Factors that influence CPAP adherence: an overview

BACKGROUND

Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea syndrome (OSAS). Consistent adherence to CPAP improves the patient's longevity and quality of life as well as public safety. However, nonadherence is a significant contributor to the growing burden of untreated OSAS, and is associated with negative consequences for the patient, public safety, and the healthcare system.

OBJECTIVE

The use of CPAP is a classic example of an effective treatment for which adherence is extremely variable. This paper examines a multiplicity of factors that influence CPAP adherence.

FACTORS

These factors are traditionally thought of in terms of patient and equipment variables, but in addition physician, family, healthcare facility, and governmental issues all contribute to CPAP adherence.

DISCUSSION

These factors are reviewed and pragmatic recommendations are made for improving clinical practice.

Measurements of sleepiness and fatigue

Sleepiness and fatigue are terms commonly used in clinical practice and research. At times sleepiness and fatigue are used interchangeably; however, each of them has distinct implications for diagnosis and treatment. The objective of this article is to review the psychometric properties of the measurements of sleepiness and fatigue. Although there are objective and subject measures to evaluate sleepiness, only rating scales are available to assess fatigue. Further research should be directed toward exploring the potential mechanisms underlying the measurements of sleepiness and fatigue. Establishing objective assessing instruments to evaluate fatigue and clarifying the relationship between objective and subjective assessments of sleepiness are crucially needed.

Perioperative practical experiences in using a level 2 portable polysomnography

PURPOSE

The objective of the study is to test the hypothesis that a level 2 portable sleep device (Embletta X100) is a reliable alternative for standard PSG in surgical patients.

METHODS

After hospital ethics approvals, preoperative patients over 18 years old were recruited. The patients for validation underwent standard PSG and Embletta X100 simultaneously in a sleep laboratory before surgery. The other patients received sleep studies with Embletta X100 perioperatively. The correlation analysis and paired Student t test between variables from Embletta and from standard PSG were used to evaluate the accuracy of Embletta. The quality of PSG recordings with Embletta was summarized.

RESULT

Twenty-one patients completed sleep study on both systems; ten females and ten males, age was 54 ± 11 and BMI was 36 ± 9. There was a significant correlation between the majority of parameters from standard PSG and Embeltta X100 with manual scoring. The inter-rater agreement was substantial to perfect at different AHI cutoffs with a Kappa coefficient of 0.69 to 1. A significant correlation between standard PSG and Embletta X100 with automatic scoring was found only in AHI and a few other parameters. In 385 patients, 1,002 perioperative PSG recordings were carried out with Embletta. Of them, 889(88.7%) were technically good and 90(9%) technically acceptable. Only 23 (2.3%) PSG recordings failed.

CONCLUSION

Embletta X100, installed by a well-trained sleep technician, is a good alternative when standard PSG was not available or impractical. Manual scoring by a certified PSG technologist is the key for reliable results.

The Berlin questionnaire for sleep apnea in a sleep clinic population: relationship to polysomnographic measurement of respiratory disturbance

The Berlin questionnaire (BQ) has been used to help identify patients at high risk of having sleep apnea in primary care and atrial fibrillation patients. The BQ may be a useful adjunct in sleep medicine and research, but it has never been validated in a sleep clinic population. The aim of the study is to determine the specificity and sensitivity of the BQ compared to the respiratory disturbance index (RDI) values obtained from two nights of polysomnographic recording in a sleep clinic population. This is a retrospective chart review study of 130 sleep clinic patients. Patients' demographics, BQ scores, RDI measurements, and sleep study parameters were extracted from the patients' chart. Of the 130 charts reviewed, the BQ identified 76 (58.5%) as being at high-risk of having sleep apnea, but overnight polysomnography found only 34 of the 130 patients (26.2%) had an RDI > 10. The BQ performed with 0.62 sensitivity and 0.43 specificity at the RDI > 10 level. Due to the low sensitivity and specificity as well as the large number of false negatives and positives, the Berlin questionnaire is not an appropriate instrument for identifying patients with sleep apnea in a sleep clinic population.

Depressive symptomatology in tertiary-care glaucoma patients

OBJECTIVE

To investigate depressive symptomatology among patients with glaucoma and to relate the findings to disease stability.

DESIGN

Cross-sectional postal survey.

PARTICIPANTS

The study sample consisted of 258 patients out of a pool of 884 respondents to a survey on health and sleep sent to 1809 glaucoma patients registered in a major tertiary glaucoma centre at the Toronto Western Hospital, Toronto, Ont.

METHODS

The Center for Epidemiologic Studies Depression Scale questionnaire was mailed along with questions related to demographic information, general health, and sleep quality. Respondents were included if (i) their diagnosis was either primary open-angle glaucoma, normal tension glaucoma, or primary angle-closure glaucoma; (ii) the disease duration was 3 years or more; (iii) clinical examinations were obtained annually; and (iv) perimetric results were reliable. Each patient's condition was classified as stable or progressive on the basis of pointwise decline in visual fields (VFs).

RESULTS

The unadjusted odds ratio for depressive symptoms was found to be 0.4 times less (95% CI 0.19-0.88) in patients with progressive VFs (n = 79) than in patients with stable VFs (n = 179). Adjusting for demographic characteristics, general health, psychiatric comorbidity, and ocular factors did not weaken this association. However, it was reduced by the increased severity of VF defects (moderate and severe).

CONCLUSIONS

In this sample of tertiary-care patients, depressive symptoms were found to be less common in patients with progressive than with stable VFs when defects were classified as early, but not when they were classified as moderate or severe.

Mirtazapine, a sedating antidepressant, and improved driving safety in patients with major depressive disorder: a prospective, randomized trial of 28 patients

OBJECTIVE

The objectives of the study were to investigate the effects of mirtazapine, a sedating antidepressant, on driving safety in major depressive disorder (MDD) patients and to observe the effect of mirtazapine on daytime alertness.

