Absolute Values of Optical Properties (μa, μ΄s, μeff and DPF) of Human Head Tissue: Dependence on Head Region and Individual

  • Felix ScholkmannEmail author
  • Hamoon Zohdi
  • Nassim Nasseri
  • Ursula Wolf
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 1072)


Background: Absolute optical properties (i.e., the absorption coefficient, μa, and the reduced scattering coefficient, \( {\mu}_{\mathrm{s}}^{\prime } \)) of head tissue can be measured with frequency-domain near-infrared spectroscopy (FD-NIRS). Aim: We investigated how the absolute optical properties depend on the individual subject and the head region. Materials and Methods: The data set used for the analysis comprised 31 single FD-NIRS measurements of 14 healthy subjects (9 men, 5 women, aged 33.4 ± 10.5 years). From an 8-min measurement (resting-state; FD-NIRS device: Imagent, ISS Inc.; bilateral over the prefrontal cortex, PFC, and visual cortex, VC) median values were calculated for μa and \( {\mu}_{\mathrm{s}}^{\prime } \) as well as the effective attenuation coefficient (μeff) and the differential pathlength factor (DPF). The measurement was done for each subject one to three times with at least 24 h between the measurements. Results: (i) A Bayesian ANOVA analysis revealed that head region and subject were the most significant main effects on μa, \( {\mu}_{\mathrm{s}}^{\prime } \) and μeff, as well as DPF, respectively. (ii) At the VC, μa, \( {\mu}_{\mathrm{s}}^{\prime } \) and μeff had higher values compared to the PFC. (iii) The differences in the optical properties between PFC and VC were age-dependent. (iv) All optical properties also were age-dependent. This was strongest for the properties of the PFC compared to the VC. Discussion and Conclusion: Our analysis demonstrates that all optical head tissue properties (μa, \( {\mu}_{\mathrm{s}}^{\prime } \), μeff and DPF) were dependent on the head region, individual subject and age. The optical properties of the head are like a ‘fingerprint’ for the individual subject. Assuming constant optical properties for the whole head should be carefully reconsidered.


Differential Pathlength Factor (DPF) Head Region Human Head Tissues Frequency-domain Near-infrared Spectroscopy (FD-NIRS) Effective Attenuation Coefficient 
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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Felix Scholkmann
    • 1
    • 2
    Email author
  • Hamoon Zohdi
    • 1
  • Nassim Nasseri
    • 1
  • Ursula Wolf
    • 1
  1. 1.University of Bern, Institute of Complementary MedicineBernSwitzerland
  2. 2.University Hospital Zurich, University of Zurich, Department of Neonatology, Biomedical Optics Research LaboratoryZurichSwitzerland

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