Background and Objective: Driver drowsiness is a cause of many traffic accidents all around the world. Driver respiration dynamics undergoes significant changes from wakefulness to sleep. The intrusive nature of current respiration monitoring methods makes them unattractive for detection of in-vehicle driver drowsiness. In this paper, changes in the respiration rate were monitored for drowsiness detection using thermal imaging, which is completely contact-free and non-intrusive.
Materials and Methods: For each frame, the driver’s face was isolated from the rest of the image. Then, the nostrils' zone was localized using physiological characteristics of face. The respiration signal was constructed by putting together the mean temperature of nostril region in all of the frames. In order to study respiration variations from wakefulness to drowsiness, a total number of 12 subjects were tested in a driving simulator. The observer rating of drowsiness (ORD) method was used to estimate the drowsiness level of the subjects.
Results: Derivation of driver respiration rate using thermal imaging was a reliable and non-intrusive method. The results were strongly correlated with those of traditional methods. Driver respiration rate decreased from wakefulness to extreme drowsiness by 3.5 breaths per minute (bpm) and its standard deviation (SD) increased by 0.7 bpm.
Conclusion: Driver respiration rate decreased and its SD increased from wakefulness to drowsiness in 12 participants of this study. The results showed that driver drowsiness could be detected even at moderate levels from analysis of the respiration rate.

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Background and Objective: Obesity is a major risk factor for the development of type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA). We aimed to assess the prevalence of obesity and risk of OSA among people with T2DM.
Materials and Methods: In a cross-sectional study, some basic, anthropometric, and physiological characteristics of 773 patients were assessed during their first visit to Diabetes Clinic of Sabzevar City, Iran. Risk of OSA was determined using the Berlin Questionnaire. Moreover, relationships among risk of OSA and basic, anthropometric, and physiological measures were evaluated using logistic regression modeling.
Results: Prevalence of overweight and obesity were 44.3% and 42.4%, respectively. Moreover, mean body mass index (BMI) (30.1 kg/m2 vs. 27.8 kg/m2) and the rate of obesity (48.6% vs. 27.8%) were significantly higher in women than in men. The findings of Berlin Questionnaire showed that 73.6% of patients were at high risk for OSA. Patients aged 51 to 60 were at elevated risk for OSA [adjusted odds ratio (AOR) = 3.60, 95% confidence interval (CI) = 1.71-7.56]. Obese patients (AOR = 1.96, 95% CI = 1.11-3.46) and high systolic blood pressure (SBP) (AOR = 2.25, 95% CI = 1.47-3.44) showed significant association with OSA.
Conclusion: More than 85% of patients with T2DM were overweight or obese, and nearly three-quarter of them may be at higher risk for OSA. As weight loss, especially through exercise, seems to have beneficial effects not only on OSA severity, but also on consequences of T2DM, weight management should be highly recommended in this population.

Background and Objective: Multiple sclerosis (MS) is an autoimmune neurologic disorder with higher prevalence in female adults. Patients with MS suffer from many consequences of the disease, which result in poor quality of life. In this study, we aimed to evaluate the sleep quality in patients with MS as an important aspect of their life and the relationship between sleep quality and different types of the disease, treatment, and individual characteristics.
Materials and Methods: A total of 152 patients diagnosed with MS at the department of neurology, West Azerbaijan Province, Iran, were enrolled in this cross-sectional study. Participants were asked to fill out a questionnaire consisting of demographic and disease characteristics, types of treatment, and the validated Persian version of Pittsburgh Sleep Quality Index (PSQI). PSQI score ≥ 5 and < 5 were categorized as poor and good sleep quality, respectively.
Results: In this study, the average of PSQI score in all patients was 9.28 ± 5.11. 105 patients (69.1%) had PSQI ≥ 5 (poor sleep quality); whereas 47 patients (31.9%) had PSQI < 5 (good sleep quality). The type of drug (Rebif) used by the patients had a significant effect on categories of self-reported sleep quality among patients (P = 0.01).
Conclusion: This study showed a high prevalence of poor sleep quality in patients with MS. More evaluations are needed for better management of sleep problems in these patients.

Background and Objective: Excessive daytime sleepiness (EDS) is a common problem in patients referred to sleep clinics, which could result in adverse consequences in their personal and social activities including motor vehicle accidents (MVAs). Epworth Sleepiness Scale (ESS) and Multiple Sleep Latency Test (MSLT) are known methods for measuring EDS. In this study, we aimed to evaluate the relationship between EDS and MVAs.
Materials and Methods: Medical records of 144 patients (106 men) with EDS referred to Baharloo Sleep Clinic, Tehran, Iran, were assessed in this cross-sectional study. All participants filled out a questionnaire including demographic characteristics, ESS, and history of MVAs due to sleepiness in the last five years and underwent full-night polysomnography (PSG) and MSLT. Sleepiness was categorized to normal, moderate, or severe according to mean sleep latency (MSL) in MSLT.
Results: Patients with history of MVAs had a significantly less MSL and higher ESS scores than those without MVAs (6.6 ± 3.9 vs. 9.3 ± 6.5, P = 0.038; and 17.9 ± 4.4 vs. 15.6 ± 5.5, P = 0.030, respectively). MVAs were reported in 41.9%, 31.0%, and 16.1% of patients with severe, moderate, and normal sleepiness, respectively. There was a significant relationship between severity of sleepiness and history of MVAs (P = 0.020). Regression analysis showed that after adjustment for age and sex, ESS and MSL remained significantly different between patients with and without MVAs.
Conclusion: ESS score and MSL would help sleep clinicians to find high-risk patients for safety-sensitive jobs, the issue which should not be overlooked by them during visits in sleep clinic.

