Journal of Sleep Sciences

A Letter to the Editor on the Importance of a Control Group in Sleep Research

Shadi Naderyan Fe'li — 2025-01-06

In this letter, the necessity of a control group in sleep studies is emphasized. Indeed, I believe that it is crucial to follow a correct methodological approach in sleep science studies. To make an evidence-based clinical decision, an appropriate control group is required to establish a valid asso-ciation between the risk factor/treatment and the outcome of an analytical sleep study. However, defining and recruiting healthy sleepers can be challenging for sleep researchers.

Insomnia Phenotype Characterization and Depression among Patients with Obstructive Sleep Apnea

Khosro Sadeghniiat-Haghighi — 2025-01-06

Background and Objective: Over 40% of individuals with obstructive sleep apnea (OSA) have reported experiencing insomnia. The combination of OSA and insomnia results in decreased sleep quality and adherence to continuous positive airway pressure (CPAP) therapy. This study aimed to assess insomnia among patients with OSA.

Materials and Methods: This cross-sectional study involved 1771 participants. Patients with a high suspicion of OSA completed the Insomnia Severity Index (ISI) and the Beck Depression Inventory (BDI-II) questionnaires. All participants underwent overnight polysomnography (PSG).

Results: In this study, 1242 (68%) of the 1771 participants were men, with a mean age of 47.18 ± 13.65 years. The average Respiratory Disturbance Index (RDI) was 41.53 ± 31.98, the mean ISI score was 12.11 ± 5.99, and the aver-age BDI score was 12.88 ± 11.22. A total of 639 (36%) participants reported moderate to severe insomnia (ISI score ≥ 15). Those with a normal RDI had mean ISI scores of 13.71 ± 6.32, while patients with mild, moderate, and severe OSA had mean ISI scores of 12.76 ± 5.96, 11.61 ± 5.92, and 11.91 ± 5.95, respectively (P = 0.001). The correlation between RDI and ISI score was 0.006 (P = 0.8). As the severity of insomnia increased, the BDI score also signifi-cantly increased (P < 0.0001).

Conclusion: A notable correlation exists between insomnia and depression; individuals with more severe insomnia re-ported higher depressive symptoms. Given the link between insomnia and OSA, it is advisable to assess insomnia in patients diagnosed with OSA.

Investigating the Relationship between Nocturnal Enuresis and Sleep Disordered Breathing Using Polysomnography Data of 5-10 Year-Old Children Referred to Qazvin Children's Hospital, Iran

Shabnam Jalilolghadr — 2025-01-06

Background and Objective: Sleep is a critical biological necessity essential for maintaining both physical and mental health in humans. Given the prevalence of nocturnal enuresis (NE) in children, this study sought to explore its potential link to sleep-disordered breathing (SDB).

Materials and Methods: This cross-sectional study involved children aged 5 to 10 years who visited Qazvin Children's Hospital, Iran, from 2016 to 2021. Data were gathered using the Iranian Children's Sleep Habits Questionnaire (CSHQ) completed by parents, alongside polysomnography (PSG) assessments conducted at the hospital. Children were catego-rized into two groups of with and without enuresis. The PSG data were analyzed to evaluate respiratory parameters in accordance with the American Academy of Sleep Medicine (AASM) guidelines.

Results: Of 124 participants, 64 (51%) were boys, with an average (standard deviation) age of 82.2 (24.4) months. Ap-proximately 39.1% of the children experienced NE. Statistically significant correlations were found between NE and several factors: body mass index (BMI) (P = 0.025), total sleep time (P = 0.026), number of hypopneas (P < 0.001), hypopnea index (P = 0.012), total apnea and hypopnea events (P = 0.004), and the overall apnea-hypopnea index (AHI) (P = 0.005). However, no significant association was established between the oxygen desaturation index, arousal index (AI), and mean oxygen saturation (P > 0.05).

Conclusion: The findings indicate an association between enuresis and obstructive sleep apnea (OSA), suggesting that treating OSA could ameliorate enuresis symptoms. Therefore, it is advisable to evaluate children with enuresis, particu-larly those who are obese, for OSA.

Predicting Pain Perception Based on Psychological Distress in Patients with Rheumatoid Arthritis: The Mediating Role of Sleep Quality

Hosein Etemadi Mehr — 2025-01-06

Background and Objective: Patients with rheumatoid arthritis (RA) often suffer from chronic pain due to the nature of the disease, and in addition to the disease itself, this pain can be aggravated under the influence of psychological fac-tors. The study aimed to predict pain perception based on psychological distress and the mediating role of sleep quality in people with RA.

Materials and Methods: This research was conducted by path analysis, including 202 patients with RA who were se-lected using the convenience sampling method. The study instruments included McGill Pain Questionnaire (MPQ), Pittsburgh Sleep Quality Index (PSQI), and Depression, Anxiety, and Stress Scale (DASS-21). Descriptive statistics reported frequency, mean, standard deviation (SD), and Pearson correlation. In analytical statistics, path analysis was used. Data were analyzed using SPSS and AMOS software.

Results: Psychological distress (anxiety, stress, and depression) had a direct, statistically significant effect on sleep quality. Sleep quality had a direct effect on pain perception. On the other hand, anxiety, stress, and depression, with the mediating role on sleep quality, had a significant influence on pain perception by 0.11, 0.12, and 0.09, respectively. Descriptive statistics showed that a significant correlation existed among independent, mediation, and criteria variables. The proposed predictive model had a good fit.

Conclusion: Along with medical treatments, we need to pay attention to the role of psychological factors such as psychological distress, depression, and sleep quality in patients with RA.

Evaluation of Sleep Quality in Patients with COVID-19 after Discharge

Sareh Mohammadi — 2025-01-04

Background and Objective: This study examines sleep quality in patients with coronavirus disease 2019 (COVID-19) after recovery, exploring demographic associations to inform post-discharge management and support.

Materials and Methods: Conducted as a cross-sectional study, sleep quality was assessed in patients with COVID-19 2-4 weeks post-discharge in Iran. A two-part survey was administered via phone, capturing demographics and Pittsburgh Sleep Quality Index (PSQI) scores.

Results: Among 147 patients (109 women and 38 men, mean age: 47.9 years), the average PSQI score was 12.48 ± 7.37, with a mean sleep duration of 6.26 ± 1.69 hours. Poor sleep was notably linked to female gender (P = 0.029), unemployment (P = 0.012), and mental health history (P = 0.021).

Conclusion: Findings underscore the importance of monitoring sleep quality in COVID-19 recovery, with targeted support potentially reducing hospital readmissions.