and that persists in some patients after therapeutic intervention. A still unanswered question is whether cognitive symptoms in OSA are primarily a consequence of sleep fragmentation and hypoxemia, or whether they coexist independently from OSA. Moreover, very little is known about OSA effects on cognitive performances in the elderly in whom an increased prevalence of OSA is present. In this review we will consider recent reports in the association between sleep apnea and cognition, with specific interest in elderly subjects, in whom sleep disturbances and age-related cognitive decline naturally occur. This will allow us to elucidate the behavioral and cognitive functions in OSA patients and to gain insight into age differences in the cognitive impairment. Clinically, these outcomes will aid clinicians in the evaluation of diurnal consequences of OSA and the need to propose early treatment.

A 3-year longitudinal study of sleep disordered breathing in the elderly

Limited and controversial data exist on the natural evolution of sleep disordered breathing (SDB) in untreated individuals. This study examines the evolution of SDB over a 3-yr period in a community-based sample of elderly subjects. From the initial cohort of 854 healthy subjects aged mean ± SD 68.4 ± 0.8 yrs, 519 untreated subjects accepted clinical and instrumental follow-up 3.6 ± 1.6 yrs later. SDB was defined as a respiratory disturbance index (RDI) >15 events · h(-1). At baseline, 202 (39%) subjects had an RDI ≤ 15 events · h(-1) and 317 (61%) had an RDI >15 events · h(-1). 3 yrs later, 280 (54%) subjects were non-SDB and 239 (46%) had SDB. Between evaluations, the RDI decreased from 22.3 ± 16.2 to 16.4 ± 13.0 events · h(-1), with a greater decrease in the number of cases with an RDI >30 events · h(-1) that in those with RDI ≥ 30 events · h(-1). In the non-SDB group, 81% had a stable RDI and 19% increased their RDI by a mean of 13.7 events · h(-1). In the SDB group, the RDI decreased to values ≤ 15 events · h(-1) in 36.6% of cases, 63.4% still having SDB. The RDI changes did not depend on weight changes. In healthy elderly subjects, the prevalence and severity of SDB did not show a tendency toward natural worsening, some cases having improvement or a remission independent of weight changes. These findings also suggest that in the elderly, natural SDB progression is still hypothetical.

Autonomic activation during sleep and new-onset ambulatory hypertension in the elderly

BACKGROUND

Sympathetic "overactivity" during night is a well recognized factor of hypertension development in adults. However, the deleterious effect of nocturnal autonomic activation in elderly remains controversial.

METHODS

Subjects, all aged 65 years at baseline, were selected from the PROOF cohort study, a prospective observational cohort of subjects. Exclusion criteria were previous myocardial infarction, stroke, heart failure, type-1 diabetes, atrial fibrillation or anti-arrhythmic drug. Normotensive subjects were selected according to: 24-h ambulatory blood pressure (BP) measurements <135/85 mm Hg, absence of self-report antihypertensive treatment. Autonomic activation during sleep was evaluated from night-time ECG Holter recording. According the %VLFI (Very-Low Frequency component of Interbeat Interval Increment evaluated from heart rate variability analysis). Subjects with new-onset ambulatory hypertension were identified after two years when daytime ambulatory blood pressure was higher than 135/85 mm Hg or when they used an antihypertensive treatment.

RESULTS

Among 428 normotensive subjects at inclusion, 62 (14.5%) were considered as hypertensives after two years. Univariate logistic regression model showed a significant association between abnormal %VLFI (>4%) and new-onset hypertension: OR = 1.78 (1.03-3.07). Male gender, increased body mass index and ambulatory systolic BP were also associated with increased risk of hypertension. After adjustment in the stepwise logistic regression, abnormal %VLFI was associated with an 82% increase in odds of new-onset hypertension, independently of systolic ABPM and body mass index.

CONCLUSION

Repeated autonomic activation during sleep, whatever the origin of the phenomenon, may trigger hypertension development in the elderly.

