Separate and Combined Influence of Cognitive Impairment and Dysarthria on Functional Communication in Multiple Sclerosis

Purpose: Dysarthria is a consequence of multiple sclerosis (MS) that can co-occur with cognitive impairment. Clinical management thus requires understanding the separate and combined effects of dysarthria and cognitive impairment on functional communication in MS. This study compared perceptual measures of intelligibility and speech severity that capture functional communication deficits for 4 operationally defined groups with MS. The relationship between communication participation and perceptual measures was also examined. Method: Forty-eight adults with MS and 12 healthy controls participated. Cognitive testing and dysarthria diagnosis determined group assignment: (a) MS with cognitive impairment (MSCI), (b) MS with a diagnosis of dysarthria and no cognitive impairment (MSDYS), (c) MS with dysarthria and cognitive impairment (MSDYS + CI), and (d) MS without dysarthria or cognitive impairment (MS). Sentence Intelligibility Test scores, scaled speech severity obtained from the Grandfather Passage, and Communication Participation Item Bank (CPIB) scores were analyzed. Results: Sentence Intelligibility Test scores approached 100% for all groups. Speech severity was greater for the MSDYS + CI and MSDYS groups versus controls. CPIB scores were greatest for the MSDYS + CI group and were not significantly correlated with either perceptual measure. Conclusions: The CPIB and speech severity were sensitive to aspects of communication problems for some groups with MS not reflected in a measure of sentence intelligibility. Findings suggest the importance of employing a variety of measures to capture functional communication problems experienced by persons with MS.