Cortical thinning related to periventricular and deep white matter hyperintensities.

Previous studies showed that white matter hyperintensities (WMH) are related to cognitive decline in patients with mild cognitive impairment (MCI) or dementia. Moreover, periventricular WMH (periventricular white matter hyperintensities (PWMH)) and deep WMH (deep white matter hyperintensities (DWMH)) may have different effects on cognition. The purpose of this study is to investigate the contributions of PWMH and DWMH to the topography of cortical thinning and to investigate the relationship among WMH, cortical thinning, and cognitive impairments. Participants included 226 patients with Alzheimer's disease or subcortical vascular dementia, and 135 patients with amnestic MCI or subcortical vascular MCI. Cortical thickness was measured using the surface based method. The topography of cortical thinning related to WMH was distributed in the frontal and perisylvian regions, which was similar to that of PWMH. In contrast, there were only small areas of cortical thinning inversely associated with DWMH, which were distributed in medial frontal and lingual gyrus. PWMH, but not DWMH, were associated with the frontal thinning and executive dysfunction; where both PWMH and frontal thinning were independently associated with executive dysfunction. Our results suggest that PWMH are associated with frontal thinning, which is further associated with frontal executive dysfunction.