METHOD

Twenty-eight patients who met the DSM-IV criteria for MDD completed the study in a university teaching hospital. Half of these patients took mirtazapine 30 mg at bedtime for 30 days. A computerized driving simulator test (DST) and the Maintenance of Wakefulness Test (MWT) were conducted at baseline and on days 2, 9, 16, and 30 after commencement of antidepressant use. Fourteen untreated depressed patients performed a DST and MWT at baseline and on days 2 and 9 to evaluate the possibility of a learning effect. Data collection was from June 2005 through January 2006.

RESULTS

There were significant linear effects of the treatment on road position at All Trials (p = .018) and on the morning sessions at 10:00 a.m. (p < .001) and 12:00 p.m. (p = .022) and on the number of crashes at All Trials (p = .034) and the 4:00 p.m. session (p = .050) for the group on active treatment. Compared with the values at baseline, those of road position at 10:00 a.m. significantly improved on days 2 (p < .05), 9 (p < .01), 16 (p < .01) and 30 (p < .01) and road position at 12:00 p.m. significantly improved on days 16 (p < .05) and 30 (p < .05). The number of crashes significantly decreased on day 30 (p < .05). The untreated patients showed no improvement in performance in any of the measures, suggesting that the results are not due to a learning effect.

CONCLUSION

A sedating antidepressant can increase driving safety in MDD patients.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00385437.

Clinical diagnosis of sleep apnea based on single night of polysomnography vs. two nights of polysomnography

PURPOSE

The purpose of this study was to investigate apnea-hypopnea index (AHI) across two polysomnographies (PSGs) to examine AHI variability and impact on clinical diagnosis.

MATERIALS AND METHODS

Two-night PSGs of 193 sleep clinic patients were reviewed, and the AHI variability was analyzed. Anonymized records from five patients with significant night-to-night AHI variability were used in this study: the two-night PSGs from two patients were represented as four individual PSGs; the two-night PSG for two others were represented as being obtained from two different sleep clinics; the last patient's PSG was shown as a two-night study. Twenty-two sleep experts attending the Associated Professional Sleep Societies meeting were recruited to make diagnoses based on the PSGs. They were told that the PSGs were from seven patients: four with single-night PSG; two with two PSGs, each one from a different clinic; and one patient with a two-night PSG.

RESULTS

Twenty-one percent of the 193 sleep clinic patients had a nightly PSG AHI variability of greater than 5. Forty-eight percent of all patients had a significantly higher AHI on the first night, and 41% had a significantly higher AHI on the second night. Using an AHI > 15 diagnostic criteria, sleep apnea would have been undetected in 20% (n = 39) of patients due to low AHI on one night. Furthermore, 13% of all patients had a more severe sleep apnea classification based on the second night of PSG. For the seven cases, 27-36% of sleep experts failed to identify sleep apnea especially when presented with the PSG containing the lower AHI. Incidences of missed sleep apnea diagnoses were reduced to 15-18% when information from two PSGs was presented to the sleep experts.

CONCLUSIONS

Utilizing a large patient population, this study supports the significant night-to-night variability in PSG respiratory variables. Identification of sleep apnea in some patients is reduced when sleep experts are provided with only one PSG recording. The clinical implication is that about 13% of sleep clinic patients might benefit from a second night of PSG.

Cardiovascular disease and health-care utilization in snorers: a population survey

STUDY OBJECTIVES

We assessed the prevalence of self-reported snoring in the Hungarian population and established whether different types of snoring are associated with cardiovascular disorders and increased health-care utilization.

DESIGN

Cross-sectional study. Door-to-door survey.

SETTING

Nationally representative population in Hungary.

PARTICIPANTS

Interviews were carried out in the homes of 12,643 persons. We used the Hungarian National Population Register as the sampling frame and implemented a clustered, stratified sampling procedure. The study population represented 0.16% of the population over the age of 18 years according to age, sex, and 150 subregions of the country.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

Thirty-seven percent of men and 21% of women reported loud snoring with breathing pauses. Hypertension, myocardial infarction, and stroke were reported by 26%, 3%, and 4% of the respondents, respectively. There was a significant increase in the prevalence of hypertension, myocardial infarction, and stroke in quiet and loud snorers, as compared with nonsnorers. Multivariate analysis showed an association between loud snoring and hypertension (odds ratio [OR]: 1.40, 95% confidence interval [CI]: 1.24-1.58), myocardial infarction (OR: 1.34, CI: 1.04-1.73), and stroke (OR: 1.67, CI: 1.32-2.11) after statistical adjustment for age, sex, body mass index, diabetes, level of education, smoking, and alcohol consumption. Loud snoring was also associated with measures of health-care use in both sexes.

CONCLUSIONS

Snoring is frequent in the Hungarian adult population, and loud snoring with breathing pauses, in contrast with quiet snoring, is associated with an increased risk of cardiovascular disease and increased health-care utilization.

Memory enhancement induced by hypothalamic/fornix deep brain stimulation

Bilateral hypothalamic deep brain stimulation was performed to treat a patient with morbid obesity. We observed, quite unexpectedly, that stimulation evoked detailed autobiographical memories. Associative memory tasks conducted in a double-blinded "on" versus "off" manner demonstrated that stimulation increased recollection but not familiarity-based recognition, indicating a functional engagement of the hippocampus. Electroencephalographic source localization showed that hypothalamic deep brain stimulation drove activity in mesial temporal lobe structures. This shows that hypothalamic stimulation in this patient modulates limbic activity and improves certain memory functions.

Hypocretin/Orexin: a molecular link between sleep, energy regulation, and pleasure

Hypocretin (Hcrt) is a neurotransmitter of the dorsal and lateral hypothalamus that regulates sleep, appetite, and energy consumption. Recent evidence indicates that it is also involved in pleasure/reward-seeking. Mutation of the Hcrt-receptor gene causes narcolepsy in canines, and Hcrt knockout mice exhibit narcolepsy-like symptoms. Human narcoleptics do not commonly have mutations in the ligand or receptor but do have degeneration of Hcrt-containing neurons, possibly through an autoimmune mechanism. When Hcrt neurons degenerate in mice, hypophagia and obesity are observed, symptoms that are also present in some human narcoleptics. This article reviews the recent literature with regard to the many functions of this single molecule. The authors suggest that eating habits and impulsivity may be topics worth exploring in the evaluation of narcoleptic patients.

