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Biomedical subjects

D L Bliwise

Publications and source records attributed to D L Bliwise.

At least 19 recordsLinked to original sources
PubMed1992

Prevalence of self-reported poor sleep in a healthy population aged 50-65.

Many population-based surveys have reported that the prevalence of poor sleep increases with age. Despite the uniformity of findings, it remains unclear to what extent age-related declines in overall physical health are related to those results. One approach to this problem has been to adjust for such confounding variables multivariately. Some prior studies using this approach have not shown the expected age-related increases in the prevalence of poor sleep. Another approach has been the study of sleep in carefully screened, healthy populations. The current study reports the prevalence of disturbed sleep in a population, ages 50-65, carefully screened for physical health as part of an ongoing study of exercise and cardiovascular function. The prevalence of self-reported trouble falling asleep every night or almost every night (1.1% M, 2.6% F), trouble awakening and returning back to sleep (4.4% M, 3.3% F), and use of hypnotic medication at least twice a week (1.6% M, 2.6% F) were consistently lower than in nearly all previous population-based studies of individuals of comparable age. This implies that when overall physical health factors are taken into account a decline in sleep quality is not necessarily an inevitable component of aging per se. As has been shown in other studies, there were small but statistically significant relationships between self-reported depression and poor sleep. Despite the low prevalence of poor sleep, about a third of the population reported feeling not well-rested and/or not getting the sleep they required. The individuals in this study also reported obtaining significantly less sleep relative to normative data from 30 years ago.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1992

Sleep in Alzheimer's disease and the sundown syndrome.

Approximately 10% of the elderly population have a dementing illness that manifests itself clinically by significant cognitive deficits. Half of these individuals have Alzheimer's disease (AD), a progressive degeneration of cortical and subcortical neurons. Disturbances of sleep and the sleep-wake rhythm are a common clinical observation in AD, as is "sundowning," the onset or exacerbation of delirium during the evening or night. Here we describe the neurologic basis for the disturbed sleep of patients with AD, the phenomenology of that disturbance, and its implications. Further, we describe the prevalence, possible causes, and treatment of sundowning.

Aged↗
PubMed1991

A preliminary study comparing sleep restriction and relaxation treatments for insomnia in older adults.

This study compared Sleep Restriction Therapy (SRT) and Relaxation Therapy (RLT) as treatments for insomnia in a sample of community-residing elderly (mean age, 69.7 years). SRT subjects (n = 10) and RLT subjects (n = 12) reported information about their sleep twice daily to a telephone recording machine for 2 weeks of baseline, 4 weeks of treatment, and 2 weeks at 3-month follow-up. Results showed sleep latency and waking after sleep onset were significantly reduced for both treatment groups under active treatment. Predictable reductions in time in bed and improved sleep efficiency reported during active treatment by SRT subjects were still apparent at 3-month follow-up; no corresponding changes were found for RLT. In both groups, increased total sleep time was reported at follow-up; the improvement for SRT subjects was approximately twice that seen in RLT. These findings, at this early stage in the development of behavioral treatments for insomnia in older adults, encourage further study.

Aged↗
PubMed1991

Inter-rater reliability for scoring periodic leg movements in sleep.

This study investigated inter-rater reliability for scoring periodic leg movements in sleep (PLMS) and related phenomena. Five highly experienced polysomnographic technologists each scored 24 nocturnal polysomnograms, the majority of which contained an appreciable number of PLMS. Results indicated high inter-rater reliability for some variables but more modest reliability for others. We discuss these findings in terms of efforts of standardization in polysomnographic scoring of sleep disorders.

Aged↗
PubMed1991

Factors associated with nightly variability in sleep-disordered breathing in the elderly.

The purpose of this study was to evaluate factors associated with nightly variability in sleep-disordered breathing. In this study, variability in sleep-disordered breathing over two consecutive laboratory nights was evaluated in 71 aged volunteers with varying levels of sleep apnea. High variability (n = 13) and low variability (n = 58) groups were formed on the basis of an absolute two-night apnea/hypopnea index difference of a minimum ten events per hour. Results indicate high variability was related to longer soft palate measurements and the presence of nasal obstruction on physical examination. Within the high variability group, variation in sleep-disordered breathing occurred within identical gross body position over the two nights. The results suggest that local, anatomic factors affecting airway patency may not be constant from night to night.

Aged↗
PubMed1991

Relative validity of self-reported snoring as a symptom of sleep apnea in a sleep clinic population.

The purpose of this study was to evaluate the relative validity of responses to three different questions about snoring as indicators for sleep apnea in a population referred to a sleep clinic. Secondary goals were to evaluate the meaning of a "don't know" response to these questions and to examine how the associations between snoring and sleep apnea are influenced by demographics. Results from 1,409 patients in a sleep clinic indicated that nearly all levels of estimated snoring frequency were associated with a greater likelihood of sleep apnea. In addition, a "don't know" response indicated a likelihood of sleep apnea. In the sample from this clinic, sensitivities approximating 90 percent were obtained in men, and specificities approximating 90 percent were obtained in women, but high diagnostic accuracy (high specificity in men; high sensitivity in women) could not be achieved with the three snoring questions used here. Generally, associations between snoring and sleep apnea were independent of age and sex. Single persons, persons living alone, and persons customarily sleeping alone of both sexes all showed associations between self-reported snoring and the presence of sleep apnea.

Confidence Intervals↗
PubMed1990

Systematic 24-hr behavioral observations of sleep and wakefulness in a skilled-care nursing facility.