Obstructive sleep apnea and the metabolic syndrome in an elderly healthy population: the SYNAPSE cohort

BACKGROUND

Obstructive sleep apnea syndrome (OSA) has been recently considered as a cause and a component of the metabolic syndrome (MetS), previous studies showing the presence of OSA in about half of middle-aged patients having MetS. To date, no study has considered the association of OSA and MetS in the elderly. In this study we examine the prevalence of MetS and its strength association among healthy elderly OSA subjects.

METHODS

A cohort of 806 subjects aged 68.5 years, participants of a 7-year follow-up study, was examined. All subjects underwent clinical evaluation, blood sample measurements, and an at-home polygraphy. OSA was assessed as an apnea/hypopnea index (AHI) >15, and MetS was diagnosed according to the Adult Treatment Panel III.

RESULTS

In the total group, 9.8% of cases met criteria for MetS with a prevalence similar in men and women. Of the entire group with Mets, 51.3% were women and 48.7% men. OSA was diagnosed in 55.9% of the sample, and among the OSA group, 12.5% had MetS. Oxyhemoglobin desaturation index (ODI, p < 0.0001) and AHI (p = 0.003) were found significantly higher in subjects with MetS than in those without it. Most of MetS components were significantly associated with AHI and ODI, the relationship stronger with ODI. After adjustment for covariables such as obesity, gender, and presence of diabetes, ODI was independently associated with three MetS components, glycemia (p < 0.0001), hypertension (p = 0.002), and triglyceride levels (p = 0.02). Sleepiness, autonomic arousal index, and sleep duration had no effect on the metabolic parameters.

CONCLUSIONS

In elderly subjects, the association between OSA and MetS was stronger for hyperglycemia and hypertension. Among factors explaining this association, hypoxemia appears to be the most important factor without any effect of indices of sleep fragmentation, sleep duration, and sleepiness.

Pulse transit time in screening sleep disordered breathing in an elderly population: the PROOF-SYNAPSE study

STUDY OBJECTIVES

Pulse transit time (PPT) has been introduced as a useful screening tool to diagnose sleep disordered breathing (SDB). Since the prevalence of SDB increases with age, the question is whether PTT could be used to diagnose SDB in the elderly. We assess the effectiveness of PTT for SDB screening in a large healthy elderly population.

SETTING

Community-based sample in home and research clinical settings.

INTERVENTION

N/A.

PARTICIPANTS

Seven hundred eighty volunteers, free of cardiac and neurologic disease, aged 68.6 ± 1.0 years, underwent ambulatory polygraphy to measure the apnea-hypopnea index (AHI). The presence of SDB was defined as an AHI of 15 or greater. The PTT was continuously monitored during the nocturnal study, and the overall autonomic arousal index (AAI) was calculated.

RESULTS

SDB was diagnosed in 447 (57.3%) subjects. In these subjects, the Bland-Altman plot for AAI revealed an underestimation with a bias of -8.04 ± 16.55 events per hour (mean ± 95% confidence interval). Receiver operating characteristic curves constructed for an AHI of 15 or greater defined an area under the curve of 0.67 and a cutoff point to AAI 32.3 events per hour, giving a sensitivity of 70.5% and a specificity of 54.7%. For prediction of an AHI of at least 30, the area under the curve was equal to 0.74 for a cutoff point of 56.3 events per hour, giving a better specificity (94.7%) but a lower sensitivity (32.2%).

CONCLUSIONS

In a healthy older population, the AAI showed moderate sensitivity for predicting SDB. This data does not allow us to use PTT as a screening tool for the diagnosis of SDB in the elderly.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

Idiopathic hypersomnia: a report of three adolescent-onset cases in a two-generation family

Idiopathic hypersomnia is an uncommon sleep disorder characterized by prolonged sleep time and excessive daytime sleepiness without cataplexy. This study concerned a case of familial occurrence. The proband expressed an idiopathic hypersomnia with long sleep time at the age of 12 years. Clinical interview and ad libitum polysomnographic study did not reveal any symptoms of narcolepsy or other sleep disorders. Family history revealed that a 20-year-old sister had experienced symptoms of hypersomnia from the age of 16 and their mother had been diagnosed with idiopathic hypersomnia previously. The diagnosis of idiopathic hypersomnia with long sleep time was confirmed in the sister by clinical interview and ad libitum polysomnography. Human leukocyte antigen (HLA) did not reveal the DQB1-0602 phenotype in the proband and relatives. This report confirms the hypothesis of a genetic predisposition in idiopathic hypersomnia.

