Formant trajectory characteristics in persons with Parkinson, cerebellar, and upper motor neuron disease

Abstract

Vocalic nuclei appear to have a good deal of importance in understanding the speech motor control deficit in dysarthria. Research in our laboratory over the past ten years has shown that the slope of formant transitions and the size of the acoustic vowel space are both predictive of the speech intelligibility deficit associated with amyotrophic lateral sclerosis (ALS). Moreover, certain aspects of formant trajectories, such as transition duration and transition extent, seem to provide useful inferences about the articulatory disorder in ALS and in Parkinson disease (PD). In the present study the investigation of vocalic nucleus production in persons with dysarthria is broadened, by reporting on formant trajectory characteristics of persons with Parkinson, cerebellar, and upper motor neuron disease due to stroke. The hypothesis of pathology-specific trajectory characteristics is evaluated, and some methodological considerations concerning the parametrization of formant trajectories are discussed. [Work supported by NIDCD DC00319.]