噪音特性、年齡與暫時性聽力損失關係之實驗研究

The Experimental Study on the Relationship between Noise Character, Age and Noise-Induced Temporary Threshold Shift (NITTS)

本研究目的在探討不同噪音特性及年齡在不同噪音位準暴露下，所引起之暫時性聽力損失效應。研究採立意取樣選擇二個年齡層，分別為20、40 (±5)歲之自願者、無耳朵疾病史且無特殊噪音暴露經驗，並經檢查聽力正常者各為15及14人為研究對象，使其重複暴露在交通噪音及4k純音之85、90、95dB SPL等不同位準噪音下30分鐘，於實驗前及暴露後2分鐘測其聽力(TTS2)，並在95dB的交通噪音暴露後，測其不同時間（暴露2分、20分、40分、60分）的聽力，以了解其暫時性聽力損失的恢復情形。此外，The Reed-Muench也被應用於噪音暴露ED50之計算。結果發現暴露音源為純音者較交通噪音更能預測TTS，且有較典型之劑量反應。TTS2恢復時間以6KHz最慢，而ED50以40歲組純音暴露最低，在6KHz僅82.8dB。

The main purpose of the study was to understand the relationship between noise character, age and noise-induced temporary threshold shift (NITTS). For this purpose, 15 healthy people who are 20 years old and 14 healthy people who are 40 (±5) years old, were selected as the sample in the study. The subjects exposed to 30 mins traffic noise and 4kHz pure tone with 3 intensity levels of 85, 90, 95 dB SPL. Audiograms were taken before and after 2 min exposure to noise (TTS2). Recovery from noise-induced temporary threshold shift was also measured at various time (2, 20, 40, and 60 min, respectively) after a 30 min exposure to a traffic noise at 95 dB. The Reed-Muench method was used to calculate ED50 of noise exposure. The results were that exposed to the pure tone could predict TTS more than exposed to the traffic noise, and had more typical dose-response effect. The TTS2 recovery time at the 6 KHz is the slowest, and the 40 years old group exposed to the pure tone responsed the lowest ED50, at the 6 KHz only 82.8 dB.