Evaluation and treatment of sleep complaints: patients' subjective responses

BACKGROUND

This study set out to evaluate whether patients' expectations affected their responses to treatment of a sleep disorder.

METHODS

Fifty consecutive patients attending a sleep clinic for the first time and who had different diagnoses of sleep disorders were included in this study. The patients completed a set of 6 questionnaires on 7 occasions as they progressed through the process of a sleep clinic referral, assessment and treatment. Self-report questionnaires were used to assess their sleepiness, fatigue and alertness. Predictor measures included mental health and individual items assessing expectation regarding the seriousness of the sleep problem. A battery of questions dealt with mental health issues, patients' expectation and their commitment to the sleep investigation and treatment process. Each patient's responses were examined over a period of 6 months.

RESULTS

Immediately following their interview with the sleep consultant, the patients' concern regarding their sleep problem was higher than the first measures obtained at baseline. Compared to prior to their first consultation with a sleep specialist, while on treatment they directed more attention to their sleep problem when problems associated with fatigue were reduced. Although there was a lessening in fatigue with treatment, subjectively rated sleepiness (Epworth Sleepiness Scale) did not vary over the study. Contact with a sleep center and the diagnosis and treatment of individual sleep problems also resulted in improved satisfaction with life.

CONCLUSIONS

Contact with and treatment at a sleep clinic was found to be beneficial. The fatigue levels were reduced and the patients had greater life satisfaction regardless of the diagnosis and treatment of their sleep disorder, although subjective sleepiness did not change. Patient expectations were not critical in determining the outcome of the sleep clinic assessment.

Sexual behaviour in sleep: an internet survey

The objective of the study was to provide further information related to newly described parasomnia variant, Sexual Behaviour in Sleep (SBS, sexsomnia). Previous studies dealt with selected population, typically middle-aged males, featuring extensive medico-legal exposure. At the same time, an anecdotal evidence suggested higher involvement of younger population, and skew towards balance between genders comparable to those seen in other non-Rapid Eye Movement (NREM) sleep parasomnias. The epidemiological information regarding this condition is still virtually non-existent. In order to sample this difficult-to-reach population, a 28-item Internet survey was posted on the sexsomnia reference site and the link was also sent to prospective respondents (mostly registered visitors to this site). The respondents were able to complete the survey anonymously, which resulted in a need for the screening of bogus and duplicate results. At the end, a total of 219 validated responses were collected and analysed. The results showed greater representation of females (31% of the total number), and wider age distribution (mean age of 30.4 years). The respondents typically reported multiple sexsomnia episodes, in most cases precipitated by body contact, stress and fatigue. Relatively small number of respondents reported involvement of legal authorities (8.6% of males and 3% of females) and participation of minors in their sexsomnia (6% of the total sample). In spite of known limitations of such surveys, the study provided much needed insight into this complex nocturnal behaviour. It confirmed the anecdotal evidence about the gender and age distribution, and provided information on some key features, such as precipitating factors, type of behaviour, medication use, personal medical history and medico-legal aspects.

Atypical presentation of NREM arousal parasomnia with repetitive episodes

The case report describes a distinct variant of non-REM (Rapid Eye Movement) arousal parasomnia, sleepwalking type, featuring repetitive abrupt arousals, mostly from slow-wave sleep, and various automatisms and semi-purposeful behaviours. The frequency of events and distribution throughout the night presented as a continuous status of parasomnia ('status parasomnicus'). The patient responded well to treatment typically administered for adult NREM parasomnias, and after careful review of the clinical presentation, objective findings and treatment outcome, sleep-related epilepsy was ruled out in favour of parasomnia.

Prevention of melatonin suppression by nocturnal lighting: relevance to cancer

The decreased melatonin production in humans and animals caused by environmental lighting, especially short wavelength lighting (between 470 and 525 nm) has been shown to be associated with an increased risk of cancer. The purpose of this study was to investigate whether blocking light in this wavelength range under bright light may prevent the suppression of melatonin, which could help to prevent cancer. Optical filter lenses were designed, allowing selective exclusion of all wavelengths below 530 nm. Salivary melatonin levels were measured under dim light (<5 lux), bright light (800 lux) and filtered light (800 lux) at hourly intervals between 2000 and 0800 h in 11 healthy young male participants (mean age 23.5+/-1.5 years). The measurements were taken during three nonconsecutive nights over a 2-week period. The Dim Light Melatonin Onset test was used as a marker of circadian phase. Nine of the 11 participants demonstrated preserved melatonin levels in filtered light similar to their dim light secretion profile. With filtered light, the participants had a mean relative amount of melatonin of 91.2 (P>0.05 between dim light and experimental condition). Unfiltered bright light drastically suppressed melatonin production with a mean relative amount of melatonin of 25.4 (P<0.05 between dim light and experimental condition). Preventing melatonin deficiencies using lenses that block light of low wavelength from reaching the retina presents a cost-effective, practical solution to the problem of increased malignancy rates in shift workers.

Sleep-disordered breathing and effects on ocular health

Sleep-disordered breathing may make the eye vulnerable due to the direct effect of hypoxia or it can involve pathways that lead to impaired autoregulation of optic nerve perfusion. In this review, we discuss our present understanding of the interactions that occur between sleep-disordered breathing and the eye, with particular attention to discussing possible links with glaucoma, nonarteritic anterior ischemic optic neuropathy, visual field defects, papilledema, and floppy eyelid syndrome. The importance of understanding these relationships is the positive benefits to ocular health that can derive when sleep-disordered breathing is diagnosed and treated.

The effect of one versus two nights of in-laboratory continuous positive airway pressure titration on continuous positive airway pressure compliance

OBJECTIVE

To investigate continuous positive airway pressure (CPAP) compliance after one versus two nights of CPAP titration.

METHOD

A chart review and a telephone questionnaire interview were conducted in 110 sleep apnea patients who received one or two nights of CPAP titration. Of these patients, 78 followed through with phone interview.

RESULTS

There was no difference in CPAP compliance between those who had one or two nights of CPAP titration. The titration pressures on the first and second nights were not significantly different. But there was significant improvement in sleep efficiency from the first to the second diagnostic night.

