Analyzing Classification Performance of fNIRS-BCI for Gait Rehabilitation Using Deep Neural Networks

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 5; p. 1932
• Main Authors: Hamid, Huma, Naseer, Noman, Nazeer, Hammad, Khan, Muhammad Jawad, Khan, Rayyan Azam, Shahbaz Khan, Umar
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.03.2022; MDPI
• Subjects: Accuracy; Algorithms; Brain research; brain-computer interface; Brain-Computer Interfaces; Classification; convolutional neural network; Discriminant Analysis; Experiments; Fitness equipment; functional near-infrared spectroscopy; Gait; Hemoglobin; Humans; long short-term memory; Medical imaging; Neural networks; Neural Networks, Computer; neurorehabilitation; Physiology; Rehabilitation; Sensors; Signal processing; Spectroscopy, Near-Infrared - methods; Support vector machines; brain-computer interface; convolutional neural network; functional near-infrared spectroscopy; neurorehabilitation; long short-term memory
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22051932

This research presents a brain-computer interface (BCI) framework for brain signal classification using deep learning (DL) and machine learning (ML) approaches on functional near-infrared spectroscopy (fNIRS) signals. fNIRS signals of motor execution for walking and rest tasks are acquired from the primary motor cortex in the brain’s left hemisphere for nine subjects. DL algorithms, including convolutional neural networks (CNNs), long short-term memory (LSTM), and bidirectional LSTM (Bi-LSTM) are used to achieve average classification accuracies of 88.50%, 84.24%, and 85.13%, respectively. For comparison purposes, three conventional ML algorithms, support vector machine (SVM), k-nearest neighbor (k-NN), and linear discriminant analysis (LDA) are also used for classification, resulting in average classification accuracies of 73.91%, 74.24%, and 65.85%, respectively. This study successfully demonstrates that the enhanced performance of fNIRS-BCI can be achieved in terms of classification accuracy using DL approaches compared to conventional ML approaches. Furthermore, the control commands generated by these classifiers can be used to initiate and stop the gait cycle of the lower limb exoskeleton for gait rehabilitation.