Hearing tests

Question 1

Rinne test

Answer 1

Hold a high frequency (512 Hz) vibrating tuning fork against the patient’s mastoid bone, then move it 1-2 cm from the auditory canal. Rinne Riiiiiiing

Ask which is louder.

Normal = Rinne positive, it is louder with air conductance

Conductive hearing loss: Louder on the mastoid

Sensorineural hearing loss: Louder by air

Question 2

Gelle test

Answer 2

Tuning for placed on the mastoid, while the pressure in the auditory canal is increased using Siegle’s pneumatic speculum.
Patient says whether the sound is quieter or the same once the pressure is increased.

If there is no pathology it will decrease hearing, by causing increased pressure on the inner ear and decreased movement of the ossicles.
A positive test = normal

A negative test = pathologic sclerosis of the ossicle and decreased movement, or total discontinuation/disruption of the ossicle chain.

Question 3

Subjective hearing tests

Answer 3

Rinne + Weber test
Gelle
Pure tone audiometry
Whisper and normal speech test

Question 4

Weber test

Answer 4

Tuning fork placed in the middle of the top of the scalp.

Normal test = same in obth ears

Conductive hearing loss = lateralization of sound to the diseased ear. Better bone conduction, seems louder on diseased side

Sensorineuroal hearing loss = lateralization to the healthy side.

Question 5

Objective hearing tests

Answer 5

Tympanometry
Auditory evoked potential recording
Otoacoustic emission tests

Question 6

Types of otoacoustic emissions

Answer 6

Spontaneous emissions, occur in 50% of normal hearing subjects due to the sensitivity of the cochlear amplification to minute sounds.

Transient evoked OAEs TE OAEs
Measured after a click stimulus, positive TE OAEs indicates in-tact middle ear/ossicle transmission as well as normal cochlear hearing. There may still be a lesion of the nerve or brain.
Requires many stimulations and responses to be averaged to clearly see the response.

Distortion product OAEs, evoked by two adjacent pure tones. Generates a more predicable tone of the evoked OAE, but can sometimes be positive even if there is no damage to cochlea.

TE OAES and DP OAEs are the ones used clinically

Stimulus frequence OAEs: evoked by a sine wave. No clinical significance.

Question 7

Auditory pathway

Answer 7

Cochlear sensory inner hair cells

Bipolar neurons of the spiral ganglion, projecting the cochlear nerve.

Cochlear nucleus in the medulla oblongata

Bilateral projections to the Superior Olivary complex

To the Inferior colliculus

Medial geniculate

Primary auditory cortex, Heschl’s gyrus, superior temporal gyrus