• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.295-298
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• 2005

We report a case of a 48-year-old man with a paradoxic upper airway obstruction and central sleep apnea that developed after an anterior cervical spinal fusion. Nine months before being admitted to this hospital, he was diagnosed with a herniated intervertebral disc between the 5th and 6th cervical spine, and the first operation was carried out. Two months later, a pseudoarthrosis has developed and a second operation, an anterior interbody fusion of the C5 and C6 using autogenous strut bone graft, was performed. After the second operation, he began to complain of snoring, excessive daytime sleepiness, insomnia, and a bizarre sound heard near the upper airway during breathing. Nasopharyngoscope and magnetic resonance imaging disclosed a paradoxical narrowing of the nasopharynx during expiration. On the overnight polysomnography, the apnea index was 8.7/h (central apnea, 7.0/h; obstructive apnea, 1.7/h). Nasal continuous positive airway pressure was applied, but he complained of pressure-intolerance, and laser-assisted uvulopalatoplasty was then performed. Two months after surgery, clinical symptoms as well as the apneas had improved markedly. We suggest that this paradoxic upper airway obstruction might be associated with the anterior cervical spinal surgery even though the mechanism is unclear. This case also emphasizes that an upper airway obstruction can contribute to the development of central sleep apnea.

• Sleep Medicine and Psychophysiology
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• v.18 no.2
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• pp.82-86
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• 2011

Objectives: The Berlin Questionnaire (BQ) has been used to help identify patients at high risk of having sleep apnea in primary care. But it has not been validated in a sleep clinic for Korean patients. The aim of this study is to evaluate the usefulness of the BQ as a screening tool for obstructive sleep apnea (OSA) for Korean patients in a sleep clinic. Methods: The BQ was prospectively applied to 121 subjects with OSA suspicion who visited to our sleep clinic. All subjects performed overnight polysomnography. OSA was defined as an apnea-hypopnea index (AHI) ${\geq}5$. We investigated the sensitivity, specificity, positive and negative predictive values of the BQ according to severity by AHI. Results: In 121 subjects, 73.6% were males, with a mean age of $48.8{\pm}13.0$ years. Twenty-five (20.6%) patients did not have OSA (AHI<5), 30 (25%) patients had mild OSA ($AHI{\geq}5$ and <15), 26 (21.4%) had moderate ($AHI{\geq}15$ and <30), and 40 (33%) had severe OSA ($AHI{\geq}30$). The BQ identified 69.4% of the patients as being at high risk for having OSA. The sensitivity and specificity of the BQ were 71.9% and 40%, for $AHI{\geq}5$, 75.8% and 38.2% for $AHI{\geq}15$, 77.5% and 34.6% for $AHI{\geq}30$, respectively. The positive and negative predictive values of the BQ were 82.1% and 27.0% for $AHI{\geq}5$, respectively. Positive and negative likelihood ratios were 1.2 and 0.7, and the overall diagnostic accuracy of the BQ was 65.3%, using an AHI cut-off of 5. Conclusion: Due to modest sensitivity and low specificity, the BQ does not seem to be an appropriate tool for identifying patients with obstructive sleep apnea in a sleep clinic population.

• Sleep Medicine and Psychophysiology
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• v.23 no.1
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• pp.16-24
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• 2016

