Sleep apnea and nocturnal myoclonus in the elderly

—Insomnia, daytime sleepiness, and nocturnal wandering, so common in the elderly, are caused largely by two specific pathophysiologic processes. Sleep apnea is a condition where respiration pauses during sleep, leading to arousal. Sleep apnea is due either to obstruction in the throat or failure of the central respiratory center. Periodic movements in sleep are characterized by frequent ankle and leg flexions, leading to arousal. Sleep apnea and periodic movements in sleep require specific diagnoses and treatments. Each process occurs in 20%–30% of people over 65, and perhaps the majority of older people have one or the other condition or both. Because of possible interactions with these sleep disorders, the widespread prescribing of sleeping pills to elderly patients is irrational and often dangerous. In the future, large-scale clinical trials will be needed to define effective long-term treatments for these conditions and to define when treatment is worthwhile.     

Is Tourette syndrome a cause of sudden infant death syndrome and childhood obstructive sleep apnea?

The cause of sudden infant death syndrome (SIDS) is unknown. Sleep-related impairment of respiratory control and arousal are postulated; hyperdopaminergic and hyposerotonergic dysfunction may contribute to events leading to infant apnea and SIDS. Psychosocial adversity and impulsive and compulsive behaviours characterize some families of SIDS victims. Tourette syndrome (TS) is a common hereditary neurobehavioral disorder characterized by the frequent presence of impulsive and compulsive behaviors. Sleep disorders are common and include sleep apnea and abnormal arousal. Hyperdopaminergic and hyposerotonergic abnormalities are postulated to contribute to the pathophyusiology of the disorder. The following is a report of the presence of incidents of infant apnea and SIDS in families in which TS was present. In an additional TS family, a child had obstructive sleep apnea syndrome (OSAS). Results of a preliminary survey suggest that TS gene carriers are at increased risk of life-threatening apneas of infancy and that the prevalence of SIDS in such families may be 2 to 5 times the prevalence in the general population. The presence in some pedigrees of sleep apnea in children and adults suggest that in some instances disorders of sleep-related ventilatory control and arousal occurring throughout the life-span share common pathophysiological mechanisms. © 1993 Wiley-Liss, Inc.     

Assessment and treatment of sleep disturbances in older adults

Sleep disturbances are common in older adults. These disturbances are often secondary to medical illness and/or medication use or are due to specific problems such as sleep disordered breathing, periodic limb movements in sleep and circadian rhythm disturbances. The prevalence of sleep disordered breathing and periodic limb movement in sleep increases with age. The circadian rhythm tends to advance with age, causing older people to awaken early in the morning. Insomnia is often caused by pain associated with medical illness. Insomnia can also be caused by stimulating medications. In institutionalized elderly, sleep becomes even more disturbed and fragmented than in community-dwelling older adults. Accurate assessment and diagnosis is crucial since effective treatment strategies are available for these sleep disturbances. The effect, prevalence and treatment of each of these conditions is reviewed.     

The evoked heart rate response to periodic leg movements of sleep.

STUDY OBJECTIVES: Periodic leg movements of sleep are currently subdivided based upon whether or not they are associated with EEG arousal. "Autonomic" arousals, characterized by elevations in heart rate and blood pressure without AASM-defined EEG changes, have been associated with daytime somnolence in experimental protocols. In this study, we will describe the heart rate response to periodic leg movements of sleep, both with and without associated arousals. DESIGN: Heart rate was averaged for each of the ten cardiac cycles before, and after, the onset of individual periodic leg movements occurring in non-REM sleep for eight patients with Periodic Limb Movement Disorder (PLMD). Records were blindly scored (without EKG data) to determine if AASM-defined EEG arousals occurred within two seconds of leg movement onset. Leg movements during wakefulness were performed by four non-patient controls as a control condition. SETTING: Sleep Disorders Center INTERVENTIONS: None MEASUREMENTS AND RESULTS: A significant rise in heart rate was observed following the onset of individual leg movements of sleep (N = 796), which was also significantly larger than that seen after waking leg movements (N = 275). Although heart rate elevation was 10%-40% higher when leg movements were associated with AASM-defined arousal, these differences did not reach statistical significance. CONCLUSIONS: Periodic leg movements of sleep are associated with cardiac acceleration, even in the absence of AASM-defined arousal. It appears premature to conclude that periodic leg movements of sleep not associated with visible EEG arousal are clinically insignificant.     

