title: Theoretical and experimental investigation of the influence of frontal sinus on the sensitivity of the NIRS signal in the adult head.
abstract: The sensitivity of the near-infrared spectroscopy signal to the brain activation depends on the thickness and structure of the superficial tissues. The influence of the frontal sinus, which is void region in the skull, on the sensitivity to the brain activation is investigated by the time-resolved experiments and the theoretical modelling of the light propagation in the head. In the time-resolved experiments, the mean-time of flight for the forehead scarcely depends upon the existence of the frontal sinus when probe spacing was shorter than 30 mm. The partial optical path length in the brain, which indicates the sensitivity of the near-infrared spectroscopy signal to the brain activation, in a simplified head model is predicted by Monte Carlo simulation. The influence of the frontal sinus on the sensitivity of the signal depends on the thickness of the skull and the depth of the frontal sinus.
authors.affiliation: Department of Electronics and Electrical Engineering, Keio University, Yokohama, Japan. okada@elec.keio.ac.jp
authors.forename: Eiji
authors.initials: E
authors.lastname: Okada
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamamoto
authors.forename: Naoya
authors.initials: N
authors.lastname: Kiryu
authors.forename: Akihisa
authors.initials: A
authors.lastname: Katagiri
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yokose
authors.forename: Takashi
authors.initials: T
authors.lastname: Awano
authors.forename: Kouji
authors.initials: K
authors.lastname: Igarashi
authors.forename: Sin
authors.initials: S
authors.lastname: Nakamura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hoshino
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Murata
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Kano
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000328:Adult; D005626:Frontal Sinus / Q000502:physiology*; D006257:Head / Q000502:physiology*; D006801:Humans; D008027:Light; D008954:Models, Biological; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013997:Time Factors