CONCLUSION

One versus two nights of CPAP titration did not affect CPAP compliance, but sleep efficiency improved on the second diagnostic night and an extra titration study may be necessary for some patients, especially those with only one diagnostic night.

Moderate exercise and bright light treatment in overweight and obese individuals

OBJECTIVE

Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals.

RESEARCH METHODS AND PROCEDURES

Twenty-five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep.

RESULTS

Body weight decreased significantly with exercise in subjects in the light and non-light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep.

DISCUSSION

This preliminary study is the first to show that addition of bright light treatment to a 6-week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.

Positive sleep state misperception – A new concept of sleep misperception

OBJECTIVES

To better define the concept of sleep misperception and analyse a category of patients who overestimate their sleep. At present, a condition of underestimation of sleep is classified as paradoxical insomnia. Overestimation of sleep has also been reported in the past, with no clear reference to corresponding polysomnographic (PSG) findings or its clinical significance.

PATIENTS AND METHODS

Patients were recruited from the general population undergoing a PSG assessment for a cross-sectional retrospective study in a sleep clinic affiliated with a tertiary health center.

RESULTS

A group of patients who overestimated their sleep had mostly non-discriminating PSG findings when compared to patients who underestimated their sleep, and correct estimators. The only parameters that were significantly different were objective sleep duration and efficiency, and, importantly, respective multiple sleep latency test (MSLT) results. The patients who overestimated their sleep had a mean MSLT result of 7.8 min, which indicates moderate daytime sleepiness. Patients who underestimated their sleep and correct estimators had the respective MSLT results of >10 min, making a statistically significant difference.

CONCLUSION

The authors identified a condition opposite the previously described sleep underestimation, and named it 'positive sleep state misperception' (PSSM). The condition is characterised by a gross overestimation of sleep. Inadequate sleep results in a clinically significant excessive daytime sleepiness, which patients were not able to predict. The authors propose a new model that incorporates both ends of the sleep misperception spectrum.

Simulator performance, microsleep episodes, and subjective sleepiness: normative data using convergent methodologies to assess driver drowsiness

OBJECTIVE

Our objective was to examine a novel standardized assessment methodology of detecting impaired driving performance due to drowsiness in a normative cohort.

METHODS

Thirty-one healthy subjects with no significant sleep, medical, and psychiatric pathology were assessed in a driving simulation paradigm. Thirty-minute simulations were repeated at two-hourly intervals (i.e., at 1000, 1200, 1400, and 1600 h). Convergent data sources included drivers' subjective ratings of sleepiness and alertness, electroencephalogram-verified microsleep (MS) episodes, and a variety of real-time driving simulator performance measures such as speed, lane tracking, reaction time (RT), and off-road events (crashes).

RESULTS

Significant diurnal fluctuations were noted on objective measures of RT, velocity, tracking, and MS events, indicating the highest risk of impairment in the afternoon. By contrast, subjective ratings of sleepiness and alertness did not demonstrate significant circadian variation. The mean incidence of MS episodes and crash risk correlated highly (r = .748).

CONCLUSIONS

This prospective study demonstrates the relevance of multiple convergent measures for comprehensive assessment. The divergence of subjective and objective assays of impairment implies that healthy individuals may not have full insights into neurophysiologically mediated performance deficits. These results will serve as normative comparators to patients presenting with daytime somnolence and may allow a more accurate prediction of potential crash risk than noninteractive daytime polysomnogram tests such as the mean sleep latency test or the maintenance of wakefulness test.

Ropinirole treatment for restless legs syndrome

In this paper we discuss therapy with ropinirole (known as adartrel in the United Kingdom) in patients with restless legs syndrome. Restless legs syndrome is characterized by an urge to move the legs, uncomfortable sensations in the legs and worsening of these symptoms during rest with at least temporary relief brought on by activity. Current recommendations suggest dopaminergic therapy (levodopa or dopamine receptor agonists like ropinirole) as the first-line treatment for restless legs syndrome. Based on the results of randomized, placebo-controlled, double-blind trials, we conclude that ropinirole is effective in reducing symptoms of restless legs syndrome in the general population. Ropinirole has no serious or common side effects that would limit its use significantly. Rebound and augmentation problems are relatively rarely seen with ropinirole, although properly designed comparative trials are still needed to address this question. It must be noted, however, that most published studies with ropinirole compare this drug with placebo. Very few studies have compared ropinirole with other drugs (L-dopa, gabapentin, opioids, benzodiazepines, other dopaminergic agents and selegiline hydrochloride). No cost-effectiveness trial has been published yet. Treatment of restless legs syndrome with ropinirole shows it to be effective, well-tolerated and safe and it can be used in restless legs syndrome in general.

Diagnosis and management of insomnia in dialysis patients

Sleep-related complaints affect 50-80% of patients on dialysis. Sleep disorders impair quality of life significantly. Increasing evidence suggests that sleep disruption has a profound impact both on an individual and on a societal level. The etiology of sleep disorders is often multifactorial: biologic, social, and psychological factors play a role. This is especially true for insomnia, which is the most common sleep disorder in different populations, including patients on dialysis. Biochemical and metabolic changes, lifestyle factors, depression, anxiety, and other underlying sleep disorders can all have an effect on the development and persistence of sleep disruption, leading to chronic insomnia. Insomnia is defined as difficulty initiating or maintaining sleep, or having nonrestorative sleep. It is also associated with daytime consequences, such as sleepiness and fatigue, and impaired daytime functioning. In most cases, the diagnosis of insomnia is based on the patient's history, but in some patients objective assessment of sleep pattern may be necessary. Optimally the treatment of insomnia involves the combination of both pharmacologic and nonpharmacologic approaches. In some cases acute insomnia resolves spontaneously, but if left untreated, it may lead to chronic sleep problems. The treatment of chronic insomnia is often challenging. There are only a few studies specifically addressing the management of this sleep disorder in patients with chronic renal disease. Considering the polypharmacy and altered metabolism in this patient population, treatment trials are clearly needed. This article reviews the diagnosis of sleep disorders with a focus on insomnia in patients on dialysis.

