Long-Term Outcomes of Acute Low-Tone Hearing Loss

노경진,이은정,박아영,최병일,손은진 대한청각학회 2015 Journal of Audiology & Otology Vol.19 No.2

Background and Objectives: Although acute low-tone hearing loss has been associated with cochlear hydrops or early stage Meniere’s disease, its prognosis in the short-term has been reported to be better than sudden hearing loss. However, recurrence of hearing loss and possible progression to Meniere’s disease remain important concerns in the clinical setting. This study aims to investigate the long-term audiological outcomes of acute low-tone hearing loss. Subjects and Methods: A retrospective review of patients presenting with a first attack of acute low-tone hearing loss was performed. Of the 77 patients, 33 were followed up for more than 3 months. Progression, recovery of hearing loss and recurrence of hearing loss were examined. Also, correlation between long-term outcomes and associated clinical factors were analyzed. Results: Twenty-five patients (75.7%) had complete hearing recovery, five patients (15.1%) had partial recovery, two patients (6.0%) had no recovery, and one patient (3.0%) had progression of hearing loss 1 month after initial treatment. Thirty-three patients were followed up for more than 3 months (mean 22 months, range 3-79 months). Recurrences of acute low-tone hearing loss were observed in five patients (15.2%). All of the recurrences occurred during the first 12 months of follow-up. Long-term prognosis correlated with the initial therapy results (R2=0.693). Conclusions: Recurrences of hearing loss were documented in five patients (15.2%), and all of these cases occurred within one year of the first attack. Audiological outcomes after initial therapy may predict the recurrence of acute low-tone hearing loss.

일측성 청력 감소를 동반한 반복된 어지럼 환자의 청력도에 따른 임상양상의 차이

박영민,김동현,김봉직,이정구,정재윤 대한이비인후과학회 2015 대한이비인후과학회지 두경부외과학 Vol.58 No.3

Background and Objectives Low frequency hearing loss is known to be the most common hearing loss form in Meniere’s disease (MD) and episodic dizziness with low frequency sensorineural hearing loss is considered a very crucial symptom for the diagnosis of MD. However, flat or high frequency hearing loss is also commonly encountered in the Ear, Nose and Throat clinic. The aim of this study is to investigate the differences in clinical manifestation between episodic dizzy patients with low frequency hearing loss (LFHL) group and non-low frequency hearing loss (non-LFHL) group. Subjects and Method We reviewed medical records of 78 patients (36 of LFHL group and 42 of non-LFHL group) who had episodic dizziness with unilateral hearing loss and analyzed clinical characteristics according to hearing loss pattern. Results The clinical features of LFHL include a predominance of female sufferers, high incidence of tinnitus and short duration of dizziness. There was no significant difference in frequency, nature of dizziness, and results of vestibular function test. Although the proportion of patients diagnosed with definite MD was higher in LFHL group at initial and final diagnosis, there were no statistically significant differences between two groups. Conclusion Therefore, when episodic dizziness is accompanied with unilateral hearing loss, not only low frequency but flat or high frequency hearing loss could be considered as a critical sign for possible progression to Meniere’s disease and careful observation should be taken.

Effect of bodybuilding athletes’ weight loss method on performance factors and immune function

Jung-Hwan Kim,Jun-Su Kim 한국운동재활학회 2023 JER Vol.19 No.6

This study was conducted on elite bodybuilders for 6 weeks using two weight loss methods (traditional method=high-weight loss vs. new method=low-weight loss). The subjects of this study were 26 male ac-tive elite bodybuilders who voluntarily wanted to participate in this ex-periment, and were divided into experimental group and traditional group. The traditional and experimental groups underwent dietary re-strictions and training for 6 weeks. The conclusion obtained from the results of this study is that in the case of anthropometric variables, there is a difference in weight class between the two groups. The ex-perimental group’s upper arm circumference was maintained com-pared to the pre-measured value after post-measurement, while the traditional group decreased, and a significant interaction effect was observed. In particular, a significant interaction effect was observed. In that the absolute value of maximum oxygen intake was significantly in-creased only in the post-experimental group compared to the pretest, and an interaction effect was observed, the use of low-weight loss method is more effective than the traditional method of high-weight loss method. An increase in some cytokines was observed despite tradition-al weight loss, but it did not cause an excessive decrease in immunity or a sharp decrease in performance factors. As a result of this experi-ment, it is judged that the use of a low-weight loss method is more pref-erable than the traditional high-weight loss method in relation to perfor-mance variables.

