1. Objective tests of the auditory system
Acoustic immittance measures
Static acoustic compliance
Tympanometry
Acoustic reflex
Otoacoustic emissions (OAE)
Transient-evoked OAE (TEOAE)
Distortion-product OAE (DPOAE)
Auditory evoked potentials
Electrocochleography (ECog)
Auditory brainstem response (ABR)
Auditory middle latency response (AMLR)
Auditory late response (ALR) 1

2. Acoustic reflex
Contraction of stapedius muscle in response to intense sound: Results in stiffening of tympanic membrane.
What to look for: Change (decrease) in tympanic membrane compliance when a signal is presented. 2

3. Terms related to acoustic reflex
Acoustic reflex threshold (ART): Around 80 dB SL.
Acoustic reflex decay: Amplitude of reflex reduces with continual stimulation.
Present tone at 10 dB above ART, maintain for 10 s, check for amplitude of the reflex.
Reflex decay normal at high frequencies.
Significant decay at low frequencies indicates lesions of auditory nerve and brainstem. 3

4. Ipsilateral vs. Contralateral acoustic reflex
Ipsilateral: Stimulus presented to one ear, reflex monitored in the same ear.
Contralateral: Stimulus presented to one ear, reflex monitored in the opposite ear. 4

5. Acoustic reflex pathway5