Adverse changes in mood and cognitive performance of house officers after night duty

Effects of night-float shifts on cognitive function among radiology residents

BACKGROUND

Many radiology programs utilize a night-float system to mitigate the effects of fatigue, improve patient care, and provide faster report turnaround times. Prior studies have demonstrated an increase in discrepancy rates during night-float shifts.

OBJECTIVES

This study was performed to examine the effects of night-float shift work on radiology resident cognition. We hypothesized that there would be diminished cognitive function on testing following night-float shifts when compared to testing following day shifts.

METHODS

Diagnostic radiology residents in their second to fifth years of residency at a single institution were recruited to participate in this pilot study. Cognitive function was evaluated using the Lumosity Neurocognitive Performance Tests (NCPT), standardized performance tests that provide real-time, objective measurements of cognitive function. Study participants completed the NCPT in 5 sessions following 5 consecutive day shifts to evaluate their baseline cognitive function. The tests were re-administered at the end of consecutive night-float shifts to assess for any changes. Sleep was objectively monitored using actigraphy devices worn around the wrist during all study weeks. Descriptive and summary statistics were performed.

RESULTS

23 prospectively recruited diagnostic radiology residents working night-float shifts took a mean 13.6 (± 5.1) neurocognitive performance tests during the study period. There was a statistically significant decline in 2 of the 6 cognitive tests administered, signifying a decrease in attention, speed, and complex reasoning ability. Night-float shifts were significantly longer than the day shifts and associated with a significantly higher study volume and cross-sectional study volume. Fitbit data demonstrated that there were no significant differences in level of activity while awake. However, participants slept significantly longer during day shifts.

CONCLUSIONS

A sample of 23 radiology residents working night-float shifts demonstrated declines in attention, speed, and complex reasoning ability following sequential administration of standardized neurocognitive performance tests. While the sample size is small, these findings demonstrate the potential deleterious effects of night-float shift work and provide evidence to support further inquiry into this phenomenon.

The prevalence of sleep deprivation and its impact among medical officers in a tertiary hospital, a cross-sectional study from Malaysia

Sleep deprivation (SD), defined as an inability to get a minimum of 7 hours of regular sleep at night is a serious health problem that impacts the performance of medical professionals. This study aims to determine the impact of sleep deprivation on perceived performance among medical officers (MOs). A cross-sectional study design involved 231 MOs from six disciplines in Hospital Tuanku Ja'afar, a tertiary center in the south of Malaysia. A self-administered questionnaire was introduced in the English language. The questionnaire involved the sociodemographic characteristics; job-related factors, and the Sleep Deprivation Impact Scale (SDIS). The SDIS is a 12-question scale, rated on a 5-point Likert scale from strongly disagree to strongly agree. A higher SDIS score reflected a higher impact of sleep deprivation. A total of 206 MOs returned the completed questionnaire yielding a response rate of 89.17%. The mean age of respondents was 31.68 (±3.49) years. Most of the respondents were female, of Malay ethnicity, and married. More than three-quarters (78.64%) reported sleep deprivation. Being less effective in communication and formulating diagnosis (3 (1.01) vs 2.5 (1.15),p = 0.005); taking longer time to do things (3.44 (1.07) vs 2.8 (1.34),p = 0.001); and feeling unsafe while driving (3.56 (1.25) vs 2.93 (1.55),p = 0.006) manifested significantly higher mean among sleep-deprived respondents. In conclusion, sleep deprivation is a prevalent problem; that adversely affects crucial functioning domains that may endanger patients and healthcare providers alike. Radical countermeasures are required to ensure satisfactory sleep duration and address areas jeopardizing MO safety.

The effects of work on cognitive functions: a systematic review

Introduction

Cognitive functions play a crucial role in individual's life since they represent the mental abilities necessary to perform any activity. During working life, having healthy cognitive functioning is essential for the proper performance of work, but it is especially crucial for preserving cognitive abilities and thus ensuring healthy cognitive aging after retirement. The aim of this paper was to systematically review the scientific literature related to the effects of work on cognitive functions to assess which work-related factors most adversely affect them.

Method

We queried the PubMed and Scopus electronic databases, in February 2023, according to the PRISMA guidelines (PROSPERO ID number = CRD42023439172), and articles were included if they met all the inclusion criteria and survived a quality assessment. From an initial pool of 61,781 papers, we retained a final sample of 64 articles, which were divided into 5 categories based on work-related factors: shift work (n = 39), sedentary work (n = 7), occupational stress (n = 12), prolonged working hours (n = 3), and expertise (n = 3).

Results

The results showed that shift work, occupational stress, and, probably, prolonged working hours have detrimental effects on cognitive functioning; instead, results related to sedentary work and expertise on cognitive functions are inconclusive and extremely miscellaneous.

Discussion

Therefore, workplace health and well-being promotion should consider reducing or rescheduling night shift, the creation of less demanding and more resourceful work environments and the use of micro-breaks to preserve workers' cognitive functioning both before and after retirement.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023439172, identifier CRD42023439172.

Predicting and mitigating fatigue effects due to sleep deprivation: A review

The deleterious effects of insufficient sleep have been well-established in the literature and can lead to a wide range of adverse health outcomes. Some of the most replicated findings demonstrate significant declines in cognitive functions such as vigilance and executive attention, psychomotor and cognitive speed, and working memory. Consequently, these decrements often lead individuals who are in a fatigued state to engage in substandard performance on everyday tasks. In the interest of curtailing these effects, prior work has attempted to identify mechanisms that predict fatigue onset and develop techniques to mitigate its negative consequences. Nonetheless, these results are often confounded by variables such as an individual’s resistance to fatigue, sleep history, and unclear distinctions about whether certain performance decrements are present due to fatigue or due to other confounding factors. Similar areas of research have provided approaches to produce models for the prediction of cognitive performance decrements due to fatigue through the use of multi-modal recording and analysis of fatigue-related responses. Namely, gathering and combining response information from multiple sources (i.e., physiological and behavioral) at multiple timescales may provide a more comprehensive representation of what constitutes fatigue onset in the individual. Therefore, the purpose of this review is to discuss the relevant literature on the topic of fatigue-related performance effects with a special emphasis on a variety of physiological and behavioral response variables that have shown to be sensitive to changes in fatigue. Furthermore, an increasing reliance on sleep loss, meant to assist in meeting the demands of modern society, has led to an upsurge in the relevance of identifying dependable countermeasures for fatigued states. As such, we will also review methods for the mitigation of performance effects due to fatigue and discuss their usefulness in regulating these effects. In sum, this review aims to inspire future work that will create opportunities to detect fatigue and mitigate its effects prior to the onset of cognitive impairments.

