Ataxic dysarthria

Although ataxic dysarthria has been studied with various methods in several languages, questions remain concerning which features of the disorder are most consistent, which speaking tasks are most sensitive to the disorder, a nd whether the different speech production subsystems are uniformly affecte d. Perceptual and acoustic data were obtained from 14 individuals (seven me n, seven women) with ataxic dysarthria for several speaking tasks, includin g sustained vowel phonation, syllable repetition, sentence recitation, and conversation. Multidimensional acoustic analyses of sustained vowel phonati on showed that the largest and most frequent abnormality for both men and w omen was a long-term variability of fundamental frequency. Other measures w ith a high Frequency of abnormality were shimmer and peak amplitude variati on (for both sexes) and jitter (for women). Syllable alternating motion rat e (AMR) wets typically stow and irregular in its temporal pattern. In addit ion, the energy maxima and minima often were highly variable across repeate d syllables, and this variability is thought to reflect poorly coordinated respiratory function and inadequate articulatory/voicing control. Syllable rates tended to be slower for sentence recitation and conversation than for AMR, but the three rates were highly similar. Formant-Frequency ranges dur ing sentence production were essentially normal, showing that articulatory hypometria is not a pervasive problem. Conversational samples varied consid erably across subjects in intelligibility and number of words/morphemes in a breath group. Qualitative analyses of unintelligible episodes in conversa tion showed that these samples generally had a Fairly well-defined syllable pattern but subjects differed in the degree to which the acoustic contrast s typical of consonant and vowel sequences were maintained. For some indivi duals, an intelligibility deficit occurred in the face of highly distinctiv e (and contrastive) acoustic patterns.