Bilateral Narrow Internal Auditory Canal With Duplication: High Resolution CT And MRI Findings

Inner ear malformations account for only 20 % of cases of congenital sensorineural hearing loss.A narrow internal auditory canal (IAC) with duplication is a very rare congenital anomaly that can be associated with other malformative ear abnormalities. Identification and characterization of these abnormalities will be crucial for the proper management of patients.We report two cases of bilateral duplicated internal auditory canal with other associated inner ear anomalies.

Hearng loss in chronic renal failure patients / 대한내과학회지

OBJECTIVES: Hearing loss, mainly a sensorineural hearing loss (SNHL), was frequently observed in patient with chronic renal failure. Although several causes and prevalence of this hearing loss had been proposed, the etiology and prevalence are still controversial. The purpose of the present study was another study to determine the prevalence, type and comparative degree of hearing loss in chronic renal failure according to various parameters. METHODS: Subjects for this study were 39 patients with hemodialysis and 10 chronic renal failure patients before hemodialysis. Pure tone audiometry was performed and pure tone average(PTA) was estimated. At same time, pure tone threshold were estimated at the range from 250 to 500(low frequency range), from 1000 to 2000(middle frequency range) and from 4000 to 8000 Hz(high frequency range). Significant hearing loss of PTA as well as the significant loss in pure tone threshold of each frequency range was defined when the loss of hearing ability was 25dB more than the normal value. The effect of alteration in age, sex, hemoglobin, lipid profile, duration of hemodialysis, underlying diseases and ototoxic drugs were evaluated. RESULT: 1) The main type of hearing loss was SNHL and it was asymptomatic and progressive. The prevalence of SNHL by means of PTA was 76% in the patient with chronic renal failure. The SNHL of high frequency range(89%), SNHL of middle frequency range(18%) and SNHL of low frequency range (45%) were observed on the basis of the pure tone threshold. 2) There was no significant difference of SNHL according to various parameters of sex, hemoglobin, lipid profile, BUN, and underlying diseases except age. 3) The patients under hemodialysis exhibited the more SNHL over all frequency ranges than those without hemodialysis and there was the more SNHL in patients of more than 2 years of hemodialysis and those of less than 2 years of hemodialysis 4) Furosemide was significantly ototoxic in patients with chronic renal failure. CONCLUSION: The type of hearing loss was mainly sensori-neural and high tone loss. The degree was slight to moderate. The prevalence was the higher than expected. Regular hemodialysis treatment seems to affect hearing loss during even 2 years of treatment. Therefore, hearing loss appeared to be related to the duration of hemodialysis. The more precise and regular audiometric monitorings were recommanded in hemodilalysis patients.

Evaluation of factors affecting sensory neural hearing loss / 예방의학회지

Reports on a potential relationship between sensory neural hearing loss(SNHL) and cardiovascular or hematologic factor show that the results are controversial. A detailed analysis of risk factors in the development of SNHL was carried out in 3,050 non-noise exposed healthy worker. The mean hearing threshold of both ears at 500, 1000, 2000, 4000, 8000Hz was measured and the effect of age, possible cardiovascular risk factor and hematologic factor (blood viscosity and hemostatic factors) on SNHL were evaluated. First, each of these were associated with loss of hearing sensitivity when univariately and multivariatively analysed. In a multiple regression model, age, sex, body mass index, WBC and total cholesterol level were independently associated with the mean of hearing sensitivity decrease at 4000 and 8000Hz. Second, study subjects were divided into two group (normal vs SNHL) and we compare the possible risk between both groups, and analysed univariate and multivariative logistic model. In a multiple logistic regression model, age, sex, body mass index, WBC and total cholesterol level, total protein, platelet were independently associated with SNHL. Our results show that we have some reliable indices of susceptibility to SNHL using cardiovascular measures or biochemical factor, but future, more extensive studies are required.