Cognitive–linguistic deficit and speech intelligibility in chronic progressive multiple sclerosis

Mackenzie, Catherine and Green, Jan (2009) Cognitive–linguistic deficit and speech intelligibility in chronic progressive multiple sclerosis. International Journal of Language and Communication Disorders, 44 (4). pp. 401-420. ISSN 1368-2822 (

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Multiple sclerosis (MS) is a disabling neurological disease with varied symptoms, including dysarthria and cognitive and linguistic impairments. Association between dysarthria and cognitive-linguistic deficit has not been explored in clinical MS studies. In MS patients with chronic progressive (CP) MS, the study aimed to investigate the presence and nature of cognitive-linguistic deficit, association between levels of cognitive-linguistic ability and speech intelligibility and of both of these with functional disability and time since onset (TSO) of MS symptoms. The Arizona Battery for Communication Disorders of Dementia (ABCD) (Bayles and Tomoeda 1993), The Assessment of Intelligibility of Dysarthric Speech (AIDS) Sentence Intelligibility Task (Yorkston and Beukelman 1984) and the Modified Barthel Activities of Daily Living Index (MBADLI) (Shah1998) were administered to 24 CP MS participants with dysarthria. 24 non neurologically impaired participants, matched for gender, age and education, formed a control group. For MS participants, linear regression analysis showed a strong association between ABCD and AIDS (Beta = .89, p = 0.005), no association between ABCD and either MBADLI or TSO, a strong association between AIDS and MBADLI (Beta = 0.60, p = .001), and a trend towards association between AIDS and TSO (Beta = -.29, p = 0.08). Correlations between the four included ABCD construct scores and between these and the total ABCD score were significant (r >.60, p <.01). For each of the 15 included ABCD measures and for the four construct scores and the overall ABCD score, MS and control group performances were significantly different (p <.01) and effect sizes were large (d >.80). The results revealed a strong association between dysarthria, as measured by connected speech intelligibility testing, and cognitive-linguistic deficit, in people with CP type MS. While some of the impairments which are associated with MS, including motor speech disorder, may influence performance on the ABCD, the data support the conclusion that marked cognitive-linguistic deficit is present in CP type MS patients with dysarthria. Deterioration was global, rather than being indicative of a construct specific deficit, and encompassed language, both expression and comprehension. Episodic memory and linguistic expression were especially affected. Speech and language therapists who work with dysarthric patients with CP MS should monitor cognitive-linguistic impairment. Awareness of this may influence assessment, intervention and management, including the information and advice given to patients and their relatives.