A comparison of three modes of hearing aid-telephone coupling

The stray magnetic field emitted by telephone receivers has been used by hearing aid wearers to improve telephone communication. Recent technical advances by Bell Canada have eliminated the magnetic field. The company sponsored the design of a hearing aid modification to compensate for the loss of this magnetic field. This report concerns the evaluation of the modification. The results of two experiments indicated that it did not provide a satisfactory substitute for the magnetic field. A by-product of this project was the development of a device (audiometer-telephone interface) which permits simulation of telephone listening, thus allowing clinical assessment of a patient's telephone communication ability.