title: Discovering EEG resting state alterations of semantic dementia.
abstract: OBJECTIVE
  Diagnosis of semantic dementia relies on cost-intensive MRI or PET, although resting EEG markers of other dementias have been reported. Yet the view still holds that resting EEG in patients with semantic dementia is normal. However, studies using increasingly sophisticated EEG analysis methods have demonstrated that slightest alterations of functional brain states can be detected.
  
  
  METHODS
  We analyzed the common four resting EEG microstates (A, B, C, and D) of 8 patients with semantic dementia in comparison with 8 healthy controls and 8 patients with Alzheimer's disease.
  
  
  RESULTS
  Topographical differences between the groups were found in microstate classes B and C, while microstate classes A and D were comparable. The data showed that the semantic dementia group had a peculiar microstate E, but the commonly found microstate C was lacking. Furthermore, the presence of microstate E was significantly correlated with lower MMSE and language scores.
  
  
  CONCLUSIONS
  Alterations in resting EEG can be found in semantic dementia. Topographical shifts in microstate C might be related to semantic memory deficits.
  
  
  CONCLUSIONS
  This is the first study that discovered resting state EEG abnormality in semantic dementia. The notion that resting EEG in this dementia subtype is normal has to be revised.
authors.affiliation: Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland. Electronic address: grieder@puk.unibe.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Grieder
authors.affiliation: Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Koenig
authors.affiliation: Department of Neuropsychiatry, Kansai Medical University, Osaka, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kinoshita
authors.affiliation: Department of Radiology, Kansai Medical University, Osaka, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Utsunomiya
authors.affiliation: Karolinska Institute, Dept. NVS, Division of Clinical Geriatrics, Stockholm, Sweden.
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
authors.affiliation: Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.affiliation: Department of Neuropsychiatry, Kansai Medical University, Osaka, Japan.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Nishida
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D004569:Electroencephalography; D005260:Female; D057180:Frontotemporal Dementia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology*
keywords: Alzheimer’s disease; EEG; EEG microstates; Resting state; Semantic dementia