Loudness Summation with Binaural Hearing Aids

Hearing-impaired persons who had been fitted with binaural hearing aids performed a loudness matching task under binaural and monaural aided conditions. Loudness summation as a function of presentation level was determined for sensation levels of 10 dB, 20 dB, 30 dB and 40 dB. The results indicated a binaural advantage comparable to that which has been reported for normal-hearing persons. The extent of the advantage ranged from approximately 3 dB to 5 dB and tended to increase as a function of sensation level. This finding adds support to the view that the advantages of binaural hearing enjoyed by normal-hearing persons may also be available to the hearing-impaired while using binaural hearing aids.