Fatigue and shift work

Shift work is a ubiquitous phenomenon and its adverse effects on workers' physical and mental health have been documented. In the sleep literature, differentiating between the symptoms of fatigue and sleepiness, and developing appropriate objective and subjective measures, have become very important endeavors. From such research, fatigue and sleepiness have been shown to be distinct and independent phenomena. However, it is not known whether shift work differentially affects fatigue and sleepiness. In an attempt to answer this question, 489 workers from a major Ontario employer completed a series of subjective, self-report questionnaires, including the Fatigue Severity Scale (FSS) and the Epworth Sleepiness Scale. Workers were separated into four groups based on the frequency with which they are engaged in shift work (never, fewer than four times per month, 1-2 days per week, 3 days or more per week). The frequency of shift work was found to have a significant effect on subjective fatigue, but not on subjective sleepiness. Compared with the subjects who never had a shift schedule, those who worked in a shift for 3 days or more had significantly higher mean score of the FSS. In agreement with previous results, a low correlation was found between workers' subjective fatigue and sleepiness scores, providing further support for the concept of fatigue and sleepiness as distinct and independent phenomena. Future research should address the possibility of using the FSS as an indicator when the frequency of shift work has become high enough to adversely affect work performance or cause health problems.

Psychomotor disturbance in depression: assessment using a driving simulator paradigm

BACKGROUND

Psychomotor disturbance is an essential feature of Major Depressive Disorder (MDD) and has been associated with impaired functioning on cognitively demanding tasks. Given the psychomotor demands required to navigate a motor vehicle and the disastrous effects of motor vehicles accidents, patients with MDD present a population of clinical interest. The goal of this investigation was to examine the association between MDD and driving ability assessed within a simulated driving paradigm.

METHODS

18 outpatients currently meeting diagnostic criteria for MDD and 29 control participants completed four 30-min simulated driving trials at 10:00 am, 12:00 pm, 2:00 pm, and 4:00 pm. Participants also completed the Beck Depression Inventory (BDI) to assess for depression severity and the Epworth Sleepiness Scale (ESS) to assess for everyday sleepiness.

RESULTS

After controlling for age and sleepiness, the depressed sample exhibited slower steering reaction times across trials (p<.05) and an increased number of crashes across trials (p<.05) when compared to controls. These differences were characterized by a medium effect size. No significant time-of-day effects were found.

LIMITATIONS

MDD patients were free of anti-depressant medication and findings may not generalize to medicated populations. Also, a rural highway driving route was used which may not generalize well to urban driving settings.

CONCLUSIONS

Patients with untreated MDD demonstrate impaired simulated driving performance. Further research into whether these findings translate into on-the-road impairment is important for public health and safety.

A new approach to the construct of alertness

OBJECTIVE

There are no psychometric measures to evaluate the critical construct of alertness. We, therefore, developed two questionnaires to measure alertness, the Toronto Hospital Alertness Test (THAT) and the ZOGIM-A, and evaluated their psychometric properties.

METHODS

We examined the correspondence between scores on the THAT and the ZOGIM-A in a sample of sleep clinic outpatients (n=96) with Maintenance of Wakefulness Test (MWT) results after an overnight sleep study, physiological sleep parameters, measures of subjective sleepiness, and two psychosocial variables (psychological well-being and emotional distress). Test-retest reliability was estimated based on responses from an independent sample of 295 sleep clinic outpatients who completed the instruments before and after an overnight sleep study.

RESULTS

High values were observed for both the THAT (r(tt)=.79) and the ZOGIM-A (r(tt)=.70). Internal consistency reliability (coefficient alpha) was also high: .96 for THAT and .83 for ZOGIM-A. Although neither of the new scales correlated significantly with measures derived from the MWT or nocturnal physiological measures, the two alertness scales did correlate significantly and as hypothesized with subjective measures of sleepiness and other psychosocial measures.

CONCLUSIONS

These results support the perspective that subjective alertness cannot be reduced to the absence of sleepiness and corroborate the psychometric adequacy of the THAT and the ZOGIM-A as unique indices of alertness that complement objective data obtained via MWT and physiological indices of sleep architecture.

Reviews: Diagnosis and Management of Sleep Apnea Syndrome and Restless Legs Syndrome in Dialysis Patients

Sleep complaints are very common in patients with end-stage renal disease (ESRD) and contribute to their impaired quality of life. Both obstructive and central sleep apnea syndromes are reported more often in patients on dialysis than in the general population. Impaired daytime functioning, sleepiness, and fatigue, as well as cognitive problems, are well known in patients with sleep apnea. Increasing evidence supports the pathophysiological role of sleep apnea in cardiovascular disorders, which are the leading cause of death in ESRD patients. Uremic factors may be involved in the pathogenesis of sleep apnea in this patient population and optimal dialysis may reduce disease severity. Furthermore, treatment with continuous positive airway pressure may improve quality of life and may help to manage hypertension in these patients. Secondary restless legs syndrome is highly prevalent in patients on maintenance dialysis. The pathophysiology of the disorder may also involve uremia-related factors, iron deficiency, and anemia, but genetic and lifestyle factors might also play a role. The treatment of restless legs syndrome involves various pharmacologic approaches and might be challenging in severe cases. In this article we review the diagnosis and treatment of sleep apnea and restless legs syndrome, with a focus on dialysis patients. We also briefly review current data regarding sleep problems after transplantation, since these studies may indirectly shed light on the possible pathophysiological role of uremia or dialysis in the etiology of sleep disorders. Considering the importance of sleep disorders, more awareness among professionals involved in the care of patients on dialysis is necessary. Appropriate management of sleep disorders could improve the quality of life and possibly even impact upon survival of renal patients.