급성 저주파 감각신경성 난청에서 스테로이드 용량에 따른 단기적 치료 효과 비교

이세아,이승재,정도영,김보경,이치규,최성준,이병돈,황규린,이종대 대한이비인후과학회 2018 대한이비인후과학회지 두경부외과학 Vol.61 No.4

Background and Objectives Acute low-tone sensorineural hearing loss refers to a condi-tion wherein thresholds increase only at low frequencies in pure-tone audiometry. Systemic steroid treatment is commonly used for acute low-tone sensorineural hearing loss without ver-tigo, but there has been no established treatment in most clinical researches. The purpose of this study is to compare and analyze the short-term effects of high- and half-dose oral steroid therapy on patients suffering from acute low-tone sensorineural hearing loss without vertigo. Subjects and Method Forty-six patients diagnosed with acute low-tone sensorineural hear-ing loss were divided into two groups and treated with high-dose (24 patients) and half-dose (22 patients) steroids, respectively. A retrospective analysis was conducted on their medical records. Results There were no significant differences between the two groups in any of the follow-ing: age, sex ratio, duration of symptoms before treatment, pure-tone hearing thresholds, low frequency hearing thresholds and speech intelligibility. However, both groups showed signifi-cant differences in hearing thresholds before and after treatment. In addition, no significant difference was noted in the recovery and recurrence rate between the two groups.Conclusion According to the results of this study, there is no difference in treatment effect between the high- and half-dose groups. Therefore, half-dose steroids may be used as a treat-ment option for acute low tone sensorineural hearing loss.

