An eye tracking based virtual reality system for use inside magnetic resonance imaging systems

Machine learning models for classifying non-specific neck pain using craniocervical posture and movement

OBJECTIVE

Physical therapists and clinicians commonly confirm craniocervical posture (CCP), cervical retraction, and craniocervical flexion as screening tests because they contribute to non-specific neck pain (NSNP). We compared the predictive performance of statistical machine learning (ML) models for classifying individuals with and without NSNP using datasets containing CCP and cervical kinematics during pro- and retraction (CKdPR).

DESIGN

Exploratory, cross-sectional design.

SETTING AND PARTICIPANTS

In total, 773 public service office workers (PSOWs) were screened for eligibility (NSNP, 441; without NSNP, 332).

METHODS

We set up five datasets (CCP, cervical kinematics during the protraction, cervical kinematics during the retraction, CKdPR and combination of the CCP and CKdPR). Four ML algorithms-random forest, logistic regression, Extreme Gradient boosting, and support vector machine-were trained.

MAIN OUTCOME MEASURES

Model performance were assessed using area under the curve (AUC), accuracy, precision, recall and F1-score. To interpret the predictions, we used Feature permutation importance and SHapley Additive explanation values.

RESULTS

The random forest model in the CKdPR dataset classified PSOWs with and without NSNP and achieved the best AUC among the five datasets using the test data (AUC, 0.892 [good]; F1, 0.832). The random forest model in the CCP dataset had the worst AUC among the five datasets using the test data [AUC, 0.738 (fair); F1, 0.715].

CONCLUSION

ML performance was higher for the CKdPR dataset than for the CCP dataset, suggesting that ML algorithms are more suitable than classical statistical methods for developing robust models for classifying PSOWs with and without NSNP.

Instant interaction driven adaptive gaze control interface

Gaze estimation is long been recognised as having potential as the basis for human-computer interaction (HCI) systems, but usability and robustness of performance remain challenging . This work focuses on systems in which there is a live video stream showing enough of the subjects face to track eye movements and some means to infer gaze location from detected eye features. Currently, systems generally require some form of calibration or set-up procedure at the start of each user session. Here we explore some simple strategies for enabling gaze based HCI to operate immediately and robustly without any explicit set-up tasks. We explore different choices of coordinate origin for combining extracted features from multiple subjects and the replacement of subject specific calibration by system initiation based on prior models. Results show that referencing all extracted features to local coordinate origins determined by subject start position enables robust immediate operation. Combining this approach with an adaptive gaze estimation model using an interactive user interface enables continuous operation with the 75th percentile gaze errors of 0.7∘ , and maximum gaze errors of 1.7∘ during prospective testing. There constitute state-of-the-art results and have the potential to enable a new generation of reliable gaze based HCI systems.

The convergence of naturalistic paradigms and cognitive neuroscience methods to investigate memory and its development

Studies that involve lab-based stimuli (e.g., words, pictures) are fundamental in the memory literature. At the same time, there is growing acknowledgment that memory processes assessed in the lab may not be analogous to how memory operates in the real world. Naturalistic paradigms can bridge this gap and over the decades a growing proportion of memory research has involved more naturalistic events. However, there is significant variation in the types of naturalistic studies used to study memory and its development, each with various advantages and limitations. Further, there are notable gaps in how often different types of naturalistic approaches have been combined with cognitive neuroscience methods (e.g., fMRI, EEG) to elucidate the neural processes and substrates involved in memory encoding and retrieval in the real world. Here we summarize and discuss what we identify as progressively more naturalistic methodologies used in the memory literature (movie, virtual reality, staged-events inside and outside of the lab, photo-taking, and naturally occurring event studies). Our goal is to describe each approach's benefits (e.g., naturalistic quality, feasibility), limitations (e.g., viability of neuroimaging method for event encoding versus event retrieval), and discuss possible future directions with each approach. We focus on child studies, when available, but also highlight past adult studies. Although there is a growing body of child memory research, naturalistic approaches combined with cognitive neuroscience methodologies in this domain remain sparse. Overall, this viewpoint article reviews how we can study memory through the lens of developmental cognitive neuroscience, while utilizing naturalistic and real-world events.

