[Nose and speech discrimination with specific hearing aid systems (author's transl)]. / Die Wirkung von Störlärm auf die Diskrimination von Sprache bei PC- und Compressionshörgeräten.

This study compares speech discrimination and the use of hearing aids of the PC (peac-clipping) system and the AGC (compression) system. After random selection 34 subjects were used and grouped according to the unit system they had been supplied with. Both groups were tested under the same conditions. During noise exposure the group supplied with the AGC aids achieved better results significantly at a 5% level. The results indicate that the assumption that PC hearing aids operate better in noise than AGC aids cannot be substantiated.

Hearing aid gain-setting performance of experienced users.

This study explores the ability of 30 experienced hearing aid users to reliably reset the gain of their hearing aids in a clinical sound field. The level of the sound-field stimulus was derived from an aided most comfortable level (MCL), which reflected a "real-life" aided gain setting. The results indicated that these subjects were able to perform all tasks with a high degree of reliability, as measured by sound field speech reception thresholds (SRT'S) AND Brüel and Kjaer acoustic analysis. Average aided operational levels for SRT and MCL were also obtained for this group.

Variable venting valve for earmolds.

The frequency response and loudness reduction characteristics of earmolds with variable venting valves (VVV) were investigated. Both side-branch and laterally vented earmolds were employed. Sound pressures were measured at 44 frequencies from 100 to 4 000 HZ in a modified HA-2 coupler with the VVV in four stages of opening: closed; 1/3 open; 2/3 open and 3/3 open. The effect of venting is primarily in the low frequencies. Little or no reduction in intensity is observed in the 'speech frequency' range and a modest amount is noted in the higher frequencies. The side-branch vented earmolds were more effective than the laterally vented earmolds. Calculated loudness reductions in phons were small. The effectiveness of the VVV, whether assessed by the frequency response or loudness reduction characteristics, is achieved within the first 1/3 of opening: further opening has little effect. The utility of the VVV, especially to the geriatric hearing aid user, is questionable.