Background and Objectives: Obstructive sleep apnea (OSA) is often undiagnosed but is an important risk factor affecting the health of an individual. The level of awareness of the illness among patients with OSA is low and is not correlated with severity of the illness. This study was conducted to compare awareness of OSA symptoms and illness between patients with OSA and simple snorers. Materials and Methods: Two hundred eighty-two patients who were suspected of having OSA participated in this study. All subjects underwent overnight polysomnography. Those with an apnea-hypopnea index (AHI) ${\geq}5$ were classified as the OSA group, while those with an AHI < 5 were classified as the simple snoring group. A sleep questionnaire, which included items on awareness of the illness, OSA, and sleep symptoms, was administered to all subjects and their bed-partners. Results: Simple snorers were much more aware of their symptoms such as snoring, irregular breathing, and apnea than were patients with OSA. Bed-partners of simple snorers were also more aware of the participants' sleep symptoms than were partners of patients with OSA. However, the duration of OSA symptoms was longer in the OSA group. In the correlation analysis, the level of awareness of OSA symptoms was negatively correlated with AHI, age, body mass index, and Epworth Sleepiness Scale score. Among the sleep questionnaire and polysomnography results, only Pittsburgh Sleep Quality Index was positively correlated with level of awareness of OSA symptoms. The minority of the respondents had heard about the treatment methods of continuous positive airway pressure and oral appliance and preferred them as treatment options. Conclusion: This study suggests that simple snorers are more aware of their symptoms than are patients with OSA. A higher severity of OSA, represented by a higher AHI, is correlated with lower awareness of one's OSA symptoms.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.25-32
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• 2008

Objectives: A few studies have compared REM sleep-dependent obstructive sleep apnea syndrome (REM-OSA) with sleep stage non-dependent apnea syndrome (SND-OSA). Despite that REM-OSA might be more common in women than men, no studies have examined the probable characteristics of women patients with obstructive sleep apnea syndrome (OSAS). This study aimed at finding out the characteristics of REM-OSA in women by comparing it with SND-OSA. Methods: Fifty-three subjects diagnosed as OSAS (AHI>5 ; AHI : apnea-hypopnea index) with nocturnal polysomnography at the Center for Sleep and Chronobiology of the Seoul National University Hospital between October 2004 and February 2006 were studied. Of them, 44 subjects with OSAS severity of mild (52 and AHI-NR<15 (AHI-R : AHI during REM sleep, AHI-NR : AHI during non-REM sleep). We compared REM-OSA group with SND-OSA as well as the criteria-determined REM-OSA cases with the visually-determined ones. Results: Among 44 subjects, 28 persons (63.6%) turned out to have REM-OSA by our criteria and 24 persons (54.5%) by visual determination. Statistically significant differences (p<0.05) were found between REM-OSA and SND-OSA groups in AHI, hypopnea index, total sleep time, total wake time, sleep efficiency index, percents of stage 1, 2 and REM sleep, and REM latency. Percent of stage REM sleep (%REM) turned out to have influence on AHI ratio (AHI-R/AHI-NR) (B=0.537, p=0.002). REM-OSA was likely to be diagnosed in milder severity of OSAS (${\chi}^2=13.117$, p<0.001) and those with higher %REM (${\chi}^2=11.325$, p=0.001). There was no significant difference between the criteria-determined and the visually-determined cases of REM-OSA. Conclusion: We suggest that REM-OSA and SND-OSA patients be differentiated in terms of pathophysiology and treatment strategies. Visual determination of REM-OSA might be useful as the screening procedure of REM-OSA. Further studies on women with OSAS and REM-OSA need to be done.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.110-115
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• 1999

Objectives: To investigate the effect of mandibular repasitioning device on airway sige and airway collapsibility in patients with obstructive sleep apnea syndrome(OSAS). Methods: Cine CT with polysomnographic monitoring was performed during sleep in nine(OSAS) patients before and after manibular repositioning device(MRD) application. Axial CT images were obtained in five upper airway levels(retropalatal-high, retroalatal-low, retroglossal, epiglottis, and hypopharynx levels). In each airway level, one axial CT image was obtained during sleep apnea period and 10 serial axial CT images were scanned every 1 second during normal sleep breathing. After wearing MRD, all CT images were obtained by the same method. The cross-sectional areas of airway were measured by automatic tracing method. The changes of minimum airway size and maximum airway size after MRD were evaluated. The airway collapsibility was calculaed before and after MRD. Results: During sleep apnea, the airway of retropalatal-low level was the most frequently narrowest site. During normal sleep breahing the minimum airway size was increased significantly after MRD at retropalatal-low level(p=0.011). The mean airway collapsibility was the highest at retropalatal-low level. MRD decreased the airway collapsibility significantly at retropalatal-low level(p=0.021) and epiglottis level(p=0.038). Conclusions: The enlargement of the minimum airway size and decreased airway collapsibility may be the therapeutic mechanism of MRD in obstructive sleep apnea.

