A 12-Channel, real-time near-infrared spectroscopy instrument for brain-computer interface applications

Abstract

Abstract-A continuous wave near-infrared spectroscopy (NIRS) instrument for brain-computer interface (BCI) applications is presented. In the literature, experiments have been carried out on subjects with such motor degenerative diseases as amyotrophic lateral sclerosis, which have demonstrated the suitability of NIRS to access intentional functional activity, which could be used in a BCI as a communication aid. Specifically, a real-time, multiple channel NIRS tool is needed to realise access to even a few different mental states, for reasonable baud rates. The 12-channel instrument described here has a spatial resolution of 30mm, employing a flexible software demodulation scheme. Temporal resolution of ~100ms is maintained since typical topographic imaging is not needed, since we are only interested in exploiting the vascular response for BCI control. A simple experiment demonstrates the ability of the system to report on haemodynamics during single trial mental arithmetic tasks. Multiple trial averaging is not required.

Triple wavelength LED driver for optical brain–computer interfaces

“…Care should also be taken to avoid clipping (this introduces harmonics and thus poor demodulation). With a frequency range of 40 kHz the LED driver is suitable for CWNIRS [7].…”

CMOS silicon avalanche photodiodes for NIR light detection: a survey

“…The commonly used non-invasive neuroimaging techniques are electro-encephalography (EEG), magneto-encephalography (MEG), PET, functional magnetic resonance imaging (fMRI), and near-infrared spectroscopy (NIRS), which is the subject of the present paper [5]. Near-infrared spectroscopy is a technique where brain tissue is penetrated by NIR radiation and the resultant absorption and scattering effects are observed to investigate the brain's function [6].…”

Correction of motion artifacts and serial correlations for real-time functional near-infrared spectroscopy

“…Due to the portability and high sample rate of fNIRS measurements, several researchers have previously explored the use of fNIRS in real-time assessments of brain activity, [10][11][12][13][14][15][16][17] biofeedback, 18 and brain-computer interfacing applications. 15,16,[19][20][21][22][23][24] These real-time applications, however, must contend with noise and artifacts often contained within the NIRS data.…”

“…15,16,[19][20][21][22][23][24] These real-time applications, however, must contend with noise and artifacts often contained within the NIRS data. In particular, the two major sources of confounding noise that affect the analysis and interpretation of fNIRS signals are serially correlated errors due to systemic physiology, such as cardiac, respiratory, and low-frequency Mayer waves (related to blood pressure regulation), and motion artifacts due to the movement or slippage of the head cap.…”