• Sleep Medicine and Psychophysiology
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• v.3 no.2
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• pp.97-107
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• 1996

• Proceedings of the KSLP Conference
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• 2011.03a
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• pp.13-13
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• 2011

• The Journal of the Korean dental association
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• v.28 no.5 s.252
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• pp.467-473
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• 1990

• The korean journal of orthodontics
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• v.47 no.6
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• pp.353-364
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• 2017

Objective: The objective of this study was to investigate the effects of miniscrew-assisted rapid palatal expansion (MARPE) on changes in airflow in the upper airway (UA) of an adult patient with obstructive sleep apnea syndrome (OSAS) using computational fluid-structure interaction analysis. Methods: Three-dimensional UA models fabricated from cone beam computed tomography images obtained before (T0) and after (T1) MARPE in an adult patient with OSAS were used for computational fluid dynamics with fluid-structure interaction analysis. Seven and nine cross-sectional planes (interplane distance of 10 mm) in the nasal cavity (NC) and pharynx, respectively, were set along UA. Changes in the cross-sectional area and changes in airflow velocity and pressure, node displacement, and total resistance at maximum inspiration (MI), rest, and maximum expiration (ME) were investigated at each plane after MARPE. Results: The cross-sectional areas at most planes in NC and the upper half of the pharynx were significantly increased at T1. Moreover, airflow velocity decreased in the anterior NC at MI and ME and in the nasopharynx and oropharynx at MI. The decrease in velocity was greater in NC than in the pharynx. The airflow pressure in the anterior NC and entire pharynx exhibited a decrease at T1. The amount of node displacement in NC and the pharynx was insignificant at both T0 and T1. Absolute values for the total resistance at MI, rest, and ME were lower at T1 than at T0. Conclusions: MARPE improves airflow and decreases resistance in UA; therefore, it may be an effective treatment modality for adult patients with moderate OSAS.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.775-781
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• 1997

Although reoxygenation is the best way to salvage hypoxic tissues, reduced oxygen species (ROS) generated during reoxygenation are blown to cause further tissue injuries and the induction of heat shock proteins (HSPs). The present study was undertaken to determine any causal relationship between the severity of hypoxia and the opposite outcomes, either beneficial or detrimental, of the subsequent reoxygenation by measuring the HSP72. To this aim, one group (6 male cats, $2.5{\sim}3.5\;kg$) was subjected to a 5-min episode of hypoventilation (H, ventilation rate: 5/min) for the induction of slight hypoxia and the other group (6 male cats, $2.4{\sim}3.7\;kg$) was subjected to a 5-min episode of apnea (A) for severe hypoxia. Each 3 animals from both groups received a 10-min episode of ventilation with $(95%\;O_2\;(0)$, whereas the remainder did not. After these procedures, all animals were allowed to be ventilated within physiological range for 1, 4, or 8 hours (1H, 1HO, 4H, 4HO, 8H, 8HO, 1A, 1AO, 4A, 4AO, 8A and 8AO groups). Control animals did not receive any manipulation. The arterial blood $pCO_2$ was significantly higher just after apnea than hypoventilation, while $pCO_2$ and pH were significantly lower just after apnea than hypoventilation. Western blot analysis revealed that the magnitude of HSP72 synthesis is larger in 1H, 4H and 8H groups than in 1HO, 4H and 8HO groups, respectively. In contrast, 1AO, 4AO and 8AO groups more induced HSP72 than 1A, 4A and 8A groups, respectively. These results suggest that the reoxygenation is beneficial after slight hypoxia but detrimental after severe hypoxia.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.7-14
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• 2001

Purpose : The lateral cephalometric Korean norms of the skeletal and pharyngeal dimension were analyzed for the diagnosis of obstructive sleep apnea syndrome(OSAS). Materials and Methods : The lateral cephalometric radiographies were taken in male(n=53) and female(n=50), who had a normal profile, class I occlusion, normal ANB $(0{\sim}4^{\circ})$ and normal Wits $Appraisal(-4{\sim}0mm)$. The X-rays were traced by two oral and maxillofacial surgeons twice. The significant differences between male-female and examiners were tested. Results : The angle of mandibular line to Nasion-Sella line was $31.12^{\circ}/33.79^{\circ}$ (in male/in female, p=0.0018). The lower Gonion angle was $73.74^{\circ}/73.74^{\circ}(p=0.9978)$. The length of the soft palate was 36.93mm/34.35mm(p=0.0002). The pharyngeal airway space was 13.42mm/11.55mm at mandibular plane level(PAS(ML))(p=0.0025). The hyoid was placed inferiorly to mandibular plane 10.18mm/7.72mm(p=0.0051). The results from this study are to be used for the diagnosis of OSAS.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.58.1-58.8
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• 2019

