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Methods to Detect Blink from the EEG Signal
Published in Narayan Panigrahi, Saraju P. Mohanty, Brain Computer Interface, 2022
Narayan Panigrahi, Saraju P. Mohanty
An electroencephalogram (EEG) is a measure of the electrical signals of the brain of a human being. It is a readily available test that provides the evidence of how the brain functions over time. Brain computer interface (BCI) is a collaboration between a brain and a device that enables EEG signals from the brain to control some external activity, such as control of a cursor or a prosthetic limb (Roy et al 2011). The interface enables a direct communication pathway between the brain and the object to be controlled. Electrooculography (EOG) is a technique for measuring the corneo-retinal standing potential that exists between the front and the back of the human eye. The resulting signal is called the electrooculogram. Tracking the movement of the eye through sensors enables us to compute and fix the position where one's eyes are focused (Panigrahi et al 2019). Study of the EOG can determine presence, attention, focus, drowsiness, consciousness, or other mental states of the subject (TejeroGimeno et al 2006; Liu et al 2013; Lin et al 2005). Event related potential (ERP) is a small voltage generated in the brain due to the occurrence of a specific event or stimuli. ERPs can be reliably measured from an EEG.
Driver State
Published in Motoyuki Akamatsu, Handbook of Automotive Human Factors, 2019
Eye movement is measured by the optical method and the electrooculograph (EOG) method. The optical method is classified into corneal reflection method and limbus tracking method. In the case of a device that adopts image measurement, such as video imaging, the pupil diameter can also be measured at the same time. The EOG method electrophysiologically detects a bioelectric phenomenon, and in the case of measuring eye movement, it detects the difference in the electrostatic capacitance of the cornea and that of the retina by sensors attached around the eyes. In particular, the optical method is capable of measuring the point of gaze and the distance and speed of gaze movement with high accuracy. It has wide application possibilities, including evaluation of how a driver is trying to capture visual information and evaluation of a driver’s information-processing workload level and attention level (Holmqvist et al., 2011).
Biopotentials and Electrophysiology Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Many organs in the human body, such as the heart, brain, muscles, and eyes, manifest their function through electric activity [1]. The heart, for example, produces a signal called the ECG (Figure 64.1a). The brain produces a signal called an EEG (Figure 64.1b). The activity of muscles, such as contraction and relaxation, produces an EMG (Figure 64.1c). Eye movement results in a signal called an EOG (Figure 64.1d), and the retina within the eyes produces the electroretinogram (ERG). Measurements of these and other electric signals from the body can provide vital clues as to normal or pathological functions of the organs. For example, abnormal heart beats or arrhythmias can be readily diagnosed from an ECG. Neurologists interpret EEG signals to identify epileptic seizure events. EMG signals can be helpful in assessing muscle function as well as neuromuscular disorders. EOG signals are used in the diagnosis of disorders of eye movement and balance disorders.
A closed-loop electrical stimulation system triggered by EOG for acupuncture therapy
Published in Systems Science & Control Engineering, 2020
Ding Yuan, Yurong Li, Tian Wang, Jianguo Chen, Dongyi Chen, Dong Lin, Yuan Yang
In our study, the EOG is used for monitoring eye movement. It is based on recording standing potentials arising from hyperpolarization and depolarization existing between the cornea and the retina. This potential can be considered as generating a steady electrical dipole with a negative pole at the fundus and a positive pole at the cornea. The standing potential in the eye can thus be estimated by measuring the induced voltage difference between electrodes placed around the eyes (vertically or horizontally, see Figure 3(b)) during eye movements (Barea, Boquete, Ortega, López, & Rodríguez-Ascariz, 2012). The EOG amplitude is in the range of 50–3500 µV, and the frequency 0.1–10 Hz (Champaty, Jose, Pal, & Thirugnanam, 2014).
The circadian effect on psychophysiological driver state monitoring
Published in Theoretical Issues in Ergonomics Science, 2021
Sylwia I. Kaduk, Aaron P. J. Roberts, Neville A. Stanton
Electrooculography (EOG) is a measure of the ocular behaviours through the resting potential of the retina, measured through the difference between potential on the retina and cornea (Siddiqui and Shaikh 2013). Similarly, to eye-tracking, it provides data about blinks and horizontal eye movements, but it does not show changes in the pupil size. The states that could be measured with EOG were drowsiness (Borghini et al. 2014), fatigue (Lal and Craig 2001), sleep (Oken, Salinsky, and Elsas 2006) and mental workload (Richter et al. 1998). The increased mental workload was associated with decreased blinking rate and blinking duration (Maglione et al. 2014). Drowsiness was reported to be correlated with the decreased saccadic eye-movements, increased slow eye-movements, increased blinking duration, delayed lid opening, and decreased lid closure (Borghini et al. 2014; Schleicher et al. 2008). It was also identified with PERCLOS (Papadelis et al. 2007). Two papers reported an increase of blinking rate due to drowsiness (Borghini et al. 2014; Papadelis et al. 2007), while one reported a decrease (Minhad, Ali, and Reaz 2017). Fatigue was reported to be associated with the increased blinking speed, the disappearance of saccadic eye movements, and an increase of PERCLOS (Lal and Craig 2002; Rodríguez-Ibáñez et al. 2011). One paper reported an increase in the blinking rate (Stern, Boyer, and Schroeder 1994), while one a decrease (Morris and Miller 1996) as an indicator of the fatigue. Sleep was identified with slow eye movements (Oken, Salinsky, and Elsas 2006). Most of the results were consistent with eye-tracking data except for the reported decrease of saccades number that contradicted the finding of Wang et al. (2017), however, saccades are very fast movements and their detection might depend on the sampling rate of the device.
Wheelchair control for disabled patients using EMG/EOG based human machine interface: a review
Published in Journal of Medical Engineering & Technology, 2021
EOG signal is recorded by placing a set of electrodes above and below on the eye to measure horizontal and vertical eye movements as shown in Figure 4. A wheelchair in the HMI system can be controlled by detecting the user’s gaze direction of the eye. EOG is based on the measurement of changes in corner retinal potential difference from positive poles of the cornea and negative poles of the retina with range are 0.4–1.0 mV [33–36,53].