Sex differences in obstructive sleep apnoea in an elderly French population

Obstructive sleep apnoea (OSA) affects females and males differently, and increases in prevalence with age. The aim of the present study was to characterise clinical, anthropometric and polygraphic sex differences in a large elderly OSA population. A total of 641 subjects aged 68 yrs were examined. Measurements of fat mass, using dual-energy X-ray absorptiometry (DEXA) and polygraphy, were obtained in all subjects. An apnoea/hypopnoea index (AHI) of >15 events·h⁻¹ identified the presence of OSA. OSA was diagnosed in 57% of the sample, 34% having a mild form and 23% having an AHI of >30 events·h⁻¹. Females with OSA exhibited a lower AHI, less severe hypoxaemia and greater peripheral fat mass, and frequently reported anxiety and depression. Comparison of females with and without OSA did not reveal significant differences in clinical, anthropometric and DEXA data. After adjustment for body mass index, hypertension, diabetes, smoking, anxiety and depression, logistic regression analysis revealed that the presence of hypertension was significantly associated with OSA risk in females (OR 1.52, p = 0.04). In a general community healthy population, the prevalence of undiagnosed OSA in females increases with age, with a risk similar to that in males. In females, the clinical spectrum, anthropometric data and fat distribution appear to be more sex-related than OSA-dependent. The occurrence of OSA contributes to hypertensive risk in elderly females.

Cognitive function and sleep related breathing disorders in a healthy elderly population: the SYNAPSE study

STUDY OBJECTIVES

Sleep related breathing disorders (SRBD) are risk factors for cognitive dysfunction in middle-aged subjects, but this association has not been observed in the elderly. We assess the impact of SRBD on cognitive performance in a large cohort of healthy elderly subjects.

DESIGN

Cross-sectional study examining the association between subjective memory test, neuropsychological battery testing and SRBD in the elderly.

SETTING

Community-based sample in home and research clinical settings.

PARTICIPANTS

827 subjects, 58.5% women, aged 68 y at study entry, participated in the study. All were free of previously diagnosed SRBD, coronary heart disease, and neurological disorders, including stroke and dementia. Clinical interview, neurological assessment, polygraphy, and extensive cognitive testing were conducted for all participants.

INTERVENTION

N/A.

MEASUREMENT AND RESULTS

SRBD (apnea-hypopnea index [AHI] > 15 events/h) was diagnosed in 445 (53%) subjects, 167 (37%) of them with AHI > 30. Minimal daytime sleepiness was found in the group; 9.2% of the population had an Epworth Sleepiness Scale score > 10. No significant association was found between AHI, nocturnal hypoxemia, and cognitive scores. Comparison of mild vs severe cases showed a trend toward lower cognitive scores with AHI > 30, affecting delayed recall and Stroop test.

CONCLUSIONS

The impact of undiagnosed SRBD on cognitive function appeared quite limited in a generally older healthy population, and only slightly affected severe cases. The implication of undiagnosed SRBD on the cognitive impairment in elderly subjects remains hypothetical and needs to be prospectively studied.

Is tidal expiratory flow limitation predictive of sleep-related disorders in the elderly?

