Dummy eye measurements of microsaccades: testing the influence of system noise and head movements on microsaccade detection in a popular video-based eye tracker

Whereas early studies of microsaccades have predominantly relied on custom-built eye trackers and manual tagging of microsaccades, more recent work tends to use video-based eye tracking and automated algorithms for microsaccade detection. While data from these newer studies suggest that microsaccades can be reliably detected with video-based systems, this has not been systematically evaluated. I here present a method and data examining microsaccade detection in an often used video-based system (the Eyelink II system) and a commonly used detection algorithm (Engbert & Kliegl, 2003; Engbert & Mergenthaler, 2006). Recordings from human participants and those obtained using a pair of dummy eyes, mounted on a pair of glasses either worn by a human participant (i.e., with head motion) or a dummy head (no head motion) were compared. Three experiments were conducted. The first experiment suggests that when microsaccade measurements make use of the pupil detection mode, microsaccade detections in the absence of eye movements are sparse in the absence of head movements, but frequent with head movements (despite the use of a chin rest). A second experiment demonstrates that by using measurements that rely on a combination of corneal reflection and pupil detection, false microsaccade detections can be largely avoided as long as a binocular criterion is used. A third experiment examines whether past results may have been affected by possible incorrect detections due to small head movements. It shows that despite the many detections due to head movements, the typical modulation of microsaccade rate after stimulus onset is found only when recording from the participants’ eyes

Speakable in quantum mechanics: babbling on

This paper consists of a short version of the derivation of the intuitionistic quantum logic L_QM (which was originally introduced by Caspers, Heunen, Landsman and Spitters). The elaboration consists of extending this logic to a classical logic CL_QM. Some first steps are then taken towards setting up a probabilistic framework based on CL_QM in terms of R\'enyi's conditional probability spaces. Comparisons are then made with the traditional framework for quantum probabilities.Comment: In Proceedings QPL 2012, arXiv:1407.842

Conway-Kochen and the Finite Precision Loophole

Recently Cator & Landsman made a comparison between Bell's Theorem and Conway & Kochen's Strong Free Will Theorem. Their overall conclusion was that the latter is stronger in that it uses fewer assumptions, but also that it has two shortcomings. Firstly, no experimental test of the Conway-Kochen Theorem has been performed thus far, and, secondly, because the Conway-Kochen Theorem is strongly connected to the Kochen-Specker Theorem it may be susceptible to the finite precision loophole of Meyer, Kent and Clifton. In this paper I show that the finite precision loophole does not apply to the Conway-Kochen Theorem

Towards remote monitoring and remotely supervised training

The growing number of elderly and people with chronic disorders in our western society puts such pressure on our healthcare system that innovative approaches are demanded to make our health care more effective and more efficient. One way of innovation of healthcare can be obtained by introducing new services which enable less pressure on the intramural health care and support a more independent living and self efficacy of patients. Two of such services are Remote monitoring and remotely supervised training (RMT). Remote monitoring enables freedom to the patient with the assurance that assistance is possible whenever required. Remotely supervised treatment enables efficient and effective user-centred training anywhere and anytime with an intensity not feasible in an intramural setting. It is our vision that remote monitoring and remotely supervised treatment applications will become very important for patients (safety, more in control, convenience), health care insurances (efficiency, cost reduction) and healthcare service providers (more effective, innovative)

Do you look where I look? Attention shifts and response preparation following dynamic social cues

Studies investigating the effects of observing a gaze shift in another person often apply static images of a person with an averted gaze, while measuring response times to a peripheral target. Static images, however, are unlike how we normally perceive gaze shifts of others. Moreover, response times might only reveal the effects of a cue on covert attention and might fail to uncover cueing effects on overt attention or response preparation. We therefore extended the standard paradigm and measured cueing effects for ore realistic, dynamic cues (video clips),while comparing response times, saccade direction errors and saccade trajectories. Three cues were compared: A social cue, consisting of a eye-gaze shift, and two socially less relevant cues, consisting of a head tilting movement and a person walking past. Similar results were found for the two centrally presented cues (eye-gaze shift and head tilting) on all three response measures, suggesting that cueing is unaffected by the social status of the cue. Interestingly, the cue showing a person walking past showed a dissociation in the direction of the effects on response times on the one hand, and saccade direction errors and latencies on the other hand, suggesting the involvement of two types of (endogenous and exogenous) attention or a distinction between attention and saccadic response preparation. Our results suggest that by using dynamic cues and multiple response measures, properties of cueing can be revealed that would not be found otherwise

