ABSTRACT
OBJECTIVE To investigate and analysis of hearing status and characteristics of China civil aviation air traffic controllers(ATC). METHODS With cluster random sampling, air conduction threshold data of 1498 ATC, who had finished the class Ⅲa medical assessment this year in a certain area were studied. The subjects were tested by pure tone audiometry, the prevalence rate of speech and high frequency hearing loss between gender groups were compared; After age correction, the threshold of different frequencies were compared between age groups. RESULTS The prevalence rate of hearing loss at speech frequency was 6.68％ in male and 1.97％ in female. The result of high frequency was 7.87％ and 1.23％ respectively. Both the threshold and prevalence rate of hearing loss of every frequency were higher in male(P<0.05); The threshold of 3000 Hz<PTA<6000 Hz; After age correction, all the threshold had statistical difference between the former age groups(P<0.05) and the result of relatively young age group was worse than the elder. (Male: corrected P<0.0083, Female: corrected P<0.017). CONCLUSION The prevalence of hearing loss in the subjects was lower than that in general population. Males were prone to it and more prevalent at 6000 Hz; The hidden trouble of noise-induced hearing loss is especially serious in the young age group; Individualized hearing protection should be implemented early.
ABSTRACT
Objective To study extended high frequency (EHF) audiometry for early detection of hearing loss in student pilots in civil aviation.Methods A total of 175 student pilots (all male,18~25 years old, mean 20.2±0.92 years) from a university flight academy were surveyed and underwent EHFA.All subjects had hearing thresholds ≤25 dB HL at conventional frequencies (0.25~8 kHz).The results were compared with the corresponding recommended standards in other countries.According to the use of personal listening devices, all the subjects were divided into the low risk group (non-use, 121 cases) and the high risk group (using>1 year, day>1 hour, 52 cases).The differences of hearing thresholds and detection rates at EHF between the two groups were compared.Results The hearing thresholds of 173 subjects (1 case of middle ear disease and 1 case with family history of hearing loss were excluded) at 9~20 kHz were slightly higher than the reference equivalent threshold sound pressure level (RETSPL) prescribed by American National Standardization Association and the age-matched thresholds recommended by a foreign literature (P<0.05 or P<0.01).The hearing thresholds in the high risk group elevated dramatically than that in the low risk group at 9,12.5,16 and 18 kHz(P<0.05 or P<0.01).As frequencies increased, the detection rate of hearing thresholds in the high risk group decreased gradually, and at 18 and 20 kHz it was significantly lower than that in the low risk group (P<0.01).Conclusion EHF audiometry is a helpful tool for early detection of noise-induced hearing loss in student pilots.Hearing health care should be emphasized in civilian student pilots.It is recommended to avoid the use of personal listening devices or reduce the use time of them.