What is the stapedius muscle reflex?
The acoustic reflex, also known as the stapedius reflex refers to an involuntary muscle contraction of the stapedius muscle in response to a high-intensity sound sti- mulus.
What happens in stapedial reflex?
In acoustic reflex testing, acoustic immittance measures are used to assess the neural pathway surrounding the stapedial reflex, which occurs in response to a loud sound (70 to 90dB above threshold). The afferent limb of the stapedial reflex is the ipsilateral eighth nerve, which leads to the brainstem.
What is the acoustic reflex of the ear?
The acoustic reflex is the contraction of the stapedius muscle elicited by the presentation of an acoustically loud sound. When either ear is presented with a loud sound, the stapedius muscles on both sides contract.
What causes Stapedial reflex?
The objective finding is an abnormal growth of response with sound level. Typically the stapedius reflex is triggered by sound levels 60 dB louder than the hearing threshold. Thus, when the hearing thresholds are raised and yet the stapedius reflex is recruited at only 30–40 dB above, recruitment is identified.
What is the purpose of acoustic reflex?
Acoustic reflexes measure the stapedius and the tensor tympani reflex generated eardrum movement in response to intense sound. They can be helpful in checking for particular types of hearing loss in situations where patient reliability is questionable. They also occasionally point to central nervous system pathology.
How do you test for acoustic reflex decay?
Reflex decay test has been developed in order to diagnose tumor-induced pathologies involving and affecting the auditory nerve. This test is usually done by giving sound that is 10 dB over the contralateral acoustic-reflex threshold at 500 or 1000 hertz (Hz) for 10 seconds.
What is normal acoustic reflex?
People with normal hearing have an acoustic reflex threshold (ART) around 70–100 dB SPL. People with conductive hearing loss (-i.e. bad transmission in the middle ear) may have a greater or absent acoustic reflex threshold. The acoustic reflex threshold is usually 10–20 dB below the discomfort threshold.
How do you test for Stapedial reflex?
The stapedial reflex can be measured with laser Doppler velocimetry. Jones et al. focused a laser on the light reflex of the manubrium in awake human subjects. The amplitude of a 500 Hz probe tone was used to monitor the vibrations of the tympanic membrane.