Functional Near-infrared Spectroscopy (fNIRS)
Functional near-infrared spectroscopy (fNIRS) is a safe new type brain imaging that is now fully portable. Similar to the fMRI functional images, fNIRS measures brain activity and shows what works and what doesn’t. Instead of a patient having to be inside of a large enclosed magnetic resonance machine (MRI) in the hospital, fNIRS is a portable device that emits light waves that are emitted by an optical headband that the patient wears in an office setting.
The functional near-infrared spectroscopy (fNIRS) sensor is attached to the patient’s forehead and is connected to a portable computing device that records the patient’s brain function as she engages in specific tasks. The data is recorded and then analyzed for changes in blood flow and oxygenation levels of the brain before, during, and after the task. We then form our conclusions about how specific parts of the brain are used for language, emotional, and cognitive abilities.
Specifically, fNIRS uses near-infrared light waves, to monitor the oxygen content of blood flowing to various parts of the brain. This light-wave data is recorded and analyzed to measure differing oxygen levels. We then use the data to generate meaningful images of brain activation. These are those brain areas that are working the most - have the most amount of oxygenated blood - and appear on the brain images the most brightly colored regions of the brain.
We evaluate the significant brain regions that were activated and correlate those images to the patient’s performance, for example how the patient performed on an expressive language task. With such a valuable combination of brightly-colored brain images and theoretical linguistic data, we now have a pretty good idea of how it all works.