• Sleep Medicine and Psychophysiology
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• v.28 no.2
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• pp.70-77
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• 2021

Objectives: Our study aims to investigate the clinical and polysomnographic variables associated with subjective sleep perception. Methods: Among the patients who underwent nocturnal polysomnography (PSG) at the Center for Sleep and Chronobiology of Seoul National University Hospital from May 2018 to July 2019, 109 diagnosed with insomnia disorder based on DSM-5 were recruited for the study, and their medical records were retrospectively analyzed. Self-report questionnaires about clinical characteristics including Pittsburgh sleep quality index (PSQI), Beck depression inventory (BDI), and Epworth sleepiness scale (ESS) were completed. Subjective sleep quality was measured using variables of subjective total sleep time (subjective TST), subjective sleep onset latency (subjective SOL), subjective number of awakenings, morning feeling after awakening, and sleep discrepancy (subjective TST-objective TST) the morning after PSG. Pearson and Spearman correlation analyses were used to determine the factors associated with subjective sleep perception. Results: In patients with insomnia, subjective TST was negatively correlated with Wake After Sleep Onset (WASO) (p = 0.001) and N1 sleep (p = 0.039) parameters on polysomnography. Also, it was negatively correlated with PSQI (p < 0.001) and BDI (p = 0.014) scores. Sleep discrepancy was negatively correlated with PSQI score (p = 0.018). Morning feeling was negatively correlated with PSQI (p = 0.019) and BDI (p < 0.001) scores. Conclusion: Our results demonstrated that subjective sleep perception is associated with PSG variables (WASO and N1 sleep) and with PSQI and BDI scores. In clinical practice, it is helpful to assess and manage insomnia patients in consideration of objective sleep variables, subjective sleep quality, and depressed mood, which can influence subjective sleep perception.

• Sleep Medicine and Psychophysiology
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• v.2 no.1
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• pp.82-90
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• 1995

Objectives : Insomnia is significantly influenced by the pre-sleep arousal, self efficacy, sleep hygiene, depression and anxiety. The authors tried to explore how these factors are related with the clinical features of sleep. Methods : Fifty three patients diagnosed as insomnia by DSM-IV criteria were studied. They filled up the pre-sleep arousal scale(PSAS), sleep efficacy scale(SES), sleep hygiene awareness and practice scale, BDI, and state and trait anxiety scales. Results: 1) The mean values of sleep-related variables were as follows : Sleep latency,136.89 minutes ; frequences of awakening during a night, 2.28 ; minutes to get back to sleep, 42.70 ; total sleep time, 180.19 minutes ; duration of illness, 72.00 months. 2) The mean scores of scales were as follows : PSAS(cognitive), 22.40 ; PSAS(somatic), 17.32 ; SES, 20.16 ; sleep hygiene knowledge, 25.96 ; caffein knowledge, 59.78 ; sleep hygiene practice, 42.12 ; BDI. 18.2 ; state anxiety, 41.24 ; trait anxiety ; 44.50. 3) In the subjects with superimposed depression, the mean frequency of awakening during a night and the mean pre-sleep arousal scale score were higher than in those without depression. 4) Frequency of awakening were correlated positively with a PSAS(a tight tense feeling in your muscle) and sleep hygiene awareness. PSAS(cognitive) were correlated positively with a PSAS(somatic). BDI correlated positively with a PSAS item(a jittery, nervous feeling in your body)and a SES item (not allow a poor night's sleep to interfere with daily activities). Anxiety scales were correlated positively with sleep hygiene practice scale sleep, and PSAS were correlated negatively with SES. Conclusions : The mean scores of PSAS, SES, sleep hygiene awareness and practice scale, BDI, state and trait anxiety scales of insomniacs were correlated either positively or negatively in insomnia patients. These factors seem to contribute to the development and maintainence of insomnia.

