The Epworth Sleepiness Scale for screening of the drowsy driving: comparison with the maintenance of wakefulness test in an Iranian sample of commercial drivers.

Traffic fatalities are a major cause of morbidity and mortality in Iran. Occupational sleep medicine field needs more cost-effective and applicable tests for screening purposes. This study reports on a pilot screening study for drowsy drivers in an urban Iranian sample of commercial drivers. The Maintenance of Wakefulness Test (MWT) measures the ability to remain awake objectively. Sleep latency in MWT is a reasonable predictor of driving simulator performance in drivers. In this study, we evaluate whether the Epworth Sleepiness Scale (ESS) and MWT are equally useful in drivers with possible Excessive Daytime Sleepiness (EDS). 46 consecutive road truck drivers in a transportation terminal entered into this study. The ESS score of patients with normal and abnormal MWT was 3.24±2.4 and 4.08±3 respectively which was not significantly differenced (P value = 0.34). No significant correlation was found between the ESS and sleep latency in MWT (r=-0.28, 95%CI= -0.58 to 0.02). By using the receiver operating characteristic analysis, the area under the curve was found to be 0.57 (95% confidence interval = 0.37- 0.77) which is not statistically acceptable (P value=0.46). Our finding showed that the MWT and ESS do not measure the same parameter.

Mirtazapine, a sedating antidepressant, and improved driving safety in patients with major depressive disorder: a prospective, randomized trial of 28 patients.

OBJECTIVE: The objectives of the study were to investigate the effects of mirtazapine, a sedating antidepressant, on driving safety in major depressive disorder (MDD) patients and to observe the effect of mirtazapine on daytime alertness. METHOD: Twenty-eight patients who met the DSM-IV criteria for MDD completed the study in a university teaching hospital. Half of these patients took mirtazapine 30 mg at bedtime for 30 days. A computerized driving simulator test (DST) and the Maintenance of Wakefulness Test (MWT) were conducted at baseline and on days 2, 9, 16, and 30 after commencement of antidepressant use. Fourteen untreated depressed patients performed a DST and MWT at baseline and on days 2 and 9 to evaluate the possibility of a learning effect. Data collection was from June 2005 through January 2006. RESULTS: There were significant linear effects of the treatment on road position at All Trials (p = .018) and on the morning sessions at 10:00 a.m. (p < .001) and 12:00 p.m. (p = .022) and on the number of crashes at All Trials (p = .034) and the 4:00 p.m. session (p = .050) for the group on active treatment. Compared with the values at baseline, those of road position at 10:00 a.m. significantly improved on days 2 (p < .05), 9 (p < .01), 16 (p < .01) and 30 (p < .01) and road position at 12:00 p.m. significantly improved on days 16 (p < .05) and 30 (p < .05). The number of crashes significantly decreased on day 30 (p < .05). The untreated patients showed no improvement in performance in any of the measures, suggesting that the results are not due to a learning effect. CONCLUSION: A sedating antidepressant can increase driving safety in MDD patients. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00385437.

Neural correlates of "absence" in interactive simulator protocols.

While much has been written about the importance of the experience of presence in simulation protocols, the role of "absence" deserves closer attention. The role of subjective experience and neurophysiologic processes involved in fluctuating states of consciousness is a key issue in developing assessment and treatment tools using interactive immersive simulator tasks. This paper proposes that when engaging in an interactive simulator task, there are fluctuations of consciousness that determine both motivational engagement and measured performance. Rather than expecting a continuous experience, both in terms of perceptual and motor output flow, factors such as circadian fluctuations, fatigue, and actual intrusion of sleep into waking consciousness are relevant in assessments and treatments using virtual environment-based tasks. These factors are particularly relevant in treatment populations with neurological and psychiatric disorders, where such disturbances are more common. To illustrate this construct, a series of experiments examining these phenomena in relation to a standardized driving-simulation protocol to detect psychomotor impairment developed for clinical and diagnostic testing in a sleep laboratory setting are reviewed.

Simulator performance, microsleep episodes, and subjective sleepiness: normative data using convergent methodologies to assess driver drowsiness.

OBJECTIVE: Our objective was to examine a novel standardized assessment methodology of detecting impaired driving performance due to drowsiness in a normative cohort. METHODS: Thirty-one healthy subjects with no significant sleep, medical, and psychiatric pathology were assessed in a driving simulation paradigm. Thirty-minute simulations were repeated at two-hourly intervals (i.e., at 1000, 1200, 1400, and 1600 h). Convergent data sources included drivers' subjective ratings of sleepiness and alertness, electroencephalogram-verified microsleep (MS) episodes, and a variety of real-time driving simulator performance measures such as speed, lane tracking, reaction time (RT), and off-road events (crashes). RESULTS: Significant diurnal fluctuations were noted on objective measures of RT, velocity, tracking, and MS events, indicating the highest risk of impairment in the afternoon. By contrast, subjective ratings of sleepiness and alertness did not demonstrate significant circadian variation. The mean incidence of MS episodes and crash risk correlated highly (r = .748). CONCLUSIONS: This prospective study demonstrates the relevance of multiple convergent measures for comprehensive assessment. The divergence of subjective and objective assays of impairment implies that healthy individuals may not have full insights into neurophysiologically mediated performance deficits. These results will serve as normative comparators to patients presenting with daytime somnolence and may allow a more accurate prediction of potential crash risk than noninteractive daytime polysomnogram tests such as the mean sleep latency test or the maintenance of wakefulness test.

