Abstract
Studies were carried out on 4 hearing aids, the products of different makers. It was found that persons with normal hearing ability-regardless of whether they were laymen or specialists-showed different preferences for these devices on the basis of the sound. Next, hearing tests were performed on normal healthy volunteers and persons with mild to moderate degrees (i. e., at 50-70 dB) of hearing loss. In addition, the subjects with hearing loss were asked to evaluate the efficacy of the hearing aid-earphone combinations in relation to daily life. Results 1) The orders of preference of the hearing aids expressed by both the normal volunteers and the subjects with hearing loss were about the same, regardless of the earphone employed. 2) The subjects were asked to evaluate the tone quality of the most preferred hearing aid in combination with each of the earphones. The results for the earphones showed N> W > P. 3) With the same 3 hearing aid-earphone combinations, evaluations were carried out in relation to daily life by the subjects with hearing loss. The results in this case showed an order of superiority of N> P> W . 4) Investigation was then made of the difference in those evaluation results. It was thus surmised that, in the case of daily life, there was a tendency for the patients with mild hearing loss (i. e., at 60 dB or less) to dislike the W characteristic.