Diagnostic Failure Rate in Detecting Perilunate Carpal Fractures and Dislocations Using Plain Wrist X-Rays

Objectives  The present study aimed to evaluate the diagnostic failure rate in detecting perilunate fractures and dislocations using plain wrist radiographs by orthopedists and orthopedic residents. A secondary objective was to identify possible groups with a greater or lesser chance of establishing a correct diagnosis.

Methods  An online questionnaire was sent to several orthopedists through e-mail, social networks, and smartphone-based communication applications to assess the rate of diagnostic failure in detecting perilunate fractures and dislocations using plain radiographs.

Results  A total of 511 responses was obtained, with a diagnostic error rate of 8.81% for simple dislocations and 1.76% for trans-scaphoid perilunate fractures. Group stratification showed that residents presented the highest error rates in simple perilunate dislocations (23.91%), whereas hand surgeons presented the lowest error rates (1.74%).

Conclusion  Compared with the literature, the failure rates found were lower, suggesting that plain radiography is effective and that the error rate may not be as high as reported.

Shift working disorders among nurses of Tehran hospital and its related factors in 2016

INTRODUCTION

Many adverse effects occur among the nurses due to shift work Hence, the present study aimed to determine the prevalence of shift work-related disorders and its related factor among the nurses at Tehran University Subsidiary Hospital, Iran, and to find solutions for managing the relevant health problems.

METHODS

In this cross-sectional study, the Survey of Shift workers (SOS) questionnaire and the Personal Information Form were used to collect data related to demographics and working conditions of 1259 randomly selected nurses working at Tehran University Subsidiary Hospital as statistical population.

RESULTS

According to the results, psychological disorders (95%), digestive problems (85%) and social problems (80%) were the most frequent problems among the subjects. Additionally, the satisfaction rate was higher among the volunteer nurses compared to nurses who were forced to do shift work (P < 0.05).

CONCLUSION

The nurses volunteered for shift work had higher satisfaction rate compared to nurses forced to shift work system; moreover, they had more job satisfaction and less shift work-related complaints. Therefore, it is important to select the nurses who are volunteer for shift work system. In addition, the shift work schedule in hospitals should be set based on workload and requirements because the shift schedule can adversely influence the social and family issues of the nurses, as well as their sleep quality and body biological process.

Exploratory study of brain waves and corresponding brain regions of fatigue on-call doctors using quantitative electroencephalogram

OBJECTIVES

It is common to find doctors working long and odd hours and many at times without rest and sleep. Despite the evidence of adverse risk, jeopardizing patient safety under the hands of fatigue doctors under such working hours has not changed in many places. It has argued that with such training and subsequent experience, such issues with patient safety reduce. Fatigue too is argued as subjective, as those who can withstand the stress still perform. Nevertheless, undeniably working under fatigue is not safe for both the patient and the doctor. This study is a novel attempt to explore and objectify the state of fatigue using quantitative EEG among post-call doctors.

METHOD

Seven volunteer post-call doctors were recruited to go through an EEG recording before and after their on-call rotation while at rest and subsequently while carrying out Stroop Test, putting their cognitive function at work.

RESULTS

The doctors have worked up to 33 hours in a row and have had sleep of an average of 1.5 hours. It is found that during task there is a statistically significant increase in theta (frontal and occipital regions) and beta (occipital region) band power while at task post-call. Alpha band power is increased in the frontal and reduced in other regions. Correlation with Stroop Test results indicated that those who have higher alpha, beta, and lower relative theta powers at the frontal region at post-call rest have higher percentage of correct congruent trials.

CONCLUSION

The results objectively imply that these fatigue doctors are under more strain while carrying out a task and corresponds to the implicated regions of brain stimulated by the task accordingly.

Sleep Quality, Perceived Stress, and Caffeinated Drinks Intake in Psychiatry Residents: A Cross-Sectional Study

Background: Medical residencies are highly demanding and stressful and have been associated with mental and emotional problems. Studies that evaluated this relationship in Italian psychiatry residents are scarce. In this study, we examined sleep quality and its association with perceived stress and caffeinated beverages consumption in Italian psychiatry residents.

Methods: Seventy-two PGY1–5 psychiatry residents at two University Hospitals in Italy were asked to complete an anonymous questionnaire. The Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were used to determine the sleep quality and the level of daytime sleepiness (EDS). In addition, we investigated perceived stress and caffeinated drinks consumption (coffee, tea, soda, energy drinks).

Results: Seventy psychiatry residents responded to the survey (97.2% response rate) (M = 34.3%, F = 65.7%; mean age = 30.5 ± 4.2 SD years). 44.3% had poor sleep quality and 15.7% had abnormal EDS. 64.3% reported significant perceived stress. Perceived stress score and coffee consumption were associated with greater likelihood of poor sleep quality.

Conclusions: Psychiatry residents have high prevalence of poor sleep quality. Future longitudinal studies are needed to investigate causality and identify appropriate coping strategies and lifestyle changes aimed to improve mental health in psychiatry trainees.

Impact of extended duty hours on medical trainees

Many studies on resident physicians have demonstrated that extended work hours are associated with a negative impact on well-being, education, and patient care. However, the relationship between the work schedule and the degree of impairment remains unclear. In recent years, because of concerns for patient safety, national minimum standards for duty hours have been instituted (2003) and revised (2011). These changes were based on studies of the effects of sleep deprivation on human performance and specifically on the effect of extended shifts on resident performance. These requirements necessitated significant restructuring of resident schedules. Concerns were raised that these changes have impaired continuity of care, resident education and supervision, and patient safety. We review the studies on the effect of extended work hours on resident well-being, education, and patient care as well as those assessing the effect of work hour restrictions. Although many studies support the adverse effects of extended shifts, there are some conflicting results due to factors such as heterogeneity of protocols, schedules, subjects, and environments. Assessment of the effect of work hour restrictions has been even more difficult. Recent data demonstrating that work hour limitations have not been associated with improvement in patient outcomes or resident education and well-being have been interpreted as support for lifting restrictions in some specialties. However, these studies have significant limitations and should be interpreted with caution. Until future research clarifies duty hours that optimize patient outcomes, resident education, and well-being, it is recommended that current regulations be followed.

Sleep and delirium in unsedated patients in the intensive care unit

BACKGROUND

Sleep deprivation and delirium are major problems in the ICU. We aimed to assess the sleep quality by polysomnography (PSG) in relation to delirium in mechanically ventilated non-sedated ICU patients.

METHODS

Interpretation of 24-h PSG and clinical sleep assessment in 14 patients. Delirium assessment was done using the confusion assessment method for the intensive care unit (CAM-ICU).

