Search PubMed⌕ Search

Biomedical subjects

M H Bonnet

Publications and source records attributed to M H Bonnet.

At least 19 recordsLinked to original sources
PubMed2001

Arousal components which differentiate the MWT from the MSLT.

STUDY OBJECTIVES: The purpose of this study was to determine the relative contribution of the instruction to maintain wakefulness versus posture change as major components determining sleep latency in the MWT as compared to the MSLT. DESIGN AND SETTING: After adaptation, subjects spent 3 nights and the following days in the laboratory. On each day, Ss had eight sleep latency measurements including four sleep latency tests from two of the following conditions: Lay down and Sleep (MSLT); Lay down and stay Awake; Sit up and Sleep; Sit up and stay Awake (MWT); and sit in a chair in front of a Computer and stay awake. PARTICIPANTS: Participants were 14 young adult normal sleepers. INTERVENTIONS: NA. MEASUREMENT AND RESULTS: Significant differences in sleep latency were found for each condition with respect to all of the others except that the Computer condition did not differ from the Sit-Awake condition. Means for conditions were: Lay-Sleep -11.1 minutes; Sit-Sleep -17.7 minutes; Lay-Awake - 21.7 minutes; Sit-Awake - 29.0 minutes; Computer - 30.1 minutes. Correlations between conditions declined as subjects sat up. CONCLUSIONS: The MWT differs from the MSLT by taking advantage of the arousal system (motivation and posture) to maintain alertness (i.e., increase sleep latency). These arousal effects are additive. MSLT results may not always correlate well with MWT results because the MWT measures the combined effects of the sleep and arousal systems while the MSLT, in ideal situations, measures only sleepiness.

Adolescent↗
PubMed2001

Impact of activity and arousal upon spectral EEG parameters.

OBJECTIVE: Increased high-frequency EEG activity in patients with insomnia has been posited to reflect increased physiological activity, increased mental content, or increased muscle artifact. In the current study, the impact of physiological arousal and increased EMG upon spectral EEG measures was examined. METHODS: Thirteen normal young adults performed eyes-open and eyes-closed maneuvers in the following conditions: (1) Initial (performed immediately after calibrations); (2) following sitting up and lying down (SIT); (3) following standing up and lying down (STAND); (4) Following a 5-min walk around the building (WALK); (5) during a 5-min mental subtraction task (MATH); (6) During 1 min of gritting teeth (GRIT); and (7) During 1 min of clenching fists (CLENCH). Observations were performed during or immediately after manipulations (AROUSED) and repeated about 10 min later (RELAXED). RESULTS: Significant increases in high-frequency spectral power were found in AROUSED vs. RELAXED conditions (significant at 26, 33, 36,40-42, 44, 46, and 48-49 Hz). Larger significant increases in spectral power were seen in the GRIT condition in the range from 24 to 50 Hz and to a lesser extent in the CLENCH condition. Spectral activity during the MATH condition was similar to that in the AROUSED condition. Heart rate was significantly increased during the GRIT and CLENCH conditions. CONCLUSIONS: In this study, gritting teeth produced large changes in spectral high-frequency power in the same range as produced by the other manipulations. The most parsimonious explanation for such data is that the increased high-frequency activity associated with various forms of arousal is not a specific cortical activity. However, because heart rate was also elevated during the GRIT condition, it implies that high-frequency spectral EEG power may still be a sign of increased central nervous system arousal, although the mechanism may be through increased muscle tension.

Adolescent↗
PubMed2000

Activity, arousal, and the MSLT in patients with insomnia.

OBJECTIVES: It has recently been shown that physiological arousal following walking increased sleep latencies during daytime naps as compared to sleep latencies following TV viewing. Patients with insomnia have been shown to have increased physiological arousal and to also have longer MSLT latencies. It was hypothesized that insomnia patients, who are at a higher state of physiological arousal, would be unable to relax while lying in bed and watching TV and therefore would have relatively longer sleep latencies in naps following TV watching (due to inability to relax) as compared to walking. DESIGN: Twelve patients with psychophysiological insomnia took Multiple Sleep Latency Tests after either watching television for 15 minutes or after a 5-minute walk following baseline, sleep deprivation, and recovery sleep conditions. SETTING: Sleep Laboratory PATIENTS: Twelve patients with psychophysiological insomnia INTERVENTIONS: Manipulation of state arousal and sleep deprivation RESULTS: Sleep latencies were significantly longer following the walk as compared to watching TV (11.9 vs. 6.9 min. respectively). Sleep latencies were 13.4 and 3.8 min. following baseline and sleep deprivation conditions. Heart period, used as a measure of physiological arousal, was significantly elevated throughout naps following the walk as compared to naps following TV viewing. Heart period was also significantly correlated with nap sleep latency. CONCLUSIONS: The insomnia patients in this study had significantly increased arousal, as measured by heart rate, and significantly longer sleep latencies after walking as compared to resting. The magnitude of these changes was similar to that seen in normal subjects in a previous study. These data, in concert with previous work, support the contention that measured sleep tendency is a combination of sleep drive and level of central nervous system arousal, where arousal has both state and trait components.