• Sleep Medicine and Psychophysiology
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• v.23 no.1
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• pp.10-15
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• 2016

Since its development in the early 70s, actigraphy has been widely used in sleep research and clinical sleep medicine as an assessment tool of sleep and sleep-wake cycles. The validation and reliability of actigraphic measures have been reasonably examined in healthy normal individuals with good sleep patterns. Recent literature suggests that the use of actigraphy could be further extended to monitor insomnia and circadian sleep-wake disturbances, and detect sleep changes associated with drug treatments and non-pharmacologic interventions, although it is generally recommended to use complementary assessments such as sleep diaries and overnight polysomnography when possible. The development of actigraphy includes its improved hardware sensors for better detection of movements and advanced algorithms to score sleep and wake epochs. In this paper, we briefly review the quantitative analysis methods of actigraphy and its potential applications in sleep research.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.59-62
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• 2012

Borderline personality disorder (BPD) is characterized by identity and interpersonal problem, affective dysregulation and pervasive severe impulsivity. Although sleep disturbances are not primary symptoms of BPD, they are important aspects of this disorder. However, clinicians and researchers did not give much attention to the sleep symptoms of BPD yet. Measured by nocturnal polysomnography, increased sleep latency as well as reduced total sleep time and sleep efficiency, and 'depression-like' REM abnormalities (i.e., reduced REM latency and increased REM density) are found in BPD patients. Co-morbid sleep disorders such as chronic insomnia, nightmare disorder or circadian rhythm sleep disorder associated with BPD have been reported. Clinicians should focus on the sleep complaints of BPD patients, and carefully manage such symptoms with sleep hygiene education, cognitive psychotherapy or light therapy.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.76-82
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• 2006

Background : The objective of this study was to understand sleep-related problems, and to determine whether the sleep questionnaires is a clinically useful method in patients who need polysomnography. Methods : Subjects were patients who performed polysomnography and who asked to answer a sleep questionnaires at the Sleep Disorders Clinic of St. Paul's Hospital, Catholic University of Korea. Baseline characteristics, past medical illness, behaviors during sleep-wake cycle, snoring, sleep-disordered breathing and symptoms of daytime sleepiness were analyzed to compare with data of polysomnography. Results : The study population included 1081 patients(849 men, 232 female), and their mean age was $44.2{\pm}12.8years$. Among these patients, 38.9% had an apnea-hypopnea index(AHI)<5, 27.9% had $5{\leq}AHI<20$, 13.2% had $20{\leq}AHI<40$, and 20.0% had $40{\leq}AHI$. The main problems for visiting our clinic were snoring(91.7%), sleep apnea(74.5%), excessive daytime sleepiness(8.0%), insomnia(4.3%), bruxism(1.1%) and attention deficit(0.5%). The mean value of frequency of interruptions of sleep was 1.6 and the most common reason was urination(46.3%). Epworth Sleepiness Scale(ESS) had a weak correlation with AHI(r=0.209, p<0.01). When we performed analysis of sleep questionnaires, there were significant differences in the mean values of AHI according to the severity of symptoms including snoring, daytime sleepiness, taking a nap and arousal state after wake(p<0.05). Conclusion : On the basis of statistical analysis of sleep questionnaires, the severity of subjective symptoms such as ESS, snoring, daytime sleepiness and arousal state after wake correlated with the AHI significantly. Therefore the sleep questionnaires can be useful instruments for prediction of the severity of sleep disorder, especially sleep-disordered breathing.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.45-53
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• 1998

