Showing papers on "Polysomnography published in 2000"

Prospective study of the association between sleep-disordered breathing and hypertension.

Abstract: Background Sleep-disordered breathing is prevalent in the general population and has been linked to chronically elevated blood pressure in cross-sectional epidemiologic studies. We performed a prospective, population-based study of the association between objectively measured sleep-disordered breathing and hypertension (defined as a laboratory-measured blood pressure of at least 140/90 mm Hg or the use of antihypertensive medications). Methods We analyzed data on sleep-disordered breathing, blood pressure, habitus, and health history at base line and after four years of follow-up in 709 participants of the Wisconsin Sleep Cohort Study (and after eight years of follow-up in the case of 184 of these participants). Participants were assessed overnight by 18-channel polysomnography for sleep-disordered breathing, as defined by the apnea–hypopnea index (the number of episodes of apnea and hypopnea per hour of sleep). The odds ratios for the presence of hypertension at the four-year follow-up study according to...

Association of Sleep-Disordered Breathing, Sleep Apnea, and Hypertension in a Large Community-Based Study

Abstract: ContextSleep-disordered breathing (SDB) and sleep apnea have been linked to hypertension in previous studies, but most of these studies used surrogate information to define SDB (eg, snoring) and were based on small clinic populations, or both.ObjectiveTo assess the association between SDB and hypertension in a large cohort of middle-aged and older persons.Design and SettingCross-sectional analyses of participants in the Sleep Heart Health Study, a community-based multicenter study conducted between November 1995 and January 1998.ParticipantsA total of 6132 subjects recruited from ongoing population-based studies (aged ≥40 years; 52.8% female).Main Outcome MeasuresApnea-hypopnea index (AHI, the average number of apneas plus hypopneas per hour of sleep, with apnea defined as a cessation of airflow and hypopnea defined as a ≥30% reduction in airflow or thoracoabdominal excursion both of which are accompanied by a ≥4% drop in oxyhemoglobin saturation), obtained by unattended home polysomnography. Other measures include arousal index; percentage of sleep time below 90% oxygen saturation; history of snoring; and presence of hypertension, defined as resting blood pressure of at least 140/90 mm Hg or use of antihypertensive medication.ResultsMean systolic and diastolic blood pressure and prevalence of hypertension increased significantly with increasing SDB measures, although some of this association was explained by body mass index (BMI). After adjusting for demographics and anthropometric variables (including BMI, neck circumference, and waist-to-hip ratio), as well as for alcohol intake and smoking, the odds ratio for hypertension, comparing the highest category of AHI (≥30 per hour) with the lowest category (<1.5 per hour), was 1.37 (95% confidence interval [CI], 1.03-1.83; P for trend=.005). The corresponding estimate comparing the highest and lowest categories of percentage of sleep time below 90% oxygen saturation (≥12% vs <0.05%) was 1.46 (95% CI, 1.12-1.88; P for trend <.001). In stratified analyses, associations of hypertension with either measure of SDB were seen in both sexes, older and younger ages, all ethnic groups, and among normal-weight and overweight individuals. Weaker and nonsignificant associations were observed for the arousal index or self-reported history of habitual snoring.ConclusionOur findings from the largest cross-sectional study to date indicate that SDB is associated with systemic hypertension in middle-aged and older individuals of different sexes and ethnic backgrounds.

Neural basis of alertness and cognitive performance impairments during sleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity.

Abstract: The negative effects of sleep deprivation on alertness and cognitive performance suggest decreases in brain activity and function, primarily in the thalamus, a subcortical structure involved in alertness and attention, and in the prefrontal cortex, a region subserving alertness, attention, and higher-order cognitive processes. To test this hypothesis, 17 normal subjects were scanned for quantifiable brain activity changes during 85 h of sleep deprivation using positron emission tomography (PET) and (18)Fluorine-2-deoxyglucose ((18)FDG), a marker for regional cerebral metabolic rate for glucose (CMRglu) and neuronal synaptic activity. Subjects were scanned prior to and at 24-h intervals during the sleep deprivation period, for a total of four scans per subject. During each 30 min (18)FDG uptake, subjects performed a sleep deprivation-sensitive Serial Addition/Subtraction task. Polysomnographic monitoring confirmed that subjects were awake. Twenty-four hours of sleep deprivation, reported here, resulted in a significant decrease in global CMRglu, and significant decreases in absolute regional CMRglu in several cortical and subcortical structures. No areas of the brain evidenced a significant increase in absolute regional CMRglu. Significant decreases in relative regional CMRglu, reflecting regional brain reductions greater than the global decrease, occurred predominantly in the thalamus and prefrontal and posterior parietal cortices. Alertness and cognitive performance declined in association with these brain deactivations. This study provides evidence that short-term sleep deprivation produces global decreases in brain activity, with larger reductions in activity in the distributed cortico-thalamic network mediating attention and higher-order cognitive processes, and is complementary to studies demonstrating deactivation of these cortical regions during NREM and REM sleep.

Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study

Abstract: Objective: To assess whether sleep apnoea syndrome is an independent risk factor for hypertension Design: Population study Setting: Sleep clinic in Toronto Participants: 2677 adults, aged 20-85 years, referred to the sleep clinic with suspected sleep apnoea syndrome Outcome measures: Medical history, demographic data, morning and evening blood pressure, and whole night polysomnography Results: Blood pressure and number of patients with hypertension increased linearly with severity of sleep apnoea, as shown by the apnoea-hypopnoea index Multiple regression analysis of blood pressure levels of all patients not taking antihypertensives showed that apnoea was a significant predictor of both systolic and diastolic blood pressure after adjustment for age, body mass index, and sex Multiple logistic regression showed that each additional apnoeic event per hour of sleep increased the odds of hypertension by about 1%, whereas each 10% decrease in nocturnal oxygen saturation increased the odds by 13% Conclusion: Sleep apnoea syndrome is profoundly associated with hypertension independent of all relevant risk factors

Age-related changes in slow wave sleep and REM sleep and relationship with growth hormone and cortisol levels in healthy men.

Abstract: ContextIn young adults, sleep affects the regulation of growth hormone (GH) and cortisol The relationship between decreased sleep quality in older adults and age-related changes in the regulation of GH and cortisol is unknownObjectiveTo determine the chronology of age-related changes in sleep duration and quality (sleep stages) in healthy men and whether concomitant alterations occur in GH and cortisol levelsDesign and SettingData combined from a series of studies conducted between 1985 and 1999 at 4 laboratoriesSubjectsA total of 149 healthy men, aged 16 to 83 years, with a mean (SD) body mass index of 241 (23) kg/m2, without sleep complaints or histories of endocrine, psychiatric, or sleep disordersMain Outcome MeasuresTwenty-four–hour profiles of plasma GH and cortisol levels and polygraphic sleep recordingsResultsThe mean (SEM) percentage of deep slow wave sleep decreased from 189% (13%) during early adulthood (age 16-25 years) to 34% (10%) during midlife (age 36-50 years) and was replaced by lighter sleep (stages 1 and 2) without significant increases in sleep fragmentation or decreases in rapid eye movement (REM) sleep The transition from midlife to late life (age 71-83 years) involved no further significant decrease in slow wave sleep but an increase in time awake of 28 minutes per decade at the expense of decreases in both light non-REM sleep (−24 minutes per decade; P<001) and REM sleep (−10 minutes per decade; P<001) The decline in slow wave sleep from early adulthood to midlife was paralleled by a major decline in GH secretion (−372 µg per decade; P<001) From midlife to late life, GH secretion further declined at a slower rate (−43 µg per decade; P<02) Independently of age, the amount of GH secretion was significantly associated with slow wave sleep (P<001) Increasing age was associated with an elevation of evening cortisol levels (+193 nmol/L per decade; P<001) that became significant only after age 50 years, when sleep became more fragmented and REM sleep declined A trend for an association between lower amounts of REM sleep and higher evening cortisol concentrations independent of age was detected (P<10)ConclusionsIn men, age-related changes in slow wave sleep and REM sleep occur with markedly different chronologies and are each associated with specific hormonal alterations Future studies should evaluate whether strategies to enhance sleep quality may have beneficial hormonal effects

Nocturnal Pulse Oximetry as an Abbreviated Testing Modality for Pediatric Obstructive Sleep Apnea