Sleep-related disorders represent an important health burden and their prevalence increases with age. In patients with snoring or sleepiness, the presence of expiratory flow limitation (EFL), determined via the negative expiratory pressure (NEP) method, is related to the apnoea/hypopnoea index (AHI). In this study, we examined whether EFL can be used to predict obstructive sleep apnoea syndrome (OSAS) in healthy asymptomatic older subjects. A group of 72-yr-old subjects (n = 448, 44% males) with a mean body mass index of 25.5±3.8 kg·m(-2) were examined. All subjects underwent spirometry, NEP (-5 cmH(2)O, sitting position) and ventilatory polygraphy (VP). Spirometry was within normal values in 88% of the group and EFL was present in 143 (32%) subjects with a higher prevalence in females (89 out of 249 versus 54 out of 199 in females and males, respectively). VP showed an AHI<15 h(-1) in 238 subjects (53%) and OSAS with an AHI ≥15 h(-1) in 47%. EFL was found in 15% of subjects with OSAS. Consequently, EFL had low sensitivity and specificity in the prediction of OSAS (31.4% and 67.7%, respectively). We conclude that the prevalence of EFL is elevated in healthy older subjects and cannot be used to predict the presence of sleep-related disorders in an older population.

Prevalence and clinical correlates of restless legs syndrome in an elderly French population: the synapse study

BACKGROUND

The occurrence of restless legs syndrome (RLS) in elderly individuals is well known but the incidence and the clinical correlates in these subjects are still unclear. The present study explores the prevalence of and assesses symptoms associated with RLS in an older French population.

METHODS

The study sample for this study comprised 318 subjects (219 women and 99 men), aged 68.6 +/- 0.8 years. All subjects underwent clinical assessment, nocturnal polygraphy, and cognitive and mood disorders evaluation. RLS was assessed with the standard validated criteria and severity was evaluated by the use of International Restless Legs Syndrome Study Group (IRLS) questionnaire.

RESULTS

RLS was present in 24.2% of the sample, prevalence being greater in women (29.7%) than in men (12.1%). The mean IRLS score was 16.6 +/- 4.8, 67% of cases having mild to moderate range. Participants with RLS reported greater hypnotic (p < .001) and antidepressant medication intake (p < .001) and had higher anxiety (p < .001) and depression (p < .001) scores. Participants with RLS had lower cognitive performances at Stroop and Verbal fluency tests than participants without RLS (p < .05 and p = .002, respectively). These associations remained significant after multivariate adjustment for medication, depression, and subjective sleep.

CONCLUSIONS

Presence of undiagnosed RLS is higher in healthy elderly participants without previously diagnosed sleep disorders, affecting women more often than men. The presence of RLS increased the risk of anxiety and mood disorders and predispose to preclinical cognitive decline independently of anxiety, mood disorders, duration and quality of sleep, and medication.

Lack of specific gray matter alterations in restless legs syndrome in elderly subjects

Magnetic resonance imaging studies using voxel-based morphometry (VBM) have been inconsistent in demonstrating volumetric differences in patients with restless legs syndrome (RLS). Since treatment, age and selection of patients may introduce a methodological bias, we conducted optimized VBM analyses in unmedicated elderly subjects reporting RLS. Two hundred-four voluntaries, 65.9 +/- 0.6 year-old, free of any significant medical condition and without previous neurological or psychiatric medication, participated at the study. After exclusion of subjects having sleep-related breathing disorders and previous silent infarct, 71 subjects, 54 without RLS (RLS-) and 17 having RLS (RLS+) were analyzed. No structural change in gray matter density was found in RLS+ subjects compared to RLS- subjects. Subjects with RLS+ symptoms showed a small gray matter volume in the left occipital region without, however, statistical significance. VBM analysis did not show any significant change in subcortical and cortical gray matter in unmedicated elderly subjects with RLS symptoms. These results confirm the lack of specificity of thalamic and subcortical changes in restless legs syndrome.

