Head-mounted Device Research Articles

Evaluating the Tobii Pro Glasses 2 and 3 in static and dynamic conditions

Over the past few decades, there have been significant developments in eye-tracking technology, particularly in the domain of mobile, head-mounted devices. Nevertheless, questions remain regarding the accuracy of these eye-trackers during static and dynamic tasks. In light of this, we evaluated the performance of two widely used devices: Tobii Pro Glasses 2 and Tobii Pro Glasses 3. A total of 36 participants engaged in tasks under three dynamicity conditions. In the “seated with a chinrest” trial, only the eyes could be moved; in the “seated without a chinrest” trial, both the head and the eyes were free to move; and during the walking trial, participants walked along a straight path. During the seated trials, participants’ gaze was directed towards dots on a wall by means of audio instructions, whereas in the walking trial, participants maintained their gaze on a bullseye while walking towards it. Eye-tracker accuracy was determined using computer vision techniques to identify the target within the scene camera image. The findings showed that Tobii 3 outperformed Tobii 2 in terms of accuracy during the walking trials. Moreover, the results suggest that employing a chinrest in the case of head-mounted eye-trackers is counterproductive, as it necessitates larger eye eccentricities for target fixation, thereby compromising accuracy compared to not using a chinrest, which allows for head movement. Lastly, it was found that participants who reported higher workload demonstrated poorer eye-tracking accuracy. The current findings may be useful in the design of experiments that involve head-mounted eye-trackers.

Efficacy of immersive extended reality (XR) interventions on different symptom domains of schizophrenia spectrum disorders. A systematic review.

Extended reality (XR) is an umbrella term for virtual reality (VR) and augmented reality (AR), both novel vectors for therapeutic intervention modalities. In VR, head-mounted devices (HMD) allow interaction with three-dimensional virtual environments and simulated avatars, while AR overlaps virtual, simulated objects to observe physical reality. Treatment through immersive VR has been studied in psychiatry, including patients suffering from schizophrenia spectrum disorders, while there has not been much attention to AR technologies in psychiatry. Our systematic review aimed to examine the currently available literature regarding the treatment efficacy of immersive VR or AR technologies on different symptom domains of schizophrenia spectrum disorders, screen for potential adverse effects, and gather data on the technological and human resource requirements of such interventions to help guide future research. We conducted a systematic literature review with database searches carried out between 9/2021 and 8/2022 through PubMed, Scopus, EBSCOhost Academic Search Premier, and Web of Science. We identified 2,157 records, 214 were assessed further for eligibility and 12 met inclusion criteria. All included articles studied immersive VR and none used AR technology. Included studies were heterogenous in nature, including AVATAR therapy (3) and CBT-based (5) VR interventions, as well as cognitive (2), social (1), and relaxation (1) training through VR. The comparison groups were either passive controls (waitlist and treatment as usual), therapeutic interventions (CBT and Integrated psychological treatment), passive VR environments, or traditional, comparable, non-virtual treatment modalities (social roleplay and progressive muscle relaxation training). Pooled together, the included studies on VR show positive treatment effects in all major symptom domains of schizophrenia spectrum disorders with hardly any adverse effects related to the intervention modalities. In this review, we have showcased how different symptom domains can be targeted through VR interventions, highlighting VR as a potential new vector for a diverse range of psychosocial therapeutic modalities that allow for completely new possibilities in the treatment of schizophrenia spectrum disorders. VR technology still requires more research and validation. Our review also shows that there are currently no studies examining AR technology in the treatment of schizophrenia spectrum disorders, indicating a distinctive research gap.

