Features of the Recognition of Speech Signals in Conditions of Vocal Competition in Health and in Impairments to Auditory Speech Function

We report here studies of the characteristics of the perception of speech signals in conditions of vocal competition based on a sex-related characteristic (male/female voice) in subjects of different ages and states of auditory-verbal function. Psychophysical measurements were carried out during simulation of a “speech cocktail” situation by simultaneous pronunciation of different words by male and female speakers. The mean fundamental tone frequency (FTF) of the male speaker was 108 ± 5.92 Hz, while that of the female speaker was 185 ± 12.03 Hz. Both speakers were standard native speakers of the Russian language. Digital recordings were equalized in intensity and mixed to generate a total test stimulus consisting of a mixture of words spoken by a male (M) voice and a female (F) voice, with synchronization of sounding start times. Test speech signals were presented via headphones or through a loudspeaker positioned in front of the listener at a distance of 50 cm. Measures of reaction time and the number of correct recognitions of words from the target speaker (M or F) were compared in four groups of subjects of different ages and hearing-speech status: adult subjects with normal hearing and speech (n = 35), adult subjects with hearing impairment (n = 26); schoolchildren with normotypical development (n = 26) and schoolchildren with speech disorders (n = 25). The results of this comparative study demonstrate deterioration in the ability to isolate target speech streams in conditions of vocal competition in hearing- and speech-impaired subjects. Differences in the perception of male and female voices were identified in subjects with hearing loss and speech problems, and this may have a biological and social basis. These results have practical significance for the development of auditory-speech training systems and modern hearing aid technologies.