Privacy-preserving datasets of eye-tracking samples with applications in XR.

Virtual and mixed-reality (XR) technology has advanced significantly in the last few years and will enable the future of work, education, socialization, and entertainment. Eye-tracking data is required for supporting novel modes of interaction, animating virtual avatars, and implementing rendering or streaming optimizations. While eye tracking enables many beneficial applications in XR, it also introduces a risk to privacy by enabling re-identification of users. We applied privacy definitions of it-anonymity and plausible deniability (PD) to datasets of eye-tracking samples and evaluated them against the state-of-the-art differential privacy (DP) approach. Two VR datasets were processed to reduce identification rates while minimizing the impact on the performance of trained machine-learning models. Our results suggest that both PD and DP mechanisms produced practical privacy-utility trade-offs with respect to re-identification and activity classification accuracy, while k-anonymity performed best at retaining utility for gaze prediction.

Gaze dynamics are sensitive to target orienting for working memory encoding in virtual reality.

Numerous studies have demonstrated that visuospatial attention is a requirement for successful working memory encoding. It is unknown, however, whether this established relationship manifests in consistent gaze dynamics as people orient their visuospatial attention toward an encoding target when searching for information in naturalistic environments. To test this hypothesis, participants' eye movements were recorded while they searched for and encoded objects in a virtual apartment (Experiment 1). We decomposed gaze into 61 features that capture gaze dynamics and a trained sliding window logistic regression model that has potential for use in real-time systems to predict when participants found target objects for working memory encoding. A model trained on group data successfully predicted when people oriented to a target for encoding for the trained task (Experiment 1) and for a novel task (Experiment 2), where a new set of participants found objects and encoded an associated nonword in a cluttered virtual kitchen. Six of these features were predictive of target orienting for encoding, even during the novel task, including decreased distances between subsequent fixation/saccade events, increased fixation probabilities, and slower saccade decelerations before encoding. This suggests that as people orient toward a target to encode new information at the end of search, they decrease task-irrelevant, exploratory sampling behaviors. This behavior was common across the two studies. Together, this research demonstrates how gaze dynamics can be used to capture target orienting for working memory encoding and has implications for real-world use in technology and special populations.

Enterprise imaging and big data: A review from a medical physics perspective.

In recent years enterprise imaging (EI) solutions have become a core component of healthcare initiatives, while a simultaneous rise in big data has opened up a number of possibilities in how we can analyze and derive insights from large amounts of medical data. Together they afford us a range of opportunities that can transform healthcare in many fields. This paper provides a review of recent developments in EI and big data in the context of medical physics. It summarizes the key aspects of EI and big data in practice, with discussion and consideration of the steps necessary to implement an EI strategy. It examines the benefits that a healthcare service can achieve through the implementation of an EI solution by looking at it through the lenses of: compliance, improving patient care, maximizing revenue, optimizing workflows, and applications of artificial intelligence that support enterprise imaging. It also addresses some of the key challenges in enterprise imaging, with discussion and examples presented for those in systems integration, governance, and data security and privacy.

A privacy-preserving approach to streaming eye-tracking data.

Eye-tracking technology is being increasingly integrated into mixed reality devices. Although critical applications are being enabled, there are significant possibilities for violating user privacy expectations. We show that there is an appreciable risk of unique user identification even under natural viewing conditions in virtual reality. This identification would allow an app to connect a user's personal ID with their work ID without needing their consent, for example. To mitigate such risks we propose a framework that incorporates gatekeeping via the design of the application programming interface and via software-implemented privacy mechanisms. Our results indicate that these mechanisms can reduce the rate of identification from as much as 85% to as low as 30%. The impact of introducing these mechanisms is less than 1.5° error in gaze position for gaze prediction. Gaze data streams can thus be made private while still allowing for gaze prediction, for example, during foveated rendering. Our approach is the first to support privacy-by-design in the flow of eye-tracking data within mixed reality use cases.

The Security-Utility Trade-off for Iris Authentication and Eye Animation for Social Virtual Avatars.

The gaze behavior of virtual avatars is critical to social presence and perceived eye contact during social interactions in Virtual Reality. Virtual Reality headsets are being designed with integrated eye tracking to enable compelling virtual social interactions. This paper shows that the near infra-red cameras used in eye tracking capture eye images that contain iris patterns of the user. Because iris patterns are a gold standard biometric, the current technology places the user's biometric identity at risk. Our first contribution is an optical defocus based hardware solution to remove the iris biometric from the stream of eye tracking images. We characterize the performance of this solution with different internal parameters. Our second contribution is a psychophysical experiment with a same-different task that investigates the sensitivity of users to a virtual avatar's eye movements when this solution is applied. By deriving detection threshold values, our findings provide a range of defocus parameters where the change in eye movements would go unnoticed in a conversational setting. Our third contribution is a perceptual study to determine the impact of defocus parameters on the perceived eye contact, attentiveness, naturalness, and truthfulness of the avatar. Thus, if a user wishes to protect their iris biometric, our approach provides a solution that balances biometric protection while preventing their conversation partner from perceiving a difference in the user's virtual avatar. This work is the first to develop secure eye tracking configurations for VR/AR/XR applications and motivates future work in the area.

Flight simulation using a Brain-Computer Interface: A pilot, pilot study.

