Functional Near Infrared Spectroscopy (fNIRS) has recently been making impressive gains as a way to measure the surface blood-flow of the brain. This can be used to indirectly quantify brain activity (in the same way as fMRI measures brain activity via blood flow changes) in a limited region. Also, because it is a low power technology, mass fNIRS devices can be made robust and portable enough for use longitudinally in extreme environments, hence some have been used on studies in parabolic flight and on Mt. Kilimanjaro. fNIRS works similarly to pulse-oximeters for the finger, but placed against the skull, using infrared light and optical sensors to detect hemoglobin. However, this limits its utility for those with long, flowing hair, making it a popular imaging modality for brain activity in the bald.
Now, a group at the University of Texas’s Dallas and Arlington campuses might have found a way around the hair problem by placing the sensors at the ends of fiber strands like a brush and will present their approach at the Optical Society’s (OSA) 94th annual meeting, Frontiers in Optics (FiO) 2010.
From the OSA:
“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,” [Douglas MacFarlane of UT Dallas] explains. “So we developed a new tip for the fNIRS fibers — a brush optrode that slides the fibers between the hair follicles. 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.”
This research is expected to open the door to portable, easy-to-use, high-density optical scanning of brain activity. For example, the University of Texas researchers’ work focuses on the imaging of changes in cortical plasticity as a function of impairment severity in children with cerebral palsy.
Image: fNIRS device (not from article) being tested on Medgadget Editor Dan Buckland in parabolic flight. Note lack of hair making for easy data collection. Credit: Steve Boxall
Full story: The Hair Brush that Reads Your Mind…