Characterization of brain microstructural abnormalities in spasmodic dysphonia using diffusion kurtosis imaging

To investigate microstructural changes in spasmodic dysphonia (SD) patients applying diffusion kurtosis imaging (DKI) data. DKI (b-values = 0, 1,000, and 2,000 s/mm²) was performed for 20 SD patients and 20 controls. DKI parameters including kurtosis fractional anisotropy (FA), mean diffusion (MD), and mean kurtosis (MK). The correlation analysis was used to assess the correlation between changes in FA and clinical measures. Compared to healthy controls, SD patients showed significantly reduced FA and increased MD in the white matter (WM) and gray matter (GM). Increases of MK had broader distributions than MD. In the WM, the FA and MD of frontal and jitter values had significant inverse correlations in SD patients. The FA and MD were negative correlated with grade, and the FA in the frontal region had a negative correlation with asthenia. Patients with SD exhibited microstructural changes in brain regions in charge of motor conduction and auditory functions. The WM diffusion metric changes had negative correlations with clinical symptoms of SD. The brain changes could modify the central control of voluntary vocalizations and may consequently be the pathophysiologic reason for SD.