Abstract: Objective. To determine the utility of pulse oximetry for diagnosis of obstructive sleep apnea (OSA) in children. Methods. We performed a cross-sectional study of 349 patients referred to a pediatric sleep laboratory for possible OSA. A mixed/obstructive apnea/hypopnea index (MOAHI) greater than or equal to 1 on nocturnal polysomnography (PSG) defined OSA. A sleep laboratory physician read nocturnal oximetry trend and event graphs, blinded to clinical and polysomnographic results. Likelihood ratios were used to determine the change in probability of having OSA before and after oximetry results were known. Results. Of 349 patients, 210 (60%) had OSA as defined polysomnographically. Oximetry trend graphs were classified as positive for OSA in 93 and negative or inconclusive in 256 patients. Of the 93 oximetry results read as positive, PSG confirmed OSA in 90 patients. A positive oximetry trend graph had a likelihood ratio of 19.4, increasing the probability of having OSA from 60% to 97%. The median MOAHI of children with a positive oximetry result was 16.4 (7.5, 30.2). The 3 false-positive oximetry results were all in the subgroup of 92 children who had diagnoses other than adenotonsillar hypertrophy that might have affected breathing during sleep. A negative or inconclusive oximetry result had a likelihood ratio of .58, decreasing the probability of having OSA from 60% to 47%. Interobserver reliability for oximetry readings was very good to excellent (κ = .80). Conclusions. In the setting of a child suspected of having OSA, a positive nocturnal oximetry trend graph has at least a 97% positive predictive value. Oximetry could: 1) be the definitive diagnostic test for straightforward OSA attributable to adenotonsillar hypertrophy in children older than 12 months of age, or 2) quickly and inexpensively identify children with a history suggesting sleep-disordered breathing who would require PSG to elucidate the type and severity. A negative oximetry result cannot be used to rule out OSA.

Effects of sleep and sleep deprivation on interleukin-6, growth hormone, cortisol, and melatonin levels in humans.

Abstract: The objective of this study was to evaluate the effects of nocturnal sleep, partial night sleep deprivation, and sleep stages on circulating concentrations of interleukin-6 (IL-6) in relation to the secretory profiles of GH, cortisol, and melatonin. In 31 healthy male volunteers, blood samples were obtained every 30 min during 2 nights: uninterrupted, baseline sleep and partial sleep deprivation-early night (awake until 0300 h). Sleep was measured by electroencephalogram polysomnography. Sleep onset was associated with an increase in serum levels of IL-6 (P < 0.05) during baseline sleep. During PSD-E, the nocturnal increase in IL-6 was delayed until sleep at 0300 h. Sleep stage analyses indicated that the nocturnal increase in IL-6 occurred in association with stage 1-2 sleep and rapid eye movement sleep, but levels during slow wave sleep were not different from those while awake. The profile of GH across the 2 nights was similar to that of IL-6, whereas the circadian-driven hormones cortisol and melatonin showed no concordance with sleep. Loss of sleep may serve to decrease nocturnal IL-6 levels, with effects on the integrity of immune system functioning. Alternatively, given the association between sleep stages and IL-6 levels, depressed or aged populations who show increased amounts of REM sleep and a relative loss of slow wave sleep may have elevated nocturnal concentrations of IL-6 with implications for inflammatory disease risk.

Practice parameters for the evaluation of chronic insomnia

Abstract: Chronic insomnia is the most common sleep complaint which health care practitioners must confront. Most insomnia patients are not, however, seen by sleep physicians but rather by a variety of primary care physicians. There is little agreement concerning methods for effective assessment and subsequent differential diagnosis of this pervasive problem. The most common basis for diagnosis and subsequent treatment has been the practitioner's clinical impression from an unstructured interview. No systematic, evidence-based guidelines for diagnosis exist for chronic insomnia. This practice parameter paper presents recommendations for the evaluation of chronic insomnia based on the evidence in the accompanying review paper. We recommend use of these parameters by the sleep community, but even more importantly, hope the large number of primary care physicians providing this care can benefit from their use. Conclusions reached in these practice parameters include the following recommendations for the evaluation of chronic insomnia. Since the complaint of insomnia is so widespread and since patients may overlook the impact of poor sleep quality on daily functioning, the health care practitioner should screen for a history of sleep difficulty. This evaluation should include a sleep history focused on common sleep disorders to identify primary and secondary insomnias. Polysomnography, and the Multiple Sleep Latency Test (MSLT) should not be routinely used to screen or diagnose patients with insomnia complaints. However, the complaint of insomnia does not preclude the appropriate use of these tests for diagnosis of specific sleep disorders such as obstructive sleep apnea, periodic limb movement disorder, and narcolepsy that may be present in patients with insomnia. There is insufficient evidence to suggest whether portable sleep studies, actigraphy, or other alternative assessment measures including static charge beds are effective in the evaluation of insomnia complaints. Instruments such as sleep logs, self-administered questionnaires, symptom checklist, or psychological screening tests may be of benefit to discriminate insomnia patients from normals, but these instruments have not been shown to differentiate subtypes of insomnia complaints.