Adolescent↗
PubMed2000

The impact of music upon sleep tendency as measured by the multiple sleep latency test and maintenance of wakefulness test.

Previous work has shown that background noise or music has a small positive impact on performance during sleep deprivation. The current study examined the effect of background music on the ability to fall asleep or remain awake. Twelve normal-sleeping young adults took multiple sleep latency tests (MSLT) and maintenance of wakefulness tests (MWT) after baseline sleep and one night of total sleep deprivation either with background music or under standard (quiet) conditions. It was hypothesized that the music would help maintain wakefulness both under baseline and sleep deprivation conditions. The results of the study showed that sleep latencies were increased in both MSLT and MWT when music was presented, but that this effect occurred primarily before subjects were sleep-deprived (a significant Music by Sleep Deprivation interaction). Sleep latencies were 15 and 11 min on the MSLT (33 and 26 min on the MWT) with Music as compared to Quiet after baseline sleep. Heart rate, used as a measure of physiological arousal, was significantly elevated in MWT and MSLT trials where music was presented. These data support previous work showing that level of arousal has an impact on measured sleep tendency which is independent of that of the sleep system. On a practical level, these data indicate that music may play a small beneficial role in helping to maintain arousal.

Adult↗
PubMed1999

Level of arousal and the ability to maintain wakefulness.

The ability to maintain wakefulness under baseline and sleep deprivation conditions was examined in a group of 14 normal young adults. Subjects participated in both standard and manipulation Maintenance of Wakefulness tests after being awake for 7, 19, and 31 h. In the manipulation Maintenance of Wakefulness tests, subjects performed varying degrees of physical activity at the onset of stage 1 to allow them to preserve wakefulness. As expected, ability to maintain wakefulness declined as time awake increased. With amount of time awake held constant, wakefulness was enhanced most after standing and doing knee bends, less after standing, less after sitting up, and least after subjects were spoken to. The improvement in alertness after doing knee bends as compared to being spoken to was of the same relative magnitude as the decrease in alertness after one night of total sleep deprivation. As expected, heart rate also increased consistently as activity increased. Each subject had a negative correlation between their EEG sleep latencies and their minimum r-r interval during the manipulation, i.e. the higher the heart rate, the longer the latency. These data were interpreted as a demonstration of the impact of discrete phasic arousal on the ability to maintain wakefulness.

Adaptation, Physiological↗
PubMed1999

The use of lorazepam TID for chronic insomnia.

Patients with primary insomnia typically complain of daytime fatigue and stress and have been shown to have long latencies on the Multiple Sleep Latency Test and increased whole body metabolism. However, typical treatment strategies for patients with insomnia rarely include any component to deal with these daytime symptoms. In the present study it was hypothesized that a 24-h treatment, lorazepam 0.5 mg TID, would be superior to an evening treatment, lorazepam 1.5 mg HS, in patients with primary insomnia. In a repeated measures crossover design, 12 patients with chronic insomnia received placebo or lorazepam 0.5 mg TID in one 4-night lab stay and placebo or lorazepam 1.5 mg HS in another lab stay. Both doses of medication were effective in improving objective and subjective measures of sleep and in reducing nocturnal whole body metabolic rate. Latencies on daytime nap testing were significantly reduced from a 14-min average to an average of 10 and 12 min, respectively, in the lorazepam 0.5 and 1.5 mg conditions. Significant differences were not found on psychomotor performance. Subjective reports of anxiety and confusion were increased in the morning after receiving lorazepam 0.5 mg in the evening but tension was reduced and subjective alertness was improved in the evening after daytime administration of lorazepam 0.5 mg. It was concluded that measurement and treatment of daytime symptoms is appropriate in patients with chronic insomnia but that rebounds in anxiety near the end of metabolic activity of lorazepam may make it a poor treatment choice.

