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Biomedical subjects

M H Bonnet

Publications and source records attributed to M H Bonnet.

At least 37 records · Page 2Linked to original sources
PubMed1995

We are chronically sleep deprived.

Data from recent laboratory studies indicate that nocturnal sleep periods reduced by as little as 1.3 to 1.5 hours for 1 night result in reduction of daytime alertness by as much as 32% as measured by the Multiple Sleep Latency Test (MSLT). Other data document that 1) 17%-57% of normal young adults have MSLT latencies of < or = 5.5 minutes, whereas < or = 50% have MSLT values of > or = 10 minutes and 2) 28%-29% of young adults reported normally sleeping < or = 6.5 hours on each weeknight. More extensive reduction of daily sleep amount is seen in nightshift workers. A minimum of 2%-4% of middle-aged adults have hypersomnolence associated with sleep apnea. Together, these data show that significant sleep loss exists in one-third or more of normal adults, that the effects are large and replicable and that similar effects can be produced in just 1 night in the laboratory. In light of the magnitude of this sleep debt, it is not surprising that fatigue is a factor in 57% of accidents leading to the death of a truck driver and in 10% of fatal car accidents and results in costs of up to 56 billion dollars per year. A recent sleep extension study suggests that the average underlying sleep tendency in young adults is about 8.5 hours per night. By comparison, the average reported sleep length of 7.2-7.4 hours is deficient, and common sleep lengths of < or = 6.5 hours can be disastrous. We must recognize the alertness function of sleep and the increasing consequences of sleepiness with the same vigor that we have come to recognize the societal impact of alcohol.

Adult↗
PubMed1995

The use of caffeine versus prophylactic naps in sustained performance.

Previous studies have shown that performance during sleep loss is improved by prophylactic naps as a function of varying nap length. Based on single-dose caffeine studies, a similar dose-response effect has been hypothesized on performance, alertness and mood during sleep loss. The present study compared the effects of repeated versus single-dose administration of caffeine and varying amounts of sleep taken prior to sleep loss on performance, mood and physiological measures during 2 nights and days of sleep loss. A total of 140 normal, young adult males participated at one of two study sites. Ninety-eight subjects at one site were randomly assigned to one of four nap conditions (0, 2, 4 or 8 hours) and 42 subjects at the second site were assigned to one of four caffeine conditions. After a normal baseline night of sleep and morning baseline tests of performance, mood and nap latency, subjects in the nap groups returned to bed at noon, 1600 hours, 1800 hours or not at all. Bedtimes were varied so that all naps ended at 2000 hours. Subjects in the caffeine groups received either a single 400-mg dose of caffeine at 0130 hours each night or repeated doses of 150 or 300 mg every 6 hours starting at 0130 hours on the 1st night of sleep loss. A placebo control group (no nap and placebo administered every 6 hours on the repeated caffeine schedule) was run at both sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

24-Hour metabolic rate in insomniacs and matched normal sleepers.

Groups of 10 objectively defined insomniacs 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. Insomniacs were defined to have increased wake time during the night but also had decreased stage 2 and rapid eye movement sleep. As expected insomniacs reported increased confusion, tension and depression and decreased vigor on the profile of mood states mood scale throughout the evaluation period as compared to the normals. Insomniacs also had decreased memory ability on the short-term memory test and the MAST. These performance and mood differences were not secondary to sleepiness because the insomniacs also had significantly increased multiple sleep latency test (MSLT) values throughout the evaluation period. In conjunction with the consistent mood, performance and MSLT differences during the day and the sleep differences at night, whole body VO2, measured at intervals across the day and throughout one night of sleep, was consistently elevated at all measurement points in the insomniacs as compared to the normals. The nocturnal increase in metabolic rate remained even after metabolic values from periods during the night containing wake time or arousals were eliminated from the data set. It was concluded that patients who report chronic insomnia may suffer from a more general disorder of hyperarousal (as measured here by a 24-hour increase in metabolic rate) that may be responsible for both the daytime symptoms and the nocturnal poor sleep. Future studies need to explore 24-hour insomnia treatment strategies that decrease hyperarousal.

Adolescent↗
PubMed1994

Impact of naps and caffeine on extended nocturnal performance.

It was hypothesized that alertness and performance during an extended work period would be improved by an afternoon nap and the subsequent use of caffeine during the night. Twelve young adults received a 4-h afternoon nap and caffeine during the night during one session and four 1-h naps during the night in a second session. After an afternoon nap, subjects had increased objective and subjective alertness, increased oral temperature, and increased performance on complex tasks like logical reasoning and correct additions when compared to the condition that allowed four nighttime naps. It was concluded that the specific scheduling of a nap period in preparation for an all-night work shift where sleep would not be allowed could result in increased alertness and performance as well as a less conflicted work situation.

Adolescent↗
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↗
PubMed1994

Effects of abstinence from smoking on sleep and daytime sleepiness.