Implementation of Augmented Reality in Dental Surgery Using HoloLens 2: An In Vitro Study and Accuracy Assessment

Computer-guided dynamic navigation systems have elevated dental implant surgery into a more patient-friendly and efficient procedure. However, commercially available systems use displays as an output for guidance. This implies that surgeons have to take their eyes off the surgery site frequently in order to accurately adjust surgical instruments. The solution for such an issue is to use augmented reality (AR) head-mounted devices to showcase all necessary guiding instructions without any distractions. In this work, the implementation of augmented reality in dental surgery using the HoloLens 2 AR headset for the assessment of accuracy is described. The experiments were performed in vitro with two implementation steps, evaluating calibration and perspective of the virtual dental model alignment accuracies using a newly created marker. The calibration results showed overall accuracy and precision surpassing the 1 mm threshold in distance-related measurements. Dependency on the side on which the marker was observed and the movement of the user’s head were considered to be the most influential factors regarding the perspective of the virtual dental model alignment accuracy estimate.

Augmented Reality and 3-Dimensional Dynamic Navigation System Integration for Osteotomy and Root-end Resection

IntroductionAugmented reality (AR) superimposes high-definition computer-generated virtual content onto the existing environment, providing users with an enhanced perception of reality. This study investigates the feasibility of integrating an AR head-mounted device into a 3-dimensional dynamic navigation system (3D-DNS) for osteotomy and root-end resection (RER). It compares the accuracy and efficiency of AR + 3D-DNS to 3D-DNS for osteotomy and RER. MethodsSeventy-two tooth roots of 3D-printed surgical jaw models were divided into two groups: AR + 3D-DNS (n = 36) and 3D-DNS (n = 36). Cone-beam computed tomography scans were taken pre and postoperatively. The osteotomy and RER were virtually planned on X-guide software and delivered under 3D-DNS guidance. For the AR + 3D-DNS group, an AR head-mounted device (Microsoft HoloLens 2) was integrated into the 3D-DNS. The 2D- and 3D-deviations were calculated. The osteotomy and RER time and the number of procedural mishaps were recorded. ResultsOsteotomy and RER were completed in all samples (72/72). AR + 3D-DNS was more accurate than 3D-DNS, showing lower 2D- and 3D-deviation values (P < .05). The AR + 3D-DNS was more efficient in time than 3D-DNS (P < .05). There was no significant difference in the number of mishaps (P > .05). ConclusionsWithin the limitations of this in vitro study, the integration of an AR head-mounted device to 3D-DNS is feasible for osteotomy and RER. AR improved the accuracy and time efficiency of 3D-DNS in osteotomy and RER. Head-mounted AR has the potential to be safely and reliably integrated into 3D-DNS for endodontic microsurgery.

Mixed Reality for Pediatric Brain Tumors: A Pilot Study from a Singapore Children’s Hospital

Mixed reality (MR) platforms for neurosurgical education, training, and clinical use have gained popularity in recent years. However, their use in pediatric neurosurgery is comparatively unexplored. We designed a study to explore the use of an MR-based application for pediatric brain tumors. The primary aim is to determine if the use of MR provides the neurosurgical team with a better understanding of the visuospatial anatomy of neoplasms in pediatric craniums and to guide operative planning. Secondary aims include exploring its use as an educational tool for junior doctors and medical students. Methods: Three-dimensional anatomical models of selected pediatric brain tumors are created and uploaded to an MR application. The processed data is transferred into designated MR head-mounted devices. At the end of the trial, users are required to fill in an evaluation form. Results: A total of 30 participants took part in this study. Based on the collated feedback data, all of them agreed that the MR platform was useful as a tool in different aspects of understanding the selected pediatric brain tumors. Conclusions: This study demonstrates a proof of concept of the feasibility of MR platforms for a better understanding of pediatric brain tumors. Further development is needed to refine the current setup to be more versatile.