• Korean Journal of Clinical Laboratory Science
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• v.46 no.3
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• pp.106-110
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• 2014

Obstructive sleep apnea-hypopnea (OSAH) is known to be related to nocturnal blood pressure (BP) and hypertension. The aim of this study was to evaluate the prevalence of hypertension according to the apnea-hypopnea grading. A total of 2,210 adults with snoring and obstructive sleep apnea were referred to our sleep center from July 2009 to May 2013. Clinical blood pressure (BP) was measured before sleeping (bedtime BP) and immediately after waking up in the next morning (morning BP). Subjects were classified into four groups based on the apnea-hypopnea index (AHI) from PSG as follows: control group (n=470) simple snoring and with AHI<5; mild group (n=577) with $AHI{\geq}5$ and <15; moderate group (n=508) $AHI{\geq}15$ and <30; and severe group (n=655) with $AHI{\geq}30$. The differences and correlations between BP and PSG parameters according to the AHI groups were analyzed. Patient's were classified as nomentensive (blood pressure <120/90 mmHg, n=700), prehypertensive (blood pressure < $140-120{\leq}mmHg$, n=1297) hypertensive (blood pressure ${\geq}140/90mmHg$, n=214) according to the office blood pressure measurements. The comparison of sleep parameters showed that OSA groups had a significantly higher stage N1 (control group vs. moderate OSA, severe OSA; $66.4{\pm}30.7$ vs. $85.5{\pm}36.6$, $128.4{\pm}57.3$, p<0.001) and total arousal number (control vs. moderate OSA, severe OSA; $110.7{\pm}47.7$ vs. $150.8{\pm}56.6$, $236.6{\pm}95.8$, p<0.001) compared to control group. The comparison of sleep parameters showed that OSA groups had a significantly lower stage N2 (control group vs. moderate OSA, severe OSA; $172.6{\pm}47.2$ vs. $150.7{\pm}50.5$, $120.3{\pm}57.4$, p<0.001), stage N3 (control group vs. moderate OSA, severe OSA; $38.4{\pm}33.4$ vs. $27.4{\pm}26.0$, $56.1{\pm}27.5$, p<0.001), REM (control group vs. moderate OSA, severe OSA; $64.3{\pm}25.5$ vs. $56.1{\pm}27.5$, $47.3{\pm}25.9$, p<0.001) and mean SaO2% (control group vs. moderate OSA, severe OSA; $90.0{\pm}3.5$ vs. $82.5{\pm}5.5$, $70.0{\pm}8.8$, p<0.001) compared to control group. The Apnea-hypopnea index was significantly higher in OSA groups, increased systolic and diastolic blood pressure than in the nomentensive group (bed time systolic pressure vs. AHI; <120 vs. 120-139, 140-159, >159; $17.5{\pm}18.6$ vs. $24.9{\pm}21.0$, $31.0{\pm}25.7$, $42.3{\pm}31.7$, p<0.001), (bed time diastolic pressure vs. AHI; 60-79 vs. 80-89, 90-99, >99; $19.3{\pm}19.7$ vs. $22.4{\pm}20.3$, $29.8{\pm}23.3$, $38.8{\pm}28.5$, p<0.001). AHI was positively correlated with morning systolic pressure, diastolic pressure, bed time systolic pressure and diastolic pressure (r=0.314, 0.279, 0.233 and 0.200, respectively, p<0.001). We conclude that BMI, Age, neck circumference and AHI increase with the blood pressure.

• The Journal of the Korean dental association
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• v.43 no.11 s.438
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• pp.713-719
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• 2005

• Sleep Medicine and Psychophysiology
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• v.3 no.2
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• pp.90-96
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• 1996

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.293-303
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• 1999

• 대한치과교정학회:학술대회논문집
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• 2000.11a
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• pp.44-44
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• 2000