A Communication Means for Totally Locked-in ALS Patients Based on Changes in Cerebral Blood Volume Measured with Near-Infrared Light

Evaluation of a 2-Channel NIRS-Based Optical Brain Switch for Motor Disabilities' Communication Tools

“…Although there are many types of switching devices, we believe these switches should be used according to the patient's motor conditions. Since our NIRS-based prototype system requires no muscle movement, the obtained switching time of about 11.5 s is acceptable for the patient in a totally locked-in state (TLS) [20]. Table 2 summarizes the switching time for each participant.…”

“…As for the first problem, we developed an on-line monitoring system, which detects the ΔC oxy on a display in real-time. Since a normal signal shows a low frequency oscillation with a fine oscillation of approximately 1.4 Hz and an abnormal signal contains noisy components [20], we can discriminate between normal and abnormal signals by inspection. If the signal shows an abnormal behavior, we change the probe position slightly toward the left or right or up or down direction until we can obtain a normal signal.…”

Triple wavelength LED driver for optical brain–computer interfaces

“…The light sources chosen were high power NIR LEDs which have features suitable for long term use in a BCI. The use of LEDs in an offline optical BCI for ALS patients [5] and for imaging neonates [2] has been demonstrated successfully by others in the literature, verifying LED applicability and indeed safety in human interfacing. In addition, a study by the authors of the safety aspects of the LEDs described here can be found in [6].…”

Client-Centred Music Imagery Classification Based on Hidden Markov Models of Baseline Prefrontal Hemodynamic Response

“…Other common noninvasive BCI technologies such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG), and positron emission topography (PET) are theoretically feasible, but are expensive and technically demanding for online applications [3]. More recently, the possibility of using near infrared spectroscopy (NIRS) as a tool in this field has been investigated due to its affordability, portability, high temporal resolution (similar to that of fMRI), and higher signal-to-noise ratio than that of EEG due to the absence of artifacts [3][4][5][6][7][8][9].…”

“…As a consequence, by measuring the intensity of the reflected light, NIRS technologies can be used to examine regional cortical activity with depths of up to 2 cm [10]. Previous research has shown that NIRS can be used to assess hemodynamic responses in the motor cortex using activities such as motor imagery [3,7], as well as in the prefrontal cortex using higher cognitive tasks such as mental arithmetic [6,11,12], working memory [13,14], and emotion induction [15,16], both in silent (e.g., [17,18]) and noisy environments [19].…”