Dipole source analysis of temporal slow waves in the elderly

Eishi Motomura, Koji Inui, Hiroyuki Ogawa, Shinji Nakase, Kenji Hamanaka, Tomoyuki Honda, Takashi Shiroyama, Takuya Matsumoto, Teruhisa Komori, Motohiro Okada, Ryusuke Kakigi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Background: Temporal low-voltage irregular δ-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.

Original languageEnglish
Pages (from-to)9-13
Number of pages5
Issue number1-2
Publication statusPublished - Jun 2008
Externally publishedYes


  • Dipole source modeling
  • Temporal low-voltage irregular δ-waves, source analysis
  • Temporal slow-wave activity, age-related

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Psychiatry and Mental health
  • Biological Psychiatry


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