title: Resting state functional connectivity differences between behavioral variant frontotemporal dementia and Alzheimer's disease.
abstract: BACKGROUND
  Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) are the most common types of early-onset dementia. Early differentiation between both types of dementia may be challenging due to heterogeneity and overlap of symptoms. Here, we apply resting state functional magnetic resonance imaging (fMRI) to study functional brain connectivity differences between AD and bvFTD.
  
  
  METHODS
  We used resting state fMRI data of 31 AD patients, 25 bvFTD patients, and 29 controls from two centers specialized in dementia. We studied functional connectivity throughout the entire brain, applying two different analysis techniques, studying network-to-region and region-to-region connectivity. A general linear model approach was used to study group differences, while controlling for physiological noise, age, gender, study center, and regional gray matter volume.
  
  
  RESULTS
  Given gray matter differences, we observed decreased network-to-region connectivity in bvFTD between (a) lateral visual cortical network and lateral occipital and cuneal cortex, and (b) auditory system network and angular gyrus. In AD, we found decreased network-to-region connectivity between the dorsal visual stream network and lateral occipital and parietal opercular cortex. Region-to-region connectivity was decreased in bvFTD between superior temporal gyrus and cuneal, supracalcarine, intracalcarine cortex, and lingual gyrus.
  
  
  CONCLUSIONS
  We showed that the pathophysiology of functional brain connectivity is different between AD and bvFTD. Our findings support the hypothesis that resting state fMRI shows disease-specific functional connectivity differences and is useful to elucidate the pathophysiology of AD and bvFTD. However, the group differences in functional connectivity are less abundant than has been shown in previous studies.
authors.affiliation: Department of Methodology and Statistics, Institute of Psychology, Leiden University Leiden, Netherlands ; Department of Radiology, Leiden University Medical Center Leiden, Netherlands ; Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands.
authors.forename: Anne
authors.initials: A
authors.lastname: Hafkemeijer
authors.affiliation: Alzheimer Center and Department of Neurology, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Christiane
authors.initials: C
authors.lastname: Möller
authors.affiliation: Department of Radiology, Leiden University Medical Center Leiden, Netherlands ; Alzheimer Center and Department of Neurology, VU University Medical Center Amsterdam, Netherlands ; Alzheimer Center and Department of Neurology, Erasmus Medical Center Rotterdam, Netherlands.
authors.forename: Elise G P
authors.initials: EG
authors.lastname: Dopper
authors.affiliation: Department of Radiology, Leiden University Medical Center Leiden, Netherlands ; Alzheimer Center and Department of Neurology, Erasmus Medical Center Rotterdam, Netherlands ; Department of Neuropsychology, Erasmus Medical Center Rotterdam, Netherlands.
authors.forename: Lize C
authors.initials: LC
authors.lastname: Jiskoot
authors.affiliation: Department of Methodology and Statistics, Institute of Psychology, Leiden University Leiden, Netherlands ; Department of Radiology, Leiden University Medical Center Leiden, Netherlands ; Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands.
authors.forename: Tijn M
authors.initials: TM
authors.lastname: Schouten
authors.affiliation: Alzheimer Center and Department of Neurology, Erasmus Medical Center Rotterdam, Netherlands ; Department of Clinical Genetics, VU University Medical Center Amsterdam, Netherlands.
authors.forename: John C
authors.initials: JC
authors.lastname: van Swieten
authors.affiliation: Alzheimer Center and Department of Neurology, VU University Medical Center Amsterdam, Netherlands ; Department of Epidemiology and Biostatistics, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Wiesje M
authors.initials: WM
authors.lastname: van der Flier
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center Amsterdam, Netherlands ; Department of Physics and Medical Technology, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Hugo
authors.initials: H
authors.lastname: Vrenken
authors.affiliation: Alzheimer Center and Department of Neurology, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Yolande A L
authors.initials: YA
authors.lastname: Pijnenburg
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Frederik
authors.initials: F
authors.lastname: Barkhof
authors.affiliation: Alzheimer Center and Department of Neurology, VU University Medical Center Amsterdam, Netherlands.
authors.forename: Philip
authors.initials: P
authors.lastname: Scheltens
authors.affiliation: Department of Radiology, Leiden University Medical Center Leiden, Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van der Grond
authors.affiliation: Department of Methodology and Statistics, Institute of Psychology, Leiden University Leiden, Netherlands ; Department of Radiology, Leiden University Medical Center Leiden, Netherlands ; Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands.
authors.forename: Serge A R B
authors.initials: SA
authors.lastname: Rombouts
keywords: Alzheimer's disease; frontotemporal dementia; functional connectivity; functional magnetic resonance imaging; neurodegenerative disorders; resting state fMRI; resting state networks