Effects of continuous positive airway pressure on sleep apnea and ventricular irritability in patients with heart failure

Abstract: Background—Patients with heart failure and systolic dysfunction may develop disordered breathing during sleep. Repeated episodes of apnea and hypopnea may result in desaturation and arousals, which could adversely affect left ventricular function. The purpose of this study was to determine the short-term effects of continuous positive airway pressure (CPAP) on sleep-disordered breathing and its consequences in heart failure patients. Methods and Results—The author prospectively studied 29 male patients whose initial polysomnograms showed 15 or more episodes of apnea and hypopnea per hour (apnea-hypopnea index, AHI). Twenty-one patients had predominately central and 8 patients obstructive sleep apnea. All were treated with CPAP during the subsequent night. In 16 patients, CPAP resulted in virtual elimination of disordered breathing. In these patients, the mean AHI (36±12 [SD] versus 4±3 per hour, P=0.0001), arousal index due to disordered breathing (16±9 versus 2±2 per hour, P=0.0001), and percent of total...

Gender differences in the polysomnographic features of obstructive sleep apnea.

Abstract: We examined the influence of gender on the polysomnographic features of obstructive sleep apnea (OSA) in a retrospective study of 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity of OSA was determined from the apnea- hypopnea index (AHI) for total sleep time (AHI(TST)), and was classified as mild (5 to 25 events/h), moderate (26 to 50 events/h), and severe (> 50/events/h). Differences in OSA during different stages of sleep were assessed by comparing the AHI during non-rapid eye movement (NREM) (AHI(NREM)) and rapid eye movement (REM) (AHI(REM)) sleep and calculating the "REM difference" (AHI(REM) - AHI(NREM)). Additionally, each overnight polysomnographic study was classified as showing one of three mutually exclusive types of OSA: (1) mild OSA, which occurred predominantly during REM sleep (REM OSA); (2) OSA of any severity, which occurred predominantly in the supine position (S OSA); or (3) OSA without a predominance in a single sleep stage or body position (A OSA). The mean AHI(TST) for men was significantly higher than that for women (31.8 +/- 1.0 versus 20.2 +/- 1.5 events/h, p < 0. 001). The male-to-female ratio was 3.2:1 for all OSA patients, and increased from 2.2:1 for patients with mild OSA to 7.9:1 for those with severe OSA. Women had a lower AHI(NREM) than did men (14.6 +/- 1.6 versus 29.6 +/- 1.1 events/h, p < 0.001), but had a similar AHI(REM) (42.7 +/- 1.6 versus 39.9 +/- 1.2 events/h). Women had a significantly higher REM difference than did men (28.1 +/- 1.5 versus 10.3 +/- 1.1 events/h, p < 0.01). REM OSA occurred in 62% of women and 24% of men with OSA. S OSA occurred almost exclusively in men. We conclude that: (1) OSA is less severe in women because of milder OSA during NREM sleep; (2) women have a greater clustering of respiratory events during REM sleep than do men; (3) REM OSA is disproportionately more common in women than in men; and (4) S OSA is disproportionately more common in men than in women. These findings may reflect differences between the sexes in upper airway function during sleep in patients with OSA.

Behavior and neurocognitive performance in children aged 5-10 years who snore compared to controls.

Abstract: Sleep disordered breathing in children is a common but largely underdiagnosed problem. It ranges in severity from primary snoring to obstructive sleep apnea syndrome (OSAS). Preliminary evidence suggests that children with severe OSAS show reduced neurocognitive performance, however, less is known about children who snore but do not have severe upper airway obstruction. Participants included 16 children referred to the Ear, Nose and Throat/Respiratory departments of a Children's Hospital for evaluation of snoring and 16 non-snoring controls aged 5-10 years. Overnight polysomnography (PSG) was carried out in 13 children who snored and 13 controls. The PSG confirmed the presence of primary snoring in seven and very mild OSAS (as evidenced by chest wall paradox) in eight children referred for snoring while controls showed a normal sleep pattern. To test for group differences in neurocognitive functioning and behavior, children underwent one day of testing during which measures of intelligence, memory, attention, social competency, and problematic behavior were collected. Compared to controls, children who snored showed significantly impaired attention and, although within the normal range, lower memory and intelligence scores. No significant group differences were observed for social competency and problematic behavior. These findings suggest that neurocognitive performance is reduced in children who snore but are otherwise healthy and who do not have severe OSAS. They further imply that the impact of mild sleep disordered breathing on daytime functioning may be more significant than previously realized with subsequent implications for successful academic and developmental progress.

