A hearing aid that will work for all deaf or hard-of-hearing people without individual fittings was forecast yesterday by research workers in the University Psycho Acoustic Laboratory.
"Regardless of the nature of their particular defects, most patients hear best with an instrument which amplifies all frequencies uniformly, or with moderate emphasis of the higher frequencies," the researchers reported in "Hearing Aids: An Experimental Study in Design Objectives," just published by the University Press.
This report, according to S. Smith Stevens, director of the Psycho-Acoustic Lab, revolutionizes the study of hearing aids, for it attacks the "dogma that hearing aids, like eye glasses, must be fitted to the detailed idiosyncrasies of the individual impairment."
Growing out of wartime research in sound sponsored by the Army and Navy, the project was originally part of a nation-wide program to assist in the rehabilitation of aural casualties.
Preliminary research by the lab revealed that "many good hearing aids were on the market and that among the better ones there was little to choose; and secondly, that none of the models brought speech to the defective ear with the clarity and crispness required for understanding under conditions of noise and stress."
To remedy these defects, the researchers set about to construct a hearing aid of their own. In the course of their work they discovered that "the electro-acoustical properties best suited to one type of hearing loss are those best suited to all, or nearly all."
Working from this theory, they drew up specifications for an all purpose aid. "When instruments are drawn up according to these specifications," according to the report, "the problem of individual fitting will almost disappear."