A Drowsiness Reduction Strategy Utilizing Visual Stimulation With Different Colors of Light: An fNIRS Study

Abstract

Drowsiness during driving is a severe problem that must be addressed to improve road safety. Numerous counter-measures have been proposed to resolve this issue like adaptive environmental settings (temperature, sound, and light). The objective of this study was to accurately predict the effects of exposure to different colors of light on human drowsiness by using functional near-infrared spectroscopy and other physical measurements (heart rate and eye closure). We targeted two regions of the brain (visual and prefrontal cortices). Twenty-three healthy subjects were investigated to evaluate all variables related to the awakening state, and twenty-one healthy subjects were also examined in the drowsy state evaluation. Eventually, the ten most suitable subjects were exposed to red, green, and blue lights under drowsy conditions, according to the experimental paradigm. Dim light was maintained in the experimental premises before and after colored light exposure to limit the results to those produced only in response to the desired stimuli. Eye closure, heart rate, and changes in oxy and deoxy hemoglobin concentrations were measured to characterize the condition (awake/drowsy) of the subject. A support vector machine classifier was used to identify the classification accuracy of awake and drowsy states. In conclusion, exposure to blue light triggered the activation of oxy hemoglobin in targeted brain regions; however, deoxy hemoglobin was not significantly affected by exposure to any of the colored lights. Noticeably, our study revealed that blue light exposure is more effective at reducing drowsiness than exposure to red and green lights.INDEX TERMS functional near-infrared spectroscopy, colored light exposure, drowsiness, sleep deprivation, heart rate, and eye closure.

Utilizing EEG and fNIRS for the detection of sleep-deprivation-induced fatigue and its inhibition using colored light stimulation

“…The research objective of this study was to evaluate the effects of exposure to red, green, and blue colors of light on human alertness level by assessing blood oxygenation changes (measured with fNIRS), EEG frequency band powers (delta, theta, alpha, beta and gamma) and other physiological measures, including EC rate and HR. This study supports our earlier findings 14 that, compared with longer wavelength light (red and green) exposure, shorter wavelength light (blue) exposure increases cognitive activity in specific brain regions under fatigued conditions. In the absence of sleep deprivation, the average of all subjects resulted in increased HbO values in comparison to the HbR values, and in the case of sleep deprivation, lower HbO values were observed in comparison to the HbR values.…”

“…A more direct and objective assessment of alertness level is provided by evaluating physiological parameters, those can be assessed continually. Fatigue-related signals may also be monitored using functional Near-Infrared Spectroscopy (fNIRS), Electroencephalogram (EEG), and functional Magnetic Resonance Imaging (fMRI) [13][14][15][16] . Several studies have employed fNIRS for drowsiness detection and also to discover association between neurophysiological responses and driver's mental state.…”