Evaluation of vestibular functions and dual task performance in individuals with noise induced hearing loss

Noise- induced hearing loss (NIHL) frequently occurs in individuals exposed to noise. Individuals with NIHL work in difficult conditions at workplaces and often have to perform dual tasks at the same time. The aim of this study is to evaluate vestibular functions and dual task performance in individuals with NIHL. This study included 50 individuals with NIHL and 25 individuals who were exposed to noise but without hearing loss. Individuals with NIHL were divided into 2 groups according to pure tone avarage. Twenty-five individuals whose NIHL was between 20 dB and 40 dB were included in the 1. group and 25 individuals with whose NIHL was higher than 40 dB were included in the 2. group. Twenty-five healthy individuals who were exposed to noise but did not have hearing loss were determined as the 3. group (control group). To assess the vestibular functions of these individuals, one-leg standing test (OLST), functional reach test (FRT), timed up and go test (TUGT) and head impulse test (HIT) were performed. Also head shaking test, spontaneous nystagmus test and caloric test were performed with videonistagmography. Visual analog scale (VAS) was used to determine the level of individuals' imbalance complaints. In order to evaluate the dual-task performances of the individuals, individuals were given cognitive and motor tasks simultaneously with TUGT. Individuals with higher NIHL (group 2) had more abnormal caloric responses (p <0.05). In addition, these individuals performed worse in eyes closed OLST and cognitive and motor dual task tests (p <0.05). However, there was no difference between the groups in terms of HIT, spontaneous nystagmus test, head shaking test, TUGT, FRT, VAS and eyes open OLST (p> 0.05). It was found that individuals with higher NIHL (> 40 dB) had more vestibular deficit and had worse dual-task performance. Vestibular evaluation and dual-task performance assessment of factory workers with GBİK can provide useful information in determining the risk of falling and fall prevention strategies in these individuals.