When it comes to measuring oxygen levels in the brain to chart neurological activity--a technique called functional near infrared spectroscopy (fNIRS)--things can get a little hairy. Literally. As in, the patient's hair gets in the way.
So researchers at the University of Texas have engineered a novel device, which they call a "brush optrode" (variant of word optode), whose fiber tips thread past hair to increase scalp contact, thereby improving signal levels as well as overall cost and efficiency of the optical scanning technique. They will present their findings at the Optical Society's 94th annual meeting, Frontiers in Optics 2010, in Rochester, N.Y., on October 26.
"The conventional fibers used in fNIRS systems terminate in a large, flat bundle, and it is easy for a patient's hair to get in the way and block the signal," says Duncan MacFarlane, professor of electrical engineering at the University of Texas at Dallas.
With the new tip for the fNIRS fibers, MacFarlane says signal levels increase 3- to 5-fold, "and patients report that the brush optrode is considerably more comfortable than the conventional fiber ends. And the brush optrode is easier to set up, which saves time and money."
The fNIRS technique uses a relative spectroscopic measurement at two near infrared wavelengths to differentiate between oxygenated and deoxygenated hemoglobin, a difference that helps measure brain activity.
Not only is fNIRS noninvasive, but it is portable and easy to use. With the hair problem out of the way and signal levels higher than ever, the researchers predict that the improved technique could also help evaluate stroke recovery, neurological changes in Alzheimer's patients, and developmental changes in children.