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Eye movements have been extensively studied with respect to visual stimulation. However, we live in a multisensory world, and how the eyes are driven by other senses has been explored much less. Here, we review the evidence on how audition can trigger and drive different eye responses and which cortical and subcortical neural correlates are involved. We provide an overview on how different types of sounds, from simple tones and noise bursts to spatially localized sounds and complex linguistic stimuli, influence saccades, microsaccades, smooth pursuit, pupil dilation, and eye blinks. The reviewed evidence reveals how the auditory system interacts with the oculomotor system, both behaviorally and neurally, and how this differs from visually driven eye responses. Some evidence points to multisensory interaction, and potential multisensory integration, but the underlying computational and neural mechanisms are still unclear. While there are marked differences in how the eyes respond to auditory compared to visual stimuli, many aspects of auditory‐evoked eye responses remain underexplored, and we summarize the key open questions for future research. [ABSTRACT FROM AUTHOR]

The present study examined music-induced dopamine release, as measured by a proxy measure of spontaneous eye blinks. Specifically, we explored the effects of uplifting and sombre tones in different sections of Vivaldi’s Four Seasons to investigate the affective content of musical pieces within one composition. Seventeen participants listened to four concertos (Major modes: “Spring” and “Autumn”, Minor modes: “Summer” and “Winter”) and a silence condition while completing a three-stimulus odd-ball attention task. Electrooculograms were recorded from electrodes placed above and under the left eye. Self-reported arousal and music preference measures were also gathered during the testing session. In addition, the P3a Event-Related Potential (ERP) component was analysed as another potential index of dopamine function. Results revealed significant differences in the blink rates during music listening and silence, with the largest effect observed for the sad, melancholic “Winter” concerto. However, no significant correlation was found between blink rate and music preference or arousal. Furthermore, no reliable association was found between blink rate and the P3a ERP component, suggesting that these measures tap into different aspects of dopamine function. These findings contribute to understanding the link between dopamine and blink rate, particularly in response to classical music. Crucially, the study’s discovery that the “Winter” concerto, with its sorrowful tone, significantly increased the blink rate highlights the significance of sad music and perhaps the programmatic qualities of this concerto to induce a strong emotional response.

To assess stress in horses, a method of monitoring eye blinks (full and half) and eyelid twitches while collecting saliva and blood samples before and after annual intensive police training was carried out. This noninvasive monitoring method was used to determine whether blood collection, which is considered invasive, is more stressful for horses than saliva collection. We discovered no significant difference in stress related manifestations between saliva sampling and blood collection in our study. In both cases, sampling (blood and saliva) reduced the number of full and half eye blinks. Based on our hypothesis, we expected a statistically significant changes in the number of eye blinks and eyelid twitches as the number of potential stressors increased (in our case, we considered police training and sampling). Saliva cortisol levels, on the other hand, revealed that police training for horses was not stressful. The method of measuring eye blinks and eyelid twitches appears to be an appropriate alternative method for monitoring stress factors in horses. [ABSTRACT FROM AUTHOR]

Eye blinks not only serve to maintain the tear film of the eye but also seem to have a functional role in information processing. People tend to inhibit an eye blink when they expect relevant information to occur in their visual environment and blink more often when the information has been processed. Recent studies have shown that this relation also holds for auditory information processing. However, only artificial auditory stimuli like tones or controlled lists of words were used in studies so far. In the current study, we tested whether there would be a temporal association between the pauses in a continuous speech stream and the listener's eye blinks. To this end, we analyzed the eye blinks of 35 participants who were instructed to attend to one of two simultaneously presented audiobooks. We found that the blink patterns of 13 participants were coupled with the speech pauses in the attended speech stream. These participants blinked more often during the pauses in the attended speech stream. Contrary to our prediction, participants did not inhibit their blinking preceding a pause in the attended speech stream. As expected, there was no evidence that the listeners' blink pattern was coupled to the pauses in the ignored speech stream. Thus, the listeners' blink patterns can reflect attention to continuous speech. [ABSTRACT FROM AUTHOR]

Behavioral differences in speed and accuracy between reading familiar and unfamiliar words are well-established in the empirical literature. However, these standard measures of skill proficiency are limited in their ability to capture the moment-to-moment processing involved in visual word recognition. In the present study, the effect of word familiarity was initially investigated using an eye blink rate among adults and children. The probability of eye blinking was higher for familiar (real) words than for unfamiliar (pseudo)words. This counterintuitive pattern of results suggests that the processing of unfamiliar (pseudo)words is more demanding and perhaps less rewarding than the processing of familiar (real) words, as previously observed in both behavioral and pupillometry data. Our findings suggest that the measurement of eye blinks might shed new light on the cognitive processes involved in visual word recognition and other domains of human cognition.