MRLab: Virtual-Reality Fusion Smart Laboratory Based on Multimodal Fusion

During the COVID-19 pandemic, online classes became the only option for many students. The main challenge for these classes was conducting risky and complex chemical or biological experiments in a domestic environment. To address this challenge, a smart experiment system called MRLab was developed. MRLab used wearables such as a smart glove and head-mounted device to record sensory data and a multimodal hybrid fusion model GVVS to interpret the user’s experimental intent, which essentially transforms the user’s abstract behavioral actions into a probabilistic set of experimental intent that can be computed. Different experiments in MRLab used different libraries of experimental intents. The SrNet model in GVVS was used to estimate the probability of the user’s gesture behavior generated from the smart glove, while the SIPA algorithm compared speech information entered during the experiment with the experimental intent library to estimate the probability of the user’s intent. At the same time, the scene visual channel monitored the information about the object the user intended to operate, with the SVF algorithm computing the probability of the intended object in real-time. The results from ANOVA and post-hoc comparative testing conducted on 21 volunteers revealed that MRLab outperformed other experiment modes, including WEB, AR, and VR, with a higher intention understanding rate, efficiency, and user satisfaction. Therefore, MRLab proved to be a useful alternative to traditional physics laboratory experiments during the pandemic, along with being an additional teaching tool for remote learning purposes.

The Implementation of Interactive VR Application and Caching Strategy Design on Mobile Edge Computing (MEC)

Virtual reality (VR) and augmented reality (AR) have been proposed as revolutionary applications for the next generation, especially in education. Many VR applications have been designed to promote learning via virtual environments and 360° video. However, due to the strict requirements of end-to-end latency and network bandwidth, numerous VR applications using 360° video streaming may not achieve a high-quality experience. To address this issue, we propose relying on tile-based 360° video streaming and the caching capacity in Mobile Edge Computing (MEC) to predict the field of view (FoV) in the head-mounted device, then deliver the required tiles. Prefetching tiles in MEC can save the bandwidth of the backend link and support multiple users. Smart caching decisions may reduce the memory at the edge and compensate for the FoV prediction error. For instance, caching whole tiles at each small cell has a higher storage cost compared to caching one small cell that covers multiple users. In this paper, we define a tile selection, caching, and FoV coverage model as the Tile Selection and Caching Problem and propose a heuristic algorithm to solve it. Using a dataset of real users’ head movements, we compare our algorithm to the Least Recently Used (LRU) and Least Frequently Used (LFU) caching policies. The results show that our proposed approach improves FoV coverage by 30% and reduces caching costs by 25% compared to LFU and LRU.

Role of virtual reality in improving the spatial perception of the kidney during flexible ureteroscopy: A feasibility study using virtual reality simulators and 3D models.

The aims were to describe a software-based reconstruction of the patient-specific kidney cavity intraluminal appearance via a head-mounted device and to estimate its feasibility for training novices. In total, 15 novices were recruited. Each novice was shown a three-dimensional reconstruction of a patient's computed tomography scan, whose kidney was printed. They then joined the surgeon in the operating room and assisted them in detecting the stone during flexible ureteroscopy on the printed model. Then, each participant did a 7-day virtual reality (VR) study followed by virtual navigation of the printed kidney model and came to the operating room to help the surgeon with ureteroscope navigation. The length of the procedure and the number of attempts to find the targeted calyx were compared. With VR training, the length of the procedure (p = 0.0001) and the number of small calyces that were incorrectly identified as containing stones were significantly reduced (p = 0.0001). All the novices become highly motivated to improve their endourological skills further. Participants noticed minimal values for nausea and for disorientation. However, oculomotor-related side effects were defined as significant. Five specialists noticed a good similarity between the VR kidney cavity representation and the real picture, strengthening the potential for the novice's education via VR training. Virtual reality simulation allowed for improved spatial orientation within the kidney cavity by the novices and could be a valuable option for future endourological training and curricula.

Augmented or Mixed Reality Enhanced Head-Mounted Display Navigation for In Vivo Spine Surgery: A Systematic Review of Clinical Outcomes.

