Audiometric classification scales for HNIR in epidemiological surveillance programs

Abstract

Noise-Induced Sensorineural Hearing Loss (HNIR) is a type of progressive, irreversible and potentially disabling deafness due to prolonged exposure to noise, which worldwide affects 16% of exposed workers.1 The person with hearing loss suffers social isolation and depression at their communication capacity and intellectual production are limited, which compromises their quality of life and socialization.1 The HNIR ranks fourth among diagnoses of occupational disease in Colombia, being 6.3% of frequency in 2004 and according to FASECOLDA (Federation of Colombian Insurers) 5.5% in 2011.2 When there is intense and prolonged occupational exposure to noise, defined as exposure to more than 85 dB during the 8 hours of the working day a day and five days a week, it can Present the Permanent Auditory Threshold Change (CUAP). NIOSH refers to CUAP as any decrease of ≥15 dB in frequencies from 500 to 6000 Hz or 8000 Hz (optional), in either ear, with respect to baseline audiometry, which is maintained over time, without returning to the thresholds. Baseline.7 This concept is commonly referred to as the "NIOSH criterion" and is an indicator of the efficacy of hearing conservation programs in occupational health.4 The diagnosis of HNIR is configured when the audiometric pattern of an exposed person presents initial changes in frequencies. (3000, 4000 Hz or 6000 Hz) with recovery at the 8000 Hz frequency. After approximately 10 to 15 years of its onset, hearing loss spreads to the mid and low frequencies (conversational frequencies) and may even compromise the frequency 8000Hz. 3