Sleep apnea: a review

Sleep apnea, although frequently unrecognized or misdiagnosed, is neither uncommon nor trivial in its effects. Patients who complain of sleep difficulty may be treated initially with sedative-hypnotics, which only reduce arousal ability and prolong apneic episodes. Sleep apnea frequently presents with psychiatric symptoms. Once suspected, its provisional identification is not difficult, although definitive diagnosis is best done in a sleep laboratory. The symptoms, examinations and assessments, pathophysiology, and treatments are reviewed in this article in relation to the three types of apnea: obstructive, central, and mixed.     

The cardiovascular response to arousal from sleep decreases with age in healthy adults

STUDY OBJECTIVES: To investigate age and gender effects on the acute blood pressure (BP) and heart rate (HR) response to arousal from sleep in healthy adults. DESIGN: Healthy young and older male and female adults were aroused from stage 2 sleep throughout the night using an auditory tone. The magnitude of the cardiovascular responses to arousal were assessed using 2 (young v older) by 2 (male v female) ANOVAs with repeated measures over time. SETTING: Sleep laboratory at the Royal Brompton Hospital, London. PATIENTS OR PARTICIPANTS: 25 healthy young (< or = 40 years, n = 15 males) and 20 healthy older adults (> or = 60 years, n = 11 males). INTERVENTIONS: Arousals (> 10 seconds) from undisturbed stage 2 sleep were induced by an auditory tone throughout the night. MEASUREMENTS AND RESULTS: Overnight polysomnography (PSG) with HR, continuous beat-by-beat arterial BP and respiratory measurements was performed. Older adults had smaller and delayed initial mean BP and HR responses to arousal compared to young adults (both P < 0.001), whereas changes in ventilation and tidal volume responses to arousal were similar between age groups (P = 0.3 and P = 0.6 respectively).There were no differences between females and males in the cardiovascular or respiratory responses to arousal from sleep. CONCLUSION: The cause of the smaller and delayed response in healthy older adults is unknown; however, we speculate that for older people with sleep apnea, in whom nocturnal arousals occur frequently, the reduced cardiovascular response may be protective against the link between sleep apnea and hypertension.     

Respiratory arousals in mild obstructive sleep apnea syndrome.

The objective of the study is to identify patients with mild sleep apnea by counting not only apneas and hypopneas, but also mild respiratory events, which do not fulfill apnea or hypopnea criteria, but result in an arousal (Type-R arousal). Arousals related to body movements (Type-M arousal) were separately counted. The influence of nasal continuous positive airway pressure (nCPAP) on respiratory and movement arousals was analyzed. Daytime sleepiness before and after nCPAP and its relationship to arousal types was investigated using the Multiple Sleep Latency Test (MSLT) and a standardised questionnaire. Twenty-two patients with a mean age of 43.6 +/- 9.2 years underwent polysomnographic evaluation on a baseline night, and during three nights with nCPAP. On the baseline night, subjects presented with a mean RDI of 10.5 +/- 7.2/h, an apnea index (AI) of 1.2 +/- 1.5/h, a hypopnea index (HI) of 9.3 +/- 6.6/h, a R index of 5.2 +/- 5.9/h, and a M index of 9.7 +/- 5.6/h. Use of nCPAP lowered the RDI (p < 0.001) and the R index (p < 0.01). Mean sleep latency in the MSLT increased with nCPAP (p < 0.05) and the patient's subjective well being improved (p < 0.01). Correlation analysis revealed a relationship between Type-R arousals and RDI and HI (r = 0.5, p < 0.01) as well as between questionnaire scores and mean sleep latency. The decrease of Type-R indicates the positive effect of nCPAP. Arousal analysis and detection of mild respiratory events associated with arousals are helpful in investigating the sleep structure and in objectifying clinical symptoms and treatment success in patients with mild OSAS.     

