SPAA 655---Diagnostic Audiology

To eliminate the possibility of cross-hearing by preoccupying the non-test ear

The reception of an acoustic signal that is presented in the TE and heard in the NTE

AC: transcortical, transcranial BC: intra-cranial (most common)

The bone oscillator on the TE mastoid sends vibrations throughout the head; stimulates both cochleas simultaneously and the better ear picks up the sound

When the signal is 40 dB HL greater than BCT i the NTE and the NTE can hear it by BC; the signal becomes so loud that it vibrates the headphones and is heard by BC

When the signal is 40 dB HL greater than the ACT in the NTE, it may be heard by the NTE by AC

1. when there is a 15 dB difference between the BC of the better ear and the AC threshold of the poor ear (BC masking) 2. If the air threshold in one ear is 40 dB worse than the BCT in the other ear (AC masking) 3. 40 dB difference between AC of good ear and AC of poor ear (AC masking)

Reduction of energy between ears as a signal crosses over (loss of perceived loudness)

Minimum amout of noise in the NTE to just mask the signal at a given hearing level in the other ear

Small shift (about 5 dB) in threshold of a pure tone when masking noise is introduced to the opposite ear

Masking noise is presented to the NTE that is of sufficient intensity to crossover to the TE and shift the threshold in the TE beyond its true value

Masking noise is presented to the NTE is no sufficient enough intensity to prevent the test signal from being heard in the NTE

The level of noise that can be varied over a small range that does not alter the threshold of a sound presented to the opposite ear

The maximum amount of note to the NTE to mask out a signal before the noise crosses back over to shift thresholds of the TE

One unmasked ear is 40 dB or more below the better ear with the poorer ear "patterning" the better ear