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Biomedical subjects

D L Arand

Publications and source records attributed to D L Arand.

31 records · Page 2Linked to original sources
PubMed1994

The use of prophylactic naps and caffeine to maintain performance during a continuous operation.

After a normal baseline night of sleep and a morning of baseline test performance, 24 young adult male subjects returned to bed from 16:00-20:00 prior to a 24 h period of sleep loss. Twelve subjects received caffeine 200 mg at 01:30 and 07:30. Performance tests (correctly completed addition problems, vigilance sensitivity, and logical reasoning correct responses) all indicated maintenance of baseline performance levels in the caffeine group after administration of caffeine while performance declined in the placebo group. Similar results were found for the Multiple Sleep Latency Test and Oral Temperature, which both remained near baseline levels throughout the observation period in subjects receiving caffeine. The results indicated that the combination of a prophylactic nap and caffeine was more effective in maintaining nocturnal alertness and performance than was the nap alone. Of more interest was the fact that the group which was given the combination of nap and caffeine was able to maintain alertness and performance at very close to baseline levels throughout a 24 h period without sleep.

Adult↗
PubMed1992

Caffeine use as a model of acute and chronic insomnia.

It was hypothesized that the metabolic effects of caffeine, which can be objectively measured (i.e. physiological, "arousal"), could be used to develop a physiological arousal model of chronic insomnia in a group of normal young adults. Twelve normal young adult males participated for 11 nights after laboratory adaptation. Subjects received 400 mg of caffeine three times a day for 7 nights and days. As predicted, the use of caffeine resulted in increased metabolic rate. Sleep efficiency was significantly reduced by caffeine and multiple sleep latency tests (MSLTs) were significantly increased. Some adaptation to the metabolic, sleep efficiency, and MSLT effects of caffeine was seen over the week of administration. Withdrawal effects (i.e. rebound sleep or sleepiness) were not seen for metabolic, MSLT or sleep variables. The data indicated that caffeine was effective in producing significant metabolic and sleep effects and that those effects were related. The results were consistent with the interpretation that a chronic decrease in sleep efficiency associated with increased physiological arousal, although producing subjective dysphoria, does not produce a physiological sleep debt.

Acute Disease↗
PubMed1991

Chronic use of triazolam in patients with periodic leg movements, fragmented sleep and daytime sleepiness.

Many studies have shown a relationship between fragmented nocturnal sleep and daytime sleepiness. In the current study, 9 patients, aged 55-79, with fragmented nocturnal sleep secondary to periodic leg movements and objective daytime sleepiness, as verified by Multiple Sleep Latency Test (MSLT), had 12 weeks of treatment with 0.125 mg of triazolam following 2 screening nights and 2 placebo baseline nights; 2 final placebo nights were placed 5 nights following the last medication night. The medication increased total sleep time and sleep efficiency throughout the administration period, as compared to average placebo values; total leg movements were not changed. Generally, daytime performance, as measured by a vigilance task, and objective alertness, as measured by MSLT, were improved following the use of triazolam. No adverse reactions or significant side effects were noted. It was concluded that 0.125 mg triazolam, when used for up to 3 months, could improve sleep and daytime function in older patients with periodic leg movements, fragmented sleep, and daytime sleepiness.

Aged↗
PubMed1991

Metabolism during normal, fragmented, and recovery sleep.

Average metabolic data (O2 uptake and CO2 output) were obtained for each 3-min period during consecutive nights of normal, experimentally fragmented, and recovery sleep in a group of 12 normal young adult males. Naturally occurring arousals and awakenings resulted in a characteristic increase in metabolism on the baseline night. The placement of brief frequent experimental arousals on the following night resulted in significantly increased metabolism throughout the night and significantly decreased sleep restoration as measured by morning performance, mood, and alertness tests, even though total sleep time was minimally reduced. Metabolic variables were significantly decreased compared with baseline on the nondisturbed recovery night that followed the sleep fragmentation night. The data cannot be used to infer that increased metabolism during sleep causes nonrestorative sleep, but the direction and time course of metabolic change accompanying arousal are consistent with that hypothesis.

Adolescent↗
PubMed1990

The use of triazolam in older patients with periodic leg movements, fragmented sleep, and daytime sleepiness.