Regulation der Atmung im Schlaf

Breathing is part of a transport system that serves gas exchange of the body. Rhythmic breathing movements are controlled by the neuronal respiratory network in the medulla oblongata, which is dependent on tonic afferents. These are partly closed feedback loops to guarantee the homeostasis of blood gases and acid–base balance, and partly non-feedback stimuli as the so-called “wakefulness drives.” Orexinergic neurons in the hypothalamus seem to play an important role in the tonic drive of respiration during wakefulness. Sleep onset markedly reduces tonic afferents, decreases the sensitivity to hypoxia and hypercapnia, and elevates arousal thresholds. Sleep unmasks the apnea threshold. If the arterial carbon dioxide partial pressure drops below this threshold due to short hyperpneic episodes, the respiratory rhythm arrests. Restless sleep with frequent changes in sleep states destabilizes the breathing pattern. The muscle atonia especially during REM sleep also affects the upper airway muscles and the intercostal muscles. Consequently, there is an increase in airway resistance. The diaphragm has to compensate these challenges by increased work. Nevertheless, in healthy subjects the blood gases only slightly change from wakefulness to sleep.     

Does sleep deprivation worsen mild obstructive sleep apnea?

STUDY OBJECTIVES: Sleep deprivation is believed to worsen obstructive sleep apnea (OSA). We assessed the effect of acute sleep deprivation on polysomnography in a cohort of subjects with mild OSA and a cohort of subjects without OSA. DESIGN: Crossover study in which subjects initially had polysomnography after a normal night's sleep or after 36 hours of sleep deprivation, followed by a 2- to 4-week interval, after which subjects were restudied under the alternate testing condition. SETTING AND PARTICIPANTS: 13 subjects with mild OSA and 16 subjects without OSA were studied in a university teaching hospital sleep laboratory. INTERVENTIONS: 36 hours of supervised sleep deprivation. MEASUREMENTS: Subjects' age, body mass index, neck circumference and Epworth Sleepiness Scale scores were measured; actigraphy and sleep diaries were used to estimate prior sleep debt before each sleep study. RESULTS: Sleep deprivation was found to significantly increase total sleep time, sleep efficiency, and rapid eye movement and slow-wave sleep time. Subjects with OSA showed a lower minimum oxygen saturation after sleep deprivation. However, subjects did not show a significantly different respiratory disturbance index, arousal index, or length of the longest apnea after sleep deprivation. CONCLUSIONS: Acute sleep deprivation did not worsen most OSA parameters as measured by polysomnography. A lower minimum oxygen saturation in mild OSA subjects after sleep deprivation may be important in patients with significant cardiorespiratory disease. More research is needed to assess whether daytime performance and function (eg, driving, sleepiness) is more greatly impaired in OSA subjects who are sleep deprived, compared to normal subjects who are sleep deprived.     

Sleep loss in elderly volunteers

Sleep, performance, and sleepiness were assessed in 10 elderly volunteers (8 women, 2 men; aged 61-77 years) before, during, and after 38 h of sleep loss. Recovery night 1 sleep showed increased total sleep and stages 3 and 4 sleep and decreased stage 1 sleep, wakefulness, brief arousals, and latency to stages 3 and 4 sleep. An increase in stage 4 sleep persisted to the second recovery night. Increased arousal threshold was suggested by a lengthening of respiratory events and a reduction in arousals associated with leg movements. Performance was impaired during sleep loss, associated with an increased tendency to fall asleep. Reported sleepiness increased, except in three subjects who denied sleepiness. Latency to sleep onset declined. All measures returned to basal values after a night of sleep. Sleep in one volunteer failed to respond to sleep loss. With this exception, the response was similar to that reported in younger volunteers, although shorter-lived.     