Effects of Patient Demographics and Examination Factors on Patient Experience in Outpatient MRI Appointments

OBJECTIVE

The objective of this article is to describe the effects of patient demographics and examination factors on patient-reported experience in outpatient MRI examinations.

METHODS

This institutional review board-waived, HIPPA-compliant quality improvement study evaluated outpatient MRI appointments from March 2021 to January 2022 using a postappointment survey consisting of a 5-point emoji scale and text-based feedback. Patient demographics and examination information were extracted from electronic medical records. Ratings ≤ 3 were categorized as negative, and ratings ≥ 4 were categorized as positive. Continuous variables were analyzed using the Kruskal-Wallis test, and categorical variables were analyzed using the Fisher's exact test. A P value less than .05 was considered significant. A natural language processing algorithm was trained and validated to categorize patient feedback.

RESULTS

A total of 3,636 patients responded to the survey. Positive ratings had a higher proportion of male respondents compared with negative ratings (47.9% versus 37.0%, P = .004). Examination characteristics were also grouped by positive or negative rating. Patients who endured longer examination time (median 54.0 min versus 44.0 min, P < .001) and longer wait time after check-in (median 61.6 min versus 46.2 min, P < .001) were more likely to give negative ratings. The most common themes of free text feedback included excellent service (84.3%), on-time service (8.4%), and comfortable intravenous line placement (0.4%). Most common negative feedback included long wait times (10.5%), poor communication (8.4%), and physical discomfort during the examination (4.2%).

CONCLUSION

Male gender, short examination duration, and on-time start were associated with positive patient ratings.

Synchronous functional magnetic resonance eye imaging, video ophthalmoscopy, and eye surface imaging reveal the human brain and eye pulsation mechanisms

The eye possesses a paravascular solute transport pathway that is driven by physiological pulsations, resembling the brain glymphatic pathway. We developed synchronous multimodal imaging tools aimed at measuring the driving pulsations of the human eye, using an eye-tracking functional eye camera (FEC) compatible with magnetic resonance imaging (MRI) for measuring eye surface pulsations. Special optics enabled integration of the FEC with MRI-compatible video ophthalmoscopy (MRcVO) for simultaneous retinal imaging along with functional eye MRI imaging (fMREye) of the BOLD (blood oxygen level dependent) contrast. Upon optimizing the fMREye parameters, we measured the power of the physiological (vasomotor, respiratory, and cardiac) eye and brain pulsations by fast Fourier transform (FFT) power analysis. The human eye pulsated in all three physiological pulse bands, most prominently in the respiratory band. The FFT power means of physiological pulsation for two adjacent slices was significantly higher than in one-slice scans (RESP1 vs. RESP2; df = 5, p = 0.045). FEC and MRcVO confirmed the respiratory pulsations at the eye surface and retina. We conclude that in addition to the known cardiovascular pulsation, the human eye also has respiratory and vasomotor pulsation mechanisms, which are now amenable to study using non-invasive multimodal imaging of eye fluidics.

Anatomical Features of the Tarsal Sinus in Patients with Pes Planus: Implications for Clinical Management

