The effect of partial sleep deprivation on computer-based measures of fitness to drive.

PURPOSE: Using a partial sleep deprivation paradigm, the aim of the study was to investigate the sensitivity of a computer-based test battery of fitness to drive to detect impairments related to sleepiness. METHODS: Forty-seven healthy subjects (34 females, mean age 26.0 ± 6.8 years) participated in a counterbalanced within-subject design of two conditions: (i) normal night sleep and (ii) partial sleep deprivation (PSD) with 4 h time in bed. For the assessment of fitness to drive, we used a validated traffic psychological test battery. Moreover, well-established measures of sleepiness highly responsive to sleep deprivation were applied: the Karolinska Sleepiness Scale (KSS), pupillography (Pupil Unrest Index (PUI) as physiological sleepiness indicator) and two sustained attention tasks (psychomotor Vigilance Task and Mackworth Clock Test). RESULTS: Subjective and physiological sleepiness were significantly increased after PSD, accompanied by large (d > 1.50 for KSS) and medium (d = 0.55 for PUI) effect sizes. Sleepiness-related performance decrements were found in both sustained attention tasks (d = 0.59-0.77). Assessing driving-related ability, PSD induced decrements only in the test domain Reaction Test (reaction time d = 0.54 and motor time d = 0.45). All other subtests-as well as the overall judgement of fitness to drive-were not significantly affected by PSD. CONCLUSION: In contrast to established tests of sustained attention and subjective sleepiness, computer-based test batteries of fitness to drive might lack sensitivity to core aspects of sleepiness as they mainly consist of short and stimulating subtests. Therefore, tasks that require sustained attention should be an essential part of traffic psychological test batteries when sleepiness is a potential issue.

Impact of overnight traffic noise on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers: Results of a pilot study.

This study aimed to evaluate the impact of traffic noise along the motorway on sleep quality, sleepiness, and vigilant attention in long-haul truck drivers. This was a randomized, crossover, within-subject controlled study. Healthy long-haul truck drivers spent 6 consecutive nights in a real truck berth with full sleep laboratory equipment. During 3 nights, subjects were exposed to replayed traffic noise alongside motorways, whereas the other 3 nights were without traffic noise. Polysomnography was recorded during the nights and numerous sleepiness tests and vigilance examinations were performed during the following standardized working day. Outcome measures were compared between noisy and silent nights using the paired Wilcoxon test. Ten healthy long-haul truck drivers with a mean age of 36.3 ± 7.3 years completed the study as planned. On noisy nights, subjects had greater latencies to the rapid eye movement (REM) phase (90 ± 32 min vs 69 ± 16 min, P = 0.074) and higher percentages of sleep stage 1 (13.7 ± 5.5% vs 11.2 ± 4.4%; P = 0.059). Subjects also rated their sleep quality as having been better during nights without noise (28.1 ± 3.7 vs 30.3 ± 6.2, P = 0.092). The impact of these differences on daytime sleepiness and vigilance was rather low; however, mean Karolinska Sleepiness Scale (KSS) scores measured during the course of the following day were higher on six out of eight occasions after noisy nights. The effects of overnight traffic noise on sleep quality are detectable but unlikely to have any major impact on the vigilant attention and driving performance of long haul-truck drivers with low nocturnal noise sensitivity. This might not be true for subgroups prone to sleeping disorders.

[Biological rhythm, sleep and jet lag]. / Biologische Rhythmen, Schlaf und Jet Lag.

Sleep is an active recovery process, which is governed by biological rhythms. This rhythmic variation influences almost all bodily functions and dictates the optimal time for sleep. Sleep itself is an inconsistent state mainly characterized by the alteration between REM and NREM sleep. Vital regenerative processes occur during sleep. Sleep is a basic prerequisite for wellbeing, health and performance. If the synchronization between sleep and the biological rhythms is disturbed, malfunctions of the organism have to be expected. Such a state can be found by a sudden shift of local time by travelling across time zones (jet lag). Therapeutic strategies can reduce the symptoms associated with the state of jet lag.

Polysomnography reveals unexpectedly high rates of organic sleep disorders in patients with prediagnosed primary insomnia.