As Brain-Computer Interface (BCI) systems advance for uses such as robotic arm control it is postulated that the control paradigms could apply to other scenarios, such as control of video games, wheelchair movement or even flight. The purpose of this pilot study was to determine whether our BCI system, which involves decoding the signals of two 96-microelectrode arrays implanted into the motor cortex of a subject, could also be used to control an aircraft in a flight simulator environment. The study involved six sessions in which various parameters were modified in order to achieve the best flight control, including plane type, view, control paradigm, gains, and limits. Successful flight was determined qualitatively by evaluating the subject's ability to perform requested maneuvers, maintain flight paths, and avoid control losses such as dives, spins and crashes. By the end of the study, it was found that the subject could successfully control an aircraft. The subject could use both the jet and propeller plane with different views, adopting an intuitive control paradigm. From the subject's perspective, this was one of the most exciting and entertaining experiments she had performed in two years of research. In conclusion, this study provides a proof-of-concept that traditional motor cortex signals combined with a decoding paradigm can be used to control systems besides a robotic arm for which the decoder was developed. Aside from possible functional benefits, it also shows the potential for a new recreational activity for individuals with disabilities who are able to master BCI control.

Human Fetal Testicular Tissue Xenotransplantation: A Platform to Study the Effect of Gonadotropins on Human Germ Cell Development In Utero.

PURPOSE: We examined the effects of long-term hCG stimulation on germ cell maturation, and Sertoli and Leydig cell function in a xenotransplantation model of the human fetal testis. MATERIALS AND METHODS: A total of 20 human fetal testes were ectopically xenografted on 20 castrated NCr male nude mice. Grafts were collected for analysis 24 weeks later. Mice were treated with saline as the control or with hCG beginning 4 weeks after the grafts were transplanted. RESULTS: Of the grafts 65% survived at 24 weeks. In contrast to untreated pregrafted samples, hCG stimulated xenografts showed significantly increased density of seminiferous tubule formation with Sertoli cell migration to the basement membrane. Germ cell proliferation and differentiation from gonocytes (M2A(+)) to prespermatogonia (MAGE-4A(+)) were observed in graft samples recovered from the hCG and nonhCG treated groups at 24 weeks of treatment. Leydig cells in hCG treated grafts produced significantly more testosterone than nonhCG treated grafts. Although further studies are required to investigate the potential for further differentiation and maturation of xenografted human fetal testes, normal in utero testicular development was reproduced under long-term hCG stimulation. CONCLUSIONS: This model represents a means to study long-term effects of gonadotoxins or hormonal stimulation on the maturation of human fetal testes.

Creating a new generation of pediatric dentists: a paradigm shift in training.

The University of California, Los Angeles (UCLA) School of Dentistry has implemented a Health Resources and Services Administration-funded program to prepare dentists for the complex and comprehensive needs of pediatric patients within rapidly changing demographics and a paradigm shift in dentistry. Traditional dental education has focused on how to respond to oral disease, whereas UCLA's program shifts the paradigm to emphasize early assessment, risk-based prevention, and disease management. A holistic approach to dental care that considers social and environmental determinants is used with minimally invasive techniques for restorative care. To support this change, pediatric dental residents receive traditional training combined with new didactics, advocacy opportunities, and applied learning experiences at community-based organizations. These new elements teach residents to recognize the causal factors of disease and to identify interventions that promote oral health at the individual, family, community, and policy level. Consequently, they are better prepared to treat a diverse group of patients who historically have faced the greatest burden of disease as well as an increased number of barriers to accessing oral health care; these consist of low-income, minority, and/or pediatric populations including children with special health needs. The program's ultimate goal is for residents to deploy these skills in treating vulnerable populations and to demonstrate greater interest in collaborating with non-dental health providers and community organizations to increase access to dental services in private or public health practice settings.

The incidence and effect of bacteriospermia and elevated seminal leukocytes on semen parameters.

OBJECTIVE: To determine the incidence of bacteriospermia and elevated seminal leukocytes (ESL) in a subfertile male population and correlate these results with semen parameters. DESIGN: Retrospective cohort study. SETTING: Canadian tertiary-level male infertility clinic and university-affiliated andrology and microbiology laboratories. PATIENT(S): Four thousand nine hundred thirty-five nonazoospermic subfertile men. INTERVENTION(S): Analysis and concurrent culture of 7,852 semen samples. MAIN OUTCOME MEASURE(S): Incidence of bacteriospermia and ESL and comparison of semen parameters between these groups. RESULT(S): The rate of bacteriospermia was 15% (22 species), and the rate of ESL was 19%, with no statistical correlation between these groups. Bacteriospermic patients (without ESL) had a statistically significant deterioration in DNA fragmentation index (DFI) only, compared with patients without bacteriospermia and ESL (24.1 vs. 21.8%). ESL alone was associated with a statistically significant deterioration in sperm concentration (20.6 vs. 55.3 × 10(6)/mL), motility (21.8 vs. 26.9%), normal morphology (12.3 vs. 17.4%), and DFI (26.5 vs. 21.8%), with no additional deterioration identified with bacteriospermia. CONCLUSION(S): Bacteriospermia and ESL were prevalent, but not statistically associated, in subfertile men. Bacteriospermia alone was associated with an increase in DFI only, but the presence of ESL was the dominant factor associated with deterioration in semen parameters.