This study examined the effect of smoking abstinence on sleep quality, daytime sleepiness, and mood in 18 subjects (10 men and 8 women) aged 35 to 49 years who had smoked at least 20 cigarettes per day for more than 2 years. Subjects were studied on two consecutive weeks following an adaptation night. During week 1 (study nights 1, 2, and 3), the subjects smoked as usual. Smoking abstinence was mandatory during week 2 beginning 3 h prior to night 4 and ending after the final tests on night 6. Complete sleep monitoring each night was followed by multiple sleep latency tests (MSLTs) throughout the day. Psychomotor tests and mood observations were performed throughout the day between the MSLTs. The results of testing when the subjects smoked were compared with those during nonsmoking days and nights. Nights 1 and 4 were considered adaptation nights and not included in the analysis. Overnight studies showed a significant increase in the number of relative arousals (a change in sleep stage to wake, stage 1 sleep, or movement), stage changes, and awakenings during smoking cessation. The MSLT latency to stage 1 sleep decreased during smoking cessation. Also during abstinence, the subjects reported that they felt more irritable, had increased feelings of anxiety, felt greater tension, and had more cravings for cigarettes. We conclude that smoking cessation is associated with increased daytime sleepiness and impaired mood. The daytime sleepiness may be due to the combination of sleep disturbance and withdrawal of the nicotine normally provided through smoking.

Adult↗
PubMed1993

Performance and alertness on 8 h and 12 h rotating shifts at a natural gas utility.

An 8 h/5-7 day shift schedule was compared with a newly instituted 12 h/2-4 day schedule in this, our second worksite study of extended workshifts. Workers completed a performance/alertness test battery, and a questionnaire on sleep patterns and other personal habits, 2-4 times a week on all shifts. After 10 months adaptation to the 12 h shift schedule, there were decrements in performance/alertness attributable to the extra 4 h on the extended shift. There were also reductions in sleep across the workweek which were most apparent on 12 h night shifts. The results are consistent with our first worksite study of 12 h shifts and indicate extra caution should be exercised when scheduling critical activities for extended workshifts, especially extended night shifts.

Adult↗
PubMed1992

Training subjective insomniacs to accurately perceive sleep onset.

Subjective insomniacs overestimate sleep latency at the beginning of their nocturnal sleep period. It was hypothesized that subjective insomniacs could be trained to accurately estimate sleep latency by learning to differentiate wakefulness from sleep. Ten subjective insomniacs were randomly assigned to one of two groups. Group 1 subjects participated in both a control and a training week; group 2 subjects participated only during a training week. Each week consisted of a baseline lab night, a training lab night (treatment or control), a home (unmonitored night) and a recovery lab night. During training, subjects were taught to use sleep markers (A, B or C) to help them more accurately estimate sleep latency and were given feedback about the accuracy of their estimates. Marker A corresponded to an electroencephalographic level of wakefulness; marker B corresponded to the initial sleep spindle; marker C corresponded to 5 minutes of continuous sleep after the first sleep spindle. In the control condition, subjects had no feedback and were not taught to use markers to help them judge sleep from wakefulness. Total sleep time and percent stage 3 sleep increased, and objective sleep latency decreased on recovery nights. After training, subjective sleep latency, correctness of estimates of sleep versus wakefulness and perceived ability to fall asleep significantly improved. This study helps to establish that subjective insomniacs can learn to more accurately estimate sleep from wakefulness with the use of sleep-wake markers.

Adolescent↗
PubMed1992

Effect of ethanol on the arousal response to airway occlusion during sleep in normal subjects.

The effect of ethanol on the arousal response to airway occlusion during non-rapid eye movement sleep was studied in normal male subjects by testing the response to the occlusion of a face mask covering the nose and mouth on a control (C) and an ethanol (E) ingestion (2 ml/kg of 50% vodka) night in random order. In part A, five subjects breathed room air while in part B another five subjects breathed a mixture of air and oxygen adjusted to maintain a baseline sleeping SaO2 of 98%. In both parts, the time to arousal (TTA) was significantly longer on E nights. The TTA (mean +/- SEM) in part A on C versus E nights was 14.6 +/- 1.9 versus 20.6 +/- 1.4 s in stage 2 and 19.9 +/- 1.9 versus 29.2 +/- 1.8 in stage 3/4 (p less than 0.01). The corresponding values in part B were 22.2 +/- 3.6 versus 39.9 +/- 8.4 in stage 2 and 32.1 +/- 4.1 versus 63.7 +/- 9.6 in stage 3/4 (p less than 0.01). In part B, the maximum deflections in airway pressure were measured at a supraglottic location during airway occlusion to reflect the degree of inspiratory effort. The maximum airway suction pressure preceding arousal was significantly higher on E nights. Conversely, the rate of increase in inspiratory effort (maximum pressure) during occlusion was decreased by E. We conclude that moderate ethanol ingestion prolongs the time to arousal following airway occlusion by increasing the threshold of inspiratory effort associated with arousal and by decreasing the rate of increase in the magnitude of inspiratory efforts.

