Statistical analysis was performed using SPSS Statistics 22 (IBM SPSS Statistics, USA). Demographic and clinical data and the values obtained from the VOI-based modeling were compared between groups using the Pearson’s χ2 test/Fisher’s exact test or the Mann–Whitney U test. Differences were considered statistically significant at <5% probability (p < 0.05) of equality. In the case of significant differences between groups, we additionally performed correction for multiple comparisons. Additionally, effect sizes were calculated using the Cohen’s d test, which were interpreted as d > 0.1: small effect; d > 0.3: medium effect; and d > 0.5: large effect (19 ).
For statistical comparison of the BPND parametric images, a two-sample t-test was performed in SPM12 (Wellcome Trust Centre for Neuroimaging, UK) between dystonia patients and controls. For interpretation of the results, T-maps data were interrogated at p = 0.005 (uncorrected) and only clusters with p < 0.05 corrected for family wise error were considered significant.
Correlation analysis between the BPND obtained from the VOI-based modeling and clinical characteristics was performed using the Spearman’s rho test. With multiple regression analysis, we then determined the influence of clinical variables with a p-value <0.05 in the univariate analysis on the BPND. Assumptions of the linear regression and multicollinearity were checked.
For statistical comparison of the BPND parametric images, a two-sample t-test was performed in SPM12 (Wellcome Trust Centre for Neuroimaging, UK) between dystonia patients and controls. For interpretation of the results, T-maps data were interrogated at p = 0.005 (uncorrected) and only clusters with p < 0.05 corrected for family wise error were considered significant.
Correlation analysis between the BPND obtained from the VOI-based modeling and clinical characteristics was performed using the Spearman’s rho test. With multiple regression analysis, we then determined the influence of clinical variables with a p-value <0.05 in the univariate analysis on the BPND. Assumptions of the linear regression and multicollinearity were checked.
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