A hybrid EEG-fNIRS framework using functional brain connectivity features achieved 77% accuracy for 0-back vs. 2-back and 83% for 0-back vs. 3-back mental workload classification.
A hybrid EEG-fNIRS framework using functional brain connectivity features improves mental workload classification accuracy compared to traditional univariate methods.
There is high demand for techniques to estimate human mental workload during some activities for productivity enhancement or accident prevention. Most studies focus on a single physiological sensing modality and use univariate methods to analyse multi-channel electroencephalography (EEG) data. This paper proposes a new framework that relies on the features of hybrid EEG-functional near-infrared spectroscopy (EEG-fNIRS), supported by machine-learning features to deal with multi-level mental workload classification. Furthermore, instead of the well-used univariate power spectral density (PSD) for EEG recording, we propose using bivariate functional brain connectivity (FBC) features in the time and frequency domains of three bands: delta (0.5-4 Hz), theta (4-7 Hz) and alpha (8-15 Hz). With the assistance of the fNIRS oxyhemoglobin and deoxyhemoglobin (HbO and HbR) indicators, the FBC technique significantly improved classification performance at a 77% accuracy for 0-back vs. 2-back and 83% for 0-back vs. 3-back using a public dataset. Moreover, topographic and heat-map visualisation indicated that the distinguishing regions for EEG and fNIRS showed a difference among the 0-back, 2-back and 3-back test results. It was determined that the best region to assist the discrimination of the mental workload for EEG and fNIRS is different. Specifically, the posterior area performed the best for the posterior midline occipital (POz) EEG in the alpha band and fNIRS had superiority in the right frontal region (AF8).
Cao et al. (Sat,) conducted a other in Mental workload. Hybrid EEG-fNIRS with functional brain connectivity (FBC) features vs. Univariate methods / single modality was evaluated on Classification accuracy for mental workload (0-back vs. 2-back and 0-back vs. 3-back). A hybrid EEG-fNIRS framework using functional brain connectivity features achieved 77% accuracy for 0-back vs. 2-back and 83% for 0-back vs. 3-back mental workload classification.