Background and Objective: Sleep disorders are one of the problems of substance abusers, which might result in emotional and logical thinking breakdown in those individuals. The main aim of the current research was to compare sleep problems in two groups of substance users and normal subjects.
Materials and Methods: This study compared 90 substance users who were referred to the addiction treatment centers with 90 subjects who were relatives as a normal group. Participants were asked to fill out Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), and STOP-BANG questionnaires. Data analysis was performed using independent t-test and descriptive indicators at the significant level of P < 0.050.
Results: The average of age was 38.21 ± 4.35 years in the addict group and 41.11 ± 5.27 in the normal group (P < 0.050). All the participants were men. Our findings indicated a significant difference between the two study groups in the PSQI (P < 0.001) and ESS (P < 0.010) scores with a higher mean score for the addict group. However, normal group showed a significantly higher mean score on the ISI and STOP-BANG compared to the addict group (P < 0.010).
Conclusion: According to the results of this study, sleep problems are common in people who are dependent on drugs, and should be given more attention.

Background and Objective: Sleep problems in industries can influence workers’ health. Shift work and its associated sleep problems are quite common among workers in different industries. The aim of this study was to assess sleep quality, insomnia, excessive daytime sleepiness (EDS), and obstructive sleep apnea (OSA) in workers of an automobile factory.
Materials and Methods: This cross-sectional study was conducted during annual periodic examination of workers from a production unit of an automobile factory. A total of 522 workers filled in questionnaires including demographic characteristics, workplace accidents, Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and STOP-BANG [snoring, tiredness, observed stop of breathing in sleep, blood pressure, body mass index (BMI), age, neck circumference, gender]. T-test and descriptive statistics were used for data analysis.
Results: The participants had mean and standard deviation (SD) age of 37.24 ± 5.73 years. Of 522 participants, 65.3%, 14.4%, and 3.3% had PSQI ≥ 5, ESS ≥ 13, and STOP-BANG ≥ 4, respectively. Higher scores of PSQI and ISI were associated with significant increase of workplace accidents (P = 0.010 and P = 0.004, respectively). Moreover, participants with rotational shift work significantly had more ISI than the ones with fixed shift work.
Conclusion: Poor sleep quality and insomnia were prevalent among studied workers with shift work. Sleep problems also had significant association with workplace accidents. This finding warrants more attention towards shift schedules of the workers and further investigation and management of identified sleep problems.

Background and Objective: Shift work, especially at nights, has negative health outcomes for the workers, their families, and affiliated organizations. Working at night is associated with shortened and disturbed sleep, daytime sleepiness, fatigue, impaired performance, and increased risk of accidents. In this study, we aimed to evaluate sleep quality in different shift schedules of Iranian workers of offshore drilling rigs.
Materials and Methods: One hundred and ninety two offshore workers of two oil rigs were enrolled in this crosssectional study. They were asked to fill out the validated and reliable Persian version of Pittsburg Sleep Quality Index (PSQI). Data regarding age, marital status, education level, smoking, shift work schedule, and body mass index (BMI) were recorded as well.
Results: Mean age and mean work experience of the participants were 37.0 ± 9.3 and 10.0 ± 8.6 years, respectively. Fifty six participants (29.2%) were fixed day shift workers, 111 (57.8%) were swing shift workers (7 days/7 nights), 6 (3.1%) were fixed night shift workers, and 19 (9.9%) were standby shift workers. Mean PSQI score of all workers was 6.73 ± 3.61, and in 69% of the subjects, total score of PSQI was ≥ 5. Night shift workers had greater score of PSQI than other three groups of shift workers.
Conclusion: This study showed that more than half of oil rig workers had poor sleep quality with the highest score among fixed night shift workers. This warrants comprehensive evaluation of the studied participants in terms of sleep disorders and related risk factors. Investigation of contributing occupational and environmental risk factors is also recommended.

Background and Objective: Central sleep apnea (CSA) is defined as cessation of breathing in the absence of ventilatory drive for at least 10 seconds. Idiopathic central sleep apnea (ICSA) is a rare disorder with unclear etiology, and diagnosis is made upon exclusion of other causes. Many of the patients with ICSA do not receive appropriate treatment.
Case Report: Here, we report a 38-year-old man with history of daily hypersomnolence and decreased concentration since two years before referring to our center. After comprehensive medical approach for CSA, he was diagnosed as ICSA. The patient did not respond and did not tolerate continuous positive airway pressure (CPAP). Zolpidem was prescribed for the patient, and he had dramatic improvement of symptoms.
Conclusion: ICSA is a rare sleep breathing disorder presenting with CSA, and may be misdiagnosed with other causes of CSA in the cases of non-appropriate medical evaluation. However, there is no definite treatment.