Developing headgear and technology for functional Near Infrared Spectroscopy (fNIRS)
Research Associate: Jamie Frasure
Principal Investigator: Angela Harrivel
Functional Near Infrared Spectroscopy (fNIRS) is a non-invasive functional neuroimaging technique that monitors neural activity in the cortex, which is the outer layer of the brain. NASA Glenn Research Center is using this technology to monitor attentional networks within the brain to determine the cognitive state of pilots during flight. The overall aim is to make air and space travel safer.
fNIRS is used for medical imaging, just like fMRI. There are several benefits to fMRI, as well as a few shortcomings. MRI machines cost millions of dollars, take up an entire room, and require the patient to lie perfectly still for accurate results, which are of a very high resolution. In comparison, fNIRS is a fraction of the cost, could fit into a suitcase, and allows the patient to be moving and active while achieving desired results. fNIRS will never compete with fMRI because its resolution is roughly ten times worse. However, fNIRS promises to allow for the practical application of functional neuroimaging outside of a hospital or laboratory setting.
fNIRS uses visible and infrared light to penetrate the scalp, skull and brain tissue in certain regions of the head. This process is non-invasive and safe for long-term usage. Light penetrates the cortex and is absorbed by the oxygenated or deoxygenated blood. The light travels to a detector, and the amplitude is measured to determine the relative changes in the concentrations of oxygenated and deoxygenated blood in that region of the brain. If the generated results show a change in a specific region, then the region may have been activated or deactivated. NASA Glenn uses an instrument which uses the wavelengths of 690 and 830 nm because those are absorbed differentially by oxygenated and deoxygenated hemoglobin, and are not interfered with by other present materials.
My Role as a Research Associate
While the technology related to fNIRS is not specific to NASA and is being researched worldwide, appropriate monitoring devices present a problem to nearly all fNIRS research. The signal and detector must be flush against the scalp for maximum penetration of the light because the signal is weak if it is even a slight bit off the scalp. The detectors and signals also can be fairly cumbersome, becoming painful after just a few minutes. The headgear needs to be comfortable for long-term wear by pilots.
The NASA Glenn Team working on this project, led by Angela Harrivel, has designated two specific aims as a function of the project. We first aim to design, produce, and validate improved fNIRS headgear. A pilot must be able to wear the equipment comfortably for long periods of time with motion availability, qualities the current headgear does not possess. The measurements must also extend beyond the hairline, because the detector and the source must rest flush against the scalp, but not be dependant on the hair for stability because of a variety of hair thicknesses. I particularly will be contributing to the design of headgear that is applicable to all head and hair types, making this technology applicable to all people. The design must be lightweight, stable, and functional.
The second aim is to demonstrate the practical applicability of fNIRS to real-time cognitive state monitoring by collecting data during human subjects trials. Data analysis is being automated to determine the relative concentrations of oxygenated versus deoxygenated hemoglobin. My particular role will be to assist with the preparations of both the headgear and the data analysis for upcoming trials. This is not just a proof of concept, but rather a demonstration that fNIRS can be applied in more than just a lab setting. Thus, the practical aspects of the headgear will be weighed against signal and data quality.