EGG open quotient in aging voices--changes with increasing chronological age and its perception.

This paper presents the results of open quotient (OQ) measurements in electroglottographic (EGG) signals of young (18-30 years) and elderly (60-82 years) male and female speakers. The paper further presents quantitative results of the relation between the EGG OQ and the perception of a speaker's age. Higgins and Saxman found a decreased EGG OQ with increased age for females, while the EGG OQ increased for males as the speaker's age increased in sustained vowel material 1. Although laryngeal degeneration due to increased age seems to occur to a lesser extent in females, the significant decrease of the OQ in elderly female voices could not be explained in terms of age-related physiological changes. Linville found increased spectral amplitudes in the region of F0 for the elderly (obtained by long-term average spectra (LTAS) measurements of read speech material), independent of gender, which could be indirectly interpreted as an increasing OQ 3. We measured the EGG OQ, not only for sustained vowels but also in vowels taken from isolated words and read speech material. To analyse the relation between breathiness in terms of an increased EGG OQ and the mean perceived age per stimulus, a perception test was carried out, in which listeners were asked to estimate speaker's age based on sustained /a/-vowels varying in vocal effort (soft-normal-loud) during production. 1) The decreased EGG OQ for elderly females originally found by Higgins and Saxman 1 is not apparent in our data for sustained /a/-vowels; for males, however, we also found an increased EGG OQ for the elderly speakers. 2) In addition, an increased EGG OQ for the group of elderly in comparison to the younger males occurs for the unstressed syllable of the word material. 3) Our results show a strong positive relation between perceived age and EGG OQ in male vowel stimuli. Regarding 2), depending on the speech task at least a male speaker's voice gets more breathy as age increases. Considering 3), increased breathiness may contribute to the listener's perception of increased age.