The longitudinal decline of white matter microstructural integrity in behavioral variant frontotemporal dementia and its association with executive function.

The longitudinal decline in the integrity of several white matter (WM) tracts in behavioral variant frontotemporal dementia (bvFTD) has been documented. However, there is yet a clear relationship between this decline and that of executive function (EF), for the WM changes to meaningfully track progression in bvFTD. We sought to validate the use of diffusion tensor imaging (DTI) in tracking the progression of bvFTD with its associated decline in EF. Baseline and 1-year follow-up DTI scans were acquired from 23 patients with bvFTD and 26 healthy controls. EF composite score was derived via multiple tests. The longitudinal changes in DTI metrics were examined in both groups. Then, among patients (N = 18), we examined the associations between these changes and that of EF. Widespread WM alterations and decline in EF were observed only in patients. This EF decline was mostly associated with the disrupted integrity of the corpus callosum and anterior corona radiata. These longitudinal findings support the use of DTI in tracking the progression of bvFTD and its associated EF decline.