This research paper provides a systematic literature review (SLR) on the current status of augmented-reality head-mounted devices (AR-HMDs) that guide and navigate spine surgeries and pedicle screw placement. Embase, Scopus, PubMed, Cochrane Library and IEEE Xplore databases were screened for the systematic literature search to collect and statistically analyze live patient clinical, procedural and user experience data. Multi-level Poisson and binominal models were used for analysis. In vivo patient data, only the clinically widely used Gertzbein-Robbins Scale, were published as an outcome in the recent heterogeneous literature. The statistical analysis supports the hypothesis that using AR-HMDs has the same clinical outcomes as using more expensive robot-assisted surgical (RAS) systems. AR-HMD-guided pedicle screw insertion is reaching its technology readiness, providing similar benefits to RAS. Further meta-analysis is expected in the future from higher case-numbered and standardized randomized clinical trials.

The Effect of Holographic Heart Models and Mixed Reality for Anatomy Learning in Congenital Heart Disease: An Exploratory Study

In this paper, we present an exploratory study on the potential impact of holographic heart models and mixed reality technology on medical training, and in particular in teaching complex Congenital Heart Diseases (CHD) to medical students. Fifty-nine medical students were randomly allocated into three groups. Each participant in each group received a 30-minute lecture on a CHD condition interpretation and transcatheter treatment with different instructional tools. The participants of the first group attended a lecture in which traditional slides were projected onto a flat screen (group “regular slideware”, RS). The second group was shown slides incorporating videos of holographic anatomical models (group “holographic videos”, HV). Finally, those in the third group wore immersive, head-mounted devices (HMD) to interact directly with holographic anatomical models (group “mixed reality”, MR). At the end of the lecture, the members of each group were asked to fill in a multiple-choice questionnaire aimed at evaluating their topic proficiency, as a proxy to evaluate the effectiveness of the training session (in terms of acquired notions); participants from group MR were also asked to fill in a questionnaire regarding the recommendability and usability of the MS Hololens HMDs, as a proxy of satisfaction regarding its use experience (UX). The findings show promising results for usability and user acceptance.

87 An Augmented Reality Burn Management Application to Guide Care in Austere Environments

Abstract Introduction Novel medical technologies are necessary to support virtual health in low bandwidth environments. When tele-mentoring is not possible, advanced clinical decision support tools can deliver essential medical knowledge to assist novice clinicians. These tools can fill knowledge gaps in specialty fields, like burn. We developed the Augmented Reality Burn Assist Manager (ARBAM), a novel, comprehensive augmented reality (AR)-based burn management platform to address key tasks in burn care. Methods A randomized 2x2 cross-over design was used to investigate if ARBAM could enhance a user’s ability to care for a simulated burn patient as compared to standard clinical practice guidelines (CPGs). We developed the software for use on a mixed reality, head-mounted device. Participants were clinicians with little to no burn care experience, and were asked to complete 4 key tasks, twice each, using either paper copies of the Joint Trauma System’s CPGs and supplemental worksheets first (Paper) or our AR technology. Tasks included calculating burn size (TBSA), performing medication dosage calculations (MC), managing a burn fluid resuscitation (FR), and performing a simulated escharotomy (EC). All tasks were evaluated for completion time and accuracy. Cross-over analysis of treatment effects used a two-sided, two-sample t-test or Wilcoxon Rank-Sum test as appropriate. Results Eleven participants were randomized: 5 started with Paper and 6 started with AR. Time to perform FR was statistically different (p&amp;lt; 0.05) with AR taking less time than Paper (4.8 vs. 7.0 mins, respectively). FR clinical performance was also better in the AR group with a mean accuracy score of 99% vs. 52% for Paper (p&amp;lt; 0.001). EC completion times were not clinically or statistically different. However, EC accuracy was 93% for AR compared to 55% for Paper (p&amp;lt; 0.001). Although not statistically different, MC performance accuracy was considerably better for AR (91%) than for Paper (66%). No differences between groups were observed for TBSA or MC completion times nor TBSA accuracy. Conclusions Compared to traditional tools, AR may enhance a clinician's ability to complete key tasks in the initial management of a burn patient. This technology may be helpful during disasters when tele-mentoring is not available. Limitations of this study include a small sample size, limited user training on the AR device, and potential carry-over effects. Therefore, generalizations cannot be made about wide-scale usage. Nonetheless, this study showed that AR may be helpful in managing lifesaving burn tasks. Applicability of Research to Practice ARBAM may enhance decision making by novice clinicians when caring for burn patients. Our data demonstrate the potential for AR-based support tools to improve burn care delivery and reduce error rates for novice clinicians, which could lead to reductions in morbidity and mortality. Future research is needed to investigate how AR technology can be used for other lifesaving interventions.

