Grey and white matter brain network changes in frontotemporal dementia subtypes

Abstract

Grey and whIte matter braIn network chanGes In frontotemporal dementIa subtypes abstract Background: Frontotemporal dementia (FTD) comprises of three clinical syndromes, behavioural-variant frontotemporal dementia (bvFTD), semantic dementia (SV-PPA), and progressive nonfluent aphasia (NFV-PPA) with unique underlying neuroanatomical deficits. To date, however, grey matter structural differences and their connecting white matter tracts in this network have been mostly characterised in comparison to controls, whereas within FTD subtype comparisons in the same patients have not been explored. Methodology: In 94 participants, including bvFTD (n = 16), SV-PPA (n = 16) and NFV-PPA (n = 16), as well as an age-matched control group (n = 46), we employed voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) to examine grey and white matter key signatures in each of the three FTD subtypes. Results: Our results showed that bvFTD had specific ventromedial prefrontal cortex and striatum grey matter atrophy along with their connecting white matter tracts compared to other FTD subtypes. By contrast, SV-PPA showed additional temporal pole grey matter damage to bvFTD and grey and white matter temporal, amygdala and insula changes compared to NFV-PPA. Finally, NFV-PPA showed mild insula grey and white matter changes compared to bvFTD but differed from SV-PPA only on anterior corpus callosum white matter changes. Conclusions: Our findings clearly indicate that not only grey matter regions of the FTD network but also their white matter connecting tracts have specific signatures for each FTD subtype. These promising findings highlight how neural network approaches can shed new light on neurodegenerative conditions and FTD in particular, which will inform future diagnostic and disease management. keywords

Multiclass characterization of frontotemporal dementia variants via multimodal brain network computational inference

“…Moreover, the functional graph theory models captured node-degree differences in the left superior occipital area ( Agosta et al, 2013 ; Reyes et al, 2018 ), left Heschl gyrus ( Agosta et al, 2013 ), and left frontal inferior pars triangularis ( Zhou et al, 2012 ). Regarding the raw structural connectivity models, and in agreement with previous research, we found alterations in the uncinate fasciculus ( Agosta et al, 2012 ; Daianu et al, 2016 ; Iaccarino et al, 2015 ; Nguyen et al, 2013 ), superior longitudinal fasciculus ( Agosta et al, 2012 ; Daianu et al, 2016 ), corpus callosum ( Tovar-Moll et al, 2014 ), dentatorubrothalamic tract ( Whitwell et al, 2011a ), and inferior fronto-occipital fasciculus ( Meijboom et al, 2017 ). Second, adding cognitive features (i.e., multifeatured approach) increased the averaged AUC performance metrics across all subject groups.…”

“…Therefore, model performance may be lower. However, the multimodal approach helps to provide information on specific functional and structural alterations capturing differential patterns in FTD ( Agosta et al, 2012 ; Nguyen et al, 2013 ; Reyes et al, 2018 ; Whitwell, 2019 ).…”

Assessment of Iron Deposition in the Brain in Frontotemporal Dementia and Its Correlation with Behavioral Traits

“…The regions were selected based on known functions of different parts of the brain and the published structural MRI studies which had objectives comparable to our study. Many of these studies have described significant GM volume loss in frontal, insula, anterior cingulate, caudate, putamen, thalamus and temporal polar regions in bvFTD (27,28,29) and predominant temporal (temporal pole, anterior hippocampus) and extra temporal (ventromedial prefrontal cortex, insula, anterior cingulate, caudate) regions in PPA. (28,30,31) Hence, the ROIs drawn on both hemispheres taking the help of e-anatomy of IMAIOS (https://www.imaios.com/en/e-Anatomy/Head-and-Neck/Brain-MRI-3D) and included: the GM at the precentral gyrus (PCG) just anterior to central sulcus, adjacent subcortical WM and CSF in the central sulcus, superior frontal gyrus (SFG) medial to superior frontal sulcus, temporal pole (TP), Insula (IN), basal ganglia regions(caudate(CAU), putamine (PUT), globus pallidus (GP), substantia nigra (SN), red nucleus (RN), frontal WM (FWM), anterior cingulate (AC), defined by the grey matter abutting and posterior to the cingulate sulcus along with adjacent medial frontal lobe, hippocampus (HP) that included its head and body, and finally, dentate nucleus (DN) (Supplementary Figure 1).…”