Eye blinks cause disruptions to visual input and are accompanied by rotations of the eyeball [1]. Like every motor action, these eye movements are subject to noise and introduce instabilities in gaze direction across blinks [2]. Accumulating errors across repeated blinks would be debilitating for visual performance. Here, we show that the oculomotor system constantly recalibrates gaze direction during blinks to counteract gaze instability. Observers were instructed to fixate a visual target while gaze direction was recorded and blinks were detected in real time. With every spontaneous blink-while eyelids were closed-the target was displaced laterally by 0.5° (or 1.0°). Most observers reported being unaware of displacements during blinks. After adapting for ∼35 blinks, gaze positions after blinks showed significant biases toward the new target position. Automatic eye movements accompanied each blink, and an aftereffect persisted for a few blinks after target displacements were eliminated. No adaptive gaze shift occurred when blinks were simulated with shutter glasses at random time points or actively triggered by observers, or when target displacements were masked by a distracting stimulus. Visual signals during blinks are suppressed by inhibitory mechanisms [3-6], so that small changes across blinks are generally not noticed [7, 8]. Additionally, target displacements during blinks can trigger automatic gaze recalibration, similar to the well-known saccadic adaptation effect [9-11]. This novel mechanism might be specific to the maintenance of gaze direction across blinks or might depend on a more general oculomotor recalibration mechanism adapting gaze position during intrinsically generated disruptions to visual input.

PurposeTo detect and quantify eye blinks during 24-hour intraocular pressure (IOP) monitoring with a contact lens sensor (CLS).MethodsA total of 249 recordings of 24-hour IOP patterns from 202 participants using a CLS were included. Software was developed to automatically detect eye blinks, and wake and sleep periods. The blink detection method was based on detection of CLS signal peaks greater than a threshold proportional to the signal amplitude. Three methods for automated detection of the sleep and wake periods were evaluated. These relied on blink detection and subsequent comparison of the local signal amplitude with a threshold proportional to the mean signal amplitude. These methods were compared to manual sleep/wake verification. In a pilot, simultaneous video recording of 10 subjects was performed to compare the software to observer-measured blink rates.ResultsMean (SD) age of participants was 57.4 ± 16.5 years (males, 49.5%). There was excellent agreement between software-detected number of blinks and visually measured blinks for both observers (intraclass correlation coefficient [ICC], 0.97 for observer 1; ICC, 0.98 for observer 2). The CLS measured a mean blink frequency of 29.8 ± 15.4 blinks/min, a blink duration of 0.26 ± 0.21 seconds and an interblink interval of 1.91 ± 2.03 seconds. The best method for identifying sleep periods had an accuracy of 95.2 ± 0.5%.ConclusionsAutomated analysis of CLS 24-hour IOP recordings can accurately quantify eye blinks, and identify sleep and wake periods.Translational relevanceThis study sheds new light on the potential importance of eye blinks in glaucoma and may contribute to improved understanding of circadian IOP characteristics.

Thirty-nine participants listened to 28 neutral and horror excerpts of Stephen King short stories while constantly tracking their emotional arousal. Pupil size was measured with an Eyelink 1000+, and participants rated valence and transportation after each story. In addition to computing mean pupil size across 1-sec intervals, we extracted blink count and used detrended fluctuation analysis (DFA) to obtain the scaling exponents of long-range temporal correlations (LRTCs) in pupil size time-series. Pupil size was expected to be sensitive also to emotional arousal, whereas blink count and LRTC’s were expected to reflect cognitive engagement. The results showed that self-reported arousal increased, pupil size was overall greater, and the decreasing slope of pupil size was flatter for horror than for neutral stories. Horror stories induced higher transportation than neutral stories. High transportation was associated with a steeper increase in self-reported arousal across time, stronger LRTCs in pupil size fluctuations, and lower blink count. These results indicate that pupil size reflects emotional arousal induced by the text content, while LRTCs and blink count are sensitive to cognitive engagement associated with transportation, irrespective of the text type. The study demonstrates the utility of pupillometric measures and blink count to study literature reception.