Adult↗
PubMed1999

Diagnosis and treatment of insomnia.

Insomnia is an extremely common complaint. Frequently, it occurs secondary to a number of medical and psychiatric conditions that directly affect the ability to initiate or maintain sleep. Insomnia can also occur secondary to behavioral factors, such as shift work, whereby patients either do not follow or control the dictates of their internal circadian rhythm or develop inappropriate conditioned responses to their sleep surroundings. Insomnia can be a primary and even lifelong complaint. Patients with primary insomnia probably have a physiologic problem that has not been clearly identified as the basis for their subjective complaint.

Diagnosis, Differential↗
PubMed1998

Sleepiness as measured by modified multiple sleep latency testing varies as a function of preceding activity.

Many studies have examined the impact of varying levels of sleep loss or sleep disturbance upon the multiple sleep latency test (MSLT). Virtually no studies have examined the impact of level of physiologic arousal upon measured sleep tendency. In the current study, 12 normal-sleeping young adults took modified multiple sleep latency tests after either watching television for 15 minutes or after a 5-minute walk. This entire protocol was repeated on another week after subjects had been partially sleep deprived by reducing their time in bed by 50%. It was hypothesized that sleep latencies would be significantly shorter after watching television as compared to walking and after partial sleep loss as compared to normal sleep and that these effects would be independent. The results of the study supported all of these hypotheses. ANOVAs showed no significant interaction effects, but sleep latencies were 11.6 and 5.8 minutes following the walk and watching television respectively. Sleep latencies were 9.8 and 7.6 minutes following baseline and partial sleep-deprivation conditions. Heart rate, used as a measure of physiological arousal, was significantly elevated throughout naps following the walk as compared to naps following television viewing. On a theoretical level, these data imply that measured sleepiness is a combination of sleep drive and physiological arousal, and these effects appear to be independent. On a practical level, these data indicate that more care may be necessary in monitoring the activity levels of patients and subjects prior to MSLT evaluations, since physiological arousal may mask the measurement of sleep tendency. Knowledge of the role of arousal in modulating sleepiness can be important in many settings.

Adolescent↗
PubMed1998

The consequences of a week of insomnia. II: Patients with insomnia.

Insomnia patients present with a consistent set of complaints that they generally report as secondary to their poor sleep, including increased tension/confusion, decreased vigor, personality disturbance, subjective overestimation of poor sleep, increased body temperature, increased 24-hour whole-body metabolic rate, and longer MSLT latencies. If there is a relationship between the poor sleep and the secondary symptoms, then particularly poor sleep should exacerbate those symptoms. Ten patients with insomnia were identified on the basis of a 2-night screening protocol, then slept in the laboratory for 10 additional nights. On 7 of the nights, the insomnia patients had their wake-after-sleep-onset increased so that their total sleep time was 80% of that on their second screening night, resulting in an average of 254 minutes (of 480 minutes in bed) of sleep. The spectrum of changes seen in these patients with insomnia who had very poor sleep for a week was characteristic of mild partial sleep deprivation, and not consistent with exacerbation of symptoms found in patients with primary insomnia. Specifically, (1) these patients had a reduction as opposed to an increase in the MSLT values, but the MSLT values at the end of the week remained within normal limits; (2) these patients had decreased (as opposed to increased) whole metabolic rate following nights of particularly poor sleep; (3) these patients tended to underestimate (rather than overestimate) their subjective sleep latency while being given particularly poor sleep; and (4) these patients displayed no significant change in body temperature, subjective anxiety, or MMPI scores following particularly poor sleep. It was concluded that the secondary symptoms reported by patients with primary insomnia are probably not related to their poor sleep per se. Data from previous studies that varied physiological arousal were used to support the contention that the secondary symptoms of patients with insomnia, and perhaps the poor sleep itself, occur secondary to central nervous system hyperarousal.

Adult↗
PubMed1998

Work schedule and task factors in upper-extremity fatigue.

We tested the combined effects of work schedule and task factors on upper-extremity fatigue in the laboratory during 8-h and 12-h shift schedules. Participants performed a simulated manual assembly task at three repetition rates and three torque loads and self-adjusted their work cycle duration to maintain fatigue at moderate levels. Work cycle durations decreased with increases in both load level and repetition rate. Fatigue was observed more quickly with increasing time on shifts and during night shifts compared with day shifts. Work schedule effects were most apparent at lighter workloads, with minimal differences at higher workloads. The highest fatigue levels were observed during 12-h night shifts, with similar levels reached by the end of both the week of 8-h night shifts and the week of 12-h day shifts. Overall durations were 20%-30% shorter than in previous short-term studies, which was likely a result of the more realistic work schedules used in this study. Results from this study could be applied to the design of work-rest schedules for manual tasks involving the upper extremities.