Night-to-night arousal variability and interscorer reliability of arousal measurements

STUDY OBJECTIVES: Measurement of arousals from sleep is clinically important, however, their definition is not well standardized, and little data exist on reliability. The purpose of this study is to determine factors that affect arousal scoring reliability and night-to-night arousal variability. DESIGN: The night-to-night arousal variability and interscorer reliability was assessed in 20 subjects with and without obstructive sleep apnea undergoing attended polysomnography during two consecutive nights. Five definitions of arousal were studied, assessing duration of electroencephalographic (EEG) frequency changes, increases in electromyographic (EMG) activity and leg movement, association with respiratory events, as well as the American Sleep Disorders Association (ASDA) definition of arousals. SETTING: NA. PATIENTS: NA. INTERVENTIONS: NA. RESULTS: Interscorer reliability varied with the definition of arousal and ranged from an Intraclass correlation (ICC) of 0.19 to 0.92. Arousals that included increases in EMG activity or leg movement had the greatest reliability, especially when associated with respiratory events (ICC 0.76 to 0.92). The ASDA arousal definition had high interscorer reliability (ICC 0.84). Reliability was lowest for arousals consisting of EEG changes lasting <3 seconds (ICC 0.19 to 0.37). The within subjects night-to-night arousal variability was low for all arousal definitions CONCLUSION: In a heterogeneous population, interscorer arousal reliability is enhanced by increases in EMG activity, leg movements, and respiratory events and decreased by short duration EEG arousals. The arousal index night-to-night variability was low for all definitions.     

Validation of sleep observations in a nursing home

Most of the studies on sleep patterns in elderly people have been performed on small samples in sleep laboratories and with the use of advanced technology. Such technology is generally unavailable either for research studies or clinical interventions with elderly people residing in the community. Additionally, the utility of the sleep laboratory in assessing sleep in the very demented patient is limited because of irregularities of electroencephalogram (EEG) patterns in this population. For these reasons, systematic sleep observations are presented as important tools in the assessment of sleep in the nursing home. Nursing homes have night-shift staff who are frequently not fully occupied and could be trained to perform sleep observations. The Observational Sleep Assessment Instrument (OSAI) documents the occurrence of sleep, as well as disruptions in sleep, breathing, snoring, myoclonic movements, and body restlessness. This study documented the validity of the OSAI by establishing interrater reliability and by correlating its results to those of a portable sleep monitor, namely, a four-channel ambulatory sleep respiratory monitor and a wrist activity monitor. Results show that the OSAI is a reliable and valid tool for examining sleep and sleep pathology in this population, and can become a useful screening tool for detecting sleep and breathing disorders.     

Sleep fragmentation and daytime sleepiness

It has been noted that clinical populations complaining of excessive daytime sleepiness (EDS) frequently have disrupted or fragmented nocturnal sleep. The relation between sleep fragmentation and daytime sleepiness has not been systematically studied. This study was designed to use correlational techniques evaluating the relation between these variables in patients complaining of EDS, patients complaining of insomnia, and asymptomatic controls. The four groups studied included patients complaining of EDS with sleep apnea (n = 15) or with periodic leg movements (n = 15), patients complaining of insomnia (n = 15), and healthy volunteers with no sleep complaint (n = 10). One night of polysomnography followed by a Multiple Sleep Latency Test was obtained for each subject. Each recording was evaluated using standard criteria and also by a four-level arousal scoring system. Across all subjects, the total number of arousals correlated significantly with sleepiness index (r = 0.48, p less than 0.001). Closer analysis of the data shows that, depending upon the sleep complaint, different types of arousals are predictive of degree of daytime sleepiness. It is concluded that the number and type of nocturnal arousals play an important role in subsequent daytime sleepiness.     

