An Epidemiologic & Audiometric Study of Noise-Induced Hearing Loss in Subway Workers / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There is no effective treatment for noise-induced hearing loss (NIHL), and for this reason, prevention is very important. The purpose of this study is to investigate the epidemiologic and audiometric properties of NIHL in subway workers. MATERIALS AND METHODS: This study included 10,792 employees who have worked in the subway. Their hearing acuity was screened out by pure tone audiometry for 1 K & 4 KHz. Of the employees, those whose hearing loss was not caused by noise were excluded from the study and the remaining 665 employees were investigated. The epidemiologic and audiometric properties were investigated on the basis of their ages and working durations. RESULTS: Among the 10,792 employees, 665 (6.2%) showed NIHL. The risk of NIHL increased significantly in individuals who had worked more than 5 years. At 4 KHz, the hearing threshold shift occured within 5 years, then reached a plateau. But below 2 KHz, it progressed gradually, becoming prominent after 10 years of noise exposure. CONCLUSION: We suggest that prevention from exposure to noise is necessary for individuals whose working duration is more than 5 years.

A Case of Monostotic-Type Fibrous Dysplasia in the Sphenoid Sinus / 대한이비인후과학회지

Fibrous dysplasia is a rare fibro-osseous lesion characterized by replacing the skeletal structure. Its main feature is the involvement of one or several bones of the skeletal and extra-skeletal systems. Fibrous dysplasia arising in the paranasal sinus is rare, especially in the ethmoid and sphenoid sinuses. Only one case of fibrous dysplasia originating in the sphenoid sinus have been reported in the regional and international literature. Recently we experienced a case of monostotic fibrous dysplasia which derived from the sphenoid sinus in a 33-year-old female. So the case will be discussed with literature review.

Audiometric Changes after Ventilating Tube Insertion in Middle Ear Effusion / 대한이비인후과학회지

Audiometric and clinical findings of 90 patients(146 ears) who were suffered from otitis media with effusion and were treated by tympanostomy tube placement at KangNam General Hospital from Apr. 1994 to Jun. 1996 were analyzed. The results were follows; 1) Sex distribution shows 52 males and 38 females. Age distribution is 4 to 81, and fifty-one percent of them are younger than 9-year-old. 2) Pre-operative pure tone average was 27.1dB in air conduction and 20.6dB in air-bone gap. Post-operative pure tone average of air conduction and air-bone gap was average 12.6dB and 7.5dB at 13th day and 9.3dB and 5.6dB at 44th day after v-tube insertion, respectively. 3) For patients younger than 9-year-old, pre-operative average air conduction threshold was lower and air-bone gap was smaller than that of older age groups. But there are no significant difference of post-operative changes between younger than age of 9 and age between 10-19. 4) There are no significant differences among the groups with different nature of effusion in pre-operative hearing threshold. However the hearing threshold changes in air conduction and air-bone gap were larger in mucoid group than serous one. 5) There are no differences in the pre-operative hearing among the groups with different amount of effusion, but changes of post-operative hearing threshold was bigger in large amount group. 6) The incidence of post-operative otorrhea was 15%(22 ears) and its incidence was higher in mucoid group than serous one.