The physiological approach to dysarthria assessment and treatment : an examination in upper motor neurone dysarthria

Abstract

With the recognition that suprabulbar lesions result in differential impairments in the speech production mechanism, there has been increasing support for the application of a component based approach to the assessment and rehabilitation of subjects with motor speech disorders. It is accepted that this approach can help the clinician to determine accurately the underlying basis for the perceptual deficits and consequently formulate more effective treatment programs. The aim of the present series of investigations was, therefore, to demonstrate how systematic physiological investigations of the motor speech subsystems, in a group of subjects with dysarthria following upper motor neurone damage, can lead to more effective and efficient clinical management than can be achieved relying on perceptual analysis alone. To this end, a series of 8 investigations were conducted involving subjects from a group of 20 patients with persistent dysarthria following upper motor neurone (UMN) cerebrovascular lesions. The performance of the cerebrovascular accident (CVA) subjects on the various instrumental and perceptual assessments conducted were compared to a group of 20 non-neurologically impaired controls matched for age and sex. The results of the investigations were subsequently discussed with respect to the nature of the physiological deficits identified in this subject group, and the potential influence these impairments may have on the verbal output of these subjects. The first of these investigations involved identifying the perceptual speech characteristics of the group of 20 CVA subjects using a battery of perceptual assessments including a detailed inventory of 32 perceptual speech dimensions, The Frenchay Dysarthria Assessment (FDA), and the Assessment of Intelligibility of Dysarthrie Speech (ASS IDS). Tlie results of these assessments revealed that the CVA subjects presented with features consistent with spastic dysartliria, though the incidence and severity of the dimensions noted were less severe than previously reported in the literature. Comparisons between the CVA and control subjects revealed reduced intelligibility in the CVA subject group and the presence of deficits in all aspects of speech production including respiration, phonation, articulation, resonance, and prosody. These findings were discussed with respect to the possible physiological basis for the identified speech deficits.