It’s often said that dark hair is bad for NIRS experiment because it absorbs more light. I heard this on day one when I started using NIRS back in 2008. I never got a chance to do a systematic experiment to compare hair colors and their effect on NIRS data quality. However based on my own experience the hair color does not affect data quality much: I myself has black hair but data quality from my own head is always very good – and I have done tons of finger tapping experiment on myself.
When I did some literature search today I found an article which addressed this issue! It was published in 2012. I actually know two of the authors, Hanli Liu and Fenghua Tian from University of Texas at Arlington. I visited them in 2011 and was grateful to their hospitality. I should have read this paper long time ago – maybe Stork will help to track new relevant publications 🙂
Go back to their paper – they did find the data quality from black hair is worse than that from brown or blonde hair, which is in turn worse than no hair. The following figures are from their publication, Improving optical contact for functional near‑infrared brain spectroscopy and imaging with brush optodes.