RESULTS

Of four patients who were delirium free, only one had identifiable sleep on PSG. Sleep was disrupted with loss of circadian rhythm, and diminished REM sleep. In the remaining three patients the PSGs were atypical, meaning that no sleep signs were found, and sleep could not be quantified from the PSGs. Clinical total sleep time (ClinTST) ranged from 2.0-13.1 h in patients without delirium. Six patients with delirium all had atypical PSGs, so sleep could not be quantified. Short periods of REM sleep were found. ClinTST was median 8.5 h (range 0.4-13.8 h). EEG reactivity and wakefulness was found in all but one PSG. Four patients were CAM-ICU "unassessable" (unresponsive to voice). PSGs were atypical without reactivity or wakefulness, even though clinical wakefulness was documented. ClinTST was median 18.3 h (range 3.7-19.8 h). Paroxystic EEG activity was found in this subgroup.

CONCLUSIONS

The objective signs of sleep were absent in all but one PSG, so even though patients were not sedated, sleep could not be quantified. Even in patients without delirium, sleep could only be quantified in one of four patients. Paroxystic activity is frequent in unsedated patients, unresponsive to voice, but the implication is unknown.

The Preservation of Cued Recall in the Acute Mentally Fatigued State: A Randomised Crossover Study

PURPOSE

The objective of this study is to investigate the impact of acute mental fatigue on the recall of clinical information in the non-sleep-deprived state. Acute mental fatigue in the non-sleep-deprived subject is rarely studied in the medical workforce. Patient handover has been highlighted as an area of high risk especially in fatigued subjects. This study evaluates the deterioration in recall of clinical information over 2 h with cognitively demanding work in non-sleep-deprived subjects.

METHOD

A randomised crossover study involving twenty medical students assessed free (presentation) and cued (MCQ) recall of clinical case histories at 0 and 2 h under low and high cognitive load using the N-Back task. Acute mental fatigue was assessed through the Visual Analogue Scale, Stanford Scale and NASA-TLX Mental Workload Rating Scale.

RESULTS

Free recall is significantly impaired by increased cognitive load (p < 0.05) with subjects demonstrating perceived mental fatigue during the high cognitive load assessment. There was no significant difference in the amount of information retrieved by cued recall under high and low cognitive load conditions (p = 1).

DISCUSSION

This study demonstrates the loss of clinical information over a short time period involving a mentally fatiguing, high cognitive load task. Free recall for the handover of clinical information is unreliable. Memory cues maintain recall of clinical information. This study provides evidence towards the requirement for standardisation of a structured patient handover. The use of memory cues (involving recognition memory and cued recall methodology) would be beneficial in a handover checklist to aid recall of clinical information and supports evidence for their adoption into clinical practice.

The fatigued anesthesiologist: A threat to patient safety?

Universally, anesthesiologists are expected to be knowledgeable, astutely responding to clinical challenges while maintaining a prolonged vigilance for administration of safe anesthesia and critical care. A fatigued anesthesiologist is the consequence of cumulative acuity, manifesting as decreased motor and cognitive powers. This results in impaired judgement, late and inadequate responses to clinical changes, poor communication and inadequate record keeping. With rising expectations and increased medico-legal claims, anesthesiologists work round the clock to provide efficient and timely services, but are the "sleep provider" in a sleep debt them self? Is it the right time to promptly address these issues so that we prevent silent perpetuation of problems pertinent to anesthesiologist's health and the profession. The implications of sleep debt on patient safety are profound and preventive strategies are quintessential. Anesthesiology governing bodies must ensure requisite laws to prevent the adverse outcomes of sleep debt before patient care is compromised.

Sleep deprivation in chronic somatoform pain-effects on mood and pain regulation

Sleep deprivation was found to exert complex effects on affective dimensions and modalities of pain perception both in healthy volunteers and patients with major depression. Considering multifaceted links between mood and pain regulation in patients with chronic somatoform pain, it is intriguing to study sleep deprivation effects for the first time in this group of patients. Twenty patients with a somatoform pain disorder according to ICD-10 diagnostic criteria were sleep-deprived for one night, followed by one recovery night. Clinical pain complaints (visual analog scale), detection- and pain thresholds (temperature and pressure) as well as mood states (Profile of Mood States) were assessed on the day prior to the experiment, on the day after sleep deprivation and on the day after recovery sleep. We found a discrepancy between significantly increased clinical pain complaints and unaltered experimental pain perception after sleep deprivation. Only the clinical pain complaints, but not the experimental pain thresholds were correlated with tiredness-associated symptoms. Total mood disturbances decreased and feelings of depression and anger improved significantly after sleep deprivation. However, these changes were not correlated with a change in clinical pain perception. We conclude that sleep deprivation may generally change the reagibility of the limbic system, but mood processing and pain processing may be affected in an opposite way reflecting neurobiological differences between emotional regulation and interoceptive pain processing.

Transferring responsibility and accountability in maternity care: clinicians defining their boundaries of practice in relation to clinical handover

OBJECTIVE

This exploratory study reports on maternity clinicians' perceptions of transfer of their responsibility and accountability for patients in relation to clinical handover with particular focus transfers of care in birth suite.

DESIGN

A qualitative study of semistructured interviews and focus groups of maternity clinicians was undertaken in 2007. De-indentified data were transcribed and coded using the constant comparative method. Multiple themes emerged but only those related to responsibility and accountability are reported in this paper.

SETTING

One tertiary Australian maternity hospital.

PARTICIPANTS

Maternity care midwives, nurses (neonatal, mental health, bed managers) and doctors (obstetric, neontatology, anaesthetics, internal medicine, psychiatry).

PRIMARY OUTCOME MEASURES

Primary outcome measures were the perceptions of clinicians of maternity clinical handover.

RESULTS

The majority of participants did not automatically connect maternity handover with the transfer of responsibility and accountability. Once introduced to this concept, they agreed that it was one of the roles of clinical handover. They spoke of complete transfer, shared and ongoing responsibility and accountability. When clinicians had direct involvement or extensive clinical knowledge of the patient, blurring of transition of responsibility and accountability sometimes occurred. A lack of 'ownership' of a patient and their problems were seen to result in confusion about who was to address the clinical issues of the patient. Personal choice of ongoing responsibility and accountability past the handover communication were described. This enabled the off-going person to rectify an inadequate handover or assist in an emergency when duty clinicians were unavailable.

CONCLUSIONS

There is a clear lack of consensus about the transition of responsibility and accountability-this should be explicit at the handover. It is important that on each shift and new workplace environment clinicians agree upon primary role definitions, responsibilities and accountabilities for patients. To provide system resilience, secondary responsibilities may be allocated as required.

The association of sleep duration and depressive symptoms in rural communities of Missouri, Tennessee, and Arkansas

PURPOSE

To determine the association between sleep duration and depressive symptoms in a rural setting.