Periodic limb movements in children: prevalence in a referred population

STUDY OBJECTIVES: To determine the prevalence of periodic limb movements of sleep (PLMS) in children referred for evaluation of sleep disorders. DESIGN: A retrospective analysis of all overnight polysomnograms (PSG) performed at a tertiary-level pediatric care facility. SETTING: All PSG studies were performed in the pediatric sleep laboratory associated with the Alberta Children's Hospital in Calgary, AB, Canada. The pediatric sleep laboratory was situated in the Foothills Hospital Alberta Lung Association Sleep Center until August 2002. At that time, the pediatric sleep laboratory was relocated to the Alberta Children's Hospital. PARTICIPANTS: All children of any age undergoing PSG for any reason between October 1999 and March 2003. MEASUREMENTS AND RESULTS: All PSG records were reviewed, and the following data was extracted: periodic limb movement index (PLM index), periodic limb movements with arousal index (PLM w/arousal index), apnea-hypopnea index (AHI), and patient demographics (age, sex, comorbidities). A total of 591 PSG studies were reviewed. Thirty-three of the 591 children (5.6%) had evidence of PLMs > 5 per hour. Twenty of the 33 (60.0%) had coexistent obstructive sleep apnea (AHI > 1/hour). Only 7 of the 591 children studied (1.2%) had evidence of PLM > 5 per hour with no other comorbidity. Two of 13 children with PLM > 5 per hour and no evidence of obstructive sleep apnea had attention-deficit/hyperactivity disorder. The prevalence of PLMS in the 28 of the 591 subjects with a preexisting diagnosis of ADHD was increased at 7.1%. CONCLUSIONS: PLMS is an uncommon disorder of childhood. In a select population at increased risk for having a sleep disorder, the prevalence of isolated PLMS is only 1.2%.     

Sleep disturbance in menopause

OBJECTIVE: To determine the sources of sleep complaints in peri- and postmenopausal women reporting disturbed sleep. DESIGN: A total of 102 women, ages 44 to 56 years, who reported disturbed sleep were recruited through newspaper advertisements. They were assessed with the Pittsburgh Sleep Quality Index and the Hamilton Anxiety and Depression Rating Scales. Complete polysomnography was performed in a controlled laboratory setting. Results were analyzed by multiple regression. RESULTS: Fifty-three percent of the women had apnea, restless legs, or both. The best predictors of objective sleep quality (laboratory sleep efficiency) were apneas, periodic limb movements, and arousals (R=0.44, P<0.0001). The best predictors of subjective sleep quality (Pittsburgh Sleep Quality Index global score) were the Hamilton anxiety score and the number of hot flashes in the first half of the night (R=0.19, P<0.001). CONCLUSIONS: Primary sleep disorders (apnea and restless legs syndrome) are common in this population. Amelioration of hot flashes may reduce some complaints of poor sleep but will not necessarily alleviate underlying primary sleep disorders. Because these can result in significant morbidity and mortality, they require careful attention in peri- and postmenopausal women.     

Preliminary longitudinal assessment of sleep in the elderly

This is a preliminary report of a longitudinal assessment of sleep architectural changes over time and rate of progression of sleep apnea (SA) and sleep-related periodic leg movements (PLMs) in the elderly. Multiple night polysomnograms were performed in 11 community resident seniors (8 women and 3 men, aged 60-72 years) and repeated 3 years (34-38 months) later. Subjects were selected who exhibited at most mild SA or PLMs at initial testing. The respiratory disturbance index (but not the movement index) showed a significant increase over 3 years. Sleep architecture did not change significantly except for an increase in frequency of stage changes that was not solely attributable to the increase in frequency of apneas/hypopneas. Together with other published longitudinal studies, these findings suggest that elderly individuals with at most mild SA or PLMs can expect no more than a mild increase in the frequency of apneas/hypopneas or PLMs over the course of a few years.     

Schlaf beim alten Menschen

Demographic development has led to an increase in elderly and geriatric patients requiring sleep medicine. In principle, the same guidelines and procedures apply to elderly patients as apply for younger patients. However, there are physiological and pathophysiological differences in relation to the sleep of the elderly that should be given attention to avoid mistreatment, so that all medical professionals are able to give patients and health-conscious seniors better information about sleep medicine.Age-related changes in sleep, according to research so far, start before the age of 70 during middle and early senior age. Generally, electrical potentials in EEG signals decrease. Slow-wave sleep is reduced in healthy old age, especially in men, as few percentage points of the total sleep time (TST) as REM sleep, and sleep efficiency decreases slightly, TST does not change. Sleep is more fractured with more nonrespiratory arousals, and the time needed to fall asleep increases somewhat. Respiratory drive steered through blood CO₂, and therefore loop gain after apnea, decrease slightly with aging. However, the elasticity of the tissue and musculature of the upper airways do too; thus, obstructive apnea and hypopnea show a slight physiological increase. Pathological changes in sleep in older people caused by, for example, the development of dementia, respiratory and cardiovascular diseases, and pain syndromes have not yet been sufficiently investigated in relation to sleep changes with healthy aging.     

