Cognitive and Behavioral Neurology 27: 206-14, 2014. PMCID: PMC4296883
Objective: To relate changes in fractional anisotropy associated with behavioral variant frontotemporal dementia to measures of apathy and disinhibition.
Background: Apathy and disinhibition are the 2 most common behavioral features of behavioral variant frontotemporal de- mentia, and these symptoms are associated with accelerated patient decline and caregiver stress. However, little is known about how white matter disease contributes to these symptoms.
Methods: We collected neuropsychiatric data, volumetric mag- netic resonance imaging, and diﬀusion-weighted imaging in 11 patients who met published criteria for behavioral variant frontotemporal dementia and had an autopsy-validated cerebrospinal ﬂuid proﬁle consistent with frontotemporal lobar degeneration. We also collected imaging data on 34 healthy seniors for analyses deﬁning regions of disease in the patients. We calculated and analyzed fractional anisotropy with a white matter tract-speciﬁc method. This approach uses anatomically guided data reduction to increase sensitivity, and localizes results within canonically deﬁned tracts. We used nonparametric, cluster-based statistical analysis to relate fractional anisotropy to neuropsychiatric measures of apathy and disinhibition.
Results: The patients with behavioral variant frontotemporal dementia had widespread reductions in fractional anisotropy in anterior portions of frontal and temporal white matter, compared to the controls. Fractional anisotropy correlated with apathy in the left uncinate fasciculus and with disinhibition in the right corona radiata.
Conclusions: In patients with behavioral variant frontotemporal dementia, apathy and disinhibition are associated with distinct regions of white matter disease. The implicated ﬁber tracts likely support frontotemporal networks that are involved in goal- directed behavior.