title: Dipole source analysis of temporal slow waves in the elderly.
abstract: BACKGROUND
  Temporal low-voltage irregular delta-waves (TLID) are often found in elderly subjects. The physiological significance of TLID has not been clarified; however, our previous studies suggest that TLID are associated with mild cerebrovascular dysfunction.
  
  
  OBJECTIVE
  The present study aimed to reveal the origin of TLID and their neural mechanisms by dipole source modeling.
  
  
  METHODS
  From electroencephalography records taken from 21 scalp electrodes, clear and typical TLID of 6 elderly subjects (mean age, 69 +/- 6.2 years) were selected. Among these, we selected and averaged 7-12 clear TLID on the left side in each subject, and estimated a single equivalent current dipole for the averaged TLID.
  
  
  RESULTS
  The best equivalent current dipoles were estimated to be located in the medial part of the temporal lobe in or near the parahippocampal gyrus in the hemisphere ipsilateral to the TLID, with a high reliability in all subjects.
  
  
  CONCLUSIONS
  Considering the source localization of TLID, TLID seem to indicate certain dysfunctions of the hippocampus or adjacent regions. This is the first study to report the cerebral origin of TLID and suggest its physiological significance.
authors.affiliation: Department of Psychiatry, Division of Neuroscience, Institute of Medical Science, Mie University Graduate School of Medicine, Tsu, Japan. motomura@clin.medic.mie-u.ac.jp
authors.forename: Eishi
authors.initials: E
authors.lastname: Motomura
authors.forename: Koji
authors.initials: K
authors.lastname: Inui
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ogawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakase
authors.forename: Kenji
authors.initials: K
authors.lastname: Hamanaka
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Honda
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiroyama
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Komori
authors.forename: Motohiro
authors.initials: M
authors.lastname: Okada
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kakigi
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000175:diagnosis / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004567:Electrodes, Implanted; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D013702:Temporal Lobe / Q000503:physiopathology*; D013997:Time Factors