Ear asymmetries and asymmetric directional microphone hearing aid fittings.

Purpose: To determine whether an asymmetry between ears for speech understanding in noise was related to performance with, or preference for, 1 of 2 asymmetric microphone fittings in which omnidirectional processing was provided to 1 ear and directional processing to the other.

Method: Twenty-eight adults with symmetric sensorineural hearing impairment were recruited from the clinic population. Sixteen individuals had symmetric hearing-in-noise ability between their right and left ears, and 12 participants had an asymmetry for speech understanding in noise between ears. A repeated measures design was used. Interactions between various microphone fittings and speech signal locations in noise were assessed in the laboratory. In addition, the listeners with asymmetry between ears for hearing in noise completed a field trial comparing the 2 fittings in everyday listening situations.

Results: Laboratory testing resulted in different patterns of performance for the 2 groups. Field trial results revealed that participants generally noticed little difference between the 2 fittings in everyday life and did not express a strong preference for 1 fitting over the other.

Conclusion: An asymmetry between ears for speech understanding in noise did not result in preference for 1 asymmetric fitting over the other in everyday listening situations.