Dysphonia Characteristics and Vowel Impairment in Relation to Neurological Status in Patients with Multiple Sclerosis.

PURPOSE: In this study, we attempted to assess the phonation and articulation subsystem changes in patients with multiple sclerosis compared to healthy individuals using Dysphonia Severity Index and Formant Centralization Ratio with the aim of evaluating the correlation between these two indexes with neurological status.

MATERIALS AND

METHODS

A sample of 47 patients with multiple sclerosis and 20 healthy speakers were evaluated. Patients' disease duration and disability were monitored by a neurologist. Dysphonia Severity Index and Formant Centralization Ratio scores were computed for each individual. Acoustic analysis was performed by Praat software; the statistical analysis was run using SPSS 21. To compare multiple sclerosis patients with the control group, Mann-Whitney U test was used for non-normal data and independent-samples t test for normal data. Also a logistic regression was used to compare the data. Correlation between acoustic characteristics and neurological status was verified using Spearman correlation coefficient and linear regression was performed to evaluate the simultaneous effects of neurological data.

RESULTS

Statistical analysis revealed that a significant difference existed between multiple sclerosis and healthy participants. Formant Centralization Ratio had a significant correlation with disease severity.

CONCLUSION

Multiple sclerosis patients would be differentiated from healthy individuals by their phonation and articulatory features. Scores of these two indexes can be considered as appropriate criteria for onset of the speech problems in multiple sclerosis. Also, articulation subsystem changes might be useful signs for the progression of the disease.