Relationship between Depressive Symptoms and Sleep Parameters in Patients with Obstructive Sleep Apnea Syndrome / 수면정신생리

OBJECTIVES: Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep-disordered breathing and often presents with comorbid depressive symptoms. In this study, we evaluated the relationship between depressive symptoms and sleep parameters as measured by nocturnal polysomnography (NPSG) and simultaneous wrist actigraphy. METHODS: Two hundred sixty-four subjects with clinically suspected cases of OSAS underwent one-night polysomnography, while simultaneously wearing a wrist actigraphy device. They also completed two questionnaires; the Epworth Sleepiness Scale-Korean version (ESS-K) and the Beck Depression Inventory (BDI). Of the cases studied, 105 subjects were proven by NSPG to have OSAS without other sleep disorders. NPSG and wrist actigraphy data from the subjects were analyzed. Pearson correlation and paired t-test were used in order to evaluate the relationship between depressive symptoms and sleep-parameters. RESULTS: Mean age of the subjects was 46.1+/-13.1 years. Means of the ESS-K score and BDI scores were 10.9+/-4.7 and 12.8+/-8.1, respectively. NPSG sleep parameters significantly differed from those of wrist actigraphy. There was no correlation found between subjects' respiratory disturbance index (RDI) and BDI scores. When directly comparing sleep parameters between subjects who were more depressed versus subjects who were less depressed, both total sleep time and sleep efficiency were decreased in the more depressed. A correlation between RDI and ESS-K scores was also found in the more depressed group. CONCLUSIONS: Although our findings suggest that there is no relationship between RDI and depressive symptoms, there are other significant differences in the sleep parameters between subjects who are more depressed versus those without depression. We recommend that patients with depression should also be evaluated for clinical symptoms of OSAS.

Relationship between Depressive Symptoms and Sleep Parameters in Patients with Obstructive Sleep Apnea Syndrome / 수면정신생리

OBJECTIVES: Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep-disordered breathing and often presents with comorbid depressive symptoms. In this study, we evaluated the relationship between depressive symptoms and sleep parameters as measured by nocturnal polysomnography (NPSG) and simultaneous wrist actigraphy. METHODS: Two hundred sixty-four subjects with clinically suspected cases of OSAS underwent one-night polysomnography, while simultaneously wearing a wrist actigraphy device. They also completed two questionnaires; the Epworth Sleepiness Scale-Korean version (ESS-K) and the Beck Depression Inventory (BDI). Of the cases studied, 105 subjects were proven by NSPG to have OSAS without other sleep disorders. NPSG and wrist actigraphy data from the subjects were analyzed. Pearson correlation and paired t-test were used in order to evaluate the relationship between depressive symptoms and sleep-parameters. RESULTS: Mean age of the subjects was 46.1+/-13.1 years. Means of the ESS-K score and BDI scores were 10.9+/-4.7 and 12.8+/-8.1, respectively. NPSG sleep parameters significantly differed from those of wrist actigraphy. There was no correlation found between subjects' respiratory disturbance index (RDI) and BDI scores. When directly comparing sleep parameters between subjects who were more depressed versus subjects who were less depressed, both total sleep time and sleep efficiency were decreased in the more depressed. A correlation between RDI and ESS-K scores was also found in the more depressed group. CONCLUSIONS: Although our findings suggest that there is no relationship between RDI and depressive symptoms, there are other significant differences in the sleep parameters between subjects who are more depressed versus those without depression. We recommend that patients with depression should also be evaluated for clinical symptoms of OSAS.

Characteristics of Sleep Pattern among Korean College Students / 수면정신생리

INTRODUNTION: The objective of the present study was to investigate bedtime, rise time and time-in-bed of Korean college students, separately on weekday and on weekend and to compare them. In addition, this study also aimed to evaluate the influence of gender, age and grade on the above sleep parmeters in Korean college students. METHODS: Information regarding bedtime and rise time, separately on weekday and on weekend, of Korean college students were obtained by self-administered questionnaire. Questionnaires of 1,825 students (1,416 females and 409 males, age 18-30 ; mean age 21.1+/-2.2) were used for statistical analyses. RESULTS: Korean college students retired to bed 50 minutes later (00 : 49 on weekday ; 01 : 40 on weekend ; t=39.67, p<0.001), rose 1 hour 58 minutes later (07 : 52 on weekday ; 09 : 50 on weekend ; t=39.46, p<0.001), and slept 1 hour 8 minutes longer (t=13.33, p<0.001) on weekend. Compared to male students, female students had earlier rise time (t=8.96, p<0.01 ; t=3.89, p<0.01) and earlier bedtime both on weekday and weekend (t=7.10, p<0.01; t=6.04, p<0.01), and shorter time-in-bed on weekday (t=1.99, p<0.01). In addition, rise time delay and time-in-bed increase on weekend were more prominent in female students than in male students (t=3.41, p<0.01 ; t=3.68, p<0.01). Grade was correlated with bedtime and rise time on weekday (beta=0.1022, p<0.01 ; beta=0.1009, p<0.01), bedtime and time-in-bed on weekend (beta=0.1096, p<0.01 ; beta=-0.0990, p<0.01), and differences between weekday and weekend of the rise time and the time-in-bed (beta=-0.0906, p<0.01 ; beta=-0.1115, p=0.02). CONCLUSIONS: In this study, Korean college students had earlier bedtime/rise time and shorter time-in-bed on weekday than on weekend. These findings suggest that weekday sleep-wake schedule of Korean college students may be advanced relative to their biological sleep-wake cycle and that this discrepancy may be associated with weekday sleep deprivation. In addition, differences of sleep patterns between weekday and weekend were more prominent in female students and students with lower grade. Therefore, discrepancy between weekday sleep-wake schedule and biological sleep-wake cycle, as well as weekday sleep deprivation, might be more serious in female or lower-grade students.

Supplemental Value of the Wrist-Worn Actigraphy in Diagnosing the Obstructive Sleep Apnea Syndrome / 수면정신생리

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+/-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+/-57.8 min (range of 274.0 to 514.1 min). Mean RDI was 21.7+/-20.4 /hour. Mean FI was 21.9+/-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.