Audiological correlates of speech understanding deficits in elderly listeners with mild-to-moderate hearing loss. II. Correlation analysis.

Abstract

The study was conducted to determine the relationship between measures of auditory performance in elderly individuals. Specifically, its goal was to uncover a set of measures correlated with the set of measures of speech understanding under specific conditions of interference to gain a better understanding of decline of the "cocktail party effect" in aging. Audiological status and auditory performance of a group of elderly (60- to 81-yr-old) individuals were determined through a test battery. When present, the hearing loss of elderly subjects was symmetrical in the two ears and, at most, moderate. The battery included tests of speech intelligibility on the word and sentence levels, with and without the presence of interfering speech. In addition pure-tone and speech reception thresholds, perception of spectrally or temporally distorted speech and auditory resolution of frequency, time, and space were tested. Two tests received special consideration: the Speech Perception In Noise Test and the Modified Rhyme Reverberation Test. Results indicated that, despite the nearly normal hearing levels that characterized much of the subject group, auditory sensitivity measures showed persistent correlation to all other measures, with the exception of auditory resolution regarding frequency, time, and space. As a set, sensitivity measures accounted for more than 85% of the variance. When auditory sensitivity was controlled for, other factors underlying speech processing in the presence of interfering stimuli were uncovered, factors most likely related to the ability to perceptually segregate one speech signal from another. The findings suggest that, to determine the relationship between audiological/auditory test results of an elderly population, it is important to remove the effects of hearing loss through appropriate statistical methods.