Sleep patterns of aged, infirm, demented, chronically institutionalized residents of a skilled-care nursing facility were studied. The purpose of this naturalistic study was to describe sleep and wakefulness (S/W) within the limits afforded by brief behavioral observations and to examine homeostasis and diurnal rhythmicity of S/W as a function of psychoactive drug intake. Observers noted S/W every 15 min, 24 hr a day for 10 days in 24 Ss. Results indicated substantial individual variation in daytime hours. Daily and weekly variation within Ss was minimal. Sleep was least likely near sunset. Ss on psychoactive drugs showed dampened diurnal variation in S/W rhythms. In Ss not on such drugs, there was a suggestion of homeostasis of S/W between sleep during the morning and evening hours. Results are discussed methodologically (viability of approach), theoretically (age-related change in sleep), and practically (potential treatments).

Aged↗
PubMed1990

Predictors of observed sleep/wakefulness in residents in long-term care.

This cross-sectional study investigated predictors of sleep/wakefulness in residents in a skilled care nursing facility. Sleep/wakefulness was defined behaviorally by observations made four times an hour over four 12-hour observation periods. Predictors studied were mental status, functional capacity, relative likelihood of cardiovascular/respiratory, musculoskeletal, and endocrine disease, psychotropic medication intake, and presence of sleep apnea. Results based on 39 residents indicated that sleep apnea was a positive consistent predictor of observed sleep in the nursing home. Apnea generally was unrelated to other predictors. We discuss these findings in terms of the viability of this technique to study sleep as well as other potential predictors of sleep/wakefulness in elderly institutionalized patients.

Aged↗
PubMed1990

Abundant REM sleep in a patient with Alzheimer's disease.

In patients with Alzheimer's disease (AD), greatly diminished REM sleep might be expected because of the cholinergic deficit in this disease and because cholinergic agonists stimulate REM sleep in humans and animals. We present here an unusual case of neuropathologically verified AD with abundant REM sleep. We suggest 4 possible explanations for this phenomenon: (1) selective cell loss in caudal midbrain/rostral pontine structures known to control sleep; (2) development of narcolepsy; (3) unrecognized affective disorder; (4) disruption of circadian timekeeping system.

Aged↗
PubMed1989

REM latency in Alzheimer's disease.

Latency to the first episode of rapid eye movement sleep (REML) has been proposed as a potential biomarker for Alzheimer's disease (AD). In this study, we compared REML values from 28 AD patients and 28 age- and sex-matched controls. We employed multiple definitions of REML and multiple cutoffs to classify patients and controls. Results indicated that the best REML definition and optimal cutoff criterion resulted in only 65% correct classifications. We discuss the longer REML in AD patients relative to controls in terms of both overall sleep disturbance and selective deterioration of the REM-cholinergic system. As REML may be relatively short in other forms of psychopathology (e.g., affective disorders), REML may still hold promise in the differential diagnosis of dementia and pseudodementia.

Aged↗
PubMed1989

Nerve conduction and creatinine clearance in aged subjects with periodic movements in sleep.

Periodic leg movements during sleep (PLMs) are non-epileptiform, repetitive limb movements that are highly prevalent among the geriatric population. The mechanisms underlying these movements are poorly understood. In this study we evaluated PLMs of 24 aged volunteers. We hypothesized that the high prevalence of PLMs seen in the aged would be related to (a) lower creatinine clearance and (b) slowed velocities/delayed latencies in the nerve conduction studies of such individuals. Results did not support hypothesis (a) but offered some equivocal support for hypothesis (b), inasmuch as aged subjects with higher levels of PLMs had delayed motor and sensory latencies in the upper limbs (median n., ulnar n.). Results are discussed in terms of central vs peripheral mechanisms involved in the generation of PLMs in elderly persons.

Aged↗
PubMed1989

A method for checking interobserver reliability in observational sleep studies.

Disturbances of the sleep/wake cycle occur frequently in nursing home residents. Because of the many technical difficulties in studying sleep and rhythms in such patients, systematic behavioral observations offer an alternative approach. In this study we describe a method for determining interrater reliability of such observations. Two individuals observed 39 nursing home residents four times per hour during daytime and nighttime hours. Results indicated high interrater reliability for both sleep/wake and the presence of apnea during sleep. Both day and night observations were made reliably. We found only 101 discrepancies of 1.160 tandem observations. These results suggests that behavioral observations are a viable approach in the study of the sleep/wake cycle in nursing home settings.

Aged↗
PubMed1989

Compliance and side effects in sleep apnea patients treated with nasal continuous positive airway pressure.

Nasal continuous positive airway pressure (CPAP) is an effective therapy for sleep apnea. We treated 144 patients with nasal CPAP and observed them for periods of as long as 25 months. No pneumothoraces occurred in any patient. Compliance rates were between 65% (90/139) and 83% (90/108), depending on the patient population considered. Demographic factors unrelated to discontinuing using CPAP included age, sex, and the presence of a housemate. Better-educated patients were less able to tolerate the equipment. Dry throat and nose and sore eyes were the most common side effects, but only sore eyes related to the amount of pressure. Side effects were unrelated to the number of months on the treatment, and obesity was related to higher pressures. Our study provides optimistic intermediate-term follow-up observations of patients on nasal CPAP therapy for sleep apnea. Whether adverse consequences occur over longer periods of time remains to be seen.

Adult↗
PubMed1989

Neuropsychological function and sleep.

Neuropsychological function and sleep in the aged have been studied for more than 20 years. The elderly studies focused on psychometric correlates of sleep architecture (REM, SWS, and various measures of sleep disturbance). More recently, psychometrics have been related to breathing disturbance in sleep, but the interpretation of such deficits in terms of hypoxemia and sleepiness remains controversial. To a large extent, all such relationships may depend upon the medical risk factors and chronic conditions affecting both neuropsychological function and sleep in old age.

Aged↗