Release from first-formant masking in presbyacusis.

Using synthetic vowels, the effects of first-formant masking on discrimination of the presence of a transition in the second formant were measured under conditions of first-formant attenuation and dichotic presentation. The subjects were 26 listeners between the ages of 61 and 91 with borderline to moderate sensorineural hearing losses. Results indicated: (1) dichotic presentation was significantly superior to monotic presentation; (2) attenuation of the first formant did not result in significant improvement of second-formant transition discrimination. Improved performance in the dichotic conditions may be related to the fact that subjects selected lower most comfortable listening levels than for monotic conditions. Results are compared to those of another study using natural speech stimuli.