Vitamin D level in relation to phonetic function among subacute stroke patients

There are many stroke patients with decreased phonation ability. Vitamin D is associated with weakness in muscle power and a decreased function of activity and is often accompanied by a deficiency of serum vitamin D in stroke patients. This study was conducted to evaluate the correlation between serum vitamin D level and phonetic function in subacute stroke patients. Among subacute stroke patients, patients with dysphonia were retrospectively recruited. Phonation function was assessed by acoustic analysis using the dysphonia severity index (DSI) and maximum phonation time for 4 corner vowels/a/,/i/,/u/, and/ae/. As a statistical method, the relationships of vitamin D levels with the maximum phonation time and DSI were evaluated using Pearson's correlation analysis and linear regression analysis. A total of 32 stroke patients with dysphonia were assessed. A positive correlation was found between vitamin D levels and the DSI of /a/, /u/, /i/, and/ae/. The DSI of/u/ was significantly lower in the group with vitamin D deficiency. Vitamin D level was associated with phonation function and its deficiency may be a factor in predicting phonation severity in stroke patients.