극소 저체중 출생아에서 청력 손상에 영향을 미치는 요인: 1,500 g미만의 청력 검사 결과

성민정,한영미,박경희,이일우,변신연 대한신생아학회 2011 Neonatal medicine Vol.18 No.2

Purpose: An association between very low birth weight infants(VLBWI) and hearing loss has long been recognized. Early identification and intervention for hearing loss benefits language and speech/cognitive development. We investigated the risk factors and clinical outcomes of hearing loss among VLBWI. Methods: We analyzed the results of auditory brainstem response (ABR) testing of VLBWI. These infants were admitted to the neonatal intensive care unit (NICU) of Pusan National University Yangsan Hospital between December 2008 and February 2011. A follow-up was conducted subsequently. Results: ABR evaluations were performed on 65 infants, and 31 showed abnormal results (47.7%). Among the 31 infants, 10 were classified with moderate/severe/profound hearing loss (15.4%). The infants with abnormal ABR had a higher incidence of low birth weight, prolonged ventilator care, cumulative dose of furosemide, and the lowest PaO_2 (P<0.05). Those with moderate/severe/profound hearing loss had a higher incidence of low Apgar scores at 5 minutes (odds ratio[OR],0.34; 95% confidence interval[CI],0.13-0.89), prolonged ventilator care (OR,1.06; 95% CI,1.01-1.12), and mild hearing loss compared to those without profound hearing loss. Follow-up evaluations on eight infants with ABR reveled improvements 5.6±3.9 months later. One infant, who had profound hearing loss in both ears, used a hearing aid. Conclusion: Factors influencing hearing loss at the first VLBWI hearing screening test included lower Apgar scores at 5 min and prolonged use of a ventilator. Most VLBWI with hearing losses were expected to recover after several months of follow-up. 목적: 양측 고도 난청은 신생아 집중치료실에서 치료를 하였던 신생아나 미숙아인 경우 위험률이 증가한다. 이에 저자들은 1,500 g 미만으로 출생한 미숙아를 대상으로 난청을 유발할 수 있는 인자들을 알아보고자 하였다. 방법: 2008년 12월부터 2011년 2월까지 부산대학교 어린이병원 신생아 중환자실에 입원한 1,500 g 미만의 미숙아 65명을 대상으로 난청의 위험 인자들의 의무 기록을 후향적으로 조사하였다. 청력 검사는 교정 연령 37주 이상이 되었을 때 ABR로 시행하였으며, 처음 검사에서 정상 청력인 환아와 난청인 환아로 분류하였다. 결과: 65명의 환아 중에서 34명은 정상으로 나왔고, 31명은 난청을 보였다(47.7%). 난청을 보인 환아 중에서 일상 생활에 지장을 주는 중도 이상의 난청을 가진 환아는 10명(15.4%) 이었다. 이들의 위험인자를 비교해본 결과 비정상군에서 청력 검사를 시행했던 시기가 늦었고, 출생 체중이 적었으며, 기계 환기를 했던 기간이 길었고, 생후 1주일간 동맥혈 가스 분석 결과 최저 산소 분압이 낮았고, 이뇨제의 누적 용량이 의미 있게 많았다 (P<0.05). 이 위험 인자를 경도 난청과 중/고도 난청/농으로 나누고 출생 체중으로 보정한 다인자 분석을 하니 5분 Apgar 점수가 증가할 때마다 중/고도 난청/농의 가능성은 낮아지고 (OR=0.34, 95% CI: 0.13-0.89), 기계 환기의 기간이 길어질 때마다 중/고도 난청/농의 가능성은 증가하였다(OR=1.06, 95% CI: 1.01-1.12). 31명의 난청 환아 중에 추적 검사를 시행한 17명 중 16명이 호전을 보였고(94.1%), ABR로 재검을 한 8명 중 7명은 호전이 될 때까지 평균 5.6개월이 소요되었으며, 1명만이 양측 농으로 나와 보청기를 착용하였다. 결론: 1,500 g 미만의 미숙아에게 처음 시행한 청력 선별 검사에서 중도 이상의 난청에 영향을 미치는 인자들은 낮은 5분 Apgar점수와 장기간의 인공 호흡기 사용이었고, 대부분이 5-6개월 이내에 청력에 호전을 보여 수개월간은 추적 검사를 시행하면서 회복되기를 기다려도 될 것으로 생각된다.

저 레이놀즈 수가 압축기 성능에 미치는 영향

최민석(Minsuk Choi),백제현(Je Hyun Baek),오성환(Seong Hwan Oh),고한영(Han Young Ko) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-

A three-dimensional computation was conducted to understand effects of the low Reynolds number on the performance in a low-speed axial compressor at the design condition. The low Reynolds number can originates from the change of the air density because it decreases along the altitude in the troposphere. The performance of the axial compressor such as the static pressure rise was diminished by the separation on the suction surface and the boundary layer on the hub, which were caused by the low Reynolds number. The total pressure loss at the low Reynolds number was found to be greater than that at the reference Reynolds number at the region from the hub to 90% span. Total pressure loss was scrutinized through three major loss categories in a subsonic axial compressor such as profile loss, tip leakage loss and endwall loss using Denton's loss model, and effects of the low Reynolds number on the performance were analyzed in detail.

