Effect of efferent-induced changes on acoustical reflex: El efecto de los cambios eferentemente inducidos sobre el reflejo acustico

Abstract

The efferent auditory pathway is known to alter the cochlear electrical properties, at low stimulus levels. This study aims to identify the effect of activation of the efferent auditory pathway through contralateral wide- and narrow-band noise at high sound levels. Acoustical reflex threshold and acoustical reflex amplitude (at ART + 10 dB) were obtained at three frequencies (500 Hz, 1 kHz, 2 kHz) in 60 normally hearing subjects, in the presence and absence of contralateral wide-and narrow-band noise (centred around reflex activating stimuli) at 30 dB SL. Results showed a consistent reduction in amplitude, and an increase in threshold, for 1- and 2-kHz tones in the presence of contralateral wideband but not narrow-band noise. Results are discussed with reference to the electrical properties of the cochlea, and the response properties of the efferent auditory pathway and cochlear nucleus.

Evaluation of the Olivocochlear Efferent System Activation After Exposure to Music in Young Individuals

“…Another mechanism of the auditory system, which protects against acoustic trauma, is the acoustic Figure 1. The hearing threshold of young individuals before exposure to music, 30 min after exposure, and after 300 min reflex that enables the contraction of the stapes muscle and decreases the volume of the voice in the face of a high-intensity sound stimulus (37). The contralateral suppression of the acoustic reflex can be an indicator to assess the function of the efferent system in high-intensity sound stimuli, and this contralateral suppression may also be detected as an amplitude drop or threshold increase in the middle ear muscle reflex (38).…”

Effect of Visual Attention on Contralateral Suppression of Acoustic Reflexes

“…Therefore, to assess function of the efferent system in individuals with hearing impairment, the findings here suggest that, instead of contralateral suppression of OAE, use of contralateral suppression of acoustic reflexes would be advantageous. However, the amount of suppression seen for contralateral suppression of acoustic reflexes is small [10], and there is a need to enhance the effect size to increase the sensitivity of the test. The results of the present study suggest that the use of a controlled active visual task can improve the effect size, and strength of suppression, compared to the no task condition.…”

“…Słowa kluczowe: koncentracja wzrokowa • próg odruchów strzemiączkowych • amplituda odruchów strzemiączkowych • tłumienie • system słuchowy eferentny one cochlea can change afferent responses in the opposite ear, an effect mediated by medial efferent system [9][10][11].…”

“…The contralateral noise reduces the movement of outer hair cells in the ipsilateral ear (because of the inhibition induced by the efferent system) causing reduction in OAE amplitude. Kumar and Barman [10] reported that contralateral suppression of the acoustic reflex may also be used as an indicator to check the functioning of the efferent system. Contralateral suppression of the acoustic reflex can be determined by a decrease in the amplitude (or increase in the threshold) of the middle ear muscle reflex by a suppressor stimulus in the contralateral ear.…”

“…Contralateral suppression of the acoustic reflex threshold (CSART) or contralateral suppression of the acoustic reflex amplitude (CSARA) is more widely applicable to the clinical population, as the middle ear stapedius reflex can be elicited even when there is moderate or moderately severe sensorineural hearing loss [10]. Hence, it can be used as a powerful diagnostic tool (compared to contralateral OAE suppression) for assessing the efferent auditory pathway.…”