Bone Conduction Audiometry - Interacoustics Affinity 2.0 Additional Information

2.0
Affinity Additional Information
1.7.3

Bone Conduction Audiometry

In bone conduction audiometry, the test signal is presented by a bone vibrator placed on the mastoid. The
bone vibrator uses the skull to transfer the vibrations to the cochlear and bypasses the outer and middle
ears. Bone conduction thresholds thereby provide a measure of the cochlear and retrocochlear function
regardless of the outer and middle ear function, therefore it allows you to distinguish between conductive,
sensorineural and mixed hearing thresholds detected through Air conduction Audiometry. The difference
which is detected between the bone and air conduction is called the air-bone gap. It is recommended to start
a hearing assessment first with air-conduction measurements, followed by bone conduction measurements.
Required Items:
•
2.0
The Affinity hardware
•
Licensed AC440 Audiometry module within your Affinity
•
A calibrated bone conductor (B81)
•
A patient response button
Test Procedure:
1) Open the AC440 module through Noah or OtoAccess™.
2) If needed select a test protocol in the List of Protocols.
3) Prior to bone conduction audiometry, perform the Air conduction audiometry, as described in section
0.
4) Place the bone conductor on the mastoid of the worst ear and choose Bone Right or Bone Left from
the channel 1 output dropdown list, and select the desired test signal (typically Tone). In the channel
2 input and output dropdown lists you can decide whether or not masking is to be employed. If so you
will need to place the headset on the patient as well.
Conduct high frequency audiometry using the normal air conduction audiometry method (see section 0
above for details).
Note: Without appropriate masking applied where necessary you cannot know which cochlea is responding,
as there is always no interaural attenuation in bone conduction audiometry. We will always assume that it is
the better ear that is responding. In the case of asymmetrical hearing losses, bone conduction masking
should always be considered.
2.0
hardware
Page 26