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© 2009 American Academy of Neurology Patterns of cortical thinning in the language variants of frontotemporal lobar degenerationFrom the Dementia Research Centre (J.D.R., J.D.W., M.M., G.R.R., A.D., M.N.R., S.O., N.C.F.), Institute of Neurology, University College London, Queen Square; and Centre for Medical Image Computing (M.M., G.R.R., S.O.), University College London, UK. Address correspondence and reprint requests to Professor Nick C. Fox, Dementia Research Centre, Institute of Neurology, Queen Square, London WC1N 3BG, UK nfox{at}dementia.ion.ucl.ac.uk Background: Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and pathologically heterogeneous neurodegenerative disorder. Two subtypes commonly present with a language disorder: semantic dementia (SemD) and progressive nonfluent aphasia (PNFA). Methods: Patients meeting consensus criteria for PNFA and SemD who had volumetric MRI of sufficient quality to allow cortical thickness analysis were recruited from a tertiary referral clinic: 44 (11 pathologically confirmed) patients with SemD and 32 (4 pathologically confirmed) patients with PNFA and 29 age-matched and gender-matched healthy controls were recruited. Cortical thickness analysis was performed using the Freesurfer software tools. Results: Patients with SemD had significant cortical thinning in the left temporal lobe, particularly temporal pole, entorhinal cortex, and parahippocampal, fusiform, and inferior temporal gyri. A similar but less extensive pattern of loss was seen in the right temporal lobe and (with increasing severity) also in left orbitofrontal, inferior frontal, insular, and cingulate cortices. Patients with PNFA had involvement particularly of the left superior temporal lobe, inferior frontal lobe, and insula, and (with increasing severity) other areas in the left frontal, lateral temporal, and anterior parietal lobes. Similar patterns were seen in the pathologically confirmed cases. Patterns of cortical thinning differed between groups: SemD had significantly more cortical thinning in the temporal lobes bilaterally while PNFA had significantly more thinning in the frontal and parietal lobes. Conclusions: The language variants of frontotemporal lobar degeneration have distinctive and significantly different patterns of cortical thinning. Increasing disease severity is associated with spread of cortical thinning and the pattern of spread is consistent with progression of clinical deficits.
Abbreviations: FDR = False Discovery Rate; FTLD = frontotemporal lobar degeneration; GNT = Graded Naming Test; PNFA = progressive nonfluent aphasia; SemD = semantic dementia.
This work was undertaken at UCLH/UCL, which received a proportion of funding from the Department of Health's NIHR Biomedical Research Centres funding scheme. The Dementia Research Centre is an Alzheimer's Research Trust Co-ordinating Centre. This work was also funded by the Medical Research Council UK. J.D.R. is supported by a Brain Exit Scholarship. J.D.W. is supported by a Wellcome Trust Intermediate Clinical Fellowship. N.C.F. holds an MRC Senior Clinical Fellowship. Disclosure: The authors report no disclosures. Medical Device: 1.5 T GE Signa scanner (General Electric, Milwaukee, WI). Received October 13, 2008. Accepted in final form February 9, 2009. This article has been cited by other articles:
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