Many studies have shown a relationship between fragmented nocturnal sleep and daytime sleepiness. In the current study, 11 patients, aged 55-75, were identified with fragmented nocturnal sleep secondary to periodic leg movements and objective daytime sleepiness as verified by the Multiple Sleep Latency Test (MSLT). In a double-blind, repeated measures, cross-over design, patients had three nights of treatment with placebo, 0.125 mg of triazolam, or 0.25 mg of triazolam following an adaptation night. Although total leg movements were not changed, the medication increased total sleep time and sleep efficiency while decreasing the number of stage changes. Generally, daytime performance and objective alertness were significantly improved following the use of triazolam. It was concluded that acute use of triazolam, particularly the 0.125 mg dose, could improve sleep and daytime function in older patients with periodic leg movements, fragmented sleep, and daytime sleepiness.

Aged↗
PubMed1990

The effect of triazolam on arousal and respiration in central sleep apnea patients.

It was hypothesized that triazolam might decrease central apneas associated with arousal periods in patients with central sleep apnea by hastening the onset of consolidated sleep. Five male patients, diagnosed as having central sleep apnea on a screening night, participated in a double-blind randomized crossover study of the effect of placebo, 0.125 mg triazolam, and 0.25 mg triazolam on sleep, respiration, and daytime function. Results indicated that the medication increased total sleep and decreased central apnea index and number of brief arousals. Improved sleep quality was reflected in improved daytime psychomotor performance and alertness. These data, if replicated, imply that benzodiazepine use may be beneficial in patients with central sleep apnea.

Aged↗
PubMed1989

Sleep loss in aging.

Tests of performance and alertness in normal older subjects undergoing sleep loss reveal loss of performance and alertness similar to that seen in younger individuals. Recovery of performance ability occurs with one night of normal sleep, even following periods of sleep loss up to 64 hours in length. Older individuals, including older individuals with primary insomnia, may tolerate sleep loss with less decrease in ability compared with their baseline than young adults and may recover function more quickly than young adults. While it has been frequently shown that older individuals perform more poorly than young adults on a broad range of tasks, these findings do not hold well for periods of nocturnal performance or performance during sleep loss. It is possible that these findings may be accounted for to some extent by the decrease in amplitude of the circadian body temperature curve in older individuals. It is unfortunate that Reynolds et al did not attempt to collect performance data in their depressed and demented patients to determine if the differential effects on mood and EEG would also be reflected in psychomotor performance.

Adult↗
PubMed1981

Respiratory patterns associated with hemoglobin desaturation during sleep in chronic obstructive pulmonary disease.

Respiration during sleep was monitored in ten patients with chronic obstructive pulmonary disease (COPD) and related to measures of hemoglobin saturation and intrathoracic pressure (ITP) or abdominal wall movement. Seven of the ten patients showed episodic hemoglobin desaturation of at least 5 percent during sleep. Two distinct patient groups could be distinguished on the basis of ITP measurements and breathing patterns. Desaturation was associated with reduced negative ITP or respiratory movement in three patients and with increased negative ITP or respiratory movement in four patients. These data suggest that desaturation may result from at least two distinct mechanisms, involving reduced respiratory effort in one group and increased upper airway occlusion in the other. Desaturation associated with reduced respiratory effort was primarily REM-sleep related and consisted of a few sustained episodes. Desaturation episodes associated with upper airway occlusion occurred in all stages of sleep and were very frequent and of short duration.

Airway Obstruction↗
PubMed1980

Determinants of oxygen desaturation in the course of ventilation during sleep in chronic obstructive pulmonary disease.

During sleep, none of 9 subjects with chronic obstructive pulmonary disease (COPD) were apneic. Despite ventilation, acute arterial oxygen desaturation of 11% or more occurred in 6 of them. The other 3 were nondesaturators (i.e., 3% or less desaturation) during sleep. The desaturation that occurred in the 6 subjects with COPD was associated with episodes of (1) esophageal pressure or abdominal respiratory movement that acutely decreased in amplitude during rapid-eye-movement (REM) sleep, or (2) esophageal pressure or abdominal respiratory movement that acutely increased in amplitude in association with snoring during non-REM and REM sleep. During daytime wakefulness, ventilatory responses to hypoxia and hypercapnia were markedly less in the 6 desaturators compared with the 3 nondesaturators and 5 healthy control subjects. The decreased ventilatory responses in the 6 desaturators appeared to result from both impaired respiratory mechanical effectiveness and impaired respiratory center responsiveness to chemoreceptor stimulation. We suggest that subjects with COPD with these respiratory impairments are predisposed to develop severe nonapneic oxygen desaturation during the added respiratory impairment of REM sleep or of what appears to be sleep-related partial upper airway obstruction.

