Near Infrared Spectroscopy (NIRS): A Pilot Study to Measure Hemoglobin Concentration Changes in the Brains of Persons who Stutter and Typically Fluent Speakers

Abstract

Near infrared spectroscopy (NIRS) is a diffuse optical technique that has been used to measure oxy-, de-oxy, and total hemoglobin concentration changes in real-time at the surface of the brain. NIRS relies on neuro-vascular coupling—Blood-Oxygenation–Level-Dependent (BOLD) response—and measures hemoglobin concentration changes through the use of a light source (infra-red) in a safe region of the electromagnetic spectrum. We conducted a pilot study with NIRS to determine whether there were hemoglobin concentration changes in the brains of persons who stutter and typically fluent speakers during reading, counting, and free speech. Results indicate that as the complexity of the task increased, the magnitude of the hemoglobin concentration change increased.Overall, these three speech tasks caused hemoglobin concentration changes in Broca's area, Wernicke's area, and other areas of the brain.