Acoustic reflex

Acoustic reflex or stapedius reflex is an involuntary muscle contraction that occurs in the middle ear in response to loud sound stimuli or when the person starts to vocalize.

Overview

When an extremely loud sound is heard, the tympanic membrane vibrates more intensely. In response to this, the stapedius muscle in the middle ear contracts. This contraction leads to a reduction in the amount of sound that is transmitted to the cochlea. The acoustic reflex helps to protect the ear from potentially damaging noise levels.

Mechanism

The acoustic reflex involves a complex pathway. It starts with the sound stimulus being detected by the auditory system. This information is then sent to the brainstem, where it is processed. The brainstem then sends a signal to the stapedius muscle, causing it to contract. This contraction reduces the vibration of the ossicles, which in turn reduces the amount of sound that reaches the cochlea.

Clinical significance

The acoustic reflex can be used in clinical settings to assess the integrity of the auditory pathway. It can also provide information about the location of a potential lesion. In addition, the acoustic reflex can be used to differentiate between sensorineural hearing loss and conductive hearing loss.

See also

• Audiology
• Hearing loss
• Otoacoustic emission
• Tympanometry

References

Acoustic reflex Resources
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