Adult↗
PubMed1992

Operation Everest II: arterial oxygen saturation and sleep at extreme simulated altitude.

Frequent sleep disturbances and desaturation during sleep are common at high altitude, but few data are available from the highest altitudes at which humans are known to sleep. Because sleep fragmentation at low altitude may impair mental function and oxygen deprivation produces lasting central nervous system abnormalities, a better understanding of the severity of sleep disturbances and oxygen desaturation at extreme altitudes is important. The purpose of this study was to determine the severity of sleep disturbance and the extent of arterial oxygen desaturation at extreme simulated altitude. Out of eight healthy male subject volunteers who started, five aged 27.2 +/- 1.5 yr completed the study during 6 weeks of progressive hypobaric hypoxia in a decompression chamber. The men were studied at barometric pressures of 760, 429, 347, 282 mm Hg and following return to 760 mm Hg. All demonstrated frequent nighttime awakenings (37.2 awakenings per subject per night at 282 mm Hg, decreasing significantly to 14.8 on return to sea level, p less than 0.05). Total sleep time decreased from 337 +/- 30 min at 760 mm Hg to 167 +/- 44 min at 282 mm Hg (p less than 0.01). Rapid eye movement (REM) sleep decreased from 17.9% +/- 6.0% of sleep time at sea level to 4.0% +/- 3.3% at 282 mm Hg (p less than 0.01). Sleep continuity as reflected by brief arousals increased from 22 +/- 6 arousals per hour of sleep at sea level to 161 +/- 66 arousals per hour at 282 mm Hg (p less than 0.01). All subjects showed arterial oxygen desaturation proportional to the altitude. The average oxygen saturation (SaO2) was 79% +/- 3% at 429 mm Hg, 66% +/- 6% at 347 mm Hg, and 52% +/- 2% at 282 mm Hg. Sleep stage had only a minimal effect on SaO2 at any altitude. SaO2 was negatively correlated with brief sleep arousals, r = -0.72, p less than 0.01. All subjects demonstrated periodic breathing with apneas throughout much of the night at 347 and 282 mm Hg. These data indicate that sleep quality progressively worsens as SaO2 decreases despite lack of progressive changes in sleep stages at altitude. This study extends previous information on the severity of desaturation during sleep, and suggests that improvements in oxygenation might prove beneficial in restoring consolidated sleep, possibly even improving daytime performance.

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

The effect of varying prophylactic naps on performance, alertness and mood throughout a 52-hour continuous operation.

The current study reports the effect of 0-8-hr naps placed prior to two consecutive nights of total sleep deprivation. A total of 104 young adult male subjects were randomly assigned to one of four prophylactic nap conditions (0, 2, 4 or 8 hr). After a normal baseline night of sleep and a morning of baseline test performance, subjects returned to bed at 1200, 1600 or 1800 hr or not at all prior to a continuous operation that extended until each subject's normal bedtime on the third following night. All subjects who napped arose at 2000 hr, and all subjects maintained the same schedule of computer-administered performance tests throughout the sleep-loss period. Results indicated that performance and alertness in all nap conditions were improved in a dose-response fashion compared to a no-nap control throughout the first 24 hr of sleep loss. However, significant improvement in nap conditions compared to the no-nap condition was not seen in many variables during the second night of sleep loss. Whereas an 8-hr nap prior to an operation maintained performance at a high level for 24-30 hr, significant improvement in alertness and performance as compared to the no-nap control was also documented by shorter naps. No nap could reverse the profound loss of alertness seen during the second night of sleep loss.

Adolescent↗
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

Infrequent periodic sleep disruption: effects on sleep, performance and mood.

In the first of two experiments, 12 normal young adults had their sleep periodically disturbed for two nights in the laboratory at three different rates: 10 min of sleep followed by 20 min of disturbance, 20 min of sleep followed by 40 min of disturbance and 40 min of sleep followed by 80 min of disturbance. Sleep and disturbance alternated throughout the night. While all disturbance conditions resulted in decreased daytime performance and increased sleepiness, the disturbance conditions did not differ from each other. In the second experiment, sleep was periodically disturbed for two nights at three new rates to act as control conditions for Experiment 1. The three conditions were: 2 min of sleep followed by 4 min of disturbance, 20 min of sleep followed by a single awakening, and 40 min of sleep followed by a single awakening. Sleep and disturbance again alternated throughout the night. As expected, sleep was less disturbed and daytime decrements were smaller in the conditions allowing 20 and 40 min of sleep followed by a single awakening. The data from both experiments were interpreted as support for sleep continuity theory; i.e., as the length of periods of consolidated sleep decrease, residual decrements increase.

Adolescent↗