Correlates of vowel clarity in the spectrotemporal modulation domain: Application to speech impairment evaluation.

This article reports on vowel clarity metrics based on spectrotemporal modulations of speech signals. Motivated by previous findings on the relevance of modulation-based metrics for speech intelligibility assessment and pathology classification, the current study used factor analysis to identify regions within a bi-dimensional modulation space, the magnitude power spectrum, as in Elliott and Theunissen [(2009). PLoS Comput. Biol. 5(3), e1000302] by relating them to a set of conventional acoustic metrics of vowel space area and vowel distinctiveness. Two indices based on the energy ratio between high and low modulation rates across temporal and spectral dimensions of the modulation space emerged from the analyses. These indices served as input for measurements of central tendency and classification analyses that aimed to identify vowel-related speech impairments in French native speakers with head and neck cancer (HNC) and Parkinson dysarthria (PD). Following the analysis, vowel-related speech impairment was identified in HNC speakers, but not in PD. These results were consistent with findings based on subjective evaluations of speech intelligibility. The findings reported are consistent with previous studies indicating that impaired speech is associated with attenuation in energy in higher spectrotemporal modulation bands.

Age Differences in Voice Evaluation: From Auditory-Perceptual Evaluation to Social Interactions.

Purpose: The factors that influence the evaluation of voice in adulthood, as well as the consequences of such evaluation on social interactions, are not well understood. Here, we examined the effect of listeners' age and the effect of talker age, sex, and smoking status on the auditory-perceptual evaluation of voice, voice-related psychosocial attributions, and perceived speech tempo. We also examined the voice dimensions affecting the propensity to engage in social interactions. Method: Twenty-five younger (age 19-37 years) and 25 older (age 51-74 years) healthy adults participated in this cross-sectional study. Their task was to evaluate the voice of 80 talkers. Results: Statistical analyses revealed limited effects of the age of the listener on voice evaluation. Specifically, older listeners provided relatively more favorable voice ratings than younger listeners, mainly in terms of roughness. In contrast, the age of the talker had a broader impact on voice evaluation, affecting auditory-perceptual evaluations, psychosocial attributions, and perceived speech tempo. Some of these talker differences were dependent upon the sex of the talker and his or her smoking status. Finally, the results also show that voice-related psychosocial attribution was more strongly associated with the propensity of the listener to engage in social interactions with a person than auditory-perceptual dimensions and perceived speech tempo, especially for the younger adults. Conclusions: These results suggest that age has a broad influence on voice evaluation, with a stronger impact for talker age compared with listener age. While voice-related psychosocial attributions may be an important determinant of social interactions, perceived voice quality and speech tempo appear to be less influential. Supplemental Materials: https://doi.org/10.23641/asha.5844102.