Sensory input as well as cognitive factors can drive the modulation of blinking. Our aim was to dissociate sensory driven bottom-up from cognitive top-down influences on blinking behavior and compare these influences between the auditory and the visual domain. Using an oddball paradigm, we found a significant pre-stimulus decrease in blink probability for visual input compared to auditory input. Sensory input further led to an early post-stimulus blink increase in both modalities if a task demanded attention to the input. Only visual input caused a pronounced early increase without a task. In case of a target or the omission of a stimulus (as compared to standard input), an additional late increase in blink rate was found in the auditory and visual domain. This suggests that blink modulation must be based on the interpretation of the input, but does not need any sensory input at all to occur. Our results show a complex modulation of blinking based on top-down factors such as prediction and attention in addition to sensory-based influences. The magnitude of the modulation is mainly influenced by general attentional demands, while the latency of this modulation allows dissociating general from specific top-down influences that are independent of the sensory domain. • Blinks are modulated by early sensory and late cognitive influences such as prediction and attention • Such influences have an effect on blink rate as well as on blink timing • Comparison of blink behavior in the visual, auditory and bimodal domain • Preparatory pre-stimulus effects are visible in visual tasks; attentional post-stimulus effects are domain independent [ABSTRACT FROM AUTHOR]

The number of elderly and disabled people worldwide has increased, and their day-to-day activities depend on others' help. Improving the quality of life of these people has become the most important responsibility of society, and it is the role of technology specialists to make their life as normal and easy as possible so that they can perform their day-to-day activities at the relevant time without others' help. Many researchers have proposed several solutions, but these have limitations such as poor performance and usability. Hence, there is a need to design a wheelchair that is smart and easy to use for the elderly and people with partial or full quadriplegia. In this paper, we propose a smart mind-based wireless controlled wheelchair (SMWCW) approach that completely controls the motion of a wheelchair wirelessly through brain signals and eye blinks to help partially quadriplegic individuals to perform their daily activities easily. In SMWCW, NeuroSky's electroencephalography (EEG) device is used by users sitting on the wheelchair to capture brain activity and the frequency of eye blinks, and it translates these data into movement commands using an Arduino microcontroller unit that is directly connected to the wheelchair to move the wheelchair. The proposed approach has been simulated, and results show its effectiveness and applicability for use by most physically disabled persons. [ABSTRACT FROM AUTHOR]

Objective: Benzodiazepines impair driving ability and psychomotor function. Eyelid parameters accurately reflect drowsiness; however, the effects of benzodiazepines on these measures have not been extensively studied. The aim of this study was to investigate the effect of benzodiazepines on eyelid parameters and evaluate their accuracy for detecting psychomotor impairment. Methods: Eyelid parameters were recorded during a psychomotor vigilance task (PVT) and driving simulation over 2 days, baseline, and after 20‐mg oral temazepam. The utility of eyelid parameters for detecting PVT lapses was evaluated using receiver operating characteristic curves, and cut‐off levels indicating impairment (≥1 and ≥2 PVT lapses per min) were identified. The accuracy of these cut‐off levels for detecting driving simulator crashes was then examined. Results: PVT and driving simulator performance was significantly impaired following benzodiazepine administration (p <.05). Average eyelid closure duration (inter‐event duration) was a reliable indicator of PVT lapses (area under the curve [AUC] of 0.87–0.90). The cut‐off value of eyelid closure duration derived from PVT AUC was able to predict driving simulator crashes with moderately high sensitivity and specificity (76.23% and 75.00%). Conclusions: Eyelid parameters were affected by benzodiazepines and accurately detected the psychomotor impairment. In particular, eyelid closure duration is a promising real‐time indicator of benzodiazepine impairment. [ABSTRACT FROM AUTHOR]

This paper presents an object acquisition and selection approach in human computer interaction systems. In this approach, objects placed over computer screen are automatically scanned and the user performs voluntary eye blinks for object selection when the focus comes over the object of interest. Here, scanning means moving the focus over objects placed on the computer screen one by one and the scanning time is the time taken to move focus from one object to the next object. The user is not required to perform any physical movement, the moving part is only the eye lids. A low cost webcam and MATLAB software with computer vision toolbox are required to implement the proposed approach. The performance of the proposed approach has been compared with the Camera Mouse for selection of text and graphic objects. The Camera Mouse utilizes facial feature tracking for mouse cursor control and dwell time for object selection. Three experiments were performed for evaluation of the proposed method in which ten healthy users voluntarily participated. The proposed method has given significantly better performance than the Camera Mouse when selection of text objects was performed in an html file. For selection of graphic objects placed on computer screen, where page scrolling is not required, no significant difference has been found in the performance of both the systems. The proposed method has also been evaluated for performing mouse analogous operations using eye blinks and a performance comparison has been made with state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Objectives: In response to calls for physiological measurement of people's fear of crime, we explored how men and women responded to self-report and physiological measures as they viewed threatening and/or crime-related images. Method: We used a gender (men vs. women) × threat (high vs. low) × crime (high vs. low) mixed-factorial design. Participants (N = 40) viewed two blocks of 40 images from the Crime and Threat Image Set (CaTIS). In one block, participants rated their pleasantness and arousal (self-report) as they viewed the images. In the second block, we recorded participants' eye blinks and galvanic skin response (GSR; physiological) as they viewed the images. Participants also completed two traditional fear of crime measures. Results: On the traditional fear of crime measures, women reported significantly more fear of crime than men. When viewing images, there was a gender dynamic for self-reports of pleasantness: women reported feeling more unpleasant when viewing high-threat images than did men. Ratings of arousal, eye blink rates and GSR did not significantly differ between men and women, but GSR and arousal ratings did significantly differ across image categories. Conclusions: We found gender differences between traditional fear of crime measures and self-reports of pleasantness, but no statistically significant differences in men's and women's physiological reactions. We propose that this is not a function of impression management, but that men and women may be interpreting their physiological responses in line with gender-socialised scripts. [ABSTRACT FROM AUTHOR]