Nocturnal rocking bed therapy: improvement in sleep fragmentation in patients with respiratory muscle weakness

Three patients with respiratory muscle weakness developed sleep fragmentation due to nonobstructive apnea and hypopnea. In two patients in whom inspiratory muscle electromyogram was recorded, the apneas and hypopneas were terminated only by arousal and excessive recruitment of accessory muscles. Nocturnal rocking bed ventilatory support resulted in immediate improvement in sleep fragmentation and inhibited arousal-associated phasic accessory muscle activation, resulting in improvement in daytime hypercapnia and subjective sleepiness. Sleep fragmentation may occur more commonly than generally appreciated in neuromuscular disease patients who are independent of daytime ventilatory support. The use of nocturnal rocking bed is an effective noninvasive method of reversing sleep fragmentation and daytime sequelae when obstructive apnea is absent.     

Daytime carryover of triazolam and flurazepam in elderly insomniacs

The effects of triazolam (0.25 mg) or flurazepam (15 mg) were evaluated in 13 elderly (ages 64-79) insomniacs. Subjects were reasonably healthy, ambulatory, and complained of disturbed sleep. Sleep apnea syndromes were ruled out by nocturnal polysomnogram. Sleep, daytime sleepiness [Multiple Sleep Latency Test (MSLT) and Stanford sleepiness scale (SSS)], performance, and mood [Profile of Mood States (POMS)] were assessed on five consecutive days. Placebo was given on nights 1 and 2; active medications were given on nights 3-5. Sleep time was increased by approximately 1 h in both groups. MSLT showed increased sleepiness with flurazepam and decreased sleepiness with triazolam. MSLT scores were unrelated to nocturnal sleep parameters in the flurazepam group and showed a pattern of correlation, though nonsignificant, in the triazolam group. Vigilance was impaired with flurazepam and unchanged with triazolam. Other performance tests showed slight improvement or no change with drugs. Mood tended to be improved after flurazepam ingestion and unchanged after triazolam. These findings suggest that, although both compounds improve nocturnal sleep in elderly insomniacs, there is significant residual sedation with flurazepam and improved daytime alertness with triazolam. Neither compound had a significant effect on nocturnal respiration in these non-sleep-apneic elderly subjects.     

Endothelial function and sleep: associations of flow‐mediated dilation with perceived sleep quality and rapid eye movement (REM) sleep

Endothelial function typically precedes clinical manifestations of cardiovascular disease and provides a potential mechanism for the associations observed between cardiovascular disease and sleep quality. This study examined how subjective and objective indicators of sleep quality relate to endothelial function, as measured by brachial artery flow‐mediated dilation (FMD). In a clinical research centre, 100 non‐shift working adults (mean age: 36 years) completed FMD testing and the Pittsburgh Sleep Quality Index, along with a polysomnography assessment to obtain the following measures: slow wave sleep, percentage rapid eye movement (REM) sleep, REM sleep latency, total arousal index, total sleep time, wake after sleep onset, sleep efficiency and apnea–hypopnea index. Bivariate correlations and follow‐up multiple regressions examined how FMD related to subjective (i.e. Pittsburgh Sleep Quality Index scores) and objective (i.e. polysomnography‐derived) indicators of sleep quality. After FMD showed bivariate correlations with Pittsburgh Sleep Quality Index scores, percentage REM sleep and REM latency, further examination with separate regression models indicated that these associations remained significant after adjustments for sex, age, race, hypertension, body mass index, apnea–hypopnea index, smoking and income (Ps < 0.05). Specifically, as FMD decreased, scores on the Pittsburgh Sleep Quality Index increased (indicating decreased subjective sleep quality) and percentage REM sleep decreased, while REM sleep latency increased (Ps < 0.05). Poorer subjective sleep quality and adverse changes in REM sleep were associated with diminished vasodilation, which could link sleep disturbances to cardiovascular disease.