• Sleep Medicine and Psychophysiology
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• v.9 no.1
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• pp.48-55
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• 2002

Objective: Stress is known to be a common cause of short-term insomnia and insomniacs often complain that stress induces sleep problems. However, previous studies on the correlation between stress and sleep do not show consistent results. We aimed to investigate the effects of minor stressful events on sleep among college students. Method: Physically and mentally healthy college student volunteers filled out a self-assessment questionnaire to evaluate their stress and sleep. To find out the status of average stress and sleep, the volunteers filled out K-DSI and daily sleep assessments on three consecutive days. In addition, we surveyed the amount of caffeine beverage intake and assessed the degree of depression and anxiety. Results: The total number of students participating in this study was 202, 101 men and 101 women. Minor stress turned out to significantly affect non-restorative sleep and secondary symptoms of insomnia (awakening difficulty, displeasure, feeling of dissatisfaction with sleep, physical uneasiness or pain at awakening, daytime sleepiness, depressive moods, tiredness and concentration difficulty). However, global PSQI score, self-reported sleeping hours, sleep latency, awakening frequency, frequency and duration of napping, were not explained by stress scores. Conclusion: In this study, minor stresses seemed to affect sleep, especially secondary symptoms caused by non-restorative sleep. We can thus infer that minor stresses impair the restorative effects of sleep by inducing arousal, and the direct relationship the two can be confirmed by polysomnogram.

• Journal of Oral Medicine and Pain
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• v.34 no.4
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• pp.371-377
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• 2009

Objectives: The aim of this study was to evaluate the differences in the polysomnography data between positional and non-positional obstructive sleep apnea (OSA) patients. Methods: Forty-seven patients diagnosed with OSA were evaluated using full night polysomnography. According to the criteria of Cartwright et al., the patients were classified into two groups with 37 positional (supine apnea-hypopnea index [AHI] $\geq$ 2x's the lateral AHI) and 10 non-positional (supine AHI < 2x's the lateral AHI) OSA patients, and the differences of polysomnography data between the two groups were evaluated. Results: There were no significant differences in demographic variables (age, gender, and BMI), daytime sleepiness, overall AHI, total arousal index, and percent time of snoring between two groups. However, AHI, arousal index, and mean oxygen saturation ($SpO_2$) of the REM sleep stage were significantly more severe in the positional OSA group than the non-positional OSA group. Mean $SpO_2$ and the lowest $SpO_2$ during overall sleep stage were also significantly lower in the positional OSA group than the non-positional OSA group. Conclusions: Our results of differences in the polysomnography data of REM sleep stage suggest that non-positional OSA patients may have higher collapsibility of the oropharyngeal airway during sleep than positional OSA patients.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.32-38
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• 2005

Objectives: Obstructive sleep apnea syndrome (OSAS) has drawn increasing attention as medical community has become to be aware of its co-morbidities and complications, especially cardiovascular complications and excessive daytime sleepiness with accident proneness. As of now, polysomnography is the standard tool to diagnose sleep apnea and estimate the treatment validity. However, its being rather expensive and inconvenient, alternate diagnostic tools have been proposed including wrist actigraphy. So far, actigraphies have been adopted usefully to field-survey sleep apnea prevalence. In this study, we attempted in a sleep laboratory setting to assess the supplemental value of actigraphy in diagnosing OSAS. Methods: This study was done at the Division of Sleep Studies, the Seoul National University Hospital. Thirty-seven clinically suspected cases of OSAS underwent the one-night polysomnography, simultaneously wearing an actigraphy on non-dominant wrist. We analyzed the data of 27 polysomnographically-proven OSAS patients (male：female 20： 7；age $47.6{\pm}12.9$ years old；age range 23 to 72 years) with no other sleep disorders. We calculated RDI (respiratory disturbance index) from the polysomnography data and FI (fragmentation index) from the actigraphy data. Pearson correlation was calculated in order to compare FI with RDI and to evaluate the supplemental diagnostic value of the actigraphy. Results: Mean total sleep time on polysomnography was $401.4{\pm}57.8\;min$ (range of 274.0 to 514.1 min). Mean RDI was $21.7{\pm}20.4/hour$. Mean FI was $21.9{\pm}13.0/hour$. RDI and FI showed significant correlation (r=0.55, p<0.01). Conclusions: Wrist actigraphy in OSAS patients generates a comparable outcome to polysomnography, in measuring the nocturnal sleep fragmentation. The actigraphy could be used supplementally in inpatients, outpatients, and field survey subjects, if polysomnography is unavailable or impossible. In follow-ups related with nasal CPAP (continuous positive airway pressure), upper airway surgery, and oral appliance in OSAS patients, the actigraphy might play a more dominant role in the future.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.126-132
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• 1999