In several fields, the need for a joint analysis of brain activity and eye activity to investigate the association between brain mechanisms and manifest behavior has been felt. In this work, two levels of attentional demand, elicited through a conjunction search task, have been modelled in terms of eye blinks, brain activity, and brain network features. Moreover, the association between endogenous neural mechanisms underlying attentional demand and eye blinks, without imposing a time-locked structure to the analysis, has been investigated. The analysis revealed statistically significant spatial and spectral modulations of the recorded brain activity according to the different levels of attentional demand, and a significant reduction in the number of eye blinks when a higher amount of attentional investment was required. Besides, the integration of information coming from high-density electroencephalography (EEG), brain source localization, and connectivity estimation allowed us to merge spectral and causal information between brain areas, characterizing a comprehensive model of neurophysiological processes behind attentional demand. The analysis of the association between eye and brain-related parameters revealed a statistically significant high correlation (R > 0.7) of eye blink rate with anterofrontal brain activity at 8 Hz, centroparietal brain activity at 12 Hz, and a significant moderate correlation with the participation of right Intra Parietal Sulcus in alpha band (R = −0.62). Due to these findings, this work suggests the possibility of using eye blinks measured from one sensor placed on the forehead as an unobtrusive measure correlating with neural mechanisms underpinning attentional demand.

During the execution of a cognitive task, the brain maintains contextual information to guide behavior and achieve desired goals. The AX-Continuous Performance Task is used to study proactive versus reactive cognitive control. Young adults tend to behave proactively in standard testing conditions. However, it remains unclear how interindividual variability (e.g., in cognitive and motivational factors) may drive people into more reactive or proactive control under the same task demands. We investigated the use of control strategies in a large population of healthy young adults. We computed the proactive behavioral index and consequently divided participants into proactive, reactive, and intermediate groups. We found that reactive participants were generally slower, presented lower context sensitivity, and larger response variability. Pupillary changes and blink rate index cognitive effort allocation. We measured, concomitantly to the task, the pupil size and frequency of blinks associated with the cue maintenance and response intervals. During the cue period, nonfrequent, nontarget cues led to increased pupil dilation and number of blinks in all participants. During the response interval, we found more errors and increased pupil dilation to the probe when all participants had to overcome a response bias generated by the frequent cue. Only reactive participants showed larger response-related pupil when they had to overcome a response bias related to the frequent probe. Contrary to expectations, groups did not differ in ocular measures in the cue period. In conclusion, interindividual differences in cognitive control between healthy adults can be mapped onto different patterns of effort allocation indexed by the pupil. [ABSTRACT FROM AUTHOR]

Immersive computer-generated environments (aka virtual reality, VR) are limited by the physical space around them, e.g., enabling natural walking in VR is only possible by perceptually-inspired locomotion techniques such as redirected walking (RDW). We introduce a completely new approach to imperceptible position and orientation redirection that takes advantage of the fact that even healthy humans are functionally blind for circa ten percent of the time under normal circumstances due to motor processes preventing light from reaching the retina (such as eye blinks) or perceptual processes suppressing degraded visual information (such as blink-induced suppression). During such periods of missing visual input, change blindness occurs, which denotes the inability to perceive a visual change such as the motion of an object or self-motion of the observer. We show that this phenomenon can be exploited in VR by synchronizing the computer graphics rendering system with the human visual processes for imperceptible camera movements, in particular to implement position and orientation redirection. We analyzed human sensitivity to such visual changes with detection thresholds, which revealed that commercial off-the-shelf eye trackers and head-mounted displays suffice to translate a user by circa 4 — 9 cm and rotate the user by circa 2 — 5 degrees in any direction, which could be accumulated each time the user blinks. Moreover, we show the potential for RDW, whose performance could be improved by approximately 50% when using our technique. [ABSTRACT FROM AUTHOR]

