Noise-induced hearing loss (NIHL), an irreversible disorder, is a common problem in industrial settings. Early diagnosis of NIHL can help prevent the progression of hearing loss, especially in speech frequencies. For early diagnosis of NIHL, audiometry is performed routinely in conventional frequencies. We designed this study to compare the effect of noise on high-frequency audiometry (HFA) and conventional audiometry. In a historical cohort study, we compared hearing threshold and prevalence of hearing loss in conventional and high frequencies of audiometry among textile workers divided into two groups: With and without exposure to noise more than 85 dB. The highest hearing threshold was observed at 4000 Hz, 6000 Hz and 16000 Hz in conventional right ear audiometry, conventional left ear audiometry and HFA in each ear, respectively. The hearing threshold was significantly higher at 16000 Hz compared to 4000. Hearing loss was more common in HFA than conventional audiometry. HFA is more sensitive to detect NIHL than conventional audiometry. It can be useful for early diagnosis of hearing sensitivity to noise, and thus preventing hearing loss in lower frequencies especially speech frequencies.

Conventional Audiometry, Extended High-Frequency Audiometry, and DPOAE for Early Diagnosis of NIHL - Iranian Red Crescent Medical Journal - - Kowsar

Purpose : The present study aimed to investigate the relationship between shift work and cognitive performance in nurses. Materials and Methods : The present before-after study was performed on 35 female nurses 25-40 years old with similar mental and physical workload. Working memory, response time and attention were assessed using Wechsler and Stroop tests. The variables were measured at the beginning and the end of working shifts in three shifts (morning, afternoon and night). An interval of 3 days was considered for performing after-shift test to eliminate the learning effect. Data were analyzed using repeated measures analysis of variance (ANOVA) . Results : At the end of all three shifts, nurse's working memory (P = 0.039) and interference score (P = 0.04) were significantly decreased, but response time was not significantly affected during a shift. The decrease in working memory after night shift was significantly higher than morning and evening shifts (P <0.001). Conclusion : The results of this study showed that shift work can affect some aspects of cognitive function (working memory and attention) in nurses, and this effect was more prominent after a night shift.