METHODS

We conducted a cross-sectional study using data from Wave 3 of the Walk the Ozarks to Wellness Project including 12 rural communities in Missouri, Arkansas, and Tennessee (N = 1,204). Sleep duration was defined based on average weeknight and weekend hours per day: short (<7), optimal (7-8), and long (>8). The primary outcome was self-reported elevated depressive symptoms. Multivariable logistic regression was used to estimate adjusted prevalence odds ratios (aPOR) and 95% confidence intervals (95% CI).

FINDINGS

Elevated depressive symptoms were common in this rural population (17%). Depressive symptoms were more prevalent among subjects with short (26.1%) and long (24%) sleep duration compared to those with optimal (11.8%) sleep duration. After adjusting for age, gender, race, education, employment status, income, and BMI, short sleep duration was associated with increased odds of elevated depressive symptoms (aPOR = 2.12, 95% CI: 1.49, 3.01), compared to optimal sleep duration. Conversely, the association between long sleep duration and depressive symptoms was not statistically significant after covariate adjustment. Similar findings were observed when we excluded individuals with insomnia symptoms for analysis.

CONCLUSIONS

This study suggests that short sleep duration (<7 hours per night) and depressive symptoms are common among rural populations. Short sleep duration is positively associated with elevated depressive symptoms. The economic and health care burden of depression may be more overwhelming among rural populations, necessitating the need to target modifiable behaviors such as sleep habits to improve mental health.

Faculty and resident perceptions regarding overnight student call during the third year OB/GYN clerkship

OBJECTIVES

The objective of this study is to identify university faculty, community physician, and resident perceptions of how a schedule that employs overnight call in addition to a traditional weekday schedule affects medical student education, well being, and patient care during the third year obstetrics and gynecology clerkship.

METHODS

In July 2007, a descriptive study was performed by distributing surveys to community teaching physicians, current residents, and faculty in the University of Hawai'i Department of Obstetrics and Gynecology. A total of 114 surveys were distributed to all current residents, clinical faculty and full-time faculty in the University of Hawai'i Department of Obstetrics and Gynecology. The survey included questions regarding the effect of the student call/work hour restrictions.

RESULTS

A response rate of 45.6% was obtained (52/114). Results demonstrate that 84.6% (44/52) of residents, faculty, and community attendings agree that third year medical students should take call during their obstetrics and gynecology clerkship. Data was analyzed utilizing Spearman correlation and Cochran-Mantel-Haenszel statistics. No statistical difference was detected in terms of age or physician type (resident vs faculty vs community attending).

CONCLUSION

Most physician-educators believe that medical students benefit from taking overnight call during their obstetrics and gynecology clerkship. Careful consideration should be given prior to elimination of overnight call in the obstetrics and gynecology clerkship.

Apprenticeships ease the transition to independent call: an evaluation of anxiety and confidence among junior radiology residents

RATIONALE AND OBJECTIVES

The aims of this study were to quantify resident anxiety when beginning independent call and to assess whether an apprenticeship experience (buddy call) can lessen anxiety and improve confidence.

MATERIALS AND METHODS

A prospective cohort comparison of two groups of radiology residents beginning independent call, one of which was provided with a buddy call experience, was performed. Anxiety and confidence were assessed using the Endler Multidimensional Anxiety Scales-State (EMAS-S), with total score, autonomic emotional, and cognitive worry components, and a five-point, Likert-type scale, respectively. Both groups were asked about the perceived value of a buddy call experience.

RESULTS

EMAS-S scores improved significantly over 5 days of call in both groups (control, n = 10, P = .0005; buddy call, n = 9, P = .0001), and image interpretation confidence correspondingly increased (control, P = .0004; buddy call, P = .003). Compared to the control group, autonomic emotional scores were significantly lower in the buddy call group on the first day of independent call (P = .040), and cognitive worry and total EMAS-S scores were significantly lower on day 5 (both P values = .03). Buddy call was independently associated with improved autonomic emotional and film interpretation confidence scores (both P values = .02). All members of the buddy call group indicated that the experience was very helpful in preparing for call.

CONCLUSIONS

Beginning independent call is associated with high anxiety, and buddy call reduces that anxiety, beyond the effect of time alone. Residents who participated in buddy call found it helpful in preparing for independent call. These findings support the use of buddy call and tiered call structures as means to introduce junior residents to independent call.

Shift Work Related to Stress, Health and Mood States

This article has two main objectives. The first is to examine the extent of stress, negative mental health outcomes and variations in mood states experienced by shift workers (N = 100) and a control group of day workers (N = 100) employed in Feeder Balancing Dairy, Ramnagar Varanasi and Kanpur, Dugdth Utpadak Sahakari Sangh (brand name Parag, Ltd. for both organisations). Second, to find out the relative contribution of stress variables and mood states in the prediction of mental health outcomes separately for both shift workers and a control group of day workers. Our overall findings concur with other studies and provide evidence that shift workers significantly experienced higher levels of job and life stress, higher indices of negative mental health outcomes (as measured by GHQ – 28) and variations in mood states as compared to day workers. The results of the present study established some significant relationships between stress and negative mental health outcomes among both shift and day group of workers. However, the magnitude of correlation coefficients is slightly higher in the day worker group. For both groups of workers significant positive correlations were found between all the dimensions of negative mental health and mood states of tense arousal, anger, energetic arousal and general arousal. The findings of step-wise multiple regression analysis indicated that amount of life stress and role conflicts were the two major predictors of negative mental health outcomes among shift workers. The results of a similar analysis carried out on day workers indicated that in the prediction of mental health of day workers, job related stressors (role ambiguity, role conflict and role overload) played a significant role. The findings further indicated that shift workers’ mood states such as anger, tense arousal and hedonic tone were also significant predictors of mental health outcomes. In day group of workers, anger coupled with low level of energetic arousal influenced their mental health. It is interesting to note, however, that in both groups of workers anger was the strongest predictor of all indices of negative mental health outcomes. Thus, the present study adds additional support to the notion that shift and night shift work is a potent source of stress. Shift work is opposed to the human circadian system and this conflict creates multiple physiological, psychological and psychosocial problems for shift workers.

Adverse effects of sleep deprivation in the ICU

The hospital is not conducive to sleep. Patients in the ICU are particularly susceptible to sleep disruption secondary to environmental and medical issues. Despite the frequency of sleep disruption in the ICU, the quality of critically ill patients' sleep is often overlooked. This article discusses the following issues essential to understanding the factors associated with sleep loss in the ICU: (1) core elements to consider from the baseline sleep history, (2) impact of the ICU environment on the ICU patient's sleep pattern, and (3) overall systematic impact of sleep deprivation on the ICU patient.

