Real-time modulation of visual feedback on human full-body movements in a virtual mirror: development and proof-of-concept

Background

Virtual reality (VR) provides interactive multimodal sensory stimuli and biofeedback, and can be a powerful tool for physical and cognitive rehabilitation. However, existing systems have generally not implemented realistic full-body avatars and/or a scaling of visual movement feedback. We developed a “virtual mirror” that displays a realistic full-body avatar that responds to full-body movements in all movement planes in real-time, and that allows for the scaling of visual feedback on movements in real-time. The primary objective of this proof-of-concept study was to assess the ability of healthy subjects to detect scaled feedback on trunk flexion movements.

Methods

The “virtual mirror” was developed by integrating motion capture, virtual reality and projection systems. A protocol was developed to provide both augmented and reduced feedback on trunk flexion movements while sitting and standing. The task required reliance on both visual and proprioceptive feedback. The ability to detect scaled feedback was assessed in healthy subjects (n = 10) using a two-alternative forced choice paradigm. Additionally, immersion in the VR environment and task adherence (flexion angles, velocity, and fluency) were assessed.

Results

The ability to detect scaled feedback could be modelled using a sigmoid curve with a high goodness of fit (R² range 89-98%). The point of subjective equivalence was not significantly different from 0 (i.e. not shifted), indicating an unbiased perception. The just noticeable difference was 0.035 ± 0.007, indicating that subjects were able to discriminate different scaling levels consistently. VR immersion was reported to be good, despite some perceived delays between movements and VR projections. Movement kinematic analysis confirmed task adherence.

Conclusions

The new “virtual mirror” extends existing VR systems for motor and pain rehabilitation by enabling the use of realistic full-body avatars and scaled feedback. Proof-of-concept was demonstrated for the assessment of body perception during active movement in healthy controls. The next step will be to apply this system to assessment of body perception disturbances in patients with chronic pain.     

How to Use the American Geriatrics Society 2015 Beers Criteria—A Guide for Patients,Clinicians, Health Systems,and Payors

The Beers Criteria are a valuable tool for clinical care and quality improvement but may be misinterpreted and implemented in ways that cause unintended harms. This article describes the intended role of the 2015 American Geriatrics Society (AGS) Beers Criteria and provides guidance on how patients, clinicians, health systems, and payors should use them. A key theme underlying these recommendations is to use common sense and clinical judgment in applying the 2015 AGS Beers Criteria and to remain mindful of nuances in the criteria. The criteria serve as a “warning light” to identify medications that have an unfavorable balance of benefits and harms in many older adults, particularly when compared with pharmacological and nonpharmacological alternatives. However, there are situations in which use of medications included in the criteria can be appropriate. As such, the 2015 AGS Beers Criteria work best not only when they identify potentially inappropriate medications, but also when they educate clinicians and patients about the reasons those medications are included and the situations in which their use may be more or less problematic. The criteria are designed to support, rather than supplant, good clinical judgment.     

Anesthesia and the developing brain: a way forward for clinical research

It is now well established that many general anesthetics have a variety of effects on the developing brain in animal models. In contrast, human cohort studies show mixed evidence for any association between neurobehavioural outcome and anesthesia exposure in early childhood. In spite of large volumes of research, it remains very unclear if the animal studies have any clinical relevance; or indeed how, or if, clinical practice needs to be altered. Answering these questions is of great importance given the huge numbers of young children exposed to general anesthetics. A recent meeting in Genoa brought together researchers and clinicians to map a path forward for future clinical studies. This paper describes these discussions and conclusions. It was agreed that there is a need for large, detailed, prospective, observational studies, and for carefully designed trials. It may be impossible to design or conduct a single study to completely exclude the possibility that anesthetics can, under certain circumstances, produce long‐term neurobehavioural changes in humans; however , observational studies will improve our understanding of which children are at greatest risk, and may also suggest potential underlying etiologies, and clinical trials will provide the strongest evidence to test the effectiveness of different strategies or anesthetic regimens with respect to better neurobehavioral outcome.     

Viral polymorphism in human papillomavirus types 33 and 35 and persistent and transient infection in the genital tract of women

BACKGROUND: Genetic polymorphism in human papillomavirus (HPV)-33 and -35 was investigated in 1055 sexually active women (732 human immunodeficiency virus [HIV] seropositive and 323 HIV seronegative). METHODS: Consecutive genital specimens obtained at 6-month intervals were screened for HPV-33 and -35 by use of MY09-MY11. HPV-33 and -35 isolates from 95 women were analyzed by polymerase chain reaction sequencing of the long control region (LCR), E6, and E7. RESULTS: For HPV-33, 101 (20%) of 506 nucleotides in the LCR were variable, compared with 10 (2.1%) of 483 nucleotides in E6 (P<.001) and 6 (1.9%) of 324 nucleotides in E7 (P<.001). For HPV-35, the proportion of variable nucleotide sites was similar between the LCR and both E6 (P=.54) and E7 (P=.33). The presence of a 78-base pair deletion in HPV-33 (relative risk [RR], 1.8 [95% confidence interval [CI], 1.2-2.7]) and the presence of nonsynonymous E7 variations in HPV-35 (RR, 2.6 [95% CI, 1.4-4.6]) were associated with persistence. When the data for HPV-33 and -35 were combined, infection by HPV isolates with nonsynonymous E7 variations (RR, 2.3 [95% CI, 1.6-3.4]; P=.001) and ethnicity (P=.04) were associated with persistence, whereas age (P = .14) and HIV infection/CD4 cell count status (P=.12) were not significantly associated with persistence, by logistic regression analysis. CONCLUSION: HPV-33 and -35 polymorphism was different between types and was associated with persistence of HPV infection.