2021 Volume 62 Issue 3 Pages 205-214
Previous studies have demonstrated that measures of second-formant (F2) movements (duration of F2 change, extent of F2 change, and F2 slope) serve as acoustic indices of articulatory deficits in dysarthric speakers. The present study is intended to determine if there is any difference between dysarthric speakers and normal speakers, to examine relationships with speech intelligibility, and to determine the magnitude of variability among target words in the acoustic measures of F2 movements. Thirteen adult speakers with mild and moderate dysarthria and normal adult speakers participated in this study. Each speaker was asked to read a passage from (the Japanese version of) "The North Wind and the Sun" aloud at his or her normal rate. The extent and duration of F2 movements were measured on the two-vowel sequence /ai/ in two target words (taiyou and gaitou). F2 duration was significantly longer, and F2 slope was significantly lower in the dysarthric subjects than in the normals. F2 slope showed a significant correlation with speech intelligibility (rs=-0.59). The coefficient of variations in the second formant movement was greater for the dysarthric speakers. These findings suggest that the indices of F2 movement would be useful for evaluating articulatory ability in Japanese-speaking dysarthric speakers.
