Association between sub‐classified white matter hyperintensities (WMH) volume and and cognitive function in patients with Alzheimer`s disease

Abstract

BackgroundWMH in MRI are common among the elderly. WMH are associated with increased cognitive impairment and risk of Alzheimer`s disease (AD). Although WMH contribute to AD pathology, their clinical implications are not fully understood. This study aimed to assess whether WMH predict AD and investigate the association between WMH (including subclassified WMH volume) and cognitive function in AD.MethodThis study enrolled 171 patients with AD. All participants underwent clinical evaluations including brain MRI study and neuropsychological tests using the CERAD‐K neuropsychological assessment battery. In addition, Charlson comorbidity index, the Korean version of the Geriatric Depression Scale short from were administered. WMH volume was calculated using automated quantification method with SPM and MATLAB image processing software. WMH were classified according to the distance from the ventricular surface. WMH located in juxtaventricular areas, within 3 mm from the ventricular surface, were classified as juxtaventricular with matter hyperintensities (JVWMH). WMH located within 3–13 mm or farther than 13 mm from the ventricular surface were classified as periventricular white matter hyperintensities (PVWMH) or deep white matter hyperintensities (DWMH), respectively. WMH volume data were right‐skewed. Consequently, WMH volume data were logarithmic transformed.ResultThe AD group had a higher mean WMH volume(20.7 ± 18.2 ml). Multivariate linear regression analysis showed that total WMH volume in AD was associated with poor performance in categorical verbal fluency test (p = 0.008) and word list memory test (p = 0.023). JVWMH volume in AD was associated with poor performance on categorical verbal fluency test (p = 0.013) and digit span test forward (p = 0.037). PVWMH volume in AD was associated with poor performance on categorical verbal fluency test (p = 0.011) and word list memory test (p = 0.021), whereas DWMH volume showed no association with cognitive dysfunction in AD.ConclusionTotal WMH, JVWMH and PVWMH were associated specifically with executive function, immediate memory, and working memory, independently of hippocampal atrophy in AD. WMH were associated with AD risk and cognitive dysfunction differentially according to the distance from the ventricular surface.