Virtual reality simulator for developing spatial skills during retrograde intrarenal pyeloscopy

Introduction. Currently, several virtual reality (VR) simulators have been described for the upper urinary tract stone surgery skill development, including retrograde or antegrade nephroscopy. However, their high cost and the lack of a detailed reconstruction of the intraluminal pelvicalyceal system (PCS) appearance limit their implementation into educational process and clinical practice.Objectives. To develop the approach for VR-reconstruction of the intraluminal appearance of the PCS via head mounted device (HMD), as well as estimate its usefulness for novices to improve spatial orientation during retrograde flexible nephroscopy.Materials &amp; methods. Five residents without experience in self-performing retrograde flexible nephroscopy participated in a 7-day training course on the VR simulator developed, during which each novice studied six variants of the PCS. For the procedure simulation, a silicone kidney model was created with the stone placed in the calyx which was selected randomly in each case. Before and after VR-course, each resident assisted the experienced urologist during simulated retrograde nephroscopy to find the stone placed according to random selection. The nephroscopy time and the number of errors in stone-finding during retrograde flexible nephroscopy were analysed.Results. There was a statistically significant decrease in nephroscopy time (on avg by 17.6 minutes, p = 0.043) and errors to find targeted calyx, which was observed once after the training one resident only.Conclusion. The described VR simulator does not require significant time, technical and financial costs, and is available for wide implementation in the training of young specialists.

AUGMENTED MASONRY DESIGN - A DESIGN METHOD USING AUGMENTED REALITY (AR) FOR CUSTOMIZED BRICKLAYING DESIGN ALGORITHMS

The Augmented Masonry Design project presents experimental research about developing and applying Augmented Reality (AR) technology for customized design algorithms, exploring a real-time, interactive, and spatial-free design method for the early architectural design stage. We aim to resolve the current 2D-based design limitations and provide architects with a 3D-4D immersive perception in AR for a practical and easy-to-use design method. Furthermore, with reference to the Covid-19 pandemic, we propose that this method could break through site accessibility and constraints by breaking the barriers of physical space. Towards this aim, we apply the Augmented Masonry Design into two prototypes: a) user interface (UI) immersive design, in which interactive inputs will communicate with design algorithms in AR through the inputs from the screen-based UI on mobile devices (e.g., smartphones and tablets); b) intuitive interaction immersive design, in which interactive inputs will be translated to design algorithms directly in AR through hand gestures on head-mounted devices (HMD) (e.g., Microsoft HoloLens). Our Findings highlight the advantages of immersive design in the initial stage of architectural drafts, which gives designers better spatial understanding and design creativity, as well as the challenges arising from the limitations of current AR devices and the lack of real physical simulation in the design system.

Head-Mounted Miniature Motorized Camera and Laser Pointer Driven by Eye Movements

Recording a video scene as seen by an observer, materializing where is focused his visual attention and allowing an external person to point at a given object in this scene, could be beneficial for various applications such as medical education or remote training. Such a versatile device, although tested at the experimental laboratory demonstrator stage, has never been integrated in a compact and portable way in a real environment. In this context, we built a low-cost, light-weight, head-mounted device integrating a miniature camera and a laser pointer that can be remotely controlled or servo-controlled by an eye tracker. Two motorizations were implemented and tested (pan/tilt and Rilsey-prisms-based). The video was both recorded locally and transmitted wirelessly. Risley prisms allowed finer remote control of camera or laser pointer orientation (0.1° vs. 0.35°), but data processing and Wi-Fi transmission incur significant latency (~0.5 s) limiting the servo-controlling by eye movements. The laser beam was spatially shaped by a Diffractive Optical Element to facilitate object illumination or recognition. With this first proof-of-concept prototype, the data stream needs to be optimized to make full use of the eye tracker, but this versatile device can find various applications in education, healthcare or research.