Sleep deprivation induced anxiety and anaerobic performance

The aim of this study was to investigate the effects of sleep deprivation induced anxiety on anaerobic performance. Thirteen volunteer male physical education students completed the Turkish version of State Anxiety Inventory and performed Wingate anaerobic test for three times: (1) following a full-night of habitual sleep (baseline measurements), (2) following 30 hours of sleep deprivation, and (3) following partial-night sleep deprivation. Baseline measurements were performed the day before total sleep deprivation. Measurements following partial sleep deprivation were made 2 weeks later than total sleep deprivation measurements. State anxiety was measured prior to each Wingate test. The mean state anxiety following total sleep deprivation was higher than the baseline measurement (44.9 ± 12.9 vs. 27.6 ± 4.2, respectively, p = 0.02) whereas anaerobic performance parameters remained unchanged. Neither anaerobic parameters nor state anxiety levels were affected by one night partial sleep deprivation. Our results suggest that 30 hours continuous wakefulness may increase anxiety level without impairing anaerobic performance, whereas one night of partial sleep deprivation was ineffective on both state anxiety and anaerobic performance. Key pointsShort time total sleep deprivation (30 hours) increases state anxiety without any competition stress.Anaerobic performance parameters such as peak power, mean power and minimum power may not show a distinctive difference from anaerobic performance in a normal sleep day despite the high anxiety level induced by short time sleep deprivation.Partial sleep deprivation does not affect anxiety level and anaerobic performance of the next day.

The effects of sleep deprivation on symptoms of psychopathology in healthy adults

BACKGROUND

Sleep loss leads to temporary changes in mood and cognition, and is associated with reduced cerebral metabolism within the prefrontal cortex, similar to findings observed in some psychiatric disorders. However, the extent to which sleep deprivation may be associated with the emergence of clinical symptoms of psychopathology in healthy normal individuals is not clear.

METHODS

The Personality Assessment Inventory (PAI) was administered to 25 healthy adults at rested baseline and again after 56h of continuous wakefulness.

RESULTS

Comparisons showed a significant global increase in PAI psychopathology scores from baseline to sleep-deprived sessions, particularly for somatic complaints, anxiety, depression, and paranoia. Mean elevations for the clinical scales remained within normal limits, however. In contrast, sleep loss was not associated with significant changes in anxiety-related disorders, manic symptoms, borderline, schizophrenic, or antisocial features.

CONCLUSIONS

Two nights without sleep may lead to a sub-clinical increase in self-reported affective symptoms of psychopathology while having little effect on symptoms of thought disorder, psychotic processes, or behavioral dysregulation. These data suggest that sleep loss may be differentially disruptive to regions of the brain involved in affective regulation and may, therefore, serve as a model for understanding the brain dysfunction associated with affective psychopathology.

The impact of fatigue on patient safety

Modern medicine is founded on a culture of diligent, fatigued physicians. Fatigue is not desirable; however, the task of managing fatigue in health care professionals is complex and an ideal solution has not been described. Solutions need to integrate the immediate need for continued high-quality patient care, education of trainees, and the limited supply of health and human resources. Exploration of alternate scheduling models, broadened scope of practice, and new models of care delivery in demonstration projects or formal studies should be performed before widespread implementation. Appropriate evaluations are essential if well-meaning but larger scale errors in the name of patient safety are to be avoided.

24 Hours On-Call and Acute Fatigue No Longer Worsen Resident Mood Under the 80-Hour Work Week Regulations

PURPOSE

Studies in on-call residents have shown that mood is worsened by fatigue as indicated by increased scores on measures of depression, anxiety, confusion, and anger using the Profile of Mood States (POMS). In prior sleep deprivation studies, mood has been shown to be more affected than either cognitive or motor performances. The purpose of this study was to examine the effect of the 80-hour work week regulations on resident mood in general and in a post-call period (PC).

METHODS

Institutional Review Board approval was obtained to survey the residents and publish the results. POMS is a 65-item adjective questionnaire that includes subscales for measuring tension-anxiety, anger-hostility, depression-dejection, vigor-activity, fatigue-inertia, and confusion-bewilderment, with the summation of the scales forming a total mood disturbance score. Surgical residents were tested at a 9 am didactic curriculum session (9 am has been shown to correlate with the nadir of performance). Residents were tested after nights off call (NOC) or after PC. Time asleep in the preceding 24 hours and other demographic data were also collected. Acute fatigue (AF) was defined as <4 hours sleep. The two-sample t-test and linear regression were used to assess differences between groups.

RESULTS

A total of 123 standardized POMS mood questionnaires were administered on 4 occasions to 51 surgical residents, 35 men and 16 women at levels PGY-1 through PGY-5. Overall, 33 tests (27%) were taken after PC and 90 (73%) were taken after NOC. Acute fatigue residents had a mean sleep time of 2.2 (+/-1.5) hours, whereas rested (R) residents had a mean sleep time of 6.7 (+/-2.2) hours (whether PC or NOC). No statistical differences in mean values of vigor, anger, depression, concentration, fatigue, tension, or total score were observed between PC and NOC or between AF and R residents. There was no significant relationship between acute sleep deprivation and total mood disturbance, whether PC or NOC. In linear relationships, NOC total score and hours slept had r2 = 0.01 (p = 0.44), whereas PC total score and hours slept had r2 = 0.07 (p = 0.14).

CONCLUSION

Although POMS was given 4 times, only 27% were PC, which reflects our 1 in 4 night in-house coverage. In contrast to earlier studies, resident mood, as measured by POMS, is no longer related to PC/NOC or acute fatigue. Previous studies have shown that loss of sleep was associated with declining mood. The lack of such a relationship in this study may be related to the new regulations. It has been assumed that people can adapt to chronic sleep loss but have a harder time coping with the effects of acute sleep deprivation. If, however, the new regulations have relieved chronic sleep deprivation, then a well-rested resident can periodically cope with the effects of acute sleep deprivation. Perhaps by eliminating chronic sleep debt, work hour restrictions seem to have removed the negative impact of PC seen in the prior era. Further studies should increase the number of residents studied, have numerous repeat NOC and PC pairs in same subjects, compare different services with different workloads, junior and senior residents, and in-house and at-home call schedules.

Worsening effect of partial sleep deprivation on indomethacin-induced gastric mucosal damage

The present study was to investigate the roles of cyclooxygenase-1 and -2 (COX-1 and COX-2) and prostaglandin (PG) on gastric mucosal integrity of partially sleep deprived (PSD) rats. A slowly moving drum was used to induce PSD. The PG levels in the gastric mucosa of PSD rats, with or without indomethacin or rofecoxib treatment, were determined. Exogenous prostaglandin E (PGE) analog, misoprostol, was administered to PSD rats to investigate the modulating effect of PG in indomethacin-induced gastric damage. It was observed that COX-1 mRNA and protein were up-regulated in the gastric mucosa of PSD rats. Selective COX-2 inhibition by rofecoxib failed to decrease mucosal PGE2 levels nor to affect mucosal integrity in both PSD and sleep undisturbed rats. However, indomethacin, a COX-1 preferential non-selective COX inhibitor, significantly reduced mucosal PGE2 content and produced more severe mucosal damage in PSD rats than in the controls. The deleterious effect of indomethacin on gastric mucosal integrity of PSD rats was significantly attenuated with the administration of misoprostol. These results suggest that PSD enhances COX-1 biosynthesis of gastroprotective PGE2 as an adaptive response of the stomach to stress. The administration of non-selective COX inhibitors to subjects with chronic sleep deprivation may induce more gastric damages.