Sleep architecture and respiratory disturbances in children with obstructive sleep apnea.

Abstract: Little is known regarding sleep architecture in children with the obstructive sleep apnea syndrome (OSAS). We hypothesized that sleep architecture was normal, and that apnea increased over the course of the night, in children with OSAS. We analyzed polysomnographic studies from 20 children with OSAS and 10 control subjects. Sleep architecture was similar between the groups. Of obstructive apneas 55% occurred during rapid eye movement (REM) sleep. The apnea index, apnea duration, and degree of desaturation were greater during REM than non-REM sleep. OSAS data from the first and third periods of the night (periods A and C) were compared. Both the overall and the REM apnea index increased between periods A and C (11 to 25/h, p < 0.02; and 24 to 51/h, p < 0.01, respectively). There was no difference in SaO2 over time. Spontaneous arousals, but not respiratory-related arousals, were more frequent during non-REM than REM sleep; these did not change from periods A to C. We conclude that children with OSAS have n...

Sleep and periodic leg movement patterns in drug-free patients with Parkinson's disease and multiple system atrophy.

Abstract: Study objective To assess and compare polygraphic sleep measures and periodic leg movement (PLM) patterns in untreated patients with mild to moderate Parkinson's disease (PD), multiple system atrophy (MSA) and healthy age-matched controls. Design Polysomnographic recordings of 2 consecutive nights were performed in 10 patients with PD (mean age 65 years, mean Hoehn and Yahr stage 2.2), 10 patients with MSA (mean age 61 years) and in a control group of 10 healthy subjects (mean age 64 years). All patients and controls were free of antiparkinsonian medication and other centrally active drugs for 2 weeks prior to polysomnography. Setting NA. Patients or participants NA. Interventions NA. Results Sleep measures for the second night showed a significantly lower total sleep time, sleep efficiency and sleep period time in PD and MSA patients compared to healthy controls. PLM-indices during sleep and wakefulness were significantly higher in PD, but not in MSA patients compared to controls. Five patients with PD and 7 patients with MSA, but no control subject, showed abnormal rapid eye movement (REM) sleep features (i.e., REM sleep without atonia or behavioral manifestations typical for REM sleep behavior disorder). Conclusions Sleep disruption and increased motor activity during REM and non REM sleep are a frequent finding in PD and MSA. An increased PLM index in untreated PD patients may be due to a dopaminergic deficit and is probably not associated with dopaminergic treatment.

Physical findings and the risk for obstructive Sleep apnea : The importance of oropharyngeal structures

Abstract: In this study, we hypothesized that anatomic abnormalities of the oropharynx, particularly narrowing of the airway by the lateral pharyngeal walls, tonsils, and tongue, would be associated with an increased likelihood for obstructive apnea among patients presenting to a sleep disorders center. To test this hypothesis, we used data from a cohort of 420 patients presenting to the Penn Center for Sleep Disorders. Associations between individual variables in the clinical evaluation model and sleep apnea as defined by a re-spiratory disturbance index greater than or equal to 15 events per hour were characterized by odds ratios (ORs) with 95% confidence intervals (CIs). Multivariable logistic regression was used to simultaneously estimate ORs for multiple variables and to control for other relevant patient characteristics. Results showed that narrowing of the airway by the lateral pharyngeal walls (OR 5 2.5; 95% CI, 1.6‐3.9) had the highest association with obstructive sleep apnea (OSA) followed by tonsillar enlargement (OR 5 2.0; 95% CI, 1.0‐3.8), enlargement of the uvula (OR 5 1.9; 95% CI, 1.2‐2.9), and tongue enlargement (OR 5 1.8; 95% CI, 1.0‐3.1). Low-lying palate, retrognathia, and overjet were not found to be significantly associated with OSA. Controlling for BMI and neck circumference, only lateral narrowing and enlargement of the tonsils maintained their significant (OR 5 2.0 and 2.6, respectively). A subgroup analysis examining differences between male and female subjects showed that no oropharyngeal risk factor achieved significance in women while lateral narrowing was the sole independent risk factor in men. These findings suggest that enlargement of the oropharyngeal soft tissue structures, particularly the lateral pharyngeal walls, is associated with an increased likelihood of OSA among patients presenting to sleep disorders centers.

Measurement of sleep in critically ill patients.

