Augmented Reality System for Digital Rectal Examination Training and Assessment: System Validation.

BACKGROUND: Digital rectal examination is a difficult examination to learn and teach because of limited opportunities for practice; however, the main challenge is that students and tutors cannot see the finger when it is palpating the anal canal and prostate gland inside the patients. OBJECTIVE: This paper presents an augmented reality system to be used with benchtop models commonly available in medical schools with the aim of addressing the problem of lack of visualization. The system enables visualization of the examining finger, as well as of the internal organs when performing digital rectal examinations. Magnetic tracking sensors are used to track the movement of the finger, and a pressure sensor is used to monitor the applied pressure. By overlaying a virtual finger on the real finger and a virtual model on the benchtop model, students can see through the examination and finger maneuvers. METHODS: The system was implemented in the Unity game engine (Unity Technologies) and uses a first-generation HoloLens (Microsoft Inc) as an augmented reality device. To evaluate the system, 19 participants (9 clinicians who routinely performed digital rectal examinations and 10 medical students) were asked to use the system and answer 12 questions regarding the usefulness of the system. RESULTS: The system showed the movement of an examining finger in real time with a frame rate of 60 fps on the HoloLens and accurately aligned the virtual and real models with a mean error of 3.9 mm. Users found the movement of the finger was realistic (mean 3.9, SD 1.2); moreover, they found the visualization of the finger and internal organs were useful for teaching, learning, and assessment of digital rectal examinations (finger: mean 4.1, SD 1.1; organs: mean 4.6, SD 0.8), mainly targeting a novice group. CONCLUSIONS: The proposed augmented reality system was designed to improve teaching and learning of digital rectal examination skills by providing visualization of the finger and internal organs. The initial user study proved its applicability and usefulness.

Intermediate-term memory in Aplysia involves neurotrophin signaling, transcription, and DNA methylation.

Long-term but not short-term memory and synaptic plasticity in many brain areas require neurotrophin signaling, transcription, and epigenetic mechanisms including DNA methylation. However, it has been difficult to relate these cellular mechanisms directly to behavior because of the immense complexity of the mammalian brain. To address that problem, we and others have examined numerically simpler systems such as the hermaphroditic marine mollusk Aplysia californica. As a further simplification, we have used a semi-intact preparation of the Aplysia siphon withdrawal reflex in which it is possible to relate cellular plasticity directly to behavioral learning. We find that inhibitors of neurotrophin signaling, transcription, and DNA methylation block sensitization and classical conditioning beginning ∼1 h after the start of training, which is in the time range of an intermediate-term stage of plasticity that combines elements of short- and long-term plasticity and may form a bridge between them. Injection of decitabine (an inhibitor of DNA methylation that may have other actions in these experiments) into an LE sensory neuron blocks the neural correlates of conditioning in the same time range. In addition, we found that both DNA and RNA methylation in the abdominal ganglion are correlated with learning in the same preparations. These results begin to suggest the functions and integration of these different molecular mechanisms during behavioral learning.

A Review of Simulators with Haptic Devices for Medical Training.

Medical procedures often involve the use of the tactile sense to manipulate organs or tissues by using special tools. Doctors require extensive preparation in order to perform them successfully; for example, research shows that a minimum of 750 operations are needed to acquire sufficient experience to perform medical procedures correctly. Haptic devices have become an important training alternative and they have been considered to improve medical training because they let users interact with virtual environments by adding the sense of touch to the simulation. Previous articles in the field state that haptic devices enhance the learning of surgeons compared to current training environments used in medical schools (corpses, animals, or synthetic skin and organs). Consequently, virtual environments use haptic devices to improve realism. The goal of this paper is to provide a state of the art review of recent medical simulators that use haptic devices. In particular we focus on stitching, palpation, dental procedures, endoscopy, laparoscopy, and orthopaedics. These simulators are reviewed and compared from the viewpoint of used technology, the number of degrees of freedom, degrees of force feedback, perceived realism, immersion, and feedback provided to the user. In the conclusion, several observations per area and suggestions for future work are provided.

Improving engineering students' understanding of classical physics through visuo-haptic simulations.

Introduction: The teaching process plays a crucial role in the training of professionals. Traditional classroom-based teaching methods, while foundational, often struggle to effectively motivate students. The integration of interactive learning experiences, such as visuo-haptic simulators, presents an opportunity to enhance both student engagement and comprehension. Methods: In this study, three simulators were developed to explore the impact of visuo-haptic simulations on engineering students' engagement and their perceptions of learning basic physics concepts. The study used an adapted end-user computing satisfaction questionnaire to assess students' experiences and perceptions of the simulators' usability and its utility in learning. Results: Feedback from participants suggests a positive reception towards the use of visuo-haptic simulators, highlighting their usefulness in improving the understanding of complex physics principles. Discussion: Results suggest that incorporating visuo-haptic simulations into educational contexts may offer significant benefits, particularly in STEM courses, where traditional methods may be limited. The positive responses from participants underscore the potential of computer simulations to innovate pedagogical strategies. Future research will focus on assessing the effectiveness of these simulators in enhancing students' learning and understanding of these concepts in higher-education physics courses.

