Mismatch of MRI White Matter Hyperintensities and Gait Function in Patients With Cerebral Small Vessel Disease

Background Cerebral small vessel disease (CSVD) is closely related to gait disorders. Previous studies have found a negative correlation between the severity of MRI white matter hyperintensities (WMH) and gait speed. However, not every individual with WMH experiences a gait disorder. Purpose To investigate the mechanisms underlying the mismatch between the severity of MRI WMH and gait impairment, in particular in subjects with severe WMH (Fazekas 3, scale 0–3) resulting from vascular disease. Study Type Cohort. Population 54 subjects with severe WMH and gait disorder (WMH‐GD; 29 males) and 114 subjects with severe WMH with no gait disorder (WMH‐nGD; 60 males). Field Strength/Sequence 3T/diffusion tensor imaging (DTI), and T1‐weighted, T2‐weighted, FLAIR, DWI, SWI. Assessment Trace‐based spatial statistics analysis (TBSS) approach (fractional anisotropy, FA; mean diffusivity; radial diffusivity; axial diffusivity); Cognitive assessment; Conventional MRI markers of CSVD (WMH, enlarged perivascular spaces, lacunae, and cerebral microbleeds); Gait parameters (gait speed; cadence; stride length; gait cycle duration; step duration; time‐up‐and‐go test, TUG). Gait disorder was defined as a TUG time exceeding 12 sec. Statistical Tests The t ‐tests, Mann–Whitney U tests, Chi‐square tests, and partial correlation analysis (Pearson or Spearman) were used. P < 0.05 with threshold‐free cluster enhancement corrected was considered statistically significant for TBSS. Results After adjusting for age, sex, height, and other conventional MRI markers of CSVD, the WMH‐nGD group showed significantly decreased FA values in the corpus callosum, bilateral superior longitudinal fasciculus, left corona radiata, and left posterior thalamic radiation. There was a significant association between FA values and TUG time, gait speed, and stride length in multiple WM tracts, independent of other conventional CSVD markers. Data Conclusion This study provides evidence for microstructural damage of specific fibers in WMH‐GD subjects compared to WMH‐nGD subjects. This may explain the mismatch between WMH and gait impairment in subjects with severe WMH. Level of Evidence 1 Technical Efficacy Stage 3