Harshavardhan Settibhaktini1, Michael G. Heinz2, Ananthakrishna Chintanpalli1
Department of Electrical and Electronics Engineering, Birla Institute of Technology and Science, Pilani Campus, Rajasthan 333031, India.
2Department of Speech, Language and Hearing Sciences, and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907-2028, USA.

Listeners hear the speech sounds with varying durations in a real-world environment. A fundamental frequency (F0) difference is an important cue that younger adults with normal-hearing utilize to segregate simultaneously presented multiple speeches. Concurrent vowel identification is studied to understand the effect of F0 difference in identifying two simultaneously presented vowels. Behavioral studies on concurrent vowel identification indicate that the ability to utilize an F0 difference cue is reduced when the stimulus-duration is reduced to 50-ms from 200-ms. Using the computational modeling, Settibhaktini and Chintanpalli [2020, Speech Commun.] showed that the lower concurrent-vowel scores across F0 differences for 50-ms could be predicted by limiting the F0-guided cue for segregation in a modified Meddis and Hewitt algorithm [1992, JASA]. Behavioral studies on concurrent vowels, with longer (>200-ms) duration, indicate that older adults had difficulty in availing F0 difference cue for identification, when compared with younger adults. To understand the age effect, Settibhaktini et al [under review, JASA] developed an older normal-hearing model by cascading a physiologically realistic auditory-nerve model [Bruce et al, 2018, Hear. Res.] with a modified Meddis and Hewitt algorithm to predict the concurrent-vowel scores. The peripheral model included endocochlear-potential loss and cochlear synaptopathy. The model scores were successful in capturing the reduced scores across F0 difference as observed in older adults. The goal of the current study is to predict the concurrent-vowel scores for older adults with shorter duration. The same older normal-hearing model was used to predict the concurrent-vowel scores but with a limited F0-guided cue in a modified Meddis and Hewitt algorithm. Our preliminary results suggest that older adults had larger difficulty in availing the F0 difference cue that resulted in reduced concurrent-vowel scores, than that of younger adults. These predictions can motivate future behavioral study in shorter duration, for which the data is currently unavailable.

Acknowledgements: This work was supported by the third author’s Outstanding Potential for Excellence in Research and Academics Grant (FR/SCM/160714/EEE) and Research Initiation Grant (no. 68), awarded by BITS Pilani, Pilani campus, Rajasthan, India and by the second author’s NIH Grant (R01-DC009838).