Perceptual and acoustic analysis of speech in individuals with spinocerebellar ataxia (SCA).

With current progress in genetic research, autosomal, dominant, hereditary, neurodegenerative diseases, affecting the cerebellum and cerebellar connections, are increasingly diagnosed as spinocerebellar ataxias (SCA). In the present study speech samples from 21 subjects with spinocerebellar ataxia (SCA), and 21 matched control subjects were analyzed using perceptual and acoustic methodology. Dysarthria assessment showed that subjects had mild or mild-moderate dysarthria. Perceptual analysis indicated that equalized stress, imprecise consonants, vocal instability, monotony and reduced speech rate were the speech parameters that yielded the highest mean perceptual ratings. A factor analysis of perceptual speech parameters revealed two main factors: Factor 1 was associated with articulatory timing and Factor 2 with vocal quality. Acoustic analysis revealed significantly reduced speech rate during text reading, reduced alternating and sequential motion rates (AMR/SMR), significantly longer and more variable syllable and pause durations, and significantly higher vocal instability for subjects with SCA compared to control subjects.