BACKGROUND In the treatment of pes planus, if the implant does not match the anatomical structures of the sinus tarsi, synovitis can develop, causing pain symptoms. In the interest of making clinical recommendations for extra-osseous talotarsal stabilization, the goal of the present study was to characterize the anatomical characteristics of the sinus tarsi in patients with pes planus using magnetic resonance imaging (MRI) scans. MATERIAL AND METHODS This was a retrospective study involving 56 pes planus patients and 56 healthy volunteers from January 2014 to May 2022. The sinus tarsi was measured for length and width, for angle with the coronal and sagittal axes, and for length of the subtalar implant. RESULTS All examined metrics showed a difference between pes planus patients and healthy participants, with the exception of the subtalar implant's length. The average sinus tarsi length and width among pes planus patients were 19.23 mm and 2.91 mm, respectively. The angle between the sinus tarsi and the coronal and sagittal axes was 21.418° and 25.077°, while the length of approach was 33.06 mm and 0.76°. The only gender differences that were statistically significant were in the length and width of the sinus tarsi. There were no notable variations between the left and right sides. CONCLUSIONS Sinus tarsi morphology may be impacted by pes planus. When treating patients with pes planus, clinicians should take these anatomical factors into consideration since they might more completely characterize the anatomical features of the sinus tarsi.

Eye tracking and eye expression decoding based on transparent, flexible and ultra-persistent electrostatic interface

Eye tracking provides valuable insight for analyzing visual attention and underlying thinking progress through the observation of eye movements. Here, a transparent, flexible and ultra-persistent electrostatic sensing interface is proposed for realizing active eye tracking (AET) system based on the electrostatic induction effect. Through a triple-layer structure combined with a dielectric bilayer and a rough-surface Ag nanowire (Ag NW) electrode layer, the inherent capacitance and interfacial trapping density of the electrostatic interface has been strongly enhanced, contributing to an unprecedented charge storage capability. The electrostatic charge density of the interface reached 1671.10 μC·m^-2 with a charge-keeping rate of 96.91% after 1000 non-contact operation cycles, which can finally realize oculogyric detection with an angular resolution of 5°. Thus, the AET system enables real-time decoding eye movements for customer preference recording and eye-controlled human-computer interaction, supporting its limitless potentiality in commercial purpose, virtual reality, human computer interactions and medical monitoring.

Effects of a 360° virtual counselling environment on patient anxiety and CCTA process time: A randomised controlled trial

INTRODUCTION

This study investigated whether a 360° virtual counselling environment (360°VCE) was more effective at decreasing patients' anxiety than routine standard of care counselling for patients undergoing coronary computed tomography angiography (CCTA), and if there was any difference in the process times for both of these groups.

METHODS

A total of 86 patients underwent CCTA in this randomised controlled trial. Patients were randomly assigned to intervention and control groups. The 360°VCE was developed using spherical panoramic images and non-immersive 360° technology. The primary outcome, anxiety, was measured using the State-Trait Anxiety Inventory (STAI). The secondary outcome, CCTA process time, was measured from the time of arrival in the department until end of examination.

RESULTS

Pre-scan anxiety was lower among patients in the 360°VCE group immediately before CCTA in comparison to patients in the control group (p = 0.015). Women demonstrated higher levels of anxiety than men in both groups. No between-group differences were discerned in CCTA process time.

CONCLUSION

Access to 360°VCE can reduce patients' pre-CCTA anxiety levels.

IMPLICATIONS FOR PRACTICE

The presented results can be used to improve patient counselling and care, reduce anxiety among patients undergoing CCTA, and optimise the CCTA examination procedure.

An Automatic Calibration Method for Kappa Angle Based on a Binocular Gaze Constraint

Kappa-angle calibration shows its importance in gaze tracking due to the special structure of the eyeball. In a 3D gaze-tracking system, after the optical axis of the eyeball is reconstructed, the kappa angle is needed to convert the optical axis of the eyeball to the real gaze direction. At present, most of the kappa-angle-calibration methods use explicit user calibration. Before eye-gaze tracking, the user needs to look at some pre-defined calibration points on the screen, thereby providing some corresponding optical and visual axes of the eyeball with which to calculate the kappa angle. Especially when multi-point user calibration is required, the calibration process is relatively complicated. In this paper, a method that can automatically calibrate the kappa angle during screen browsing is proposed. Based on the 3D corneal centers and optical axes of both eyes, the optimal objective function of the kappa angle is established according to the coplanar constraint of the visual axes of the left and right eyes, and the differential evolution algorithm is used to iterate through kappa angles according to the theoretical angular constraint of the kappa angle. The experiments show that the proposed method can make the gaze accuracy reach 1.3° in the horizontal plane and 1.34° in the vertical plane, both of which are within the acceptable margins of gaze-estimation error. The demonstration of explicit kappa-angle calibration is of great significance to the realization of the instant use of gaze-tracking systems.