Association between C-reactive protein and unrecognised sleep-disordered breathing in the elderly

Elevated levels of C-reactive protein (CRP) have been reported in patients with sleep-disordered breathing (SDB) and may represent an inflammatory marker of cardiovascular risk. However, the association of CRP with SBD in presumed healthy elderly subjects is unknown. In total, 851 (58.5% females) 68-yr-old subjects, who were free of any known cardiac or sleep disorders, were prospectively examined. Subjects underwent unattended polygraphy, and the apnoea/hypopnoea index (AHI) and oxyhaemoglobin desaturation index (ODI) were assessed. Elevated levels of CRP were found on the morning after the sleep study in patients with more severe SDB. A significant correlation was found between CRP levels, time spent at night with arterial oxygen saturation <90% and ODI. No association was found between CRP levels and AHI. After adjustments for body mass index, smoking status, hypertension, diabetes and dyslipidaemia, a significant association remained between CRP levels and ODI >10 events.h(-1). CRP levels were frequently increased in a large sample of elderly subjects free of major cardiovascular disease. CRP levels were not correlated with the AHI and the indices of sleep fragmentation; the ODI >10 events.h(-1) was the strongest predictor of raised CRP level. The present results suggest that, in the elderly, intermittent hypoxaemia may underlie inflammatory processes leading to cardiovascular morbidity.

Obstructive sleep apnoea/hypopnea influences high-density lipoprotein cholesterol in the elderly

BACKGROUND AND PURPOSE

An association between obstructive sleep apnoea/hypopnea (OSAH) and cardiovascular risk factors such as dyslipidemia has been described in adults and high-risk populations.

PATIENTS AND METHODS

We examined this association in a prospective cohort (SYNAPSE study) of 846 elderly (68.5+/-1.1 years) volunteers (41.6% of men). No subject presented with recognized OSAH syndrome, heart disease, or any neurological disorder. Unattended at-home polygraphy was done by all subjects. OSAH severity was defined as moderate (apnoea/hypopnea index: AHI>15/h) or severe (AHI>30/h). High-density lipoprotein cholesterol (HDL-c) was measured by immuno-separation-based homogenous assay.

RESULTS

The prevalence of severe cases reached 21.5% (AHI mean+/-SD: 43.5+/-11.9). Using univariate linear regression analysis, AHI (R=-0.172; p<0.0001), oxyhemoglobin desaturation index (ODI) (R=-0.108; p<0.002), mean SaO(2) (R=0.125; p<0.0003) and Nadir SaO(2) (R=0.094; p<0.007) were significantly associated with HDL-c. Multiple regression analysis demonstrated that male gender, BMI, waist to hip ratio, ODI, and AHI represent independent predictors of HDL-c. Logistic regression analysis showed a significant association between severe OSAH and low HDL-c serum levels (p<0.03) after adjustment for gender, BMI, hypertension, glycaemia, waist to hip ratio, alcohol intake and treated dyslipidemia. The association appears more evident in subjects free of lipid-lowering medications and beta-blockers (p<0.007). There was no independent association of OSAH syndrome with low-density lipoprotein (LDL) cholesterol.

CONCLUSION

Unrecognized moderate to severe apnoea/hypopnea syndrome was independently associated with low HDL-c serum levels in the present cross-sectional based elderly population. This could explain the deleterious effect of OSAH syndrome on cardiovascular risk.

Neurobiology of sleep fragmentation: cortical and autonomic markers of sleep disorders

New insights into the physiopathological correlates of arousal and sleep fragmentation have recently been gained through experimental and clinical studies in healthy individuals and in patients with sleep disorders. The development of new analyses of autonomic system during sleep, has enriched the knowledge of sleep fragmentation derived from electroencephalographic analysis and has made possible the characterization of other phasic events arising from sleep, such as autonomic arousals. All of these studies provide evidence in support of the hypothesis that autonomic activations without cortical involvement are an epiphenomena of sleep fragmentation and altered sleep continuity, similar to that induced by cortical activation. This review begins by describing the latest findings on type of arousal response, with regards to the effect of arousing stimuli on the brain and the autonomic system. It then focuses on the hotly debated issue on experimental and clinical physiopathology of the arousals without cortical activation, highlighting the results of novel studies on the neural substrates mediating these response. Finally, we address the current question on clinical significance of sleep fragmentation to understand if arousal per se, cortical or autonomic, has an impact on daytime functioning, cardiovascular consequences and cognitive sequelae.