Brain-computer interface (BCI) based on functional near-infrared spectroscopy (fNIRS) is a new-type human-computer interaction technique. To explore the separability of fNIRS signals in different motor imageries on the single limb, the study measured the fNIRS signals of 15 subjects (amateur football fans) during three different motor imageries of the right foot (passing, stopping and shooting). And the correlation coefficient of the HbO signal during different motor imageries was extracted as features for the input of a three-classification model based on support vector machines. The results found that the classification accuracy of the three motor imageries of the right foot was 78.89%±6.161%. The classification accuracy of the two-classification of motor imageries of the right foot, that is, passing and stopping, passing and shooting, and stopping and shooting was 85.17%±4.768%, 82.33%±6.011%, and 89.33%±6.713%, respectively. The results demonstrate that the fNIRS of different motor imageries of the single limb is separable, which is expected to add new control commands to fNIRS-BCI and also provide a new option for rehabilitation training and control peripherals for unilateral stroke patients. Besides, the study also confirms that the correlation coefficient can be used as an effective feature to classify different motor imageries.
Sleep is a complex physiological process of great significance to physical and mental health, and its research scope involves multiple disciplines. At present, the quantitative analysis of sleep mainly relies on the “gold standard” of polysomnography (PSG). However, PSG has great interference to the human body and cannot reflect the hemodynamic status of the brain. Functional near infrared spectroscopy (fNIRS) is used in sleep research, which can not only meet the demand of low interference to human body, but also reflect the hemodynamics of brain. Therefore, this paper has collected and sorted out the related literatures about fNIRS used in sleep research, concluding sleep staging research, clinical sleep monitoring research, fatigue detection research, etc. This paper provides a theoretical reference for scholars who will use fNIRS for fatigue and sleep related research in the future. Moreover, this article concludes the limitation of existing studies and points out the possible development direction of fNIRS for sleep research, in the hope of providing reference for the study of sleep and cerebral hemodynamics.
Objective To observe the effects of selecting different cognitive tasks during dual-task stepping training assisted by a pelvic weight support rehabilitation robot on cerebral cortex activation and task performance in convalescent period stroke patients. Methods Convalescent period stroke patients treated at Huashan Hospital, Fudan University between June 2023 and July 2024 were selected. Patients were recruited and conducted a self-controlled study. Patients were subjected to a self controlled study and received AB regimen training. The plan A underwent dual-task verbal fluency-stepping training assisted by the pelvic weight support rehabilitation robot, while the plan B performed dual-task serial subtraction-stepping training assisted by the pelvic weight support rehabilitation robot. During the intervention process, near-infrared equipment was used to collect relative oxyhemoglobin (HbO2) concentrations in six brain areas including prefrontal cortex (PFC), supplementary motor area (SMA), and primary motor cortex (PMC). The correct response rate and average number of steps were collected. Results A total of 20 patients were included. Among them, there were 16 males and 4 females. The average number of steps in Plan A were higher than those in Plan B (P<0.05). The correct response rate and the relative increase in HbO2 concentration of PFC, PMC, and SMA in both hemispheres of Plan A was higher than that in Plan B, but there was no statistically significant difference between the groups (P>0.05). Conclusions Compared with the dual-task serial subtraction-stepping training assisted by the pelvic weight support rehabilitation robot, the dual-task verbal fluency-stepping training assisted by the pelvic weight support rehabilitation robot can significantly increase the mean number of steps in the dual tasks.