OBJECTIVE: It is a matter of debate whether patients with primary insomnia require a polysomnographic examination in order to exclude specific sleep disorders such as sleep apnea syndrome (SAS) or periodic limb movements (PLM). Using a prospective design, we investigated the prevalence of organic sleep disorders by means of polysomnography (PSG) in a series of patients who were previously diagnosed with primary insomnia. This diagnosis was based on a clinical exam and an ambulatory monitoring device or previous PSG. METHODS: Seventy-seven women and 16 men (mean age 55.12 ± 13.21 years) who were admitted for cognitive behavioral therapy for insomnia were evaluated by PSG including cardiorespiratory parameters and tibialis EMG. Among them, 50 patients had undergone a clinical exam by a sleep specialist; in 18 patients, actigraphy or portable monitoring had been performed to exclude SAS or PLM; 25 patients had undergone PSG in another sleep lab previously. RESULTS: In 32 patients (34% of the sample), a PSG revealed a specific sleep disorder (SAS 16; PLMD 11; both 5), resulting in therapeutic consequences for 21 patients (SAS 10; PLMD 9; both 2). SAS and PLM patients were older and SAS patients had a higher body mass index than insomnia patients without additional findings. CONCLUSION: Indications for a PSG should be handled less restrictively in the diagnostic workup of older insomnia patients since they have a higher risk of comorbid sleep disorders even in the absence of the clinical signs of SAS or PLM.

The influence of age and sex on sleep latency in the MSLT-30--a normative study.

STUDY OBJECTIVES: The Multiple Sleep Latency Test-30 (MSLT-30) is a variation of the Multiple Sleep Latency Test with a fixed duration of 30 minutes for each of 5 test sessions. It requires less effort for reliable recording and is not susceptible to on-line scoring errors. The aim of the study was to provide normative data for the clinical use of the MSLT-30 and to evaluate the influence of age, sex, and other sociodemographic variables. DESIGN: An MSLT-30, along with measures of mood, objective, and subjective sleepiness was performed in a sample of healthy subjects in a balanced quota design. SETTING: Sleep laboratory in a sleep disorders center. PARTICIPANTS: One hundred subjects with no complaint of sleep disturbance or daytime sleepiness, 10 men and 10 women each from 5 age decades from 20 to 69 years. INTERVENTIONS: None. RESULTS: Mean latency to sleep stage 1 or any other sleep stage was 13.9 +/- 6.9 minutes. The SL-30 showed a clear quadratic association with age, with the shortest latencies in the middle age groups. No correlation was found between the mean latency to sleep stage 1 or any other sleep stage and sociodemographic variables or other measures of daytime sleepiness (Epworth Sleepiness Scale, vigilance test), mood scales, sleep quality (Pittsburgh Sleep Quality Index), and amount of prior sleep. CONCLUSIONS: Sleep latencies in normal subjects are age dependent in a quadratic fashion, with a minimum in middle-aged subjects. This reconciles the findings of a long mean sleep latency in the MSLT of adolescents and of an increase on the mean sleep latency with age in adults.

The influence of polysomnography on the Multiple Sleep Latency Test and other measures of daytime sleepiness.

INTRODUCTION: According to its guidelines, the Multiple Sleep Latency Test (MSLT) should be performed following an all-night polysomnography (PSG). However, the sleep quality and consequently the MSLT results may be affected by PSG and by the fact that a subject sleeps under unfamiliar conditions. The aim of this study was to examine whether PSG performed in a sleep laboratory has any influence on the MSLT and other measures of daytime sleepiness. METHODS: Twenty healthy subjects with a mean age of 35.9+/-10.1 years underwent two MSLT examinations, and the 2 examination days were at least 4 weeks apart. In addition, on each occasion a monotonous vigilance task (VT) was performed and the subjects were asked to fill out the Epworth Sleepiness (ESS) and Visual Analogue Scales (VAS). In a cross-over design, a group of 10 subjects underwent a MSLT (MSLT-P) following a PSG and, on a second occasion, a MSLT (MSLT-N) was performed without a prior PSG. Vice versa, a second group of 10 subjects underwent first MSLT-N and then MSLT-P. RESULTS: None of the MSLT parameters differed significantly between MSLT-P and MSLT-N. The other measures of daytime sleepiness (VT, ESS, VAS) also showed no evidence of significant differences between days with and without a prior PSG. CONCLUSIONS: The results of MSLT and other measures of daytime sleepiness in healthy subjects are not influenced by the fact whether or not the subjects had a PSG the night prior to MSLT.

Shortened night sleep impairs facial responsiveness to emotional stimuli.