Abstract: Research to evaluate interventions to promote sleep in critically ill patients has been restricted by the lack of brief, inexpensive outcome measures. This article describes the development and testing of an instrument to measure sleep in critically ill patients. A convenience sample of 70 alert, oriented, critically ill males was studied using polysomnography (PSG), the gold standard for sleep measurement, for one night. In the morning the patients completed the Richards-Campbell Sleep Questionnaire (RCSQ), a five-item visual analog scale. Internal consistency reliability of the RCSQ was .90 and principal components factor analysis revealed a single factor (Eigenvalue = 3.61, percent variance = 72.2). The RCSQ total score accounted for approximately 33% of the variance in the PSG indicator sleep efficiency index (p < .001). The data provide support for the reliability and validity of the RCSQ.

Habitually sleepy drivers have a high frequency of automobile crashes associated with respiratory disorders during sleep.

Abstract: Sleepiness is a common cause of traffic crashes with a cost of billions of dollars per year. A recent study has found that 2 to 3% of drivers are habitually sleepy while driving. However, there has not been a controlled study to define the characteristics, driving performance, or automobile crash rate of habitually sleepy drivers. The prevalence of respiratory disorders during sleep, and whether these respiratory disorders contribute to the increased automobile crash frequency, is unknown in habitually sleepy drivers. We interviewed 4,002 randomly selected drivers to define the prevalence of drivers who are habitually sleepy while driving. We studied the habitually sleepy drivers and an age- and sex-matched control group of drivers. These studies included reporting of daytime sleepiness, automobile crashes, driving performance and sleep studies. Of the 4, 002 drivers interviewed, 145 (3.6%, confidence interval [CI] = 3.1 to 4.3) were habitually sleepy while driving. The habitually sleepy drivers reported a significantly higher frequency of auto crashes than control subjects (the adjusted odds ratio [OR] was 13.3, CI = 4. 1 to 43). The habitually sleepy drivers had a significantly higher prevalence of respiratory sleep disorders than control subjects. For a total respiratory events index (apneas, hypopneas, and other respiratory effort-related arousals) >/= 15 the adjusted OR was 6.0, CI = 1.1 to 32. In the habitually sleepy drivers group, the frequency of sleep apnea (apnea-hypopnea index) between subjects with or without auto crashes was not statistically different. However, if we consider total respiratory events index, this frequency of respiratory sleep disorders was significantly higher in subjects with automobile crashes (the adjusted OR for a total respiratory event index >/= 15 was 8.5, CI = 1.2 to 59). Habitually sleepy drivers are a large group of drivers (1 of 30 drivers) who are involved in several fold more automobile crashes than control subjects. As these excess auto crashes can be explained in part by the presence of respiratory disorders during sleep, which are treatable, many automobile crashes in these sleepy drivers may be preventable. Our findings suggest that asking about excessive sleepiness while driving may better predict which subjects with breathing disorders during sleep have crashes than asking about overall sleepiness.

Automated analysis of digital oximetry in the diagnosis of obstructive sleep apnoea

Abstract: Background—The gold standard diagnostic test for obstructive sleep apnoea (OSA) is overnight polysomnography (PSG) which is costly in terms of time and money. Consequently, a number of alternatives to PSG have been proposed. Oximetry is appealing because of its widespread availability and ease of application. The diagnostic performance of an automated analysis algorithm based on falls and recovery of digitally recorded oxygen saturation was compared with PSG. Methods—Two hundred and forty six patients with suspected OSA were randomly selected for PSG and automated oV line analysis of the digitally recorded oximeter signal. Results—The PSG derived apnoea hypopnoea index (AHI) and oximeter derived respiratory disturbance index (RDI) were highly correlated (R = 0.97). The mean (2SD) of the diVerences between AHI and RDI was 2.18 (12.34)/h. The sensitivity and specificity of the algorithm depended on the AHI and RDI criteria selected for OSA case designation. Using case designation criteria of 15/h for AHI and RDI, the sensitivity and specificity were 98% and 88%, respectively. If the PSG derived AHI included EEG based arousals as part of the hypopnoea definition, the mean (2SD) of the diVerences between RDI and AHI was ‐0.12 (15.62)/h and the sensitivity and specificity profile did not change significantly. Conclusions—In a population of patients suspected of having OSA, oV line automated analysis of the oximetry signal provides a close estimate of AHI as well as excellent diagnostic sensitivity and specificity for OSA. (Thorax 2000;55:302‐307)

