Effect of Body Mass Index on Auricular Morphology and Auditory Functions

Abstract

In this study, we aimed to investigate the relationship between the body mass index (BMI) and the morphometric properties of auricula and its acoustic gain characteristics. A total of 45 participants between 18 and 45 years of age were enrolled into the study. Participants’ height and weight measurements were recorded for the BMI calculation. On both sides, the morphometric properties of the auricula were measured and recorded. Additionally, the participants were subjected to multidirectional dynamic real ear measurements (REMs) to specify the intensity and frequency values of the maximum hearing gain. Participants consisted of 24 women and 21 men. The mean BMI was 23.42. The mean auricular area was 22.70 cm2. Statistically significant positive correlation was found between the auricular area and BMI ( r = 0.427, P = .03). The mean postauricular sulcus angle was 20.99°. The mastoid-helix distance was 16.07 mm. There was no statistically significant correlation between BMI level and postauricular sulcus angle and mastoid-helix distance ( P > .05). The mean dynamic REM measurement was evaluated. The maximum acoustic gain at anterior, lateral, and posterior vectorial stimulation was calculated as 20.9, 24.2, and 20.7 dB Sound Presure Level (SPL), respectively. Statistically significant negative correlation was found between the three directions acoustic gain level and BMI in the statistical examination ( r = −0.365, r = −0.386, r = −0.453, respectively, and P < .05 for all). The results of acoustic gain frequency were 2967.4, 2963, and 2934 Hz, respectively. There was no statistically significant correlation between acoustic gain frequency and BMI ( P > .05). When participants were grouped according to their BMI, participants with a BMI >25 had a statistically significantly bigger auricular area and lower maximum acoustic gain when compared with those with BMI <25 ( P < .05). We found that the auricular area increased with BMI. We think that this is related to soft tissue thickening of the auricula related to high BMI. In addition, we found that the acoustic gain level decreased inversely with BMI. We believe that the decrease in acoustic gain is due to the increase of acoustic resistance after the increase of soft tissue thickness. In conclusion, we think that BMI has a negative effect on auditory function according to findings in our study.