The paper presents a study of neurovascular and metabolic development from newborns to elderly. The phase and coupling of oxy-hemoglobin (∆[HbO]) and deoxy-hemoglobin (∆[Hb]) concentration changes measured by functional near-infrared spectroscopy (fNIRS) were employed to track this biological and neurological processes. The phase difference increases from newborns to 3-4 months-olds babies, then persists throughout adulthood until finally being disrupted at the old age. The children’s phase-locking index (PLI) is the highest, followed by that of adults. These two groups’ PLI are significantly higher than those of infants and the elderly (p<0.001). A hemodynamic model was used to explain the observations and found close associations with cerebral autoregulation and speed of blood flow. Lastly, the effects of anti-phase trend of ∆[HbO] and ∆[Hb] with the influence of noise were analyzed. The results showed that the random noise is a non-negligible factor in calculation the phase difference and coupling strength in fNIRS data analysis. In summary, we demonstrate that the phase-related parameters measured by fNIRS can be used to study the brain and assess brain health throughout the lifespan.
Tracking Brain Development from Neonates to the Elderly by Hemoglobin Phase Measurement using Functional Near-infrared Spectroscopy https://www.embs.org/jbhi/wp-content/uploads/sites/18/2021/06/01-2.png 1269 635 Journal of Biomedical and Health Informatics (JBHI) //www.embs.org/jbhi/wp-content/uploads/sites/18/2022/06/ieee-jbhi-logo2x.png