Neuroanatomical substrates of attention processing speed in early dementia with Lewy bodies (DLB): A white‐matter voxel‐based morphometry and diffusion tensor imaging study

Abstract

AbstractBackgroundBased on a previous study (Botzung et al., 2019) that revealed the importance of grey matter (GM) integrity in the striatum for attention processing speed, the purpose of this study was now to examine, in early DLB patients, the relationship between impaired attentional speed performances and white matter changes.MethodWe administered the Trail Making Test A (TMTA) to 73 prodromal to moderate DLB patients (mean MMSE = 26.4) and 30 control subjects (mean MMSE = 28.9) to assess attention processing speed. Three‐dimensional (3D) MRI and Diffusion‐weighted images (DTI) were acquired for all participants and correlational analyses were performed in the patient group using WM‐VBM, fractional anisotropy (FA) and mean diffusivity (MD).ResultBehavioral results showed significantly impaired performances in patients in comparison to control subjects (p = .004). In addition, correlational analyses using WM‐VBM revealed negative WM correlations in the anterior corpus callosum and in the anterior cingulum (p < .05 FDR). Using DTI (p < .05 FDR), correlated with TMTA scores, we found reduced FA in bilateral frontal and posterior regions, and increased MD in bilateral anterior and posterior networks.ConclusionWM‐VBM analysis revealed the involvement of anterior corpus callosum and cingulum, which could indicate a disruption of the loops connecting striatal regions and the prefrontal cortex. Changes in both FA and MD also correlate with impaired attentional speed: further DTI analyses are still ongoing to question the degree of which white matter tracts are disrupted between the striatum and cortical anterior and posterior networks, respectively.