Eye blinking is one of the most frequent human actions. The control of blinking is thought to reflect complex interactions between maintaining clear and healthy vision and influences tied to central dopaminergic functions including cognitive states, psychological factors, and medical conditions. The most imminent consequence of blinking is a temporary loss of vision. Minimizing this loss of information is a prominent explanation for changes in blink rates and temporarily suppressed blinks, but quantifying this loss is difficult, as environmental regularities are usually complex and unknown. Here we used a controlled detection experiment with parametrically generated event statistics to investigate human blinking control. Subjects were able to learn environmental regularities and adapted their blinking behavior strategically to better detect future events. Crucially, our design enabled us to develop a computational model that allows quantifying the consequence of blinking in terms of task performance. The model formalizes ideas from active perception by describing blinking in terms of optimal control in trading off intrinsic costs for blink suppression with task-related costs for missing an event under perceptual uncertainty. Remarkably, this model not only is sufficient to reproduce key characteristics of the observed blinking behavior such as blink suppression and blink compensation but also predicts without further assumptions the well-known and diverse distributions of time intervals between blinks, for which an explanation has long been elusive. [ABSTRACT FROM AUTHOR]

Background EEG signals are often contaminated with artefacts, particularly with large signals generated by eye blinks. Deletion of artefact can lose valuable data. Current methods of removing the eye blink component to leave residual EEG, such as blind source component removal, require multichannel recording, are computationally intensive, and can alter the original EEG signal. New method Here we describe a novel single-channel method using a model based on the ballistic physiological components of the eye blink. This removes the blink component, leaving uncontaminated EEG largely unchanged. Processing time allows its use in real-time applications such as neurofeedback training. Results Blink removal had a success rate of over 90% recovered variance of original EEG when removing synthesised eye blink components. Fronto-lateral sites were poorer (∼80%) than most other sites (92–96%), with poor fronto-polar results (67%). Comparisons with existing methods When compared with three popular independent component analysis (ICA) methods, our method was only slightly (1%) better at frontal midline sites but significantly (>20%) better at lateral sites with an overall advantage of ∼10%. Conclusions With few recording channels and real-time processing, our method shows clear advantages over ICA for removing eye blinks. It should be particularly suited for use in portable brain-computer-interfaces and in neurofeedback training. [ABSTRACT FROM AUTHOR]

We have developed two new methods that use sparse recovery and active learning techniques for near real-time artifact identification and removal in electroencephalography (EEG) recordings. The first algorithm, called Correlated Sparse Signal Recovery addresses the problem of structured sparse signal recovery when statistical rather than exact properties describing the structure of the signal are appropriate, as in the elimination of eye movement artifacts; such tasks cannot be done efficiently using structured models that assume a common sparsity profile of fixed groups of components. Our algorithm learns structured sparse coefficients in a Bayesian paradigm. Using it, we have successfully identified and subtracted eye movement (structured) artifacts in real EEG recordings resulting in minimal data loss. Our method outperforms Independent Component Analysis and standard sparse recovery algorithms by preserving both spectral and complexity properties of the denoised EEG. Our second method uses a new active selection algorithm that we call Output-based Active Selection (OAS). When applied to the task of detection of EEG epochs containing other non-structured artifacts from an ensemble of detectors, OAS boosts accuracy of the ensemble from 91 to 97.5% with only 10% active labels. Our methods can also be applied to real-time artifact removal in magnetoencephalography and blood pressure signals. [ABSTRACT FROM AUTHOR]

This paper covers a new technology by placing electrodes on forehead of person around the eyes for recording the eye movements, this technique is called Electrooculography (EOG). It is basically focused on the concept of recording down the polarization potential which is also called corneal-retinal potential (CRP), this is resting potential between retina and cornea. The potential is called electrooculogram. This is a tiny electrical potential that can be found out using electrodes that are comparative to eye displacement. Electrooculography is a means of control for allowing the handicapped, mainly people with eye-motor coordination, which allow them live independent lives. This is a very good assistive system for disabled people with less money. This total command control EOG lets users to guide it with a high intensity of comfort ability. Systems which are becoming more popular day by day are HCI (Human Computer Interaction) that are Eye tracking based. To such systems Electrooculogram (EOG) functions as basic source of input. This integral process of analysis of electrooculogram is called Electrooculography. The paper we are presenting gives basic idea on Electrooculography and its use and applications in different HCI systems. In this work we have also included detection of eye blinks from EOG signal. Conclusively it throws light on various issues concerned with Electrooculography. [ABSTRACT FROM AUTHOR]