Sleep deprivation does not affect operative results in cardiac surgery

BACKGROUND

There has been an increasing trend towards the mandatory reduction in work hours for physicians because of the fear that sleep-deprived (SD) surgeons are more prone to make mistakes. We hypothesized that sleep deprivation would not be associated with increased morbidity or mortality in cardiac operations.

METHODS

A retrospective review was done of all cases performed by all attending cardiac surgeons from January 1994 to April 2003. Complication rates of cases performed by SD surgeons were compared with cases done when the surgeons were not sleep-deprived (NSD). A surgeon was deemed sleep deprived if he or she performed a case the previous evening that started between 10:00 pm and 5:00 am, or ended between the hours of 11:00 pm and 7:30 am.

RESULTS

A total of 6,751 cases were recorded in the Society of Thoracic Surgeons database over the 9-year period examined. Of these, 339 cases (5%) were performed by SD surgeons, and 6,412 (95%) cases were performed by NSD surgeons. Mortality rates for coronary artery bypass operations showed no significant differences (1.7% [SD = 4/223] vs 3.1% [NSD = 133/4206)] p = 0.34). Operative (p = 0.47), pulmonary (p = 0.60), renal (p = 0.93), neurologic (p = 0.11), and infectious (p = 0.87) complications of all cases also failed to show any statistically significant differences in any group. Perfusion times, cross-clamp times, and the use of blood products were also similar between groups.

CONCLUSIONS

Sleep deprivation does not affect operative morbidity or mortality in cardiac surgical operations. These data do not support a need for work hour restrictions on surgeons.

Partial sleep deprivation compromises gastric mucosal integrity in rats

The gastric mucosa is most susceptible to stress that has been shown to induce mucosal damage in humans and animals. This study aims to explore the underlying mechanisms of partial sleep deprivation, as a source of psychophysiological stress, on gastric functions and its effect on mucosal integrity. Sprague-Dawley rats were partially sleep deprived (PSD) for 7 or 14 days by housing inside slowly rotating drums. Gastric tissues and plasma were sampled at the end of the sleep deprivation periods and mucosal lesion scores were evaluated. Morphological examination was performed after Hematoxylin and Eosin staining. Plasma levels of noradrenaline, adrenaline, gastrin, histamine and somatostatin were determined with enzyme immunoassays. Gastric acidity was measured with acid-base titration in pylorus ligated rats. Gastric mucosal blood flow was evaluated with Laser Doppler Flowmetry. It was found that gastric lesions were induced in about 30%-50% of the PSD rats. Gastric acidity as well as plasma levels of noradrenaline, gastrin and histamine were elevated. Gastric mucosal blood flow and plasma somatostatin level were on the contrary reduced, especially in rats with PSD for 14 days. It is concluded that partial sleep deprivation compromises gastric mucosal integrity by increasing gastric acidity, plasma levels of noradrenaline, gastrin, histamine, and decreasing gastric mucosal blood flow. These results provided experimental evidence on the gastric damaging effects of PSD and it could be one of the risk factors contributing to gastric ulcer formation.

Resident duty hours in American neurosurgery

The unexpected death of Libby Zion, at New York Hospital in 1984, led to a series of investigations that recently resulted in profound changes in resident duty hours. On July 1, 2003, the Accreditation Council for Graduate Medical Education (the governing body of all residency programs in the United States) mandated the following work hours rules: no more than 80 hours per week, no more than 24 hours of continuous patient care (with an added 6-hour transition period), 1 day in 7 free of patient care responsibilities, and a minimum of 10 rest hours between duty periods. These rules are based on a considerable body of scientific study indicating that sleep loss affects cognitive performance and, possibly, patient care. The new work hours have stimulated vigorous debate, both pro and con. Those arguments are reviewed.

Over-expression of inducible heat shock protein 70 in the gastric mucosa of partially sleep-deprived rats

BACKGROUND

Previous findings have demonstrated increased expression of inducible heat shock protein 70 (iHSP70) in the gastric mucosa of rats exposed to partial sleep deprived (PSD). The purpose of this study was to investigate the functional role of iHSP70 and its relationship with acid secretion in the stomachs of PSD animals.

METHODS

A slowly rotating drum was used to induce PSD in male Sprague-Dawley rats with or without omeprazole treatment. Gastric mucosal samples were harvested for iHSP70 mRNA and protein analysis with RT-PCR and Western blotting, respectively. Enzyme immunoassay was used to determine plasma gastrin level and gastric acidity was measured by titration. The modulating effect of PSD on 0.6 M hydrochloric acid (HCl)-induced gastric damage was also evaluated.

RESULTS

PSD increased plasma gastrin, gastric acidity and expression of iHSP70, while significantly reducing HCl-induced gastric damage. Omeprazole administration decreased gastric acidity and reversed iHSP70 over-expression in PSD rats.

CONCLUSIONS

PSD increases gastric acidity which enhances expression of mucosal iHSP70. Over-expression of iHSP70 may be a protective homeostatic response of the stomach to stress induced by PSD and acid secretion.

Qualitative similarities in cognitive impairment associated with 24 h of sustained wakefulness and a blood alcohol concentration of 0.05%

Previous studies that have quantified fatigue-related cognitive impairment as blood alcohol concentration (BAC) equivalents have been limited by two issues: the effect of practice on tests of cognition and, more importantly, the statistic used to quantify change in cognitive performance. The current study addressed these issues by adopting an ABACA design, which allowed for the adequate control of practice effects, and by using effect size metrics, which enabled direct comparisons to be made in performance impairments as a result of fatigue (i.e. sustained wakefulness of 24 h) and alcohol (i.e. BAC of 0.05%). Cognitive performance under the fatigue and alcohol conditions required the use of the CogState battery. It was demonstrated that fatigue caused greater impairment than alcohol on the speed of continuous attention and memory and learning, and on the accuracy of complex matching. Alcohol was more detrimental than fatigue only on the accuracy of memory and learning. Performances on the remaining tasks were the same for both the fatigue and alcohol conditions. These differences and similarities in performance impairment are discussed emphasizing the deleterious cognitive effects of relatively short periods of sustained wakefulness.

