Is masking noise presented through bone conduction?
To prevent this phenomenon causing an erroneous measurement, you can use masking noise to occupy the good ear (non-test ear) while testing the other ear [1-3]. Masking can be applied to air conduction, bone conduction, and speech audiometry.
What is masking in audiogram?
Masking is a procedure clinicians use while conducting audiometry to separate ears acoustically. Masking allows for a clinician to get ear specific thresholds, without the non-test ear assisting the test ear to hear – resulting in better thresholds.
How do you mask a speech audiometry?
In this paper a simplified approach to selecting appropriate contralateral masking levels in suprathreshold speech audiometry was described. Specifically, effective masking level is equal to the presentation level of the speech signal in dB HL at the test ear minus 20 dB: dB EM = PLT−20 dB.
Is masking needed for speech testing?
As a reminder about speech recognition testing, masking is frequently needed because the test is being presented at a level above threshold, in many cases well above the threshold.
When should you mask for bone conduction testing?
Bone conduction testing in persons with hearing loss should be done with masking to prevent sound from the stimulated side from going over to the good side. Air conduction testing should be done when there is a 40 db or greater threshold.
Why is masking noise used in pure tone bone conduction?
Sound is transmitted through bone conduction and allows the patient to hear the tone in the non-test ear. Masking in audiology is the act of playing white noise into the non-test ear to prevent it from hearing the tones that crossover from the test ear.
What is clinical masking?
Clinical masking is an application of the masking phenomenon used to alleviate cross-hearing. In clinical masking we put noise into the nontest ear because we want to assess the hearing of the test ear. In other words, the masking noise goes into the NTE, and the test signal goes into the TE.
What is the purpose of speech audiometry?
Speech audiometry provides information on word recognition and about discomfort or tolerance to speech stimuli. Speech audiometry outcomes help also in setting the gain and maximum output of hearing aids for patients with moderate to severe hearing losses.
What is a normal speech recognition threshold?
Normal results would include air and bone thresholds of 25 dB or better, an MCL of approximately 50 dB, a Speech Reception Threshold of around 15 dB, a Word Recognition Score of 100% and type-A tympanometry.
Why do we mask for bone-conduction?
How do you mask for bone-conduction?
For bone-conduction, to mask the non-test ear, add 10 dB HL to the Air Conduction threshold in the non-test ear and add the occlusion effect (Air Conduction non-test ear + 10 dB HL + occlusion effect). That is the level you can start masking at.
What frequencies are tested for bone conduction?
The testing procedure is repeated at specific frequencies from 250 to 8000 hertz (Hz, or cycles per second) for each ear, and the thresholds are recorded on a graph called an audiogram. Bone conduction testing is done by placing an oscillator on the mastoid process and measuring threshold at the same frequencies.