Evoking stress reactivity in virtual reality: A systematic review and meta-analysis

BACKGROUND

Virtual reality (VR) research probes stress environments that are infeasible to create in the real world. However, because research simulations are applied to narrow populations, it remains unclear if VR simulations can stimulate a broadly applicable stress-response. This systematic review and meta-analysis was conducted on studies using VR stress tasks and biomarkers.

METHODS

Included papers (N = 52) measured cortisol, heart rate (HR), galvanic skin response (GSR), systolic blood pressure (SBP), diastolic blood pressure (DBP), respiratory sinus arrhythmia (RSA), parasympathetic activity (RMSSD), sympathovagal balance (LF/HF), and/or salivary alpha-amylase (sAA). Effect sizes (ES) and confidence intervals (CI) were calculated based on standardized mean change of baseline-to-peak biomarker levels.

RESULTS

From baseline-to-peak (ES, CI), analyses showed a statistically significant change in cortisol (0.56, 0.28-0.83), HR (0.68, 0.53-0.82), GSR (0.59, 0.36-0.82), SBP (.55, 0.19-0.90), DBP (.64, 0.23-1.05), RSA (-0.59, -0.88 to -0.30), and sAA (0.27, 0.092-0.45). There was no effect for RMSSD and LF/HF.

CONCLUSION

VR stress tasks elicited a varied magnitude of physiological stress reactivity. VR may be an effective tool in stress research.

Technology Behavior Model—Impact of Extended Reality on Patient Surgery

Smart surgery is a new way to utilize smart devices to change existing surgeries. Smart glasses can enhance the surgical procedure so that the patient can understand the procedure more intuitively. Surgery is for patients, and patient acceptance of extended reality surgery is the purpose of this study. This study uses the technology behavior model, which is more in line with the user’s assessment of the acceptance behavior of the new technology. A triangulated research approach was used, which applies to this study for a specific patient population. Primary data were collected from hospitals through questionnaires and were statistically analyzed by CB&PLS-SEM multimodel using SmartPLS software. It was concluded that patients were influenced by operational emotional factors in undergoing extended reality surgery. The study provides a basis for future research related to the practical application of smart surgery from the patient’s perspective in viewing and accepting surgery.

Let's Play the fMRI-Advantages of Gamified Paradigm in Examining the Motor Cortex of Young Children

Background: Performing functional magnetic resonance imaging (fMRI) examination is difficult when a child needs to stay awake and cooperate. Many techniques help to prepare them for the study but without modification of the examination protocol. The objective of this research was to prepare a gamified motor paradigm (“computer game”) that will improve the fMRI examination of young children. Methods: After preparing a dedicated application the fMRI examination was performed on 60 healthy children (10 girls and 10 boys in each age group of 4, 5, and 6 years old). Each child performed the gamified and a standard motor paradigm, both based on squeezing a rubber bulb. The effectiveness of squeezing were compared. Results: With the application of the gamified paradigm children completed significantly more active blocks (3.3 ± 1.4) than for the standard paradigm (2.2 ± 1.6) (p < 0.0001). In mixed-effects Poisson regression, age (IRR = 1.9; 95%CI: 1.5−2.5) and application of gamified paradigm (IRR = 5.6; 95%CI: 1.1−28.0) were significantly associated with more completed blocks. Conclusions: The gamified motor paradigm performed better than a standard paradigm in the fMRI examination of children between 4 and 6 years old. It allowed a significant increase in the number of completed active blocks and also better squeezing effectiveness in each block.