Abstract Details

Title Cortical Microstructure in Primary Progressive Aphasia: a multicenter study

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) S14 - Behavioral and Cognitive Neurology (2:00 PM-2:08 PM)

Poster/Presentation
Number 001

Background CMD is a novel biomarker that has shown higher sensitivity than CTh to detect neurodegeneration in different diseases. However, its utility in primary progressive aphasia (PPA) is unknown.

Objective We aimed to compare cortical mean diffusivity (CMD) and cortical thickness (CTh) in PPA subtypes and to determine their ability to predict longitudinal clinical decline.

Design/Methods We included 227 participants (135 PPA and 92 age-matched controls) recruited at the University of California San Francisco (UCSF) and the Catalan Frontotemporal Dementia Initiative (CATFI) with a three-Tesla MRI including structural and diffusion-weighted sequences. PPA participants met consensus criteria for non-fluent variant PPA (nfvPPA, n=62), semantic variant PPA (svPPA, n=35) or logopenic variant PPA (lvPPA, n=38). Disease severity was assessed at baseline and at one year with the FTLD version of the Clinical Dementia Rating sum of boxes (CDR-FTLD-SB). CTh and CMD were computed using a previously published surface-based approach. We compared group differences in CTh and CMD between each PPA subtype and controls. In participants from CATFI, we defined three neurodegenerative signatures for each PPA subtype. For each participant from UCSF, we calculated the mean CTh and CMD at each neurodegenerative signature and we compared the ability of mean CTh and CMD to predict the longitudinal change of CDR-FTLD-SB over time for each PPA subtype.

Results The group comparison revealed mean diffusivity changes and cortical thinning in the expected cortical areas for each PPA subtype. In all group analyses, we observed CMD increases and cortical thinning in overlapping regions. However, CMD increases also expanded to other areas that are involved with disease progression in all PPA subtypes. We observed the same results when we analyzed participants from UCSF and CATFI separately. CMD was an independent predictor of longitudinal CDR-FTLD-SB change.

Conclusions CMD could be a valuable biomarker of neurodegeneration in PPA subtypes.

Authors/Disclosures
Ignacio Illan-Gala, Sr., MD, PhD (Hospital de la Santa Creu i Sant Pau) PRESENTER	Dr. Illan-Gala has nothing to disclose.
Victor Montal	No disclosure on file
	No disclosure on file
Neus Falgàs Martínez (UCSF)	Neus Falgàs Martínez has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Daniel Alcolea Rodriguez (Hospital Sant Pau)	Daniel Alcolea Rodriguez has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche Diagnostics. Daniel Alcolea Rodriguez has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Fujirebio Europe. Daniel Alcolea Rodriguez has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Fujirebio Europe. Daniel Alcolea Rodriguez has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Roche Diagnostics. Daniel Alcolea Rodriguez has received personal compensation in the range of $0-$499 for serving on a Speakers Bureau for Nutricia. The institution of Daniel Alcolea Rodriguez has received research support from Fujirebio - Europe. Daniel Alcolea Rodriguez has received intellectual property interests from a discovery or technology relating to health care.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Rafael G. Blesa, MD (Hospital De La Santa Creu I Sant Pau)	Dr. Blesa has nothing to disclose.
Howard J. Rosen, MD (UCSF)	Dr. Rosen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eisai Pharmaceuticals. Dr. Rosen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. The institution of Dr. Rosen has received research support from NIH. The institution of Dr. Rosen has received research support from State of CA. Dr. Rosen has a non-compensated relationship as a Consultant with Alector that is relevant to AAN interests or activities. Dr. Rosen has a non-compensated relationship as a Consultant with Prevail Therapeutics that is relevant to AAN interests or activities. Dr. Rosen has a non-compensated relationship as a consultant with Alchemab that is relevant to AAN interests or activities.
Bruce L. Miller, MD, FAAN (University of California, San Francisco)	Dr. Miller has nothing to disclose.
Maria Luisa Gorno Tempini, MD, PhD (UCSF Memory and Aging Center)	The institution of Dr. Gorno Tempini has received research support from NIH.
	No disclosure on file
Alberto Lleo, MD (Hospital De La Santa Creu I Sant Pau)	Dr. Lleo has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Lleo has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Roche. The institution of Dr. Lleo has received research support from Instituto de Salud Carlos III. The institution of Dr. Lleo has received research support from Generalitat de Calalunya (PERIS). The institution of Dr. Lleo has received research support from BBVA Foundation. The institution of Dr. Lleo has received research support from La Caixa Foundation. Dr. Lleo has received intellectual property interests from a discovery or technology relating to health care.
Juan Fortea, MD, PhD (Hospital of Sant Pau)	Dr. Fortea has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. Dr. Fortea has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for AC Inmune. Dr. Fortea has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Roche. The institution of Dr. Fortea has received research support from NIH. Dr. Fortea has received intellectual property interests from a discovery or technology relating to health care.