저탄수화물 고지방 다이어트의 효과

김정환 대한비만학회 2016 The Korean journal of obesity Vol.25 No.4

It appears that a low-carbohydrate high-fat diet is more effective in weight loss than conventional low-fat diets for short-term periods of approximately 6 months. However, for long-term periods of about 1 year or more, the effects of a low-carbohydrate diet are reduced and the difference in weight loss between low-carbohydrate and low-fat diets disappears. A low-carbohydrate diet can lead to low triglycerides and high HDL cholesterol, and may even lead to an increase in LDL cholesterol. The effects of a low-carbohydrate diet on glycemic control are not clear, and there is no effect on blood pressure. A low-carbohydrate diet may lead to cardiovascular disease, and can increase cardiovascular and all-cause mortality. 저탄수화물 고지방 다이어트는 전통적인 저지방 다이어트에 비해 체중 감량 면에서는 단기간의 체중 감량 효과가 더 크지만 장기적인 체중 감량이나 체중 유지 효과는 거의 없는 것으로 보인다. 지질 대사에 있어서 중성지방의 감소와 HDL 콜레스테롤의 증가에는 뚜렷하게 효과를 보이지만 총 콜레스테롤과 LDL 콜레스테롤은 차이가 없거나 저지방 다이어트에 비해 효과가 나쁜 경우도 있고 때로는 안 좋은 영향을 미치는 경우도 있다. 저탄수화물 다이어트의 혈당 강하 효과도 일부 긍정적인 효과를 기대해볼 수도 있지만 뚜렷하지는 않고 혈압 조절에서는 영향이 없다. 전체 심혈관질환의 위험으로 보면 저탄수화물 다이어트가 사망률의 증가의 보고가 있어 조심하여야 한다.

저 레이놀즈 수가 압축기 성능에 미치는 영향에 대한 수치적 연구

최민석(Minsuk Choi),백제현(Je Hyun Baek),정희택(Hee Taeg Chung),오성환(Seong Hwan Oh),고한영(Han Young Ko) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.2

A three-dimensional computation was conducted to understand effects of the low Reynolds number on the performance in a low-speed axial compressor at the design condition. The low Reynolds number can originates from the change of the air density because it decreases along the altitude in the troposphere. The performance of the axial compressor such as the static pressure rise was diminished by the separation on the suction surface with full span and the boundary layer on the hub, which were caused by the low Reynolds number. The total pressure loss at the low Reynolds number was found to be greater than that at the reference Reynolds number at the region from the hub to 85% span. Total pressure loss was scrutinized through three major loss categories in a subsonic axial compressor such as the profile loss, the tip leakage loss and the endwall loss using Denton's loss model, and the effects of the low Reynolds number on the performance were analyzed in detail.

Effects of Low Reynolds Number on Loss Characteristics in Transonic Axial Compressor

CHOI, Minsuk,BAEK, Je Hyun,PARK, Jun Young,OH, Seong Hwan,KO, Han Young THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIEN 2010 Transactions of the Japan Society for Aeronautical Vol.53 No.181

<P>A three-dimensional computation was conducted to understand effects of low Reynolds numbers on loss characteristics in a transonic axial compressor, Rotor 67. As a gas turbine becomes smaller and it operates at high altitude, the engine frequently operates under low Reynolds number conditions. This study found that large viscosity significantly affects the location and intensity of the passage shock, which moves toward the leading edge and has decreased intensity at low Reynolds number. This change greatly affects performance as well as internal flows, such as pressure distribution on the blade surface, tip leakage flow and separation. The total pressure ratio and adiabatic efficiency both decreased by about 3% with decreasing Reynolds number. At detailed analysis, the total pressure loss was subdivided into four loss categories such as profile loss, tip leakage loss, endwall loss and shock loss.</P>

Implementation of Low Loss Radome with Hexa mesh for Ku-Band

Seo Kang,JeongJin Kang 국제문화기술진흥원 2022 International Journal of Advanced Culture Technolo Vol.10 No.4

In this study, the insertion loss and phase delay according to the multi-layer structure radome parameters were analyzed using the boundary value solution approach, and the multi-layer structure and hexa mesh structures with low-loss electrical characteristics for the Ku-band transmission/reception frequency of 10.7 ~ 14.5 GHz were designed and manufactured. A hexa mesh was applied to minimize radio wave transmission and scattering, which lowered the transmittance refractive index according to the radio incident angle and minimized dielectric loss through high-density foam. Similar to the simulation result, the transmission loss obtained the gain in a specific receiving frequency band, and in the transmission frequency band, an excellent low loss characteristic was obtained with an insertion loss of 0.8dB or less. The results of this study can be used in radio transmission radomes of low-weight, low-cost end-system protection devices.