Obstructive sleep apnea is common in medically refractory epilepsy patients

Abstract: Background: Previous reports have documented the coexistence of obstructive sleep apnea (OSA) and epilepsy and the therapeutic effects of treatment on seizure frequency and daytime sleepiness. The authors’ objective was to determine the prevalence of OSA and its association with survey items in a group of patients with medically refractory epilepsy undergoing polysomnography (PSG). Methods: Thirty-nine candidates for epilepsy surgery without a history of OSA underwent PSG as part of a research protocol examining the relationship of interictal epileptiform discharges to sleep state. Subjects also completed questionnaires about their sleep, including validated measures of sleep-related breathing disorders (Sleep Apnea Scale of the Sleep Disorders Questionnaire [SA/SDQ]) and subjective daytime sleepiness (Epworth Sleepiness Scale [ESS]). Results: One-third of subjects had OSA, defined by a respiratory disturbance index (RDI) ≥ 5. Five subjects (13%) had moderate to severe OSA (RDI > 20). Subjects with OSA were more likely to be older, male, have a higher SA/SDQ score, and more likely to have seizures during sleep than those without OSA (p Conclusions: In our sample, previously undiagnosed obstructive sleep apnea was common, especially among men, older subjects, and those with seizures during sleep. The impact of treating OSA on seizure frequency and daytime sleepiness in medically refractory epilepsy patients warrants further controlled study.

Symptoms of stress and depression as correlates of sleep in primary insomnia.

Abstract: Objective Previous studies have not evaluated the clinical correlates of the electroencephalographic spectral profile in patients with insomnia. In the preliminary study described here, we evaluated the extent to which symptoms of stress and depression are associated with subjective sleep complaints and quantitative measures of sleep in individuals with chronic insomnia. Methods Subjects were 14 healthy adults who met criteria for primary insomnia as specified in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. Measures of stress, depression, and subjective sleep quality were collected before subjects participated in a two-night laboratory sleep series. We hypothesized that elevated symptoms of stress and depression would be associated with subjective sleep complaints and electroencephalographic evidence of hyperarousal during sleep. Hyperarousal during sleep was defined as decreases in delta power and elevations in alpha and beta power throughout non-rapid eye movement sleep, and symptoms of stress were defined as the tendency to experience stress-related intrusive thoughts and the interaction between intrusion tendency and the number of recent stressful events (subjective stress burden). Results A stronger tendency to experience stress-related intrusive thoughts was associated with greater sleep complaints and a trend toward higher beta power, whereas increases in subjective stress burden were associated with decreases in delta power. In addition, elevations in subclinical symptoms of depression were associated with greater sleep complaints and elevations in alpha power. Conclusions Observed relationships among symptoms of stress, depression, subjective sleep complaints, and electroencephalographic power may be relevant to the discrepancy between subjective and objective measures of sleep in patients with insomnia and may be more broadly applicable to sleep complaints in association with stressful life events and major depression.

Systematic Review and Meta-analysis of the Literature Regarding the Diagnosis of Sleep Apnea

Abstract: To establish the evidence base for the diagnosis of sleep apnea (SA) in adult patients, a systematic review of the literature from 1980 through November 1, 1997 was performed. Diagnostic studies were included if they reported results of any test to establish or support a diagnosis of SA, in comparison to a diagnosis from a full polysomnogram (PSG). Test results were meta-analyzed using fixed effects models and summary receiver operating characteristic curves (ROCs) to examine consistency of tests within and between diagnostics vs. the "gold standard" of PSG. From a total of 937 studies, 249 fit the broad eligibility criteria for inclusion in the clinical trial database and its data were extracted from these reports; useable data for statistical analyses were reported in 71 studies (7,572 patients). The sensitivity and specificity of partial channel and partial time PSGs appeared most promising as replacements for full PSG in patients suspected of obstructive SA. Clinical prediction rules (multivariate models) were also promising. Studies of portable sleep monitors, radiologic or morphologic features, and focused questionnaires were too heterogeneous to be meta-analyzed. In general, the diversity of study designs and objectives were very high and the methodological rigor of these studies as assessments of diagnostic tests was very low. Thus, we are still not in a position to recommend standardization of diagnostic methodology for sleep apnea. Instead, our recommendations for future research include standardization of terms and diagnostic criteria, and consistently reported statistics to enhance the utility of this literature.

Periodic limb movements in sleep: state-dependent excitability of the spinal flexor reflex.