Sleepiness is not the inverse of alertness: evidence from four sleep disorder patient groups

The constructs "sleepiness" and "alertness" are often assumed to be reciprocal states of consciousness. This distinction is of increasing concern in relation to psychomotor performance tasks such as driving. We developed two separate subjective scales of alertness to complement existing sleepiness scales. Subjective sleepiness and alertness were compared in four groups of sleep-disordered patients. In a 175-patient cohort [25 narcoleptics and 50 each with sleep apnea, insomnia and periodic leg movement disorder (PLMD)], the Epworth Sleepiness Scale (ESS) was used to measure sleepiness while the Toronto Hospital Alertness Test (THAT) and ZOGIM Alertness Scale (ZOGIM-A) were used to measure alertness. Significant differences existed for sleepiness scores, with narcoleptics scoring highest on the ESS, followed by sleep apnea, with similar ESS scores for insomnia and PLMD. By contrast, alertness scores on both the THAT and ZOGIM-A did not differ significantly between the four groups. Sleepiness scores show a correlation of close to nil to alertness scores for the combined sleep disorder patient cohort, with the exception of insomnia patients, where a modest but significant inverse relationship was noted between sleepiness and alertness. Subjective states of impaired alertness and excessive sleepiness are independent constructs in the evaluation of sleep-disordered patients. The specific primary sleep disorder diagnosis may play a relevant role in mitigating this interrelationship.

Chronic Insomnia in Kidney Transplant Recipients

BACKGROUND

Recent studies confirmed that sleep disorders have a significant impact on various aspects of health in patients at different stages of chronic kidney disease. At the same time, there is an almost complete lack of information on the prevalence and correlates of insomnia in kidney transplant recipients.

METHODS

In a cross-sectional study, the Athens Insomnia Scale was used to assess the prevalence of insomnia in a large sample of kidney transplant recipients compared with wait-listed dialysis patients and also a matched group obtained from a nationally representative sample of the Hungarian population.

RESULTS

The prevalence of insomnia was 15% in wait-listed patients, whereas it was only 8% in transplant recipients (P < 0.001), which, in turn, was not different from the prevalence of this sleep problem in the sample of the general population (8%). Prevalences of insomnia in the transplant group were 5%, 7%, and 14% for the groups with glomerular filtration rates (GFRs) greater than 60 mL/min (> 1.00 mL/s), 30 to 60 mL/min (0.50 to 1.00 mL/s), and less than 30 mL/min (< 0.5 mL/s), respectively (P < 0.01). However, estimated GFR was no longer associated significantly with insomnia in the transplant population after statistical adjustment for several covariates. In a multivariate model, insomnia was significantly and independently associated with treatment modality (transplantation versus wait listing), as well as the presence of depression, restless legs syndrome, and high risk for obstructive sleep apnea syndrome, and with self-reported comorbidity.

CONCLUSION

The prevalence of insomnia was substantially less in the transplant group than in wait-listed dialysis patients and similar to that observed in the general population. Because this condition potentially is treatable, attention should be directed to the appropriate diagnosis and management of insomnia in the kidney transplant recipient population.

Distinguishing sleepiness and fatigue: focus on definition and measurement

Sleepiness and fatigue are two interrelated, but distinct phenomena; observed in a number of psychiatric, medical and primary sleep disorders. Despite their different implications in terms of diagnosis and treatment, these two terms are often used interchangeably, or merged under the more general lay term of 'tired'. Sleepiness is multidimensional and has many causes (multidetermined) and distinguished from fatigue by a presumed impairment of the normal arousal mechanism. Despite its ubiquity, no clear consensus exits as yet as to what constitutes sleepiness. Definitions of sleepiness, to date, are at best operational definitions, conceptualized so as to produce specific assessment instruments. As a result, while a number of subjective and objective measurement tools have been developed to measure sleepiness, each only captures a limited aspect of an otherwise heterogeneous entity. Fatigue is an equally complex phenomenon, its nature captured by a number of conceptualizations and definitions. Measures of fatigue have remained subjective, with a 'gold standard' for its measurement remaining elusive. Despite a high prevalence and high degree of morbidity, fatigue has remained a relatively under appreciated symptom, from both a clinical and research point of view.

Subjective fatigue and subjective sleepiness: two independent consequences of sleep disorders?

The objective of this investigation was to evaluate subjective fatigue versus subjective sleepiness as independent consequences of sleep disorders. Furthermore, we tried to explore how these symptoms relate to alertness, depressive symptoms and illness intrusiveness. In a prospective observational study, 283 sleep-disordered patients referred to a hospital-based sleep laboratory for various indications over a 1-year period were evaluated vis-à-vis fatigue and sleepiness. All patients completed five subjective questionnaires, underwent objective sleep recording and attended a clinical interview with a sleep specialist. The subjective questionnaires included the Epworth Sleepiness Scale, the Fatigue Severity Scale, the Toronto Hospital Alertness Test, the Illness Intrusiveness Rating Scale and the Center for Epidemiologic Studies-Depression Scale. Only 4% of the total sample was referred to the sleep clinic due to a complaint of excessive fatigue compared with 17% for excessive daytime sleepiness. However, during the assessment, 64% of referred patients reported pathological fatigue without overlap of sleepiness and only 4% reported pathological sleepiness without overlap of fatigue. Pearson's correlation analysis indicated a weak association (r=0.18) between subjective fatigue and sleepiness in the total sample. Analysis of variance testing showed strong association between those patients with prominent fatigue and depressive symptoms (P<0.01) and illness intrusiveness (P<0.001). The findings support the notion that subjective fatigue and sleepiness can be independent manifestations of sleep disorders. Furthermore, predominantly fatigued individuals with sleep disorders seem vulnerable to additional negative consequences due to possible interplay between amplified fatigue and psychological distress.

Polysomnographic and symptomatological analyses of major depressive disorder patients treated with mirtazapine

OBJECTIVE

This study aimed to characterize the effects of mirtazapine on polysomnographic sleep, especially slow wave sleep (SWS) and rapid eye movement (REM) sleep, as well as its effects on clinical symptoms in patients with major depressive disorder (MDD).

METHOD

Sixteen MDD patients were treated with mirtazapine 30 mg taken 30 minutes before bedtime. Polysomnographic and subjective sleep, as well as other clinical data, were collected at baseline and on Days or Nights 2, 9, 16, 30, and 58 during treatment. We used repeated measures analysis of variance, including pairwise comparison, to analyze data statistically.

