REGIONAL DISTRIBUTION OF WHITE MATTER HYPERINTENSITY CORRELATES WITH COGNITION IN THE ALFA COHORT

Background White matter hyperintensities (WMH) have been associated with reduced cognition on multiple domains in older adults [1]. The purpose of this study is to assess the relationship between regional WMH load and cognitive performance in a cohort of cognitively normal subjects. Methods T1 and FLAIR MRI sequences were acquired for a total of 561 subjects of the ALFA cohort [2]. We used the algorithm from Sudre et al [3] to automatically segment WMH. WMH load was normalized by total intracranial brain volume and averaged over the main cerebral lobes and discretized in four layers each, considering the radial distance to the ventricles [4]. Cognition was quantified by mean of z scores of subtests from WAIS IV, mainly assessing executive function and visuospatial reasoning, and the Memory Binding Test (MBT) [5]. Associations with regional WMH were assessed with univariate non-parametric tests (Model 1), and after correcting by age, sex and education (Model 2). We used a customized bullseye's representation similar to [4] to depict significant results (p<0.05). Results As expected, higher WMH loads were associated to worse cognitive performance being this relation strongly modulated by age, especially in frontal and parietal lobes (Figure 1). After correction, lower executive function was related to periventricular WMH load in frontal and temporal areas. Lower memory performance was associated with a pattern of higher WMH in frontal, temporal and occipital areas. Deep white matter hyperintensities in occipital regions were related to lower paired recall score. Conclusions Our approach reveals the specific contribution of WMH to subtle cognitive alterations after accounting for known confounders. Our results are in line with existing literature supporting a relationship between lower scores related to executive functions with higher periventricular WMH loads, whereas memory is related with higher presence of both periventricular and juxtacortical lesions [1]. Our work extends current knowledge on the regional WMH effect on cognition in middle-aged cognitively healthy subjects. [1] Bolandzadeh N, BMC Neurology (2012) [2] Molinuevo JL, Alz & Dem. TRCI (2016) [3] Sudre CH, IEEE Trans Med Imaging (2015) [4] Sudre CH, J Neuroradiol (2017) [5] Buschke H, in Dementia and Memory (2014)