Characterizing stroke-affected speech using F0 and duration-based features

This paper presents a study of pitch (F0) and duration related features of transition and non-transition regions of speech, carried out to better understand and characterize speech recorded from stroke patients. A speech corpus consisting of read speech as well as five sustained vowels, recorded from 50 stroke patients and 50 healthy speakers in a clinical environment, was developed for this purpose. A gender specific statistical analysis of F0 contour showed that median F0 of an utterance shows consistent trend in distinguishing utterances from the stroke patients and healthy control speakers across all vowel categories. The utterances from female speakers of the stroke study group tended to have a lower F0 median in comparison with that of the healthy control group. In contrast, male speakers in the stroke study group exhibited a higher F0 median compared to the control group. The durations of the transition and non-transition (steady state) regions in the utterances were estimated by an analysis of the gradient of cepstral coefficient vector as a function of frame index. The male and female speakers of the stroke study group showed shorter transition regions with higher relative transition areas as compared to those of the healthy control group. In contrast, the non-transition (steady state) regions tend to show longer duration in the stroke study group. The observed statistical trends in the F0 and duration analysis were validated using one-way ANOVA tests.