Abstract
All measurement was done on forty three patients with unilateral nerve deafness under clinical condition.
1. Test-retest variation:
Both tests were carried out by the same observer (author) with the same apparatus at the interval of twenty to forty minutes.
In order to investigate the cause of the test-retest variation, the variations obtained with three different types of bone conduction receivers and an air conduction receiver were compared.
This revealed that inconsistency in physical value of the auditory stimulus due to unstable fixation of the instruments had most contributed to the test-retest variation.
2. Points of receiver application:
A receiver placed on the mastoid process gave a better sensisitivity by ten decibels than that placed on the middle forehead. No statistical significance was found in individual variation in either case.
Therefore, fixation on the mastoid process is considered to be better.
3. Interaural acoustic attenuation:
The average interaural acoustic attenuation was six to twelve decibels, although this range was
subject to change with test frequency. Each measured value, however, ranged much wider.
In order to decide which ear has better bone conduction, therefore, it is essential to pay attention to the relative position of the threshold curves of both ears on the whole.