Methylphenidate Does Not Improve Cognitive Function in Healthy Sleep-Deprived Young Adults

Background

Abuse of methylphenidate, a treatment of attention-deficit/hyperactivity disorder, is reported to be increasing among students for the purpose of improving cognition.

Methods

A single capsule, containing methylphenidate (20 mg) or placebo, was administered to healthy young adults orally following 24 hours of sleep deprivation. Measurements included percent change in score from sleep-deprived baseline on four standardized tests of cognitive function: Hopkins Verbal Learning, Digit Span, Modified Stroop, and Trail Making tests. Measurements also included percent changes in blood pressure and heart rate from sleep-deprived baseline and plasma methylphenidate concentration.

Results

Differences in cognitive test performance were not observed between intervention groups. In subjects receiving methylphenidate, mean percent changes from baseline for systolic blood pressure and heart rate were increased relative to placebo between 90 and 210 minutes following capsule administration (maximum increases of 9.45% and 11.03%, respectively). The timing of peak differences in physiologic measures did not correlate with peak serum methylphenidate concentrations. Exit questionnaire ratings of “capsule effect” and perceived performance on the postcapsule administration of the most challenging cognitive test were both higher ( p = .044 and p = .009, respectively) for the methylphenidate group than for the placebo group. Conclusions: Cognitive improvement among sleep-deprived young adults was not observed following methylphenidate administration. Benefits perceived by abusers may relate to increased confidence and sense of well-being, as well as to sympathetic nervous system stimulation. Moreover, methylphenidate administration results in physiologic effects that could be harmful to certain individuals.

Association between quantitative EEG and neurocognition in methamphetamine-dependent volunteers

OBJECTIVE

Exposure to methamphetamine is associated with long-lasting reductions in markers for dopaminergic neurons in preclinical models and in humans. These changes may be associated with alterations in brain electrical activity and in cognition.

METHODS

The sample included 9 methamphetamine-dependent subjects and 10 non-drug-using volunteers. Methamphetamine-dependent subjects were hospitalized for 4 days to document abstinence; non-drug-using volunteers were studied as outpatients. EEGs were recorded in the eyes-closed resting state, and absolute EEG power in each frequency band (0.5-4 Hz, 4-8 Hz, 8-12 Hz, and 12-20 Hz) was measured using a fast Fourier transform. EEG power was log-transformed prior to analysis. Cognition was measured using computerized reaction time tasks.

RESULTS

Within the methamphetamine-dependent group only, increased theta quantitative EEG (QEEG) power correlated significantly with reaction time on tasks that were more difficult or that were degraded by fatigue. Increased theta QEEG power also correlated with reduced accuracy on a working memory task.

CONCLUSIONS

Increased QEEG power in the theta band is associated with worse performance on reaction time tasks in the methamphetamine-dependent sample but not in the non-drug-using volunteers.

SIGNIFICANCE

Methamphetamine dependence is associated with pathological alterations in brain electrical activity and in cognitive performance. QEEG appears to provide a sensitive measure of methamphetamine-associated alterations in brain function.

Attention and working memory in resident anaesthetists after night duty: group and individual effects

AIMS

To investigate the effects of a single period of night duty on measures of attention and working memory in a group of residents (registrars) in anaesthesiology. Emphasis was placed on individual deficits using a reference point of the equivalent effect of a blood alcohol concentration (BAC) >0.05% determined by other researchers.

METHODS

There were 33 subjects aged 26-42 years. Night duty was performed on a weekly basis. Baseline assessments were conducted at either 08 15 or 08 55 preceding night duty and repeated 24-25 hours later, just after the completion of duty. Questionnaires included items regarding duration of sleep and the Stanford Sleepiness Scale. A battery of four reaction time (RT) tasks of increasing difficulty, lasting approximately 35 minutes, was administered on a personal computer. These ranged from simple RT to progressively more complex RT tasks incorporating working memory. A significant change was regarded as >15% deterioration in respect of speed or accuracy.

RESULTS

The mean duration of sleep preceding night duty was 7.04 hours and 1.66 hours during the period of night duty. Intergroup comparisons revealed significant prolongation in mean response speed in the first three tests. Mean accuracy was significantly reduced only in respect of the two more complex tests. A >15% deterioration in response speed occurred in up to 30% of subjects on a single task, rising to 52% (17/33) overall. Deterioration occurred in a patchy distribution in most subjects, involving no more than one or two of the four tasks. As regards accuracy, the prevalence of deterioration increased with task complexity.

CONCLUSIONS

Results are in general agreement with previous group analyses. A new dimension was added by the analysis of a broad spectrum of individual response to sleep deprivation. The effects of sleep loss in residents cannot be overlooked, even in a relatively benign work schedule.

Occupational stress, job satisfaction and health state in male and female junior hospital doctors in Greece

This study investigates the occupational stress amongst 355 male and female Greek junior hospital doctors (JHDs) working in the Greater Athens area. The initial phase of the research involved in‐depth interviews with a random stratified sample of sixty JHDs, both male and female, in a variety of specialties of junior hospital staff. An extended version of the occupational stress indicator (OSI) questionnaire was developed, incorporating additional items based on the results of the qualitative part of the study, and on previous research findings in the same area. The sample consisted of 193 males and 162 females JHDs, who completed the OSI. Analyses of the data demonstrated that, overall, JHDs presented significantly higher levels of sources of pressure than the normative population and other comparative occupational samples. As regards the various sub‐group comparisons, bivariate analyses revealed that there were significant differences between male and female JHDs in certain aspects of pressure (“career and achievement” and “home/work interface”). Multivariate analyses revealed that predictors of physical and mental ill health and job dissatisfaction were type A behaviour and “demands of the profession” respectively. The research implications of the findings are discussed.

The effect of sleep disruption on performance of anaesthetists--a pilot study

Fatigue has been implicated in the occurrence of critical incidents. Using a driving simulator to assess vigilance, we investigated the effect of sleep disruption on the ability of anaesthetists to maintain vigilance after a night on-call. Following an undisturbed night of sleep, subjects demonstrated a significant improvement in their vigilance scores. Subjects failed to demonstrate this following a disturbed night. The timing of disturbance had a bearing on performance. Subjects' performance was worse if their sleep had been disturbed in the first third of the night. The effect of sleep disruption on vigilance has implications for patient safety during anaesthesia.

Adverse drug reactions: current issues and strategies for prevention and management

Adverse drug reactions (ADRs) are common, frequently serious and cause considerable morbidity and mortality. In addition to human costs, ADRs place considerable economic burden on society and already-stretched healthcare systems. Much work has been done to determine potential causes, commonly responsible drugs and susceptible patient groups. To this end, various national pharmacovigilance schemes exist to collate information about ADRs. Despite this, levels of ADR reporting are universally poor, with ADRs remaining a significant clinical problem. Therefore, more effective dissemination and implementation of available knowledge is needed, together with better use of the systems already in place. Local ADR centres and teams, in close liaison with national centres, appear to be an important part of this process and need to be developed within healthcare systems. In addition, there is now evidence to suggest that better use of informatics will help to facilitate this, together with wider availability of electronic notes and greater use of computer-prescribing. Although advancing technology may help to make the use of medicines safer, more effective and more specific in the future, investment to develop informatics infrastructure and local ADR teams is now needed in our healthcare systems.