Spontaneous eye blink rate is modulated by task demands and internal state, and is demonstrated to reflect central dopamine activity. Also, spontaneous eye blinks are strategically timed around salient stimuli. This study investigates whether children with attention deficit hyperactivity disorder (ADHD) show reduced blink rates, blink modulation and blink timing, and whether this is influenced by stimulant medication. The electrooculogram was measured in 18 typically developing children, 16 children with ADHD off methylphenidate (Mph), and 16 children with ADHD on Mph during a rest period and during performance of a 60-min visual selective attention task. Blink rate and timing was extracted from the electrooculogram. No evidence was found for aberrant blink rate or blink modulation in children with ADHD off Mph. All groups increased blink rates from rest to task, and no group differences were found in blink rate during rest and task, or in the modulation of blink rate from rest to task. Time-on task resulted in a similar increase in blink rates in all three groups. Stimulant medication appeared not to influence blink rate and blink modulation, except that in the ADHD off Mph group the blink rate was enhanced only under conditions with performance feedback. All groups inhibited blinks before stimulus presentation and strategically timed their blinks after the stimulus. Children with ADHD off Mph showed reduced blink inhibition before the stimulus; however, given the low incidence (<1 % of the trials) and long latency this is not likely to impair their visual intake. [ABSTRACT FROM AUTHOR]

Electroencephalography (EEG) offers a platform for studying the relationships between behavioral measures, such as blink rate and duration, with neural correlates of fatigue and attention, such as theta and alpha band power. Further, the existence of EEG studies covering a variety of subjects and tasks provides opportunities for the community to better characterize variability of these measures across tasks and subjects. We have implemented an automated pipeline (BLINKER) for extracting ocular indices such as blink rate, blink duration, and blink velocity-amplitude ratios from EEG channels, EOG channels, and/or independent components (ICs). To illustrate the use of our approach, we have applied the pipeline to a large corpus of EEG data (comprising more than 2000 datasets acquired at eight different laboratories) in order to characterize variability of certain ocular indicators across subjects. We also investigate dependence of ocular indices on task in a shooter study. We have implemented our algorithms in a freely available MATLAB toolbox called BLINKER. The toolbox, which is easy to use and can be applied to collections of data without user intervention, can automatically discover which channels or ICs capture blinks. The tools extract blinks, calculate common ocular indices, generate a report for each dataset, dump labeled images of the individual blinks, and provide summary statistics across collections. Users can run BLINKER as a script or as a plugin for EEGLAB. The toolbox is available at https://github.com/VisLab/EEG-Blinks. User documentation and examples appear at http://vislab.github.io/EEG-Blinks/. [ABSTRACT FROM AUTHOR]

Here we report a system which can be operated using electroencephalography (EEG) signals generated during eye blink and thus may be useful for persons with locomotive and other disabilities for performing their day-to-day activities. EEG signals are processed by a microcontroller and based on programming, the microcontroller takes a decision to perform the desired task by actuating a corresponding device from several devices connected to the system. An important feature of the system is that it can be adapted to particular needs of the user and can be attached/detached for actuation of different appliances according to the user's condition and requirements. [ABSTRACT FROM AUTHOR]

The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6–0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes. [ABSTRACT FROM PUBLISHER]

Oculomotor behavior and parameters are known to be affected by the allocation of attention and could potentially be used to investigate attention disorders. We explored the oculomotor markers of Attention-deficit/hyperactivity disorder (ADHD) that are involuntary and quantitative and that could be used to reveal the core-affected mechanisms, as well as be used for differential diagnosis. We recorded eye movements in a group of 22 ADHD-diagnosed patients with and without medication (methylphenidate) and in 22 control observers while performing the test of variables of attention (t.o.v.a.). We found that the average microsaccade and blink rates were higher in the ADHD group, especially in the time interval around stimulus onset. These rates increased monotonically over session time for both groups, but with significantly faster increments in the unmedicated ADHD group. With medication, the level and time course of the microsaccade rate were fully normalized to the control level, regardless of the time interval within trials. In contrast, the pupil diameter decreased over time within sessions and significantly increased above the control level with medication. We interpreted the suppression of microsaccades and eye blinks around the stimulus onset as reflecting a temporal anticipation mechanism for the transient allocation of attention, and their overall rates as inversely reflecting the level of arousal. We suggest that ADHD subjects fail to maintain sufficient levels of arousal during a simple and prolonged task, which limits their ability to dynamically allocate attention while anticipating visual stimuli. This impairment normalizes with medication and its oculomotor quantification could potentially be used for differential diagnosis. [ABSTRACT FROM AUTHOR]

