The Characteristics of Tinnitus and Hearing Threshold: In Workers with Noise Induced Hearing Loss from a Hospital Setting / 대한산업의학회지

ABSTRACT

OBJECTIVES: This study was carried out to define the relationship between the characteristics of tinnitus and hearing threshold (puretone and speech) in workers with noise induced hearing loss (NIHL). METHODS: A total of 189 cases(378 ears) from workers with compensation claims for NIHL during 2004-2009 were investigated. Various factors, including age, work carriers, body mass index (BMI), blood pressure, noise exposure level of worksite hearing threshold, speech discrimination score, pitch match, and loudness of tinnitus were analyzed. RESULTS: The average hearing threshold of all subject was 44.2 dBHL, puretone audiometry thresholds in subjects with tinnitus were lower than the non-tinnitus group (except at 8000 Hz). Using speech audiometry, the tinnitus group showed a lower speech recognition threshold and speech discrimination score. The tinnitus group also had an average tinnitus frequency of 4195.2 Hz, loudness of 73.6 dB, and tinnitus sensation average of 6.0 dBSL. These frequencies of tinnitus were in the lowest puretone audiometry frequencies. Tinnitus loudness had a strong relationship with puretone and speech audiometry thresholds. CONCLUSIONS: In cases beyond moderate hearing loss, the tinnitus group had a better puretone (except 8000 Hz) and speech hearing status, and most comfortable loudness (MCL) level. In addition, puretone and speech audiometry thresholds increase with tinnitus loudness.