Biomedical subjects

D L Bliwise

Publications and source records attributed to D L Bliwise.

95 records · Page 6Linked to original sources

PubMedDate not supplied

Sleep apnea in Alzheimer's disease.

Mental deterioration accompanying sleep apnea has been noted frequently. Because sleep apnea increases with age, such deficits raise the possibility that dementia in the elderly could be related to sleep apnea. In this study we investigated this possibility cross-sectionally by comparing respiration during sleep in 28 patients with Alzheimer's disease (AD) and 25 nondemented controls. We hypothesized that higher levels of sleep apnea would be present in AD patients. Our results indicated no significant differences between AD patients and controls but those few AD patients who desaturated during sleep experienced morning confusion. The findings imply that AD and sleep apnea are two separate conditions which may still interact in the aged.

Aged↗

PubMedDate not supplied

MSLT-defined sleepiness and neuropsychological test performance do not correlate in the elderly.

This study investigated whether a sensitive, physiological measure of alertness/sleepiness, the Multiple Sleep Latency Test (MSLT), was related to neuropsychological test performance in elderly individuals. We hypothesized that the greater likelihood of falling asleep during the daytime on the MSLT would be related to relatively poorer performances on a variety of neuropsychological tests. Results from a homogeneous sample of 35 relatively well-educated, high functioning, elderly community volunteers confirmed the presence of characteristic levels of daytime alertness which were stable within individuals (r = .70 to .73) and showed large variation across individuals (coefficients of variation: 54-84%). Despite this wide intersubject variability, MSLT-defined alertness/sleepiness was unrelated to neuropsychological test results. We discuss these results in terms of the performance deficits known to accompany sleepiness in experimental studies of sleep deprivation and in terms of the behavioral slowing known to occur in normal aging.

Aged↗

PubMedDate not supplied

PTSD-related hyperarousal assessed during sleep.

Posttraumatic stress disorder is widely understood to include "persistent symptoms of increased arousal." This presumption has rarely been tested under conditions in which effects of anticipatory anxiety could be ruled out. In this study, heart rate and electroencephalogram spectral power were assessed during sleep, a state free of most sources of artifact contaminating indices of tonic arousal. Fifty-six unmedicated nonapneic Vietnam combat-related inpatients with posttraumatic stress disorder (PTSD) and 14 controls spent 3 or more nights in the sleep laboratory during which their electrocardiograms and electroencephalograms were continuously recorded. Heart rate and electroencephalogram spectral power were quantified continuously off-line and averaged by sleep stage over all postadaptational nights. Sleep heart rate exhibited no group differences and no covariation with the severity of subjective hyperarousal reported by PTSD patients. PTSD patients exhibited a trend toward reduced low-frequency electroencephalogram spectral power during nonrapid-eye-movement (NREM) sleep. This reduction was significant during slow-wave sleep in those subjects producing scoreable slow-wave sleep. The relationship of rapid-eye-movement (REM) beta-band power to NREM beta-band power was different in PTSD patients and controls, with the patients exhibiting more beta in REM versus NREM sleep than controls. In patients, NREM sleep sigma-band electroencephalogram spectral power exhibited a positive correlation with subjective hyperarousal. Finally, a novel and surprisingly strong inverse correlation between REM-NREM sleep heart rate difference and REM percent of sleep was observed in PTSD patients only. In summary, peripheral and central measures of tonic arousal during sleep demonstrated contrastive relations to PTSD diagnostic and symptom status. The data suggest that more consideration should be directed to mechanisms of central arousal in PTSD.

Adult↗

PubMedDate not supplied

Treating insomnia: pharmacological and nonpharmacological approaches.

Insomnia is a commonly encountered condition in clinical practice. The prevalence of self-reported poor sleep increases with age and is more common in women. There are clear associations between poor sleep and psychiatric disturbance; however, causality in this regard may be complex, and there are at least some insomniacs who show high somatic tension without marked psychopathology. The development of chronic insomnia can be conceptualized as involving predisposing, precipitating, and perpetuating factors. Pharmacological treatments for insomnia most typically involve judicious and intermittent usage of a benzodiazepine hypnotic. A variety of such medications are available, with varying absorption and elimination characteristics. Benzodiazepines are preferred over antidepressants in the treatment of insomnia in individuals without major psychiatric disorder because of fewer side effects and a larger margin of safety. Nonpharmacological treatments typically rely on elements of sleep hygiene, stimulus control, sleep restriction, and chronotherapy. The establishment of good patient-clinician rapport and the working through of unfounded beliefs and unrealistic expectations of the sleep experience are also important components of the behavioral treatment of insomnia. Use of such techniques, particularly when combined in a treatment package, has shown appreciable benefits in improving sleep.

Humans↗

PubMedDate not supplied

Hemodialysis disrupts basic sleep regulatory mechanisms: building hypotheses.

BACKGROUND: The proposition that hemodialysis may induce alterations in the sleep-wake cycle is based on two clinical observations: (a) Patients on dialysis frequently sleep during and after dialysis, and (b) the procedure often is associated with temperature elevations. A review of pertinent literature showed that sleepiness and temperature are physiologically related, and that these two variables are important indicators of sleep and circadian regulatory processes. OBJECTIVES: To describe possible associations among hemodialysis, body temperature, and sleepiness; to assist in building hypotheses; and to provide direction for future research. METHODS: Three exploratory studies were performed to investigate (a) dialysis-associated elevations in body temperature, (b) changes in body temperature patterns across the day, and (c) alterations in daytime sleepiness. RESULTS: The current study demonstrated that many patients manifest dialysis-associated episodic elevations of body temperature, changes in the circadian pattern of body temperature, and increases in daytime sleep propensity. In the context of the Two-Process Model of Sleep Regulation, these alterations provide a parsimonious explanation for the poor subjective sleep quality, prolonged sleep latency, and daytime sleepiness reported by these patients. CONCLUSIONS: These preliminary studies lead to the suggestion that hemodialysis may disrupt basic sleep regulatory mechanisms, and that further investigation in this area is warranted.

Adult↗