title: Functional connectivity and microstructural white matter changes in phenocopy frontotemporal dementia.
abstract: OBJECTIVE
  Phenocopy frontotemporal dementia (phFTD) is a rare and poorly understood clinical syndrome. PhFTD shows core behavioural variant FTD (bvFTD) symptoms without associated cognitive deficits and brain abnormalities on conventional MRI and without progression. In contrast to phFTD, functional connectivity and white matter (WM) microstructural abnormalities have been observed in bvFTD. We hypothesise that phFTD belongs to the same disease spectrum as bvFTD and investigated whether functional connectivity and microstructural WM changes similar to bvFTD are present in phFTD.
  
  
  METHODS
  Seven phFTD patients without progression or alternative psychiatric diagnosis, 12 bvFTD patients and 17 controls underwent resting state functional MRI (rs-fMRI) and diffusion tensor imaging (DTI). Default mode network (DMN) connectivity and WM measures were compared between groups.
  
  
  RESULTS
  PhFTD showed subtly increased DMN connectivity and subtle microstructural changes in frontal WM tracts. BvFTD showed abnormalities in similar regions as phFTD, but had lower increased DMN connectivity and more extensive microstructural WM changes.
  
  
  CONCLUSIONS
  Our findings can be interpreted as neuropathological changes in phFTD and are in support of the hypothesis that phFTD and bvFTD may belong to the same disease spectrum. Advanced MRI techniques, objectively identifying brain abnormalities, would therefore be potentially suited to improve the diagnosis of phFTD.
  
  
  CONCLUSIONS
  • PhFTD shows brain abnormalities that are similar to bvFTD. • PhFTD shows increased functional connectivity in the parietal default mode network. • PhFTD shows microstructural white matter abnormalities in the frontal lobe. • We hypothesise phFTD and bvFTD may belong to the same disease spectrum.
authors.affiliation: Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Meijboom
authors.affiliation: Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: R M E
authors.initials: RME
authors.lastname: Steketee
authors.affiliation: Neuropsychology, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: I
authors.initials: I
authors.lastname: de Koning
authors.affiliation: Psychiatry, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: Osse
authors.affiliation: Neuropsychology, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.|Neurology, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: L C
authors.initials: LC
authors.lastname: Jiskoot
authors.affiliation: Neurology, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: F J
authors.initials: FJ
authors.lastname: de Jong
authors.affiliation: Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van der Lugt
authors.affiliation: Neurology, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands.
authors.forename: J C
authors.initials: JC
authors.lastname: van Swieten
authors.affiliation: Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre, Rotterdam, The Netherlands. marion.smits@erasmusmc.nl.
authors.forename: M
authors.initials: M
authors.lastname: Smits
mesh_terms: D000328:Adult; D000368:Aged; D056324:Diffusion Tensor Imaging / Q000379:methods; D018450:Disease Progression; D005260:Female; D057180:Frontotemporal Dementia / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology*
keywords: Diagnosis; Diffusion tensor imaging; Frontotemporal dementia; Functional magnetic resonance imaging; White matter