Objectives: The purposes of this study were to investigate 1) the incidence of insomnia, 2) the clinical characteristics of the insomniacs, 3) the correlation of severity of insomnia with somatic complaints and psychological distresses, and 4) the beliefs and attitudes about sleep in patients with chronic renal failure on hemodialysis. Methods: The author evaluated 153 patients, receiving hemodialysis therapy at the four outpatients hemodialysis units in Pusan, Korea. The patients had completed a self-administered questionnaire package, which consisted of basic demographic findings, questions characterizing insomnia, Beck Depression Inventory(BDI), Spielburger's State-Trait Anxiety Inventory(STAI), and visual analogue scales measuring quantitatively the severity of the self-perceived psychological and somatic symptoms. And several laboratory data were collected. Diagnosis of insomnia was made in the base of insomnia criteria of DSM-IV and international classification of sleep disorders. Subjects were dichotomized into those who reported any characteristics of insomnia or those who had no insomnia during the preceding two weeks. Results: Insomnia was found in 100(65.4%) of 153 patients. No statistical differences were found between the patients with and without insomnia in terms of age, gender, education, marital status, mean duration of hemodialysis and all considered laboratory findings except serum albumin. The patients with insomnia had significantly higher BDI score and predialysis systolic blood pressure, and lower serum albumin as compared to non-insomnia group. Significant differences were found between two groups in terms of self-perceived distress such as sadness, anxiety, worry, pruritus, and dysfunction of daily life. The data showed statistically significant correlation between insomnia severity and some variables such as physical dysfunction, pruritus, bone pain, sadness, anxiety, worry, dysfunction of daily life and excessive daytime sleepiness. The patients with insomnia had significantly several dysfunctional beliefs and attitudes about sleep than those without insomnia. Conclusion: These results indicate that insomnia is very common in hemodialysis patients and likely contribute to the impaired quality of life experienced by many these patients. The author suggests that physical and psychological distresses would be reduced and the quality of life could be improved if their sleep disturbances are properly ameliorated in patients on hemodialysis.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1039-1046
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• 1998

Background: Sleep-related breathing disorders(SRBD) and periodic leg movements disorder(PLMD) are both common, and are considered as separate sleep disorders. However, both disorders show high comorbidity. SRBD and PLMD can result in excessive daytime sleepiness and insomnia due to frequent sleep fragmentation. So, it is very important to consider the presence of PLMD, when we are dealing with the diagnosis and management of SRBD. The objectives of this study were to determine the incidence of PLMD in patients with SRBD, and to describe any differences between patients with and without PLMD. Method: The authors reviewed the sleep recordings of 106 patients with a final diagnosis of SRBD(obstructive sleep apnea or upper airway resistance syndrome), who underwent full nocturnal polysomnography, including the monitoring of the anterior tibialis electromyogram. All sleep records were recorded and scored using the standard criteria. The data was analyzed by the student t-test. Result: 106 patients(M=76, F=30) were included in the analysis. Data revealed a mean age of $49.5{\pm}13.6$ years, a respiratory disturbance index(RDI) of $22.3{\pm}25.4$/hour sleep, a lowest oxygen saturation of $84.9{\pm}11.3%$, a maximal esophageal pressure of $-41.0{\pm}19.1cmH_2O$, and PLM index(PLMI) of $13.1{\pm}22.4$movements/hour sleep. Forty four percent(47 of 106 patients) had a PLMI of greater than 5 on this study. The mean age of the patients with PLMD was significantly higher than that of the patients without PLMD(p<0.005). Female patients with SRBD accompanied more PLMD(p<0.05). The apnea index of the patients with PLMD was significantly lower than that of the patients without PLMD(p<0.01). The percentage of stage 1 sleep in the patients with PLMD was significantly lower than that of the patients without PLMD(p<0.05). Conclusion: The prevalence of PLMD in the patients with SRBD was high at 44.3%. The patients with PLMD were older and had more high RDI in comparison to the patients without PLMD, which was consistent with previous findings. The authors recommend that more careful consideration of PLMD is required when diagnosing and treating SRBD.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.23-32
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• 2019

Objectives: Insomnia is not only the most common sleep-related disorder, but also is one of the most important. Knowledge of the comorbidities of insomnia is essential for proper treatment including pharmacological and non-pharmacological methods to prevent disease chronification. This study aimed to determine sleep clinic patients' knowledge of insomnia. Methods: This study recruited 44 patients (24 males and 20 females; mean age $54.11{\pm}16.30years$) from the sleep clinic at National Center for Mental Health. All subjects were asked to complete a self-report questionnaire about their reasons for visiting a sleep clinic and about their knowledge of treatment and comorbidities of insomnia. Results: The reasons for visiting the sleep clinic were insomnia symptoms of daytime sleepiness, irregular sleeping time, nightmares, snoring, and sleep apnea, in that order. Of the responders, 72.7% had a comorbidity of insomnia, and 22.7% showed high-risk alcohol use. In addition, 70.5% of responders chose pharmacological treatment of insomnia as the first option and reported collection of information about treatment of insomnia mainly from the internet and medical staff. More than half (52.3%) of the respondents reported that they had never heard about non-pharmacological treatments of insomnia such as cognitive behavioral treatment (CBT-I) or light therapy. The response rate about comorbidities of varied, with 75% of responders reporting knowledge of the relation between insomnia and depression, but only 38.6% stating awareness of the relation between insomnia and alcohol use disorder. Of the total responders, 68.2% were worried about hypnotics for insomnia treatment, and 70% were concerned about drug dependence. Conclusion: This study showed that patients at a sleep clinic had limited knowledge about insomnia. It is necessary to develop standardized insomnia treatment guidelines and educational handbooks for those suffering from insomnia. In addition, evaluation of alcohol use disorders is essential in the initial assessment of sleep disorders.