Real-Time Navigation with Guide Template for Pedicle Screw Placement Using an Augmented Reality Head-Mounted Device: A Proof-of-Concept Study.

This study aims to explore the real-time navigation with guide template using an augmented reality head-mounted device (ARHMD) for pedicle screw placement. The spatial coordinate relationships between augmented reality images and real objects were established through the custom-made guide template, and the registration and tracking were completed using an ARHMD. The feasibility and accuracy of this method were verified by pedicle screw placement in 2 lumbar models. According to the Gertzbein-Robbins grading scale, the accuracy of pedicle screw placement was assessed. The navigation errors were estimated by measuring the deviation values of entry point and trajectory angle. A total of 20 pedicle K-wires were placed into L1-L5 in 2 lumbar models, which were successfully completed, with an average time of 11.5min per model and 69s per screw. The overall K-wires placement accuracy was 100% (20 screws). The navigation error was 2.77 ± 0.82mm for the deviation value of entry point, and 3.03° ± 0.94° for the deviation value of trajectory angle. The application of an ARHMD combined with guide template for pedicle screw placement is a promising navigation approach.

VR-Based Immersive Service Management in B5G Mobile Systems: A UAV Command and Control Use Case

The management of remote services, such as remote surgery, remote sensing, or remote driving, has become increasingly important, especially with the emerging 5G and Beyond 5G technologies. However, the strict network requirements of these remote services represent one of the major challenges that hinder their fast and large-scale deployment in critical infrastructures. This article addresses certain issues inherent in remote and immersive control of virtual reality (VR)-based unmanned aerial vehicles (UAVs), whereby a user remotely controls UAVs, equipped with 360° cameras, using their head-mounted devices (HMD) and their respective controllers. Remote and immersive control services, using 360° video streams, require much lower latency and higher throughput for true immersion and high service reliability. To assess and analyze these requirements, this article introduces a real-life testbed system that leverages different technologies (e.g., VR, 360° video streaming over 4G/5G, and edge computing). In the performance evaluation, different latency types are considered. They are namely: 1) glass-to-glass latency between the 360° camera of a remote UAV and the HMD display; 2) user/pilot’s reaction latency; and 3) the command/execution latency. The obtained results indicate that the responsiveness (dubbed Glass-to-Reaction-to-Execution—GRE–latency) of a pilot, using our system, to a sudden event is within an acceptable range, i.e., around 900 ms.

Quantifying the impact of hearing-aid microphone placement and head-mounted devices on binaural cues from head-related transfer functions

Emerging techniques for assessment and training of spatial hearing use virtual reality (VR) devices to present auditory-visual cues. Sounds may be processed using head-related transfer functions (HRTFs), which capture directional acoustic cues, and visuals may be presented using a head-mounted display (HMD). For users of hearing devices such as hearing aids or cochlear implants, microphone placement may alter the binaural cues carried by the HRTF. Cues may also be distorted in presentations that combine HMD visuals with loudspeaker audio. This work seeks to understand these impacts by measuring and creating a database of HRTFs in the presence of hearing aids and HMDs. HRTFs were recorded within an anechoic chamber, using a standard manikin in a loudspeaker array located on the horizontal plane. Recordings were made with real sound sources of 5.625° resolution and virtual sources of 1° resolution. We will compare interaural time and level differences (ITDs and ILDs) from HRTFs measured through hearing-aid microphones with varied microphone placement (i.e., behind-the-ear and in-the-ear) and the presence versus absence of an HMD during the HRTF recording. Results will provide insights regarding HRTFs for individuals with hearing devices, as well as characterization of the HMD impact on VR-guided individual HRTF measurement.

