Neuroanamtomical correlates of executive dimensions in the behavioral variant of frontotemporal dementia

SOL FITTIPALDI; ADOLFO M. GARCÍA; SANDRA BAEZ; AGUSTÍN IBÁÑEZ; LUCAS SEDEÑO; TERESA TORRALVA; SOFÍA ABREVAYA; FACUNDO MANES

Congreso; 11th International Conference on Frontotemporal Dementia; 2018

Executive functions (EFs) encompass a broad range of cognitive processes. Most executive screening batteries provide a global, unitary EF score, hindering the differentiation of the various domains it subsumes. We used a lesion model method to dissociate three different executive dimensions of a frontal screening tool (the INECO Frontal Screening; IFS): response inhibition and set shifting, working memory (WM), and abstraction capacity. We evaluated which brain areas were associated to each dimension, based on the performance of 26 patients with behavioral variant frontotemporal dementia (bvFTD) ?a neurodegenerative disease characterized by executive impairments traceable with the IFS? and 29 healthy controls (HCs). First, we compared behavioral outcomes between groups. Then, we evaluated gray matter volume using voxel-based morphometry. Next, we explored the association between gray matter volume and behavioral performance in the three dimensions via multiple regression analysis. BvFTD patients showed worse scores than HCs in all the executive dimensions, alongside an expected pattern of fronto-tempo-insular atrophy. Response inhibition and set-shifting results were positively associated with the integrity of fronto-temporo-insular regions, posterior cingulate, and basal ganglia regions related to EFs and motor control. WM was positively related to a more specific prefrontal atrophy pattern, including orbitofrontal and frontopolar (BA 10) cortices. Abstraction capacity showed a positive association with a more widespread pattern of fronto-temporal regions. Furthermore, brain areas related to the three dimensions were consistent with the atrophy pattern of bvFTD. These findings highlight the utility of a neurodegenerative lesion model to dissociate the different dimensions that compose EFs, underscoring the validity of the IFS to tackle alterations in bvFTD. Supported by grants from CONICET, CONICYT/FONDECYT Regular (1170010), FONDAP 15150012, INECO Foundation, and the Inter-American Development Bank.