Neuropsychologische Frührehabilitation

Zusammenfassung: Die neurologische Frührehabilitation hat im letzten Jahrzehnt stark an Bedeutung gewonnen. In diesem Artikel wird ein neuropsychologisches Behandlungskonzept für Patienten mit schwersten Bewusstseinsstörungen (Wachkoma, akinetischer Mutismus, stuporartige Antriebsstörung und Somnolenz) zur Diskussion gestellt. Schwerpunkt des Konzepts ist eine Konzentration auf die Handlungsebene und eine Interpretation der Syndrome als schwere Form der Negativsymptomatik, während die übliche Einordnung als Aufmerksamkeitsstörung in Frage gestellt wird. Die für die einzelnen Syndrome vorhandene Literatur zu neuroanatomischen Ursachen, zu neuropsychologischen Modellvorstellungen und zu funktionellen bzw. pharmakologischen Behandlungsansätzen wird jeweils kurz dargestellt und es werden daraus spezifische neuropsychologische Therapievorschläge abgeleitet. Aus der Analyse folgt, dass die Neuropsychologie einen wesentlichen Beitrag zur Behandlung dieser schwerst beeinträchtigten Patienten der Phase B der neurologischen Rehabilitation leisten könnte, bis heute aber kaum empirische Daten über die Wirksamkeit vorliegen.

Sleep deprivation and junior doctors' performance and confidence

PURPOSE OF STUDY

To determine whether sleep deprivation affects not only junior doctors' performance in answering medical questions but whether their ability to judge their own performance is also affected by lack of sleep.

METHODS

A questionnaire based follow up study in two district general hospitals of the Carmarthenshire NHS Trust. Eleven house officers and 15 senior house officers (SHOs) within the medical directorate participating in the on-call rota were recruited between July 1999 and May 2000.

RESULTS

SHOs answered significantly more questions correctly (p=0.04) and were more confident than house officers when they were either correct or incorrect (p<0.001). Length of unbroken or continuous sleep is associated with more correct answers (p=0.03) and higher energy (p=0.09) and confidence (p=0.07) scores self rated by the profile of mood states. Length of continuous sleep was not related to the appropriateness of confidence, as measured by the "within-subject confidence-accuracy correlation" (p=0.919).

CONCLUSIONS

SHOs performed better than house officers even allowing for sleep loss. Sleep deprivation had adverse effects on mood and performance but junior doctors can still monitor their performance and retain insight into their own ability when sleep deprived.

Sleep patterns and sleep disruptions in kindergarten children

Assessed sleep patterns and sleep disruptions in kindergarten children and investigated the relation between sleep measures derived from objective and subjective evaluation methods. The sleep patterns of 59 normal kindergarten children (mean age = 5.5 years) were monitored for 4 to 5 consecutive nights by means of activity monitors (actigraph) and by means of parental daily sleep logs. The correlation between the actigraphic measures and the daily parental logs indicated that parents were accurate reporters of sleep schedule measures. However, parents were less accurate in assessing sleep quality measures, significantly underestimating the number of night-wakings and overestimating the quality of their children's sleep. Fragmented sleep was found, by means of activity monitoring, in 41% of the children.

The effect of total sleep deprivation on cognitive functions in normal adult male subjects

This study was conducted to evaluate the effect of acute sleep deprivation on cognitive functions. A total of 18 healthy right handed males were deprived of sleep for 24 hours. Luria-Nebraska Neuropsychological Battery and calculation & digit-span subtest of K-WAIS were administered before and after sleep deprivation in order to examine the changes of cognitive functions. There were no differences in freedom from distractibility, tacile function, visual function, reading, writing, arithmetic and intellectual process function. However, the cognitive functions such as motor, rhythm, receptive & expressive speech, memory and complex verbal arithmetic function were decreased after sleep deprivation. All of these functions are known to be related to the right anterior hemisphere. For localization scales, the scores of right frontal and right temporal dysfunction scale were increased after sleep deprivation. These results indicate that sleep deprivation has a negative effect on cognitive functions, especially those associated with right anterior hemisphere or subcortical areas.

Shift work modifies the circadian patterns of heart rate variability in nurses

OBJECTIVE

The influence of shifting the work-sleep cycle on the circadian rhythm of cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV).

METHODS

The subjects were 10 healthy Japanese female nurses aged 33+/-3 (S.D.) years. The subjects underwent ambulatory 24-h electrocardiogram (ECG) recordings on the days of day shift (working from 08:00 to 17:00 h) and night shift (working from 21:40 to 08:40 h). Variables of the frequency domain of HRV were calculated for three activity states (work, awake but not working, and sleep).

RESULTS

The mean values of HRV variables over 24 h were not different between day shift and night shift. For both shifts, variables related to the sympathetic control (low frequency component in normalized units and low/high frequency component ratio) were the largest during the work period and the smallest during the sleep period, while an opposite order was present for variables related to the vagal control (high frequency component in absolute value and normalized units). HRV variables in each activity state were not different between the two shifts.

CONCLUSIONS

The circadian rhythm of cardiac autonomic activity is largely modified by the level of physical activity regardless of the clock hour, which may have clinical implications when studying the circadian fluctuations of the onset of cardiovascular disease in shift workers.

Alterations of host defence system after sleep deprivation are followed by impaired mood and psychosocial functioning

In healthy humans, sleep deprivation (SD) has consistently been demonstrated to impair different parameters of the host defence system and of psychosocial functioning. However, the individual timing of these alterations and their possible association have remained unknown so far. We therefore investigated functional measures of the individual host defence system as well as of subjective well-being and psychosocial performance in 10 healthy male adults before and after SD, as well as after recovery sleep. In detail, we examined the number of leukocytes, granulocytes, monocytes, lymphocytes, B cells, T cells, T helper and cytotoxic T cells, natural killer (NK) cells as well as the interleukin-1 beta (IL-1 beta) release from platelets after serotonin (5-HT) stimulation. Mood and psychosocial performance (excitement, energy, ability to work and timidity) were measured by visual analogue scales. Taken together, SD induced a deterioration of both mood and ability to work, which was most prominent in the evening after SD, while the maximal alterations of the host defence system could be found twelve hours earlier, i.e., already in the morning following SD. Our findings therefore suggest an SD-induced alteration of these psychoimmune response patterns in healthy humans preceding deterioration of mood and psychosocial functioning.