Sleep deprivation deteriorates mood, impairs the recognition of facial expressions, and affects the ability to regulate emotions. The present study investigated the effect of partial sleep deprivation on facial responses to emotional stimuli. Thirty-three healthy undergraduates were tested twice: after a night with (i) 8h and (ii) 4h sleep. Self-reported sleepiness and sustained attention (Psychomotor Vigilance Task) were assessed. Emotional reactivity was measured with facial Electromyogram (EMG) while participants were asked to respond with either compatible or incompatible facial muscles to emotional stimuli in order to study whether partial sleep deprivation caused slower reactions mainly in response to incompatible stimuli (due to an additional effort to suppress the compatible reaction caused by decreased inhibitory control) or in response to both compatible and incompatible stimuli. Self-reported sleepiness and reaction times in a sustained attention task significantly increased after one night of partial sleep deprivation. Facial reactions to emotional stimuli were decelerated. No significant interaction between sleep restriction and compatibility of the muscle to the picture valence could be observed. Hence, volitional facial reactions in response to emotional stimuli were slower after one night of reduced sleep, but affective inhibitory control was not significantly impaired. However, slowed facial responding to emotional stimuli may affect social interaction after sleep restriction.

The options available in cognitive behavioral therapy to prevent chronification of insomnia.

Insomnia is a very frequent problem among the general population, and it has a high socio-economic impact on health care management. It produces high costs because of absenteeism and accidents, and it is considered to be a risk factor for the development of psychiatric diseases and other medical disorders. However, only a low proportion of insomniacs ever seek professional help. The reasons are still unknown, but most insomniacs probably consider their problem untreatable unless they undergo a therapy with hypnotics. Knowledge about alternative therapy methods beyond sleep medication is scarce, and specialized psychotherapy is not always available. Since dysfunctional behavior and beliefs are considered to be the central perpetuating factors for primary insomnia, the role of educational programs in terms of prevention and treating mild forms of insomnia is discussed. These workshops could be a part of a step-by-step treatment of insomnia as has been proposed recently by Espie.

"As needed" pharmacotherapy combined with stimulus control treatment in chronic insomnia--assessment of a novel intervention strategy in a primary care setting.

Discontinuous, nonnightly hypnotic therapy in the treatment of chronic insomnia is likely to offer benefits such as maintained efficacy while preventing unnecessary long-term nightly use associated with the risk of tolerance and dependence. Based on the favorable results seen in four zolpidem studies using increasing degrees of flexibility in drug intake schedule, we developed the concept further and investigated "as needed" zolpidem pharmacotherapy amended by the optional use of stimulus control in conditions close to the "real life" practice. In a prospective, observational open study in 550 primary care settings throughout Germany, 2690 patients with chronic insomnia (mean age 59 years, 66% female, 50% with pharmacotherapy pretreatment) were treated with zolpidem according to an "as-needed" (pro re nata) administration treatment schedule (up to five tablets per week, intake nights chosen by the patient), amended by the optional use of behavioral therapy (stimulus control) during drug-free nights. After the three weeks' treatment period, in two thirds of patients (63%) the weekly number of tablets used was reduced in contrast to baseline. The average zolpidem tablet number taken decreased by 28% (from 3.7 to 2.6 per week; p < 0.00001) without any significant impact on the treatment efficacy assessed through the CGI. The subjective latency to sleep onset was reduced from a mean of 74 27 min (p < 0.00001) and total sleep time increased from 5.0 to 6.8 h (p < 0.00001). Efficacy of treatment was rated as very good or good in 93% by the investigators. Adverse events were observed only in 1.2% of patients and were generally of mild nature. No serious adverse event occurred. These results underline the validity of the zolpidem "as needed" treatment concept. It is feasible in a safe and effective manner also in a primary care setting and can be amended by stimulus control. Further research is warranted on the contributions of both treatment components to effectiveness and on the efficacy and safety issues of long-term use.

[Performance improvement and compliance of schizophrenic patients participating in the computerbased cognitive training with X-Cog]. / Leistungsfortschritte und Compliance schizophrener Patienten bei der Teilnahme am computergestützten kognitiven Training mit der Software X-Cog.

This study aimed to examine performance improvement and compliance of schizophrenic patients participating in computerbased cognitive training with X-Cog(R). 20 patients (5 women, 15 men) with the diagnosis of schizophrenia (ICD10 F20.X) were trained ten weeks (twice a week, duration 1h) using the software X-Cog(R) in different wards of the Bezirksklinikum Regensburg. After the evaluation of the feedback given by the computer it could be demonstrated that the patients showed marked practice improvements. Moreover it appeared very less leisure hours what could be shown by an evaluation of the regularity of participation. This study gives first indications that X-Cog(R) could be a useful way to increase individual performance, motivation and especially the continuity of participation in a therapy of schizophrenic patients training using a computerbased cognitive training software.