Stimulus and Subject Factors Affecting Contralateral Suppression of Acoustic Reflexes

Abstract

Contralateral Suppression of Acoustic Reflex is used as a diagnostic tool to measure the functioning of the medial efferent auditory system. The study assessed the effect of different reflex eliciting signals and the ear and gender effect on contralateral suppression of acoustic reflexes. A clinical observational design was used to achieve the objective. 30 normal hearing subjects between age group of 17-30 years were randomly selected. A comparison between baseline acoustic reflex threshold and amplitude (at 10 dB SL) with the presence and absence of 40 dB SL white noise in the contralateral ear was recorded. The results of the study showed that there was suppression of acoustic reflex threshold and reflex amplitude for 500Hz, 1000 Hz, and 2000 Hz, low band noise, high band noise, broad band noise and clicks. However, there was no significant difference in the amount of suppression of acoustic reflex threshold and reflex amplitude across stimuli, gender and across left and right ears. The result of the study shows that there is no effect of different stimuli on contralateral suppression of acoustic reflexes. In addition, there was no ear effect and gender effect on contralateral suppression of acoustic reflexes. Further studies with all the stimuli on hearing impaired population are essential to know whether the method can be used for a larger clinical population.