RESULTS

Mirtazapine administration increased total SWS and the SWS in the first sleep cycle, but not SWS in the second sleep cycle. The medication increased REM latency and the duration of the first REM episode; it also decreased the number of REM episodes. Simultaneously, mirtazapine significantly reduced wake-after-sleep onset and scores on the Athens Insomnia Scale. After patients took the medication, scores on the Hamilton Depression Rating Scale-17 (HDRS-17) decreased rapidly and continuously. The changes on the Beck Depression Inventory-II were consistent with those on the HDRS-17. The medication has a tendency to increase weight.

CONCLUSIONS

Mirtazapine significantly improved sleep quality, reversed sleep markers of depression, and reduced depressive symptoms in this group of MDD patients.

What Is the Driving Performance of Ambulatory Surgical Patients after General Anesthesia?

Background

Ambulatory surgical patients are advised to refrain from driving for 24 h postoperatively. However, currently there is no strong evidence to show that driving skills and alertness have resumed in patients by 24 h after general anesthesia. The purpose of this study was to determine whether impaired driver alertness had been restored to normal by 2 and 24 h after general anesthesia in patients who underwent ambulatory surgery.

Methods

Twenty patients who underwent left knee arthroscopic surgery were studied. Their driving simulation performance, electroencephalographically verified parameters of sleepiness, subjective assessment of sleepiness, fatigue, alertness, and pain were measured preoperatively and 2 and 24 h postoperatively. The same measurements were performed in a matched control group of 20 healthy individuals.

Results

Preoperatively, patients had significantly higher attention lapses and lower alertness levels versus normal controls. Significantly impaired driving skills and alertness, including longer reaction time, higher occurrence of attention lapses, and microsleep intrusions, were found 2 h postoperatively versus preoperatively. No significantly differences were found in any driving performance parameters or electroencephalographically verified parameters 24 h postoperatively versus preoperatively.

Conclusions

Patients showed lower alertness levels and impaired driving skills preoperatively and 2 h postoperatively. Based on driving simulation performance and subjective assessments, patients are safe to drive 24 h after general anesthesia.

Sleep-disordered breathing, cardiac arrhythmia, and panic disorder

Sleep-disordered breathing often presents as a cardiac or psychiatric problem. Such presentation may lead to suboptimal diagnostic and therapeutic decisions. The authors present a case in which a patient's condition improved only after the primary disorder was diagnosed and properly managed.

Sleep apnea, hypertension, and the effects of continuous positive airway pressure

BACKGROUND

Sleep apnea is being studied as a risk factor for hypertension. This observational chart review was conducted to determine the long-term effects of continuous positive airway pressure (CPAP) treatment on blood pressure (BP) in a sample of sleep apnea patients from urban and rural populations.

METHODS

This study was conducted using data from 180 clinical charts from 1995 to 2002. Patients were identified as hypertensive or normotensive by their initial BP values before they were diagnosed with sleep apnea and were also reviewed after the use of CPAP.

RESULTS

Of the patients diagnosed with sleep apnea, 32% were found to have hypertension (mean systolic BP: 164.4 +/- 20.3 mmHg; mean diastolic BP: 96.9 +/- 5.3 mmHg). The average use of CPAP was 12.1 +/- 22.4 months. The hypertensive group showed a significant reduction in BP with CPAP use: systolic BP dropped by an average of 11.2 mmHg (P < .001) and diastolic BP dropped by an average of 5.9 mmHg (P < .001).

CONCLUSIONS

Our results confirm that frequency of hypertension is increased among sleep apnea patients. The long-term use of CPAP in hypertensive patients with sleep apnea is associated with a significant decrease in BP to levels that considerably decrease cardiovascular risk.

Blocking low-wavelength light prevents nocturnal melatonin suppression with no adverse effect on performance during simulated shift work

Decreases in melatonin production in human and animals are known to be caused by environmental lighting, especially short-wavelength lighting (between 470 and 525 nm). We investigated the novel hypothesis that the use of goggles with selective exclusion of all wavelengths less than 530 nm could prevent the suppression of melatonin in bright-light conditions during a simulated shift-work experiment. Salivary melatonin levels were measured under dim (<5 lux), bright (800 lux), and filtered (800 lux) light at hourly intervals between 2000 and 0800 h in 11 healthy young males and eight females (mean age, 24.7 +/- 4.6 yr). The measurements were performed during three nonconsecutive nights over a 2-wk period. Subjective sleepiness was measured by self-report scales, whereas objective performance was assessed with the Continuous Performance Test. All subjects demonstrated preserved melatonin levels in filtered light similar to their dim-light secretion profile. Unfiltered bright light drastically suppressed melatonin production. Normalization of endogenous melatonin production while wearing goggles did not impair measures of performance, subjective sleepiness, or alertness.

The effects of nefazodone on women with seasonal affective disorder: clinical and polysomnographic analyses

OBJECTIVE

To outline the clinical and polysomnographic changes induced by nefazodone in patients with seasonal affective disorder.

METHODS

Twelve patients were enrolled, and 9 of them studied, in an open-label trial with objective and subjective measurements. The mean age of the studied patients was 45 (range 35-58) years. They met Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), criteria for major depressive disorder and current major depressive episode with seasonal patterns. The patients' mean baseline score on the Seasonal Patterns Assessment Questionnaire (SPAQ) was 15.7 (standard deviation [SD] 5.3). The total nefazodone treatment period was 8 weeks, and the daily dosages were 100 mg in week 1, 200 mg in week 2, 300 mg in week 3, and up to 400 mg in weeks 4-8. Each patient received the 29-item version of the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety (HAM-A) and 2-night polysomnographic assessments on 3 occasions: before treatment (baseline, W0), at the end of week 4 (W4) and at the end of week 8 (W8).