Background: The aim of this study is to investigate the relationship between gender-specific and obesity-related airway anatomy in patients with obstructive sleep apnea (OSA) by using cephalometric analyses. Methods: We retrospectively evaluated 206 patients with suspected OSA undergoing polysomnography and anthropometric measurements such as body mass index, neck circumference, and waist-hip ratio. We checked lateral cephalometry to measure tissue landmarks including angle from A point to nasion to B point (ANB), soft palate length (SPL), soft palate thickness (SPT), retropalatal space (RPS), retrolingual space (RLS), and mandibular plane to hyoid (MPH). Results: Male with OSA showed significantly increased SPL (P = .006) compared with controls. SPL and MPH had significant correlation with apnea-hypopnea index (AHI) and central obesity. Female with OSA showed significantly increased ANB (P = .013) and SPT (P = .004) compared with controls. The receiver operating characteristic curves revealed that SPT in male and ANB and SPT in female were significant in model 1 (AHI ≥ 5) and model 2 (AHI ≥ 15). MPH was also significant for male in model 2. Conclusion: Male and female with OSA had distinct anatomic features of the upper airway and different interactions among soft palate, mandible, and hyoid bone.

• Imaging Science in Dentistry
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• v.46 no.3
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• pp.167-171
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• 2016

Purpose: Obstructive sleep apnea (OSA) is a common medical disorder with serious complications if untreated. Dentists play a vital role in the early diagnosis of this condition, thereby improving patients' prognoses. The purpose of this study was to identify patients with a high risk of OSA using simple cephalometric measurements in patients receiving routine dental care. Materials and Methods: The present study was conducted on 206 patients divided into a high-risk group and a control group after answering the Berlin questionnaire. Cephalometric analysis of a digital cephalogram was performed to measure the upper airway diameter (UAD) and mandibular-to-hyoid bone distance (MP-H) by 2 observers at 2 different times. Results: Among 206 patients, 93 (45%) were included in the high-risk group and 113 (55%) were in the control group. No significant difference was present between the groups with regard to gender, and the patients ranged in age from 18 to 65 years. The UAD measurements in the high-risk group were significantly lower than in the control group, and the MP-H measurements were significantly higher in the high-risk group than in the control group. The UAD was lower in middle-aged patients in both groups. Conclusion: Our study found that the UAD was lower in individuals with a high risk of OSA. Also, we found that middle-aged individuals of both genders were more likely to develop OSA. Dentists play a vital role in diagnosing patients at a high risk for OSA via thorough clinical examinations, risk factor analyses, and simple cephalometric analyses.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.113-123
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• 2020

Obstructive sleep apnea (OSA) among sleep disorders is one of relatively common diseases. Patients can be checked for the disease through sleep polysomnography. However, as far as he diagnosis of OSA using polysomnography (PSG) is concerned, many practical problems such as an increasing number of patients, expensive testing cost, discomfort during examination, and the limited number of people for testing have been pointed out. Accordingly, for the purpose of substituting PSG researchers have been actively conducting studies on OSA diagnosis based on machine learning using bio signals. In this regard, we review a rich body of existing OSA diagnosis studies applying machine learning techniques based on bio-signal data. As a result, this paper presents a novel taxonomy of the reviewed studies and provides their comprehensive comparative analysis results. Also, we reveal various limitations of the studies using the bio signals and suggest several improvements about utilization of the used machine learning methods. Finally, this paper presents future research topics related to the application of machine learning techniques using bio signals.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.201-209
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• 2014

Obstructive sleep apnea syndrome(OSAS) is a respiratory disease caused by partial or complete obstruction of the upper airway during sleep. In this paper, we proposed the optical flow method to analyze the upper airway dynamic changes during respiration for children with OSAS and control subjects. We compared the absolute value of difference between inspiration and expiration for airway area analysis method and optical flow method for 5 children with OSAS and 6 control subjects. From the statistical analysis, airway area analysis method and optical flow method are statistically significant at the 0.1 (p value is 0.0977) and 0.01 (p value is 0.0011) significance level respectively. From this simulations, the optical flow method could provide more accurate information to diagnose the OSAS patients than the traditional airway area analysis method.