Audiological diagnosis of hearing loss in individuals exposed to industrial noise

Abstract

Introduction Noise has direct harmful effects on hearing, leads to hearing loss and disables communication. To prevent disability, certain measures must be taken, audiological selection of susceptible individuals. Objective Our aim was to show the clinical usefulness of supraliminal tests (Tone Decay Test, Reflex Decay Test) on workers exposed to industrial noise. Method Research method involved 50 workers who were exposed to industrial noise their entire working life (experimental group) and the same number of unexposed workers (control group). Both groups were conducted by non-invasive diagnostic methods: medical history, ENT examination and audiological testing (liminal tonal audiometry, audiometry and tympanometry supraliminal with registration of stapedial reflexes), before the start of working hours exposure to industrial noise. Results There was a statistically significant difference (p = 0.024) correlated to pathological audiogram according to the length of service in the group exposed to noise above 20 years (48%). Pathological audiogram is dominant in both groups in age from 41-50 years with 45%, so that correlated with length of service over 20 years, we see statistically significant differences. Sensorineural hearing lossis dominating in the experimental group with the fall of hearing of 41-60dB (34%), while in the control group 72% has normal hearing. Cochlear damage is found in 90.5% of the experimental and control 100% damage grupe. Both sided hearing impairment is present at 84% of the experimental and 75% of the control group. The presence of skotoma 4KHz in the experimental group with SN hearing loss was 90.5%, Tone Decay Test was positive in 32% of the experimental and 4% of the control group - a sign of retrocochlear lesion or hypersensitive hearing. Fatigue acoustic reflex (Reflex Decay Test), an indicator in forecasting impact of noise on bearing represented a 100% in the experimental group and 75% in the control group of patients with hearing impairment. Conclusion Audiological tests should be introduced into clinical practice during periodic examinations of workers exposed to industrial noise to prevent disability.