RESULTS

There were statistically significant improvements in depression, anxiety, sleep latency and sleep efficiency during the 8-week treatment protocol. Repeated-measures analysis of variance results indicated that nefazodone has a time-dependent effect on both HAM-D and HAM-A scores. After 8 weeks of nefazodone therapy, HAM-D scores decreased from 33.4 (SD 8.1) to 11.6 (SD 5.6) (F(2,14) = 13.68, p = 0.001) and HAM-A decreased from 26.6 (SD 7.0) to 11.5 (SD 11.1) (F(2,14) = 13.46, p = 0.001). The results of paired t tests show that, compared with baseline, HAM-D and HAM-A scores decreased at both W4 (p = 0.004 and p = 0.002, respectively) and W8 (p = 0.002 and p = 0.005, respectively). The time-dependent effects on stage 1 sleep (F(2,16) = 6.06, p = 0.011) and periodic leg movement index (F(2,16) = 4.31, p = 0.035) were also significant. The mean sleep latency of these patients decreased from 39.9 (SD 32.7) minutes at W0 to 16.6 (SD 15.3) minutes at W8 (p < 0.05). Sleep efficiency increased from 78.8% (SD 14.6%) at W0 to 91.5% (SD 5.5%) at W8 (p < 0.05). Stage 1 sleep decreased from 4.9% (SD 1.9%) at W0 to 3.4% (SD 2.6%) at W8 (p < 0.05).

CONCLUSIONS

The results of this preliminary study indicate that nefazodone not only has favourable antidepressant and anxiolytic effects but also enhances sleep efficiency and sleep latency.

Validation of a Short Questionnaire in English and French for Use in Patients with Persistent Upper Gastrointestinal Symptoms Despite Proton Pump Inhibitor Therapy: The Pass (Proton Pump Inhibitor Acid Suppression Symptom) Test

BACKGROUND: The management of persistent symptoms during acid suppression therapy in patients with gastroesophageal reflux disease or dyspepsia might be improved if patient-physician communication regarding the presence and character of these persistent symptoms were facilitated.

AIM: To validate a short, simple questionnaire (the Proton pump inhibitor [PPI] Acid Suppression Symptom [PASS] test), in English and French, to identify patients with persistent acid-related symptoms during PPI therapy and document their response to a change in therapy.

METHODS: Patients with persistent acid-related symptoms on PPI therapy were interviewed to produce a draft, five-item questionnaire; content validity was evaluated by focus groups comprising English- and French-speaking patients. Psychometric validity was subsequently evaluated in a multicentre, family practice-based study of English- and French-speaking patients with persistent acid-related upper gastrointestinal symptoms despite PPI therapy. The PASS test, Global Overall Symptom scale, Gastrointestinal Symptom Rating Scale (GSRS), Quality of Life in Reflux and Dyspepsia questionnaire and Reflux Disease Questionnaire were completed at baseline and repeated after one week while patients continued their original PPI therapy. All patients then received esomeprazole 40 mg once daily for four weeks, after which all questionnaires and an evaluation of overall treatment effect were completed.

RESULTS: Content validity was established in 20 English- and 16 French-speaking patients. Psychometric validation in 158 English- and 113 French-speaking patients revealed good-to-excellent test-retest reliability coefficients: 0.76 for English; 0.68 for French. For construct validity, the PASS test showed moderate-to-high correlation with the GSRS scale (0.51 for English; 0.43 for French). After four weeks of therapy, the PASS test score fell to zero in 30% of English- and 33% of French-speaking patients, while the Global Overall Symptom score fell to one (no symptoms) in 32% of patients (English- and French-speaking); the PASS test demonstrated good responsiveness in comparison with the GSRS, Reflux Disease Questionnaire and Quality of Life in Reflux and Dyspepsia questionnaire.

CONCLUSION: The five-item PASS test is a valid tool for the evaluation of persistent acid-related symptoms in patients receiving PPI therapy. It demonstrates good content validity, test-retest reliability, responsiveness and construct validity in both English and French forms. The PASS test is a simple, clinically applicable tool for the identification of patients with persistent acid-related symptoms during therapy and the assessment of their responses to a change in therapy.

Psychiatric aspects of late-life insomnia

Epidemiological trends towards a 'graying' population make the issue of insomnia in the elderly an increasingly important research and clinical topic. It is often challenging to determine how much of a psychiatric dimension there is to a clinical condition that is best viewed as both as a symptom and a true psychosomatic entity in its own right. To categorize insomnia as either psychiatric or medically based risks oversimplification of the complexities of sleep disruption in the elderly. Normal senescence-related changes in sleep architecture and circadian rhythms must be considered, as well as the frequent medical comorbidities that may affect sleep. Psychiatric diagnoses to consider include mood and anxiety disorders, which may be affected equally by physiological and psychological changes implicit in old age. Sleep disruption related to dementia is of particular interest to clinicians involved with patients in long-term care facilities. Insomnia may occasionally be iatrogenically induced or exacerbated, and particularly antidepressants must be carefully selected for this reason. Light therapy and behavior therapies are important in multimodal treatment of insomnia, and sleep hygiene includes both regular physical and social activities to preserve entrainment of circadian rhythms affecting sleep.

Increased utilization of health services by insomniacs--an epidemiological perspective

OBJECTIVES

Epidemiological data describing the prevalence of sleep complaints in Hungary and its region are lacking; furthermore, limited information is available on health care use by individuals with sleep complaints. We assessed the prevalence of sleep complaints, insomnia in particular, in a nationally representative sample of the Hungarian population and assessed health care utilization by insomniacs.

METHODS

Cross-sectional study, enrolling a nationally representative sample (N=12,643) of the adult Hungarian population. A battery of questionnaires was administered during a home interview. The Athens Insomnia Scale (AIS), additional questions on sleep behavior, as well as questions on current medical therapy for somatic and mental disorders were included in the battery of questionnaires administered. Psychosocial and demographic characteristics were also tabulated.

RESULTS

Forty-seven percent of the sample reported at least one complaint related to sleep. Based on the AIS we report a 9% prevalence of insomnia in the total sample. Sleep deprivation was highly prevalent in the younger and middle-aged groups. The frequency of sleep problems increased with age. Individuals diagnosed with insomnia reported more frequent utilization of health services, including sick leave, emergency visits and hospitalization, than those without insomnia.

CONCLUSION

Sleep complaints and sleep deprivation are frequent problems in the Hungarian population and are associated with increased health care utilization. The prevalence of insomnia in our sample was similar to what has been previously reported from other countries. The high prevalence of sleep-deprived individuals warrants further attention. Interventions that effectively improve insomnia may also reduce health care utilization by the affected individuals.