Motor unit properties in the biceps brachii of stroke patients assessed with surface array EMG

As a consequence of a stroke, both motor control as well as motor unit (MU) characteristics may change, e.g. MU size has been reported to increase due to reinnervation. The aim of the present study was to investigate how differences between the affected and unaffected side of hemiparetic stroke patients are reflected in surface array electomyography parameters

Extending remote patient monitoring with mobile real time clinical decision support

Large scale implementation of telemedicine services such as telemonitoring and teletreatment will generate huge amounts of clinical data. Even small amounts of data from continuous patient monitoring cannot be scrutinised in real time and round the clock by health professionals. In future huge volumes of such data will have to be routinely screened by intelligent software systems. We investigate how to make m-health systems for ambulatory care more intelligent by applying a Decision Support approach in the analysis and interpretation of biosignal data and to support adherence to evidence-based best practice such as is expressed in treatment protocols and clinical practice guidelines. The resulting Clinical Decision Support Systems must be able to accept and interpret real time streaming biosignals and context data as well as the patient’s (relatively less dynamic) clinical and administrative data. In this position paper we describe the telemonitoring/teletreatment system developed at the University of Twente, based on Body Area Network (BAN) technology, and present our vision of how BAN-based telemedicine services can be enhanced by incorporating mobile real time Clinical Decision Support. We believe that the main innovative aspects of the vision relate to the implementation of decision support on a mobile platform; incorporation of real time input and analysis of streaming\ud biosignals into the inferencing process; implementation of decision support in a distributed system; and the consequent challenges such as maintenance of consistency of knowledge, state and beliefs across a distributed environment

The effects of the global structure of the mask in visual backward masking

The visibility of a target can be strongly affected by a trailing mask. Research on visual backward masking has typically focused on the temporal characteristics of masking, whereas non-basic spatial aspects have received much less attention. However, recently, it has been demonstrated that the spatial layout is an important determinant of the strength of a mask. Here, we show that not only local but also global aspects of the mask's spatial layout affect target processing. Particularly, it is the regularity of the mask that plays an important role. Our findings are of importance for theoretical research, as well as for applications of visual masking

Constraints on Macroscopic Realism Without Assuming Non-Invasive Measurability

Macroscopic realism is the thesis that macroscopically observable properties must always have definite values. The idea was introduced by Leggett and Garg (1985), who wished to show a conflict with the predictions of quantum theory. However, their analysis required not just the assumption of macroscopic realism per se, but also that the observable properties could be measured non-invasively. In recent years there has been increasing interest in experimental tests of the violation of the Leggett-Garg inequality, but it has remained a matter of controversy whether this second assumption is a reasonable requirement for a macroscopic realist view of quantum theory. In a recent critical assessment Maroney and Timpson (2017) identified three different categories of macroscopic realism, and argued that only the simplest category could be ruled out by Leggett-Garg inequality violations. Allen, Maroney, and Gogioso (2016) then showed that the second of these approaches was also incompatible with quantum theory in Hilbert spaces of dimension 4 or higher. However, we show that the distinction introduced by Maroney and Timpson between the second and third approaches is not noise tolerant, so unfortunately Allen's result, as given, is not directly empirically testable. In this paper we replace Maroney and Timpson's three categories with a parameterization of macroscopic realist models, which can be related to experimental observations in a noise tolerant way, and recover the original definitions in the noise-free limit. We show how this parameterization can be used to experimentally rule out classes of macroscopic realism in Hilbert spaces of dimension 3 or higher, including the category tested by the Leggett-Garg inequality, without any use of the non-invasive measurability assumption.Comment: 20 pages, 10 figure

Reliability of MUAP properties in multi-channel array EMG recordings of trapezius and SCM

Muscle activity can be assessed non-invasively by means of surface electrodes places at the skin overlyin a muscle. When multiy-channel array electrodes are used, it is possible to extract motor unit action potentials (MUAP's) from the EMG signals with a segmentation approach based on the Continuous Wavelet Transform... The objective of the present study was to determine the test-retest reliability of the mentioned parameters during different tasks of the shoulder and neck muscles