technetium-tc-99m-bicisate and Frontotemporal-Dementia

The brain reserve hypothesis posits that there are individual differences in the ability to cope with brain pathology, and that brain damage extent and clinical symptoms are not tightly linked. If cognitive reserve hypothesis has been demonstrated in Alzheimer Disease and Frontotemporal Dementia (FTD), no evidence of reserve mechanisms on behavioural disturbances has been corroborated yet. In FTD, distinct behavioural phenotypes may be identified.. To test the behavioural reserve hypothesis in behavioural variant FTD (bvFTD).. As previously demonstrated, bvFTD patients were grouped into four behavioural phenotypes, i.e. "disinhibited", "apathetic", "language", and "aggressive", by means of Confirmatory Factor Analysis on behavioural assessment. Educational achievement was considered as proxy measure of reserve on behavioural disturbances, and cerebral SPECT as an indirect expression of brain pathology. On each group, the effect of education on brain damage was assessed by slope analysis.. A specific effect of education attainment on "disinhibited" phenotype was observed, the higher the education, the greater the hypoperfusion in the right inferior frontal gyrus and the left medial frontal gyrus and right caudate (P<0.001). On the other behavioural phenotypes, no effect of education was reported in modulating brain damage.. We suggest that in neurodegenerative diseases the concept of brain reserve might be extended, as compensatory mechanisms are in action not only for cognitive deficits but for behavioural disturbances as well.

Topics: Aged; Behavior; Brain; Brain Mapping; Caudate Nucleus; Cognitive Reserve; Cysteine; Educational Status; Factor Analysis, Statistical; Female; Frontal Lobe; Frontotemporal Dementia; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Radiopharmaceuticals; Regression Analysis; Tomography, Emission-Computed, Single-Photon

Behavioural variant of frontotemporal dementia (bvFTD) frequently presents complex behavioural changes, that rarely occur in isolation. Targeting behavioural phenotypes instead of single behavioural symptoms may potentially provide a disease model in which to investigate brain substrates of behavioural abnormalities.. To identify behavioural phenotypes and to assess the associated brain correlates in a cohort of patients with bvFTD.. Two hundred and seven consecutive individuals fulfilling clinical criteria for bvFTD were enrolled. Each participant's caregiver completed frontal behavioural inventory on 24 key behavioural disturbances. Confirmatory factor analysis (CFA) models were applied, and behavioural phenotypes identified. For each phenotype, a score was derived based on the "best" CFA model (Bifactor CFA). One hundred two participants underwent SPECT scan. A regression analysis between scores for each factor and regional cerebral blood flow was carried out (P<0.001).. One "general" behavioural phenotype and four factors were identified, that were termed "disinhibited", "apathetic", "aggressive", and "language" phenotypes. The most robust brain correlate was identified for "disinhibited" phenotype, in the region of the anterior cingulated and anterior temporal cortex, bilaterally, and for apathetic phenotype in the left dorsolateral frontal cortex. As expected, language phenotype correlated with greater hypoperfusion in the left frontotemporal lobes. No significant correlation between aggressive phenotype and regional cerebral blood flow was found. Moreover, the "general" behavioural severity was associated with greater damage in the right frontal lobe.. Behavioural phenotypes are associated with specific brain damage in bvFTD, involving distinct cerebral networks.

Topics: Aged; Behavioral Symptoms; Brain; Brain Mapping; Cysteine; Female; Frontotemporal Dementia; Humans; Male; Middle Aged; Organotechnetium Compounds; Phenotype; Psychiatric Status Rating Scales; Radiopharmaceuticals; Statistics as Topic; Tomography, Emission-Computed, Single-Photon