Influence of age on speech intelligibility in babble noise

Problems with hearing aids, particularly with regard to speech intelligibility in the presence of noise, are commonly reported by older individuals in everyday practice. The main goal of this study was to measure differences in speech intelligibility between older and younger people and to establish how speech intelligibility in competitive noise differs between younger and older populations with similar hearing status. More than 400 persons were tested using the Czech Test of Sentence Intelligibility in Babble Noise and divided into younger (40-65 years) and older (66-85 years) age groups. Test performance was compared between age groups based on subgroups stratified by SRT values (speech reception threshold in word audiometry in silence). Results showed a significant correlation between older age and diminished sentence intelligibility in competitive noise. Evaluation using a nonparametric U-test showed a statistical difference between the younger and older groups in sentence intelligibility, with a speech signal presented at 65 dB sound pressure level (SPL) and competitive babble noise also presented at 65 dB SPL. Increased difficulty in the use of hearing aids in older users is related, among other things, to a reduced ability to discriminate speech not only in silence but particularly in competitive variable noise due both to their aging auditory functions and to a diminished capacity to differentiate the time factors of sounds. It is probably connected with the diminished function of inhibitory neurons.