National Aeronautics and Space Administration

Glenn Research CenterGlenn Research Center

Angela Harrivel

Angela Harrivel explains to the Academy students how functional Near Infrared Spectroscopy works, as an aid to examining pilots' mental states.Pilot Cognition Study Using Functional Near-Infrared Spectroscopy

Tuesday, July 14th, 2009, StudioPlus Conference Room – North Olmsted, OH

Angela Harrivel is a NASA Biomedical Engineer who is currently conducting research which focuses on the mental state of pilots who are experiencing stress during flight conditions. The ability to monitor a pilot’s mental condition using real-time data acquisition techniques is being developed by researchers at Glenn Research Center in Cleveland, Ohio.

The goal of this technology is to monitor a pilot’s state of mental awareness, as well as the degree of mental overload, during vital phases of flight such as an in-air emergency. If the data indicates that the pilot is becoming overwhelmed by the amount of information being presented in the cockpit, a computer could identify this sensation and curtail the cockpit’s information to convey only the highest-priority information. In this way, the pilot would benefit from a reduced workload during a high-stress situation.

Ms. Harrivel is utilizing a new brain scanning technique known as functional near infrared spectroscopy (fNIRS) which measures the flow of oxygenated blood in the brain. This system employs fiber-optic cable to transmit near-infrared light to the scalp. Once on the scalp, the light diffuses and attenuates as it travels deeper into living tissue. Photodiode detectors are placed around the scalp to measure the intensity of the diffused signal. Fortunately, the optical diffusivity of oxygenated hemoglobin in the blood is significantly different from that of deoxygenated hemoglobin.

Due to this difference in optical diffusivity, fNIRS can distinguish areas in the brain which are active (the body increases the supply of oxygenated blood) and inactive (the supply of oxygenated blood will level off or decrease). Due to the unique properties of the brain, the exact geometric location of an active region of the brain directly corresponds to the type of activity a person is doing. Thus, fNIRS can tell the difference between an overexerted pilot and one who is calm; it can even sense when a pilot is feeling boredom or fatigue.

Currently, the experimental headgear developed at Glenn is impractical for aviation use. The headgear is too heavy, restrictive, irritating, and cumbersome for practical use. This is why Ms. Harrivel is now focusing her attention on the miniaturization and improvement of the optical headgear system. To improve comfort, she has installed grommet-like cushioning device which acts as the optical interface instead of raw fiber optic cabling.

She has also been working with Jamie Frasure, a 2009 NASA Glenn Academy student, on new geometric designs for the headgear. One thought centered upon the concept of a hair barrette which could be easily and repetitively worn by pilots. This barrette would quickly and easily part the hair as it was placed on the head, thus providing an excellent point of contact for the optical sensors to interface with the scalp. Further work needs to be done to implement, test, and verify the efficacy of this design.

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