Hamoon Zohdi, Felix Scholkmann, Ursula Wolf
Neurophotonics, Vol. 7, Issue 02, 025006, (June 2020) https://doi.org/10.1117/1.NPh.7.2.025006
TOPICS: Neurophotonics, Physiology, Brain, Finite element methods, Statistical analysis, Beam propagation method, Tissues, Carbon monoxide, Reliability, Tissue optics
Significance: Our study reveals that frontal cerebral oxygenation asymmetry (FCOA), i.e. a difference in the oxygenation between the right and left prefrontal cortex (PFC), is a real phenomenon in healthy human subjects at rest.
Aim: To investigate FCOA, we performed a study with 134 healthy right-handed subjects with the systemic physiology augmented functional near infrared spectroscopy (SPA-fNIRS) approach.
Approach: Subjects were measured 2 to 4 times on different days resulting in an unprecedented number of 518 single measurements of the absolute values of tissue oxygen saturation (StO2) and total hemoglobin concentration ([tHb]) of the right and left PFC. Measurements were performed with frequency-domain functional near-infrared spectroscopy. In addition, the cardiorespiratory parameters were measured simultaneously.
Results: We found that (i) subjects showed an FCOA (higher StO2 on the right PFC), but not for tHb; (ii) intrasubject variability was excellent for both StO2 and tHb, and fair for FCOA; (iii) StO2 correlated significantly with blood CO2 concentration, [tHb] with heart rate, respiration rate (RR), and the pulse–respiration quotient (PRQ), and FCOA with RR and PRQ; (iv) FCOA and StO2 were dependent on season and time of day, respectively; (v) FCOA was negatively correlated with the room temperature; and (vi) StO2 and tHb were not correlated with the subjects mood but with their chronotype, whereas FCOA was not dependent on the chronotype.
Conclusion: Our study demonstrates that FCOA is real, and it provides unique insights into this remarkable phenomenon.