Standalone Optode for Functional Near-Infrared Spectroscopy Acquisition

Functional near-infrared spectroscopy(fNIRS) is a non-invasive modality that can measure brain activation based on its hemodynamic response. It has high spatial resolution and it is robust from motion artifacts and safe due to the absence of radiation. This study investigates the ability to create an optode module to acquire fNIRS signals. Several such optodes can be connected using a central controller to obtain signals from several regions of the scalp simultaneously but the main focus of this paper is on the optode module. It has a photodiode, near-infrared light emitting diodes, and a Cortex M4 microcontroller. Its operation is verified using the Valsalva maneuver, The readings obtained from this prototype along with possible improvements are also discussed in detail.