Effects of earmold type on ability to locate sounds when wearing hearing aids

To determine whether the choice of earmold type can affect aided auditory localization.

1) for sensorineural hearing losses with good low-frequency hearing (Low group, n = 10), the use of open earmolds could avoid decrements in horizontal plane localization found with closed (occluding) earmolds; 2) for sensorineural losses with good high-frequency hearing (High group, n = 12), the use of open earmolds could result in better vertical plane localization than could the use of closed earmolds; and 3) for conductive/mixed hearing losses (CM group, n = 19), the choice of earmold type-hard short, soft short, or soft long-could affect aided localization.

Aided and unaided auditory localization was tested for the above three groups of hearing-impaired listeners when wearing bilaterally fitted hearing aids.

For the Low group, results were inconclusive because nine listeners showed virtually perfect horizontal localization with both closed and open earmolds. For the High group, two listeners showed improved vertical plane localization with open earmolds. These were the only listeners with HTLs of 30 dB or better at 6000 Hz and 8000 Hz. For the CM group, aided horizontal plane localization was significantly better than unaided localization for about half of the listeners and was similar for the other half. There was no significant group difference for the three earmold types. For some individuals, one earmold type was better than the others.

The choice of earmold can effect aided localization, but the specific effects need further elucidation. Audiologists should be aware that people with conductive or mixed hearing losses may have poor auditory localization and that this may be improved by the fitting of hearing aids.