This work presents the development of a robotic wheelchair that can be commanded by users in a supervised way or by a fully automatic unsupervised navigation system. It provides flexibility to choose different modalities to command the wheelchair, in addition to be suitable for people with different levels of disabilities. Users can command the wheelchair based on their eye blinks, eye movements, head movements, by sip-and-puff and through brain signals. The wheelchair can also operate like an auto-guided vehicle, following metallic tapes, or in an autonomous way. The system is provided with an easy to use and flexible graphical user interface onboard a personal digital assistant, which is used to allow users to choose commands to be sent to the robotic wheelchair. Several experiments were carried out with people with disabilities, and the results validate the developed system as an assistive tool for people with distinct levels of disability. [ABSTRACT FROM AUTHOR]

Abstract: In applied contexts, psychophysiological measures have a long tradition to evaluate the user state. EEG correlates that indicate mechanisms of information processing, however, are hardly accessible since discrete time stamps that are necessary for this approach are commonly not available in natural situations. However, eye blinks may close this gap. Eye blinks are assumed to mark distinct points in information processing, necessary to segment the incoming data stream. By using mobile EEG in a simulated working situation we demonstrate that eye-blink-related potentials provide reliable information about cognitive processing in distinct working environments. During cognitive tasks, an increase in the fronto-central N2 component as well as evoked theta activity can be shown, both indices of enhanced cognitive control. The posterior P3 is reduced during physical tasks (sorting of boxes), probably reflecting the more continuous nature of this task. The data are discussed within a model of dopaminergic modulation of blink activity that involves both task specific aspects like executive control and modulating influences of motivation or fatigue. [Copyright &y& Elsevier]

Many studies have shown that covert visual attention precedes saccadic eye movements to locations in space. The present research investigated whether the allocation of attention is similarly affected by eye blinks. Subjects completed a partial-report task under blink and no-blink conditions. Experiment 1 showed that blinking facilitated report of the bottom row of the stimulus array: Accuracy for the bottom row increased and mislocation errors decreased under blink, as compared with no-blink, conditions, indicating that blinking influenced the allocation of visual attention. Experiment 2 showed that this was true even when subjects were biased to attend elsewhere. These results indicate that attention moves downward before a blink in an involuntary fashion. The eyes also move downward during blinks, so attention may precede blink-induced eye movements just as it precedes saccades and other types of eye movements. [ABSTRACT FROM AUTHOR]

As an interface phenomenon, prosody interacts with all components of grammar, even though it is often subsumed under the broad area of phonology. In sign languages, an equivalent system of prosody reveals interesting results with regard to modality-independent notions of language structure. This paper presents data from a study on German Sign Language (Deutsche Gebärdensprache, DGS) and investigates prosodic cues on the basis of annotated video data. The focus of the study was on eye blinks and their use in prosodic structuring of signed utterances. Systematic methodology, annotation, and statistical evidence provided the basis for a thorough analysis of blinking behavior in DGS. The results suggest a consistent use of certain eye blinks as markers to indicate prosodic phrase boundaries. A constant 70%/30% ratio of prosodic and non-prosodic blinks further indicates the efficient use of this device. Even though some aspects of blinking are subject to inter-signer variation, the prosodic use of blinks is intriguingly similar across signers. However, blinks are not obligatory boundary markers in DGS. I propose an analysis that takes into account various factors such as syntactic constituency, prosodic structuring, and particularly the interplay of various nonmanuals such as eye gaze, head nods, and facial expressions. The fine-grained distinction of blinks resulting from a modified categorization for eye blinks and additional statistical computations give insight into how visual languages realize phrase boundaries and prosodic marking and to what extent they use the system consistently. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the mean rate and time-dependent sequential organization of spontaneous eye blinks in adults with intellectual and developmental disability (IDD) and individuals from this group who were additionally categorized with stereotypic movement disorder (IDD+SMD). The mean blink rate was lower in the IDD+SMD group than the IDD group and both of these groups had a lower blink rate than a contrast group of healthy adults. In the IDD group the n to n +1 sequential organization over time of the eye-blink durations showed a stronger compensatory organization than the contrast group suggesting decreased complexity/dimensionality of eye-blink behavior. Very low blink rate (and thus insufficient time series data) precluded analysis of time-dependent sequential properties in the IDD+SMD group. These findings support the hypothesis that both IDD and SMD are associated with a reduction in the dimension and adaptability of movement behavior and that this may serve as a risk factor for the expression of abnormal movements. [Copyright &y& Elsevier]

