An Investigative Study on Cognitive Decline among Textile Industry Workers with Occupational Noise-Induced Hearing Loss

Abstract

Background and Aim: Occupational noise exposure is considered the second most common risk factor in the industry, which results in auditory and non-auditory health effects. The possibility of cognitive decline as one of the non-auditory health effects may be associated with noise-induced hearing loss (NIHL). This study aimed to investigate the cognitive decline among textile workers with NIHL.
 Methods: A total of 30 male textile workers (mean age: 41.2±4.1 years and mean years of noise exposure: 18.9±5.4 years) with symmetrical NIHL (mean 49.3±4.5 dB at 4 kHz) and 30 healthy male textile office staff (aged-matched) with normal hearing and no history of noise exposure were included in this study. Exclusion criteria were included any deficit in ear function, neurological problems, and head trauma. Hearing thresholds were obtained by air and bone conduction audiometry. Workers’ cognitive performance was investigated by two psychological tests: Corsi block and Stroop tests.
 Results: The Corsi block indicators including block span (p=0.022) and visuospatial working memory (p=0.002) showed a significant difference between the two groups. Also, the Stroop test indicators including total test time (p<0.001) and response time (p<0.001) showed a significant difference between the two groups. Multiple linear regression analyses showed that workers with a higher hearing threshold at 3 kHz had a lower cognitive performance from both tests.
 Conclusion: Our findings support the role of NIHL as a risk factor of developing cognitive decline in textile workers.
 Keywords: Cognitive decline; noise-induced hearing loss; industrial worker; Corsi block test; Stroop test