Abstract: Objective: To test the hypothesis that periodic limb movements (PLMs) are related to spinal flexor reflexes (FRs), the authors compared the state-dependent changes in FR excitability in 10 patients with restless legs syndrome (RLS) and PLMs with those from matched controls. Background: PLM is a disorder of motor control during sleep, frequently occurring in RLS. Clinically, PLMs resemble spinal FRs. Methods: FRs were obtained by electrically stimulating the medial plantar nerve and recording from antagonist leg and thigh muscles bilaterally. Results: Compared with controls, patients had significantly increased spinal cord excitability, as indicated by lower threshold and greater spatial spread of the FR, which was more prominent during sleep. Multiple late responses were seen during sleep in all patients and in some controls at higher threshold. The most prominent of these responses had a very long duration and a latency range of 250 to 800 msec, and because of its close temporal relationship to the FR stimulus, the authors considered it was a late, high-threshold component of the FR (FR3). The authors also found a similarity between the pattern of muscle recruitment and spatial spread of late components of the FR and those of spontaneous PLMs. Conclusions: The results support the hypothesis that PLMs in RLS and FRs share common spinal mechanisms and suggest that PLMs may result from enhanced spinal cord excitability in RLS patients. Because dopaminergic mechanisms are involved in spinal FR control, the results are consistent with the current view that RLS is a disorder of dopaminergic function.

Sleep and Alertness in Children with ADHD

Abstract: Objective : To evaluate sleep and alertness and to investigate the presence of possible underlying sleep/wake disorders in children with attention-deficit/hyperactivity disorder (ADHD). Method : After 3 nights of adaptation in a room reserved for sleep studies in the department of child psychiatry, children underwent polysomnography (PSG) followed by the Multiple Sleep Latency Test (MSLT) and reaction time tests (RT) during the daytime. Thirty boys diagnosed as having ADHD (DSM-IV), aged between 5 and 10 years, and 22 age- and sex-matched controls participated in the study. All children were medication-free and showed no clinical signs of sleep and alertness problems. Results : No significant differences in sleep variables were found between boys with ADHD and controls. The mean latency period was shorter in children with ADHD. Significant differences were found for MSLT 1, 2 and 3 ( p <.05). Mean reaction time was longer in children with ADHD, with significant differences in all tests ( p <.05). Number and duration of sleep onsets measured by the MSLT correlated significantly with the hyperactivity-impulsivity and inattentive- passivity indices of the CTRS and CPRS. Conclusion : Children with ADHD were more sleepy during the day, as shown by the MSLT, and they had longer reaction times. These differences are not due to alteration in the quality of nocturnal sleep. The number of daytime sleep onsets and the rapidity of sleep-onsets measured as MSLT were found to be pertinent physiological indices to discriminate between ADHD subtypes. These results suggest that children with ADHD have a deficit in alertness. Whether this deficit is primary or not requires further studies.

Daytime predictors of sleep hypoventilation in Duchenne muscular dystrophy.

Abstract: Sleep hypoventilation is an inevitable consequence of Duchenne muscular dystrophy (DMD), usually preceding daytime respiratory failure. Appropriate scheduling of polysomnography and the introduction of noninvasive ventilation (NIV) during sleep are not defined. Our aim was to determine the parameters of daytime lung function associated with sleep hypoventilation in patients with DMD. As our method we chose a prospective comparison of wakeful respiratory function (spirometry, lung volumes, maximal mouth pressures, arterial blood gases) with outcomes of polysomnography. All measurements were made with subjects breathing air. Nineteen subjects were studied. The FEV(1) was correlated with Pa(CO(2)) (r = -0.70, p /= 2%); a Pa(CO(2)) of >/= 45 mm Hg was an equally sensitive (91%) but more specific (75%) indicator while a base excess of >/= 4 mmol/L was highly specific (100%) but less sensitive (55%). After introduction of NIV during sleep (n = 8), there was a significant reduction in wakeful Pa(CO(2)) (54 +/- 7.4 to 49.1 +/- 4 mm Hg, p /= 45 mm Hg, particularly if the base excess is >/= 4 mmol/L; (3) the decrease in wakeful Pa(CO(2)) after NIV administered during sleep implicates sleep hypoventilation in the pathogenesis of respiratory failure; and (4) impaired ventilatory drive is a possible mechanism for respiratory failure, as the NIV-associated decrease in wakeful Pa(CO(2)) occurs despite a further decline in ventilatory capacity, suggesting continuing deterioration in respiratory muscle function.