Electroencephalographic Changes during Intravenous Olfactory Stimulation in Humans

Hirofumi Harada, Fumihide Rikimaru, Takashi Mori, Masahiro Tanaka, Kimio Shiraishi, Toshihiko Kato

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The intravenous olfaction test with thiamin propyl disulfide (TPD) is a simple procedure widely used in Japan. An olfactory stimulus is provided by intravenous injection of TPD (2 ml) over the course of 20 sec. The subject smells n-propyl mercaptan (a decomposition product of TPD discharged from the blood into alveoli) in expired air after treatment. In this preliminary study we recorded electroencephalograms (EEGs) in normal subjects during three stages: 1) eyes-closed rest (prestimulus), 2) olfactory sensation after TPD injection, and 3) disappearance of sensation. In each of these stages, we calculated and compared EEG powers according to the band components of each electrode position. This study was designed a) to evaluate by frequency analysis EEG changes during olfactory sensation after TPD injection, and b) to identify the most significant changes in EEG power according to frequency band and electrode location. During the intravenous olfactory stimulation, alpha 2 and beta 2 waves were activated over the frontal and temporal regions. After disappearance of olfactory sensation, these waves decreased in the same regions. EEG powers returned to prestimulus levels.

Original languageEnglish
Pages (from-to)189-192
Number of pages4
JournalClinical EEG and Neuroscience
Issue number4
Publication statusPublished - Oct 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neurology
  • Clinical Neurology


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