Objectives : The change of sleep patterns commonly occurs in association with the pregnancy. This study was to investigate sleep habits during the course of normal pregnancy. Methods : Sleep habits questionnaire was administered to healthy women in their first trimester(TR1) of pregnancy and then the same questionnaire was repeatedly administered during their second(TR2) and third(TR3) trimesters. The following aspects were assessed : patterns of night sleep, daytime status, sleep posture, reasons for sleep alteration, and the experience of any particular parasomnias, as well as sleep problem-related treatment or medication. Data analysis was based on 26 women who maintaind good health throughout their pregnancy and completed the questionnaire three times. Results : In comparisons between each trimester and non-pregnant state, total night sleep time, daytime tiredness, and sleepiness were significantly increased in all trimesters. Sleep latency was significantly decreased in TR1 and TR2, but not in TR3. In addition, refreshed feeling on waking the following day was significantly decreased and the number of awakenings during night sleep was significantly increased in TR3, but not in TR1 and TR2. In comparisons between trimesters, there was a significant increase in sleep latency, daytime sleepiness and the number of awakenings during night sleep and a significant decrease in refreshed feeling on waking the following day in TR3 compared to TR1 and TR2. Over the course of pregnancy, the rate of lateral position during sleep was gradually increased and all the pregnant women took the lateral sleeping posture in TR3. The major reasons for sleep pattern alteration were nausea, vomiting and heartburn in TR1, urinary frequency, fetal movement and ache in hips in TR2, and urinary frequency, fetal movement, cramp in legs and backache in TR3. Conclusion : These findings are expected to be useful for educating pregnant women about sleep hygiene. In future studies, the underlying factors and mechanisms regarding sleep patterns during pregnancy will need to be clarified.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.209-210
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• 2009

수면단계는 수면감성을 평가하는데 있어서 중요한 생리지표로서 사용되어왔다. 그러나 수면다원검사를 이용한 전통적 수면단계 분류방법은 뇌전도, 안전도, 심전도, 근전도 등을 종합적으로 측정하므로 수면단계를 비교적 정확히 분류할 수 있지만 피험자에게 심한 구속감을 주는 문제가 있다. 본 연구에서는, 각성상태에서 교감신경계가 지배적인 반면에 수면 중에는 부교감신경계가 더 활동적인 점에 착안하여 수면단계를 간단히 분류할 수 있는 방법을 찾고자 수면단계에 따른 심박동변이도(heart rate variability: HRV)를 분석하였다. 단일채널 심전도를 이용하여 수면단계별로 HRV 의 교감신경계/부교감신경계 활성도의 비율을 분석한 결과, W(wakefulness) 단계가 NREN(non REM) 2 단계, 3 단계, 4 단계에 비하여 높게 나타났으며, NREM 4 단계는 REM(rapid eye movement) 단계와 NREM 1단계에 비하여 낮게 나타났다. 또한 교감신경계/부교감신경계 활성도 비율의 수면단계에 따라 변화하는 양상은 W, REM, NREM 1, 2, 3, 4 단계의 순으로 단조 감소하였다.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.34-42
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• 2000

Objectives: Periodic limb movements in sleep(PLMS) is a moderately prevalent disorder, of which pathophysiology remains largely unknown. PLMS has been reported to be common in patients with obstructive sleep apnea syndrome(OSAS), but reports on their relationship have been inconsistent in previous studies. Inconsistency of results may be attributable to insufficient number of the study subjects. We attempted to explore the influence of OSAS on PLMS in a large number of subjects. Methods: Three hundred and twenty subjects(M : F=192:128) with PLMS, as identified by the nocturnal polysomnography, were studied. Sample mean age was 53.1(SD=15.1) years and their mean periodic limb movement index(PLMI) is 25.2/hr (SD=24.8). PLMS subjects were divided into two groups, based on the presence or absence of OSAS. Periodic limb movement indices and sleep parameters between two groups were analyzed to evaluate the effects of OSAS on PLMS. Results: Each of PLMI and PLMI with arousal(PLMAI) correlated positively with age. PLMI of men was larger than that of women (p<0.01). The presence of comorbid OSAS independently had influence on PLMI(t=-2.20, p<0.05), but not PLMAI. There were no significant differences between the two groups in their PLMI, PLMAI and sleep parameters. However, the two groups differed in PLMI-correlated sleep parameters. In PLMS subjects with comorbid OSAS, PLMI was negatively correlated with each of slow wave sleep time and REM sleep time. In subjects without comorbid OSAS, PLMI was negatively correlated with sleep efficiency. Conclusion: PLMS patients with OSAS turned out to have increased PLMI than those without OSAS We suggest that OSAS patients may have subtle autonomic arousals and these arousals could, in part, express themselves as PLM.