Monitoring Lesion Area Progression in Stargardt Disease: A Comparison of En Face Optical Coherence Tomography and Fundus Autofluorescence.

Purpose: To compare longitudinal changes in en face spectral domain-optical coherence tomography (SD-OCT) measurements of ellipsoid zone (EZ) and retinal pigment epithelium (RPE) loss to changes in the hypoautofluorescent and hyperautofluorescent (AF) areas detected with short-wavelength (SW)-AF in ABCA4-associated retinopathy. Methods: SD-OCT volume scans were obtained from 20 patients (20 eyes) over 2.6 ± 1.2 years (range 1-5 years). The EZ, and RPE/Bruch's membrane boundaries were segmented, and en face slab images generated. SubRPE and EZ slab images were used to measure areas of atrophic RPE and EZ loss. These were compared to longitudinal measurements of the hypo- and abnormal AF (hypoAF and surrounding hyperAF) areas. Results: At baseline, the en face area of EZ loss was significantly larger than the subRPE atrophic area, and the abnormal AF area was significantly larger than the hypoAF area. The median rate of EZ loss was significantly greater than the rate of increase in the subRPE atrophic area (1.2 mm2/yr compared to 0.5 mm2/yr). The median rate of increase in the abnormal AF area was significantly greater than the increase in the hypoAF area (1.6 mm2/yr compared to 0.6 mm2/yr). Conclusions: En face SD-OCT can be used to quantify changes in RPE atrophy and photoreceptor integrity. It can be a complementary or alternative technique to SW-AF with the advantage of monitoring EZ loss. The SW-AF results emphasize the importance of measuring changes in the hypo- and abnormal AF areas. Translational Relevance: The findings are relevant to the selection of outcome measures for monitoring ABCA4-associated retinopathy.

Aripiprazole attenuates the medial prefrontal cortex morphological and biochemical alterations in rats with neonatal ventral hippocampus lesion.

Schizophrenia is a neurodevelopmental disorder characterized by a loss of dendritic spines in the medial prefrontal cortex (mPFC). Multiple subclinical and clinical studies have evidenced the ability of antipsychotics to improve neuroplasticity. In this study, it was evaluated the effect of the atypical antipsychotic aripiprazole (ARI) on the behavioral and mPFC neuronal disturbances of rats with neonatal ventral hippocampus lesion (nVHL), which is a heuristic developmental model relevant to the study of schizophrenia. ARI attenuated open field hyperlocomotion in the rats with nVHL. Also, ARI ameliorated structural neuroplasticity disturbances of the mPFC layer 3 pyramidal cells, but not in the layer 5 neurons. These effects can be associated with the ARI capability of increasing brain-derived neurotrophic factor (BDNF) levels. Moreover, in the animals with nVHL, ARI attenuated the immunoreactivity for some oxidative stress-related molecules such as the nitric oxide synthase 2 (NOS-2), 3-nitrotyrosine (3-NT), and cyclooxygenase 2 (COX-2), as well as the reactive astrogliosis in the mPFC. These results contribute to current knowledge about the neurotrophic, anti-inflammatory, and antioxidant properties of antipsychotics which may be contributing to their clinical effects and envision promising therapeutic targets for the treatment of schizophrenia.

Second-generation antipsychotic olanzapine attenuates behavioral and prefrontal cortex synaptic plasticity deficits in a neurodevelopmental schizophrenia-related rat model.

Second-generation antipsychotics are the drugs of choice for the treatment of neurodevelopmental-related mental diseases such as schizophrenia. Despite the effectiveness of these drugs to ameliorate some of the symptoms of schizophrenia, specifically the positive ones, the mechanisms beyond their antipsychotic effect are still poorly understood. Second-generation antipsychotics are reported to have anti-inflammatory, antioxidant and neuroplastic properties. Using the neonatal ventral hippocampus lesion (nVHL) in the rat, an accepted schizophrenia-related model, we evaluated the effect of the second-generation antipsychotic olanzapine (OLZ) in the behavioral, neuroplastic, and neuroinflammatory alterations exhibited in the nVHL animals. OLZ corrected the hyperlocomotion and impaired working memory of the nVHL rats but failed to enhance social behavior disturbances of these animals. In the prefrontal cortex (PFC), OLZ restored the pyramidal cell structural plasticity in the nVHL rats, enhancing the dendritic arbor length, the spinogenesis and the proportion of mature spines. Moreover, OLZ attenuated astrogliosis as well as some pro-inflammatory, oxidative stress, and apoptosis-related molecules in the PFC. These findings reinforce the evidence of anti-inflammatory, antioxidant, and neurotrophic mechanisms of second-generation antipsychotics in the nVHL schizophrenia-related model, which allows for the possibility of developing more specific drugs for this disorder and thus avoiding the side effects of current schizophrenia treatments.