Sleepiness is not the inverse of alertness: evidence from four sleep disorder patient groups.

The constructs "sleepiness" and "alertness" are often assumed to be reciprocal states of consciousness. This distinction is of increasing concern in relation to psychomotor performance tasks such as driving. We developed two separate subjective scales of alertness to complement existing sleepiness scales. Subjective sleepiness and alertness were compared in four groups of sleep-disordered patients. In a 175-patient cohort [25 narcoleptics and 50 each with sleep apnea, insomnia and periodic leg movement disorder (PLMD)], the Epworth Sleepiness Scale (ESS) was used to measure sleepiness while the Toronto Hospital Alertness Test (THAT) and ZOGIM Alertness Scale (ZOGIM-A) were used to measure alertness. Significant differences existed for sleepiness scores, with narcoleptics scoring highest on the ESS, followed by sleep apnea, with similar ESS scores for insomnia and PLMD. By contrast, alertness scores on both the THAT and ZOGIM-A did not differ significantly between the four groups. Sleepiness scores show a correlation of close to nil to alertness scores for the combined sleep disorder patient cohort, with the exception of insomnia patients, where a modest but significant inverse relationship was noted between sleepiness and alertness. Subjective states of impaired alertness and excessive sleepiness are independent constructs in the evaluation of sleep-disordered patients. The specific primary sleep disorder diagnosis may play a relevant role in mitigating this interrelationship.

Psychomotor disturbance in depression: assessment using a driving simulator paradigm.

BACKGROUND: Psychomotor disturbance is an essential feature of Major Depressive Disorder (MDD) and has been associated with impaired functioning on cognitively demanding tasks. Given the psychomotor demands required to navigate a motor vehicle and the disastrous effects of motor vehicles accidents, patients with MDD present a population of clinical interest. The goal of this investigation was to examine the association between MDD and driving ability assessed within a simulated driving paradigm. METHODS: 18 outpatients currently meeting diagnostic criteria for MDD and 29 control participants completed four 30-min simulated driving trials at 10:00 am, 12:00 pm, 2:00 pm, and 4:00 pm. Participants also completed the Beck Depression Inventory (BDI) to assess for depression severity and the Epworth Sleepiness Scale (ESS) to assess for everyday sleepiness. RESULTS: After controlling for age and sleepiness, the depressed sample exhibited slower steering reaction times across trials (p<.05) and an increased number of crashes across trials (p<.05) when compared to controls. These differences were characterized by a medium effect size. No significant time-of-day effects were found. LIMITATIONS: MDD patients were free of anti-depressant medication and findings may not generalize to medicated populations. Also, a rural highway driving route was used which may not generalize well to urban driving settings. CONCLUSIONS: Patients with untreated MDD demonstrate impaired simulated driving performance. Further research into whether these findings translate into on-the-road impairment is important for public health and safety.

What is the driving performance of ambulatory surgical patients after general anesthesia?

BACKGROUND: Ambulatory surgical patients are advised to refrain from driving for 24 h postoperatively. However, currently there is no strong evidence to show that driving skills and alertness have resumed in patients by 24 h after general anesthesia. The purpose of this study was to determine whether impaired driver alertness had been restored to normal by 2 and 24 h after general anesthesia in patients who underwent ambulatory surgery. METHODS: Twenty patients who underwent left knee arthroscopic surgery were studied. Their driving simulation performance, electroencephalographically verified parameters of sleepiness, subjective assessment of sleepiness, fatigue, alertness, and pain were measured preoperatively and 2 and 24 h postoperatively. The same measurements were performed in a matched control group of 20 healthy individuals. RESULTS: Preoperatively, patients had significantly higher attention lapses and lower alertness levels versus normal controls. Significantly impaired driving skills and alertness, including longer reaction time, higher occurrence of attention lapses, and microsleep intrusions, were found 2 h postoperatively versus preoperatively. No significantly differences were found in any driving performance parameters or electroencephalographically verified parameters 24 h postoperatively versus preoperatively. CONCLUSIONS: Patients showed lower alertness levels and impaired driving skills preoperatively and 2 h postoperatively. Based on driving simulation performance and subjective assessments, patients are safe to drive 24 h after general anesthesia.

Psychiatric aspects of late-life insomnia.

Epidemiological trends towards a 'graying' population make the issue of insomnia in the elderly an increasingly important research and clinical topic. It is often challenging to determine how much of a psychiatric dimension there is to a clinical condition that is best viewed as both as a symptom and a true psychosomatic entity in its own right. To categorize insomnia as either psychiatric or medically based risks oversimplification of the complexities of sleep disruption in the elderly. Normal senescence-related changes in sleep architecture and circadian rhythms must be considered, as well as the frequent medical comorbidities that may affect sleep. Psychiatric diagnoses to consider include mood and anxiety disorders, which may be affected equally by physiological and psychological changes implicit in old age. Sleep disruption related to dementia is of particular interest to clinicians involved with patients in long-term care facilities. Insomnia may occasionally be iatrogenically induced or exacerbated, and particularly antidepressants must be carefully selected for this reason. Light therapy and behavior therapies are important in multimodal treatment of insomnia, and sleep hygiene includes both regular physical and social activities to preserve entrainment of circadian rhythms affecting sleep.