Off-Axis Polarization Volume Lens for Diffractive Waveguide

In augmented reality diffractive waveguide technology, the light field needs to be collimated before being transmitted into the diffractive waveguide. Conventional schemes usually require additional collimating optics to collimate the light from the micro-image source and guide it into the waveguide in-coupling elements. In order to meet the needs of head-mounted devices and further miniaturize the equipment, this paper proposes a waveguide device that combines collimation and coupling by using a reflective polarization volume lens (PVL). A related model is also established and simulated to calculate the diffraction and transmission characteristics of the PVL element, and is then improved to fit the experiment. The diffraction lens studied in this paper has high diffraction efficiency with a large off-axis angle, which can fold the optical path and reduce considerably the volume of the optical system when applied to the waveguide system.

Continuous non-invasive estimates of cerebral blood flow using electrocardiography signals: a feasibility study

This paper describes a potential method to detect changes in cerebral blood flow (CBF) using electrocardiography (ECG) signals, measured across scalp electrodes with reference to the same signal across the chest—a metric we term the Electrocardiography Brain Perfusion index (EBPi). We investigated the feasibility of EBPi to monitor CBF changes in response to specific tasks. Twenty healthy volunteers wore a head-mounted device to monitor EBPi and electroencephalography (EEG) during tasks known to alter CBF. Transcranial Doppler (TCD) ultrasound measurements provided ground-truth estimates of CBF. Statistical analyses were applied to EBPi, TCD right middle cerebral artery blood flow velocity (rMCAv) and EEG relative Alpha (rAlpha) data to detect significant task-induced changes and correlations. Breath-holding and aerobic exercise induced highly significant increases in EBPi and TCD rMCAv (p < 0.01). Verbal fluency also increased both measures, however the increase was only significant for EBPi (p < 0.05). Hyperventilation induced a highly significant decrease in TCD rMCAv (p < 0.01) but EBPi was unchanged. Combining all tasks, EBPi exhibited a highly significant, weak positive correlation with TCD rMCAv (r = 0.27, p < 0.01) and the Pearson coefficient between EBPi and rAlpha was r = − 0.09 (p = 0.05). EBPi appears to be responsive to dynamic changes in CBF and, can enable practical, continuous monitoring. CBF is a key parameter of brain health and function but is not easily measured in a practical, continuous, non-invasive fashion. EBPi may have important clinical implications in this context for stroke monitoring and management. Additional studies are required to support this claim.

Advances in applications of head mounted devices (HMDs): Physical techniques for drug delivery and neuromodulation.

Head-mounted medical devices (HMDs) are disruptive inventions representing laboratories and clinical institutions worldwide are climbing the apexes of brain science. These complex devices are inextricably linked with a wide range knowledge containing the Physics, Imaging, Biomedical engineering, Biology and Pharmacology, particularly could be specifically designed for individuals, and finally exerting integrated bio-effect. The salient characteristics of them are non-invasive intervening in human brain's physiological structures, and alterating the biological process, such as thermal ablating the tumor, opening the BBB to deliver drugs and neuromodulating to enhance cognitive performance or help to manipulate prosthetic. The increasing demand and universally accepted of them have set off a dramatic upsurge in HMDs' studies, seminal applications of them span from clinical use to psychiatric disorders and neurological modulation. With subsequent pre-clinical studies and human trials emerging, the mechanisms of transcranial stimulation methods of them were widely studied, and could be basically came down to three notable approach: magnetic, electrical and ultrasonic stimulation. This review provides a comprehensive overviews of their stimulating mechanisms, and recent advances in clinic and military. We describe the potential impact of HMDs on brain science, and current challenges to extensively adopt them as promising alternative treating tools.