• Sleep Medicine and Psychophysiology
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• v.12 no.2
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• pp.117-121
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• 2005

Objectives: The purpose of this study was to assess the difference of subjective daytime sleepiness level between primary insomnia patients and healthy control subjects. We also investigated the relationship between subjective daytime sleepiness level and variables of nocturnal polysomnograghic sleep architecture of insomnia patients. Method: Total subjects were 87 patients with primary insomnia diagnosed with polysomnography and 88 normal controls. The daytime sleepiness level in each group was measured by Korean version of Epworth Sleepiness Scale (ESS). The correlations of ESS score and nocturnal polysomnographic variables were calculated in the patient group. Results: Patients with insomnia had the lower ESS scores than the control group. In patients group, the ESS score showed significant negative correlations with total sleep time, sleep efficiency%, and stage 2 sleep time%. The ESS score also showed significant positive correlations with number of awakenings, number of awakenings more than 2 minutes, and wake after sleep onset time. Conclusions: Insomnia patients showed lower level of subjective daytime sleepiness that may indicate their higher alertness comparing to control subjects. Daytime sleepiness of patients with insomnia was associated with polysomnographic variables including total sleep time, sleep efficiency%, stage 2 sleep time% and disrupted continuity of nocturnal sleep.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.27-33
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• 2000

Objectives: The sensitivity and accuracy of thermistor airflow signal has been debated. The purposes of this study were to compare apnea-hypopnea index(AHI) detected from a conventional thermistor signal and a nasal pressure transducer of airflow(NPT), to evaluate the value of NPT for the diagnosis of upper airway resistance syndrome(UARS), and to measure airway pressure fluctuations which produced respiratory arousals in UARS by naso-oro-esophageal manometer catheter. The subjects were 30 patients with obstructive sleep apnea syndrome [mild(540), 10), and 6 UARS patients. Airway resistance arousal in this study was defined as arousals which were not associated with apnea or hypopnea of thermistor signal, but showed significant decrease of nasal airflow pressure just before arousal and a prompt recovery of nasal airflow pressure after arousal. The airway pressure fluctuations were measured during 260 airway resistance arousals observed in 10 patients with OSAS, 2 with UARS. Results: Mean AHIs of patients with OSAS were 33.4 by thermistor and 48.4 by NPT. The AHIs of mild, moderate and severe OSAS groups were 10.2, 32.1, 65.4 respectively by thermistor and 23.1, 45.9, 76.4 by NPT. The mean AHI of patients with UARS was 3.2 by thermistor and 10.8 by NPT. The mean AHI of patients with nonspecific arousals was 2.7 by thermistor and 4.4 by NPT. The mean airway pressure changes during respiratory arousals of different groups were $8.7\;cmH_2O$ in mild OSAS, $11.4\;cmH_2O$ in moderate OSAS, $24.7\;cmH_2O$ in severe OSAS and $6.6\;cmH_2O$ in UARS. Conclusion: The nasal pressure transducer of airflow was more sensitive and accurate for assessing respiratory disturbances of patients with OSAS and was extremely helpful for the diagnosis of UARS without esophageal pressure monitoring. From the results, we would like to propose carefully the NPT diagnostic criteria for sleep disordered breathing as follows: NPT-AHI 5-15 $\rightarrow$ UARS, 15-35 $\rightarrow$ mild OSAS, 35-55 $\rightarrow$ moderate OSAS and >55 $\rightarrow$ severe OSAS.