title: Working memory and language network dysfunctions in logopenic aphasia: a task-free fMRI comparison with Alzheimer's dementia.
abstract: We aimed to determine whether network-level functional connectivity differs in 2 clinical variants of Alzheimer's disease: logopenic primary progressive aphasia (lvPPA) and dementia of the Alzheimer's type (DAT). Twenty-four lvPPA subjects with amyloid deposition on positron emission tomography and task-free functional magnetic resonance imaging were matched to 24 amyloid-positive DAT subjects and 24 amyloid-negative controls. Independent-component analysis and spatial-temporal dual regression were used to assess functional connectivity within the language network, left and right working memory networks, and ventral default mode network. lvPPA showed reduced connectivity in left temporal language network and inferior parietal and prefrontal regions of the left working memory network compared with controls and DAT. Both groups showed reduced connectivity in the parietal regions of the right working memory network compared with controls. Only DAT showed reduced ventral default mode network connectivity compared with controls. Aphasia severity correlated with connectivity in the left working memory network within lvPPA. Patterns of network dysfunction differ across these 2 clinical variants of Alzheimer's disease, with lvPPA particularly associated with disruptions in the language and left working memory networks.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA. Electronic address: whitwell.jennifer@mayo.edu.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Whitwell
authors.affiliation: Department of Neurology (Behavioral Neurology), Mayo Clinic, Rochester, MN, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Jones
authors.affiliation: Department of Neurology (Speech Pathology), Mayo Clinic, Rochester, MN, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Duffy
authors.affiliation: Department of Neurology (Speech Pathology), Mayo Clinic, Rochester, MN, USA.
authors.forename: Edythe A
authors.initials: EA
authors.lastname: Strand
authors.affiliation: Department of Psychiatry and Psychology (Neuropsychology), Mayo Clinic, Rochester, MN, USA.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Machulda
authors.affiliation: Department of Health Sciences Research (Biostatistics), Mayo Clinic, Rochester, MN, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Przybelski
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Prashanthi
authors.initials: P
authors.lastname: Vemuri
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Gregg
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA; Department of Information Technology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Gunter
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA; Department of Information Technology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Senjem
authors.affiliation: Department of Neurology (Behavioral Neurology), Mayo Clinic, Rochester, MN, USA.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Petersen
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
authors.affiliation: Department of Neurology (Behavioral Neurology), Mayo Clinic, Rochester, MN, USA.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Josephs
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D001037:Aphasia / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology*; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D016229:Amyloid beta-Peptides
keywords: Alzheimer's disease; Functional imaging; Language; MRI; Primary progressive aphasia