Impact of Industrial Noise-Induced Hearing Disorders on Workers Cognition and Auditory Memory

Hearing loss and tinnitus are two auditory effects of hearing system damage due to occupational noise exposure. These factors can have non-auditory effects by themselves and impact on brain cognitive performance. In our study، the effect of occupational noise-induced hearing loss and tinnitus on cognition and auditory-verbal memory was investigated. Our study was done on 42 male workers aged 40 to 56 years in three groups of workers with 1) hearing loss، 2) hearing loss and tinnitus and 3) normal hearing. Workers in two first groups had a long history of working in environments with excessive noise، and third group was matched control workers with normal hearing. Hearing impaired persons had symmetrical moderate falling sensory-neural hearing loss in the both ears. For all subjects، Mini-Mental State Examination and Rey Auditory-Verbal Learning Tests were performed in identical conditions. Normal hearing group had higher scores in all stages of the Rey Auditory-Verbal Learning test than two other groups and their means differences in three A1، Sum and Recognition stages were significant (p≤0. 034). Similar finding was observed in the Mini-Mental Examination test too (p≤0. 025). Our study revealed effect of noise induced hearing loss and tinnitus due to prolonged exposure to noise over the limit on general cognition and auditory-verbal memory. Given the preventable nature of auditory and non-auditory effects of occupational noise، administration and control of hearing conservation programs and training of workers can be the suitable and proposed solution.