The effect of hearing aid use on the user's residual hearing. A follow-up study

This paper reports on a follow-up study into the effect of hearing aid amplification on the user's residual hearing. Four groups of deaf children; 18 in group A, 14 in group B, 15 in group C and 8 in group D were followed up for a period of four consecutive years. The children in group A and in group B were using monaural hearing aids throughout this period with maximum acoustic outputs ranging from 130-136 dB SPL and 116--128 dB SPL respectively. The children in group C were not using hearing aids during the first three years but during the fourth year they were monaurally fitted with similar hearing aids as those issued to children in group B. The children in group D were using binaural hearing aids during the first three years but in the fourth year they were restricted to only one hearing aid. The hearing aid levels of the children at 500, 1 000, 2 000 and 4 000 Hz were ascertained both at the beginning of the investigation, at subsequent 6-monthly intervals for the first three years and at the end of the fourth year. It was found that the hearing acuity of the hearing aided ears showed slight "improvement" during the investigation while the hearing acuity of the unaided ears showed slight "deterioration" in all frequencies tested.