Chronic Disease↗
PubMedDate not supplied

Metabolic rate and the restorative function of sleep.

It has been shown that performance improves during sleep more rapidly after sleep deprivation than during normal sleep. Recovery after sleep deprivation is also characterized by a different sleep stage distribution and by a decreased metabolic rate compared to a normal night of sleep. The present study examined whether sleep during a period of increased metabolic rate was less restorative than a normal period of sleep. Twelve normal young adults participated for two 4-day periods. In each period, an undisturbed baseline sleep night was followed by baseline testing. On the subsequent night, Ss slept a total of 212 min, starting at 0200 h after consuming placebo or 400 mg of caffeine. After the nap, subjects remained awake for 41 h until beginning an undisturbed night of recover sleep. During the period of sleep loss, subjects remained at the sleep laboratory where they performed computer tests and MSLTs. The caffeine produced a significant increase in metabolic rate during the nap. Although total sleep time was held constant, there was an increase in stage 1 and a decrease in stage 4 sleep after caffeine use. Performance on addition and vigilance tasks was significantly decreased after the caffeine plus nap condition. However, no significant difference were found on the MSLT, and subjective vigor was significantly greater following the caffeine and nap combination. It was concluded that the beneficial effect of sleep in maintaining performance was decreased by increased physiological activation during sleep.

Adolescent↗
PubMedDate not supplied

Physiological activation in patients with Sleep State Misperception.

OBJECTIVE: Sleep State Misperception insomnia has been commonly viewed as a perceptual or psychological problem. It was hypothesized that Sleep State Misperception insomnia, like psychophysiological insomnia, could be associated with increased physiological activation, here indexed by whole body metabolic rate. METHOD: Groups of nine patients with Sleep State Misperception insomnia and age-, sex-, and weight-matched normal sleepers were evaluated on sleep, performance, mood, personality, and metabolic measures over a 36-hour sleep laboratory stay. RESULTS: Sleep State Misperception insomniacs had a subjective history of poor sleep and perceived their laboratory sleep as poor but had electroencephalogram (EEG) parameters that did not differ statistically from matched normal controls. Sleep State Misperception insomniacs had abnormal MMPI values and were subjectively more confused, tense, depressed, and angry than matched normals. Sleep State Misperception insomniacs also had a significantly increased 24-hour metabolic rate, compared with matched normals. CONCLUSIONS: The overall increase in whole body oxygen use was less than that seen in psychophysiological insomniacs but was consistent with the view that Sleep State Misperception insomnia may be a mild version or a precursor to psychophysiological insomnia.

Adolescent↗
PubMedDate not supplied

Heart rate variability in insomniacs and matched normal sleepers.

OBJECTIVE: It was hypothesized that psychophysiological insomniacs, who have been shown to have elevated heart rate, body temperature, and whole body metabolic rate, would also have increased low frequency and decreased high frequency power in the spectral analysis of their heart period data. METHOD: Groups of 12 objectively defined insomniacs and age-, sex-, and weight-matched controls with normal sleep were evaluated on sleep and EKG measures over a 36-hour sleep laboratory stay. RESULTS: Heart period was decreased (ie, heart rate was increased) and its SD was decreased in all stages of sleep in the insomniacs compared with the controls. Spectral analysis revealed significantly increased low frequency power and decreased high frequency power in insomniacs compared with controls across all stages of sleep. CONCLUSIONS: Because increased low frequency spectral power is an indicator of increased sympathetic nervous system activity, these data imply that chronic insomniacs could be at increased risk for the development of disorders, such as coronary artery disease, that are related to increased sympathetic nervous system activity.

Adult↗