Adult↗
PubMed1997

Heart rate variability: sleep stage, time of night, and arousal influences.

Spectral analysis was used to assess heart rate variability in consecutive 5-min epochs during the night in 12 normal adults. Simultaneous time coding of EEG and digitized EKG allowed examination of heart rate variability as a function of sleep stage, time of night and presence of EEG arousal. The results replicated previous studies in showing increases in high frequency components and decreases in low frequency components of heart rate variability across NREM sleep stages and opposite changes in REM sleep and wake. These results are consistent with sympathetic nervous system activation during REM sleep and wake periods. The shift in heart rate variability seen during REM sleep began in NREM sleep several minutes prior to standardly scored REM and often continued beyond the end of REM sleep. EEG arousals during Stage 2 and to some extent REM sleep were also associated with changes in heart rate variability which were consistent with sympathetic activation. An examination of beat to beat intervals in proximity to EEG arousals showed heart rate acceleration at least 10 beats prior to the EEG arousal. The arousal data along with Stage 2 sleep transition data support the contention that increases in central nervous system sympathetic activity precede and possibly play a role in the initiation of REM sleep and arousals during sleep.

Adolescent↗
PubMed1997

Sleep latency measures of caffeine effects during sleep deprivation.

Studies of stimulants during sleep deprivation have used performance assessment batteries (PABs) and occasionally the multiple sleep latency test (MSLT) as measures. Another type of sleep latency test, the maintenance of wakefulness test (MWT), assesses ability to remain awake without assistance, rather than ability to go to sleep. The MWT previously has not been used in studies of stimulants during sleep deprivation. This study of caffeine during 64 h without sleep included a PAB, the MSLT, and a single MWT trial per day. The PAB and the MSLT were sensitive to caffeine effects during the first 24 h without sleep. The MWT demonstrated that caffeine improved ability to remain awake even after 2 nights of sleep deprivation. Ability to go to sleep and ability to stay awake during sleep deprivation appear to be affected differently by caffeine. PAB testing may fail to detect this stimulant effect because technicians prevent subjects from nodding off during PAB testing, an external support not available to subjects during the MWT and also not available in many real-world work environments. The MWT was more sensitive to stimulant amelioration of sleep-deprivation effects. The findings need to be validated with MWTs at other times of day and with other stimulants.

Adult↗
PubMed1996

The consequences of a week of insomnia.

A yoked control study used sleep recordings from 10 insomniacs to produce similar sleep patterns in a group of matched normal sleepers for 7 nights to determine if specific electroencephalographic (EEG) sleep patterns were responsible for the secondary insomnia symptoms reported by the insomniacs. Specifically, it was found that insomniacs display increased tension/confusion, decreased vigor, personality disturbance, subjective over-estimation of poor sleep, increased body temperature, increased 24-hour whole body metabolic rate, and increased multiple sleep latency test (MSLT) values. Normal sleepers given the nocturnal EEG parameters of insomniacs displayed decreased tension, decreased vigor, decreased body temperature, and decreased MSLT values. The spectrum of changes seen in the normal sleepers given an insomniac sleep pattern was characteristic of mild partial sleep deprivation and not consistent with symptoms found in patients with primary insomnia. It was concluded that the secondary symptoms reported by patients with primary insomnia are probably not related to their poor sleep per se. Data from previous studies that varied physiological arousal were used to support the contention that the secondary symptoms of insomnia, including poor sleep, occur secondary to central nervous system hyperarousal.

Adult↗
PubMed1996

[Sleep fragmentation as the cause of daytime sleepiness and reduced performance].

Studies in healthy young adults revealed that periodic arousals during the night result in increasing sleepiness as a function of the interval of time between arousals. When arousals are frequent, deficits similar to those seen after total sleep deprivation have been found. Observed decrements appear to be specifically related to EEG arousals and do not require complete awakening. In patients with fragmenting sleep disorders such as periodic leg movements and central sleep apnea, improved nocturnal sleep is related to increased alertness and daytime performance.

Adult↗
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↗