Abstract: Objective: Independent component analysis (ICA) can disentangle multi-channel electroencephalogram (EEG) signals into a number of artifacts and brain-related signals. However, the identification and interpretation of independent components is time-consuming and involves subjective decision making. We developed and evaluated a semi-automatic tool designed for clustering independent components from different subjects and/or EEG recordings. Methods: CORRMAP is an open-source EEGLAB plug-in, based on the correlation of ICA inverse weights, and finds independent components that are similar to a user-defined template. Component similarity is measured using a correlation procedure that selects components that pass a threshold. The threshold can be either user-defined or determined automatically. CORRMAP clustering performance was evaluated by comparing it with the performance of 11 users from different laboratories familiar with ICA. Results: For eye-related artifacts, a very high degree of overlap between users (phi>0.80), and between users and CORRMAP (phi>0.80) was observed. Lower degrees of association were found for heartbeat artifact components, between users (phi<0.70), and between users and CORRMAP (phi<0.65). Conclusions: These results demonstrate that CORRMAP provides an efficient, convenient and objective way of clustering independent components. Significance: CORRMAP helps to efficiently use ICA for the removal EEG artifacts. [Copyright &y& Elsevier]

We tested the hypothesis derived from eye blink literature that when liars experience cognitive demand, their lies would be associated with a decrease in eye blinks, directly followed by an increase in eye blinks when the demand has ceased after the lie is told. A total of 13 liars and 13 truth tellers lied or told the truth in a target period; liars and truth tellers both told the truth in two baseline periods. Their eye blinks during the target and baseline periods and directly after the target period (target offset period) were recorded. The predicted pattern (compared to the baseline periods, a decrease in eye blinks during the target period and an increase in eye blinks during the target offset period) was found in liars and was strikingly different from the pattern obtained in truth tellers. They showed an increase in eye blinks during the target period compared to the baseline periods, whereas their pattern of eye blinks in the target offset period did not differ from baseline periods. The implications for lie detection are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The objective of this study is the development and evaluation of efficient neurophysiological signal statistics, which may assess the driver’s alertness level and serve as potential indicators of sleepiness in the design of an on-board countermeasure system. Methods: Multichannel EEG, EOG, EMG, and ECG were recorded from sleep-deprived subjects exposed to real field driving conditions. A number of severe driving errors occurred during the experiments. The analysis was performed in two main dimensions: the macroscopic analysis that estimates the on-going temporal evolution of physiological measurements during the driving task, and the microscopic event analysis that focuses on the physiological measurements’ alterations just before, during, and after the driving errors. Two independent neurophysiologists visually interpreted the measurements. The EEG data were analyzed by using both linear and non-linear analysis tools. Results: We observed the occurrence of brief paroxysmal bursts of alpha activity and an increased synchrony among EEG channels before the driving errors. The alpha relative band ratio (RBR) significantly increased, and the Cross Approximate Entropy that quantifies the synchrony among channels also significantly decreased before the driving errors. Quantitative EEG analysis revealed significant variations of RBR by driving time in the frequency bands of delta, alpha, beta, and gamma. Most of the estimated EEG statistics, such as the Shannon Entropy, Kullback–Leibler Entropy, Coherence, and Cross-Approximate Entropy, were significantly affected by driving time. We also observed an alteration of eyes blinking duration by increased driving time and a significant increase of eye blinks’ number and duration before driving errors. Conclusions: EEG and EOG are promising neurophysiological indicators of driver sleepiness and have the potential of monitoring sleepiness in occupational settings incorporated in a sleepiness countermeasure device. Significance: The occurrence of brief paroxysmal bursts of alpha activity before severe driving errors is described in detail for the first time. Clear evidence is presented that eye-blinking statistics are sensitive to the driver’s sleepiness and should be considered in the design of an efficient and driver-friendly sleepiness detection countermeasure device. [Copyright &y& Elsevier]

Abstract: The study focuses on possible after effects of noise-induced sleep disturbances on inhibitory brain processes reflecting in performance changes and alternations of inhibition-related components of event-related potentials (ERPs). Following a quiet night and three nights, in which railway noise was presented with different levels, twelve women and ten men (19–28 years) performed a visual Go/Nogo task that contained stimuli either compatible or incompatible with a response. Noise-induced sleep disturbances are highly evident in worsening of subjective sleep quality but did not show up in significant changes of reaction time and error rate. A smaller N2 amplitude and longer latency to incompatible than to compatible stimuli as well as an unspecific attenuation of N2 amplitude under Noise were found. The amplitude of the fronto-central P3 was reduced under Noise compared to baseline only in Nogo trials. The amplitude of the parietal P3 in Go trials was smaller to incompatible than to compatible stimuli but was not affected by Noise. Disturbed sleep was associated with a decreased blink rate during task performance. The results suggest that physiological costs to maintain performance are increased after noisy nights. Decisional processes underlying overt responses (Go-P3) are less vulnerable to noise-disturbed sleep than those related to inhibition (Nogo-N2, NoGo-P3). The deficits may have been compensated by increased on-task concentration and thereby did not become apparent in the performance data. Inhibition-related ERPs may be more sensitive indicators of moderate sleep disturbances caused by noise than performance measures. [Copyright &y& Elsevier]