Kent, Ray D.

Computer-based analysis systems are increasingly available for the clinical assessment of speech and voice functions. These systems have the potential to provide immediate quantitative information to assist clinical assessment and treatment. The Multi-Dimensional Voice Program (MDVP) is a computer program that can calculate as many as 33 acoustic parameters from a voice sample. The MDVP appears to have potential for rapid quantitative assessments of voice in both research and clinical applications. This report evaluates the robustness and reliability of MDVP for vocal analyses of 32 individuals with dysarthria of various etiologies. It is concluded that the reliability is generally very good and that MDVP has potential as a tool for the semi-automatic analysis of voice samples in dysarthria. Some parameters appear to hold particular value in the description of voice qualities in these speech disorders.

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, and whether the different speech production subsystems are uniformly affected. Perceptual and acoustic data were obtained from 14 individuals (seven men, seven women) with ataxic dysarthria for several speaking tasks, including sustained vowel phonation, syllable repetition, sentence recitation, and conversation. Multidimensional acoustic analyses of sustained vowel phonation showed that the largest and most frequent abnormality for both men and women was a long-term variability of fundamental frequency. Other measures with a high frequency of abnormality were shimmer and peak amplitude variation (for both sexes) and jitter (for women). Syllable alternating motion rate (AMR) was typically slow and irregular in its temporal pattern. In addition, the energy maxima and minima often were highly variable across repeated 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 during sentence production were essentially normal, showing that articulatory hypometria is not a pervasive problem. Conversational samples varied considerably across subjects in intelligibility and number of words/ morphemes in a breath group. Qualitative analyses of unintelligible episodes in conversation showed that these samples generally had a fairly well-defined syllable pattern but subjects differed in the degree to which the acoustic contrasts typical of consonant and vowel sequences were maintained. For some individuals, an intelligibility deficit occurred in the face of highly distinctive (and contrastive) acoustic patterns.

More than 30 years ago, Darley, Aronson, and Brown (1969) proposed clinicoanatomic correlations for seven perceptual types of dysarthria. These correlations have not been systematically re-examined even though imaging technologies developed in recent years provide the means to do so. This review considers data from published imaging studies as well as data from selected medical interventions to evaluate the current state of knowledge that relates lesion site to the nature of a speech disturbance. Although the extant data are not sufficient to allow a complete evaluation of the seven types of dysarthria described by Darley et al., relevant information has been reported on lesions of the pyramidal pathway, extrapyramidal pathway, and cerebellum. In general, the results are best explained by an equivalence mode of brain-behavior relationship in which a type of dysarthria is associated with a lesion in one of two or more brain structures. Criteria also are proposed for future studies of clinicoanatomic relationships in neurogenic communication disorders.