Introduction
The acoustic reflex (AR) describes the involuntary contraction of the stapedius tendon in response to high-intensity sound (Emanuel, 2009). An intricate neural network, receiving afferent input from the vestibulocochlear nerve and sending efferent output to the facial nerve, controls contraction (Emanuel, 2009). The reflex is intensity-dependent, as particular intensities cause the contraction. Once contracted, it lessens the vibrations traveling through the stapes footplate as it pulls the stapes away from the oval window, decreasing the energy to the cochlea and compliance (Emanuel, 2009). Furthermore, it is a bilateral phenomenon as stimulation in one ear evokes an AR in the opposite ear as well, involving contralateral and …show more content…
However, Lüscher conducted the first report of the AR in humans in 1930 using direct microscopic examination of the stapedius through a perforated tympanic membrane (Wilson et al, 1984). He observed sustained stapedius contractions in response to intense sound. Additionally, he noted the frequency-specificity of AR adaptation. This phenomenon was further supported by Kobrak, Lindsay and Perlman (1941) who studied stapedius contractions from high-intensity sound stimulation and the effects of frequency change (Wilson et al, …show more content…
The male participant involved in our study regularly smokes. It was found that smokers given nicotine prior to high-intensity sound exhibited significantly lower ARs when sound was stimulated (Lam et al, 2008). Therefore, if nicotine was used on the testing day, ARs could have been affected.
Silman and Gelfand (1981) studied the decreased growth of the AR magnitude in the elderly, compared to younger individuals. They compared ARs of 18 subjects under 30yearsold compared to those above 50yearsold (elderly) at a range of frequencies. They found the AR magnitude was significantly lower in the elderly, consistent with age-related changes in the auditory system and stapedius muscle. The participant tested was a 36yearold male, and therefore could have slower reflexes compared to someone under 30yearsold.
The aim of this study was to test ARs and compare results with the participant’s pure-tone thresholds. We hypothesise that sound stimulation at a sufficient intensity will evoke an AR response, measured by the minimum intensity required to elicit the response. Furthermore, the outcome may be useful to quantitatively estimate any hearing loss, as the participant’s pure-tone and AR thresholds will be
The acoustic reflex (AR) describes the involuntary contraction of the stapedius tendon in response to high-intensity sound (Emanuel, 2009). An intricate neural network, receiving afferent input from the vestibulocochlear nerve and sending efferent output to the facial nerve, controls contraction (Emanuel, 2009). The reflex is intensity-dependent, as particular intensities cause the contraction. Once contracted, it lessens the vibrations traveling through the stapes footplate as it pulls the stapes away from the oval window, decreasing the energy to the cochlea and compliance (Emanuel, 2009). Furthermore, it is a bilateral phenomenon as stimulation in one ear evokes an AR in the opposite ear as well, involving contralateral and …show more content…
However, Lüscher conducted the first report of the AR in humans in 1930 using direct microscopic examination of the stapedius through a perforated tympanic membrane (Wilson et al, 1984). He observed sustained stapedius contractions in response to intense sound. Additionally, he noted the frequency-specificity of AR adaptation. This phenomenon was further supported by Kobrak, Lindsay and Perlman (1941) who studied stapedius contractions from high-intensity sound stimulation and the effects of frequency change (Wilson et al, …show more content…
The male participant involved in our study regularly smokes. It was found that smokers given nicotine prior to high-intensity sound exhibited significantly lower ARs when sound was stimulated (Lam et al, 2008). Therefore, if nicotine was used on the testing day, ARs could have been affected.
Silman and Gelfand (1981) studied the decreased growth of the AR magnitude in the elderly, compared to younger individuals. They compared ARs of 18 subjects under 30yearsold compared to those above 50yearsold (elderly) at a range of frequencies. They found the AR magnitude was significantly lower in the elderly, consistent with age-related changes in the auditory system and stapedius muscle. The participant tested was a 36yearold male, and therefore could have slower reflexes compared to someone under 30yearsold.
The aim of this study was to test ARs and compare results with the participant’s pure-tone thresholds. We hypothesise that sound stimulation at a sufficient intensity will evoke an AR response, measured by the minimum intensity required to elicit the response. Furthermore, the outcome may be useful to quantitatively estimate any hearing loss, as the participant’s pure-tone and AR thresholds will be