821 research outputs found

    Neural markers of suppression in impaired binocular vision

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    Even after conventional patching treatment, individuals with a history of amblyopia typically lack good stereo vision. This is often attributed to atypical suppression between the eyes, yet the specific mechanism is still unclear. Guided by computational models of binocular vision, we tested explicit predictions about how neural responses to contrast might differ in individuals with impaired binocular vision. Participants with a history of amblyopia (N = 25), and control participants with typical visual development (N = 19) took part in the study. Neural responses to different combinations of contrast in the left and right eyes, were measured using both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Stimuli were sinusoidal gratings with a spatial frequency of 3c/deg, flickering at 4 Hz. In the fMRI experiment, we also ran population receptive field and retinotopic mapping sequences, and a phase-encoded localiser stimulus, to identify voxels in primary visual cortex (V1) sensitive to the main stimulus. Neural responses in both modalities increased monotonically with stimulus contrast. When measured with EEG, responses were attenuated in the weaker eye, consistent with a fixed tonic suppression of that eye. When measured with fMRI, a low contrast stimulus in the weaker eye substantially reduced the response to a high contrast stimulus in the stronger eye. This effect was stronger than when the stimulus-eye pairings were reversed, consistent with unbalanced dynamic suppression between the eyes. Measuring neural responses using different methods leads to different conclusions about visual differences in individuals with impaired binocular vision. Both of the atypical suppression effects may relate to binocular perceptual deficits, e.g. in stereopsis, and we anticipate that these measures could be informative for monitoring the progress of treatments aimed at recovering binocular vision

    Importance of surgical assembly technique on the engagement of 12/14 modular tapers

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    Fretting-corrosion at the modular taper junction in total hip replacements (THR), leading to implant failure, has been identified as a clinical concern and has received increased interest in recent years. There are many parameters thought to affect the performance of the taper junction, with the assembly process being one of the few consistently identified to have a direct impact. Despite this, the assembly process used by surgeons during THR surgery differs from a suggested ‘ideal’ process. For example, taper junctions of cutting tools should be pushed together rather than impacted, while ensuring as much concentricity as possible between the male and female taper and loading axis. This study devised six simple assembly methodologies to investigate how surgical variations affect the success of the compressive fit achieved at the taper interface compared to a controlled assembly method, designed to represent a more ‘ideal’ scenario. Key findings from this study suggest that a more successful and repeatable engagement can be achieved by quasi-statically loading the male and female taper concentrically with the loading axis. This was shown by a greater disassembly to assembly force ratio of 0.626 ± 0.07 when assembled using the more ‘ideal’ process, compared to 0.480 ± 0.05 when using a method closer to that used by a surgeon intraoperatively. Findings from this study can be used to help inform new surgical instrumentation and an improved surgical assembly method

    Participation and satisfaction after spinal cord injury: results of a vocational and leisure outcome study

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    Study design: Survey. Objectives: Insight in (1) the changes in participation in vocational and leisure activities and (2) satisfaction with the current participation level of people with spinal cord injuries (SCIs) after reintegration in society. Design: Descriptive analysis of data from a questionnaire. Setting: Rehabilitation centre with special department for patients with SCIs, Groningen, The Netherlands. Subjects: A total of 57 patients with traumatic SCI living in the community, who were admitted to the rehabilitation centre two to 12 years before the current assessment. Main outcome measures: Changes in participation in activities; current life satisfaction; support and unmet needs. Results: Participation expressed in terms of hours spent on vocational and leisure activities changed to a great extent after the SCI. This was mainly determined by a large reduction of hours spent on paid work. While 60% of the respondents successfully reintegrated in work, many changes took place in the type and extent of the job. Loss of work was partially compensated with domestic and leisure activities. Sports activities were reduced substantially. The change in participation level and compensation for the lost working hours was not significantly associated with the level of SCI-specific health problems and disabilities. As was found in other studies, most respondents were satisfied with their lives. Determinants of a negative life satisfaction several years following SCI were not easily indicated. Reduced quality of life was particularly related to an unsatisfactory work and leisure situation. Conclusions: Most people with SCI in this study group were able to resume work and were satisfied with their work and leisure situation

    Unguided low intensity cognitive behaviour therapy for anxiety and depression during the COVID-19 pandemic: A randomised trial.

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    The COVID-19 pandemic has had a severe impact on mental health worldwide, with increased rates of anxiety and depression widely documented. The aim of this study was to examine unguided low intensity cognitive behaviour therapy for anxiety and depression during the pandemic. A sample of 225 individuals in Australia and the United Kingdom (M age 37.79, SD = 14.02, range 18-80 years; 85% female) were randomised into intervention or waitlist control. The intervention group demonstrated significant decreases in anxiety (d = 0.36 [0.18, 0.54]) and depression (d = 0.28 [0.11, 0.45]) compared to controls. The majority of participants (96%) rated the intervention as useful, and most (83%) reported they spent 30 min or less reading the guide, with 83% agreeing the intervention was easy to read. The results indicate that low intensity cognitive behaviour therapy has efficacy in reducing anxiety and depression during the COVID-19 pandemic. There is an urgent need to disseminate low intensity psychological therapies to improve mental health in this challenging time

    A 3D computed tomography based tool for orthopedic surgery planning

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    Series : Lecture notes in computational vision and biomechanics, vol. 19The preparation of a plan is essential for a surgery to take place in the best way possible and also for shortening patient’s recovery times. In the orthopedic case, planning has an accentuated significance due to the close relation between the degree of success of the surgery and the patient recovering time. It is important that surgeons are provided with tools that help them in the planning task, in order to make it more reliable and less time consuming. In this paper, we present a 3D Computed Tomography based solution and its implementation as an OsiriX plugin for orthopedic surgery planning. With the developed plugin, the surgeon is able to manipulate a three-dimensional isosurface rendered from the selected imaging study (a CT scan). It is possible to add digital representations of physical implants (surgical templates), in order to evaluate the feasibility of a plan. These templates are STL files generated from CAD models. There is also the feature to extract new isosurfaces of different voxel values and slice the final 3D model according to a predefined plane, enabling a 2D analysis of the planned solution. Finally, we discuss how the proposed application assists the surgeon in the planning process in an alternative way, where it is possible to three-dimensionally analyze the impact of a surgical intervention on the patient.(undefined

    Whole plant cannabis extracts in the treatment of spasticity in multiple sclerosis: a systematic review

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    <p>Abstract</p> <p>Background</p> <p>Cannabis therapy has been considered an effective treatment for spasticity, although clinical reports of symptom reduction in multiple sclerosis (MS) describe mixed outcomes. Recently introduced therapies of combined Δ<sup>9</sup>-tetrahydrocannabinol (THC) and cannabidiol (CBD) extracts have potential for symptom relief with the possibility of reducing intoxication and other side effects. Although several past reviews have suggested that cannabinoid therapy provides a therapeutic benefit for symptoms of MS, none have presented a methodical investigation of newer cannabinoid treatments in MS-related spasticity. The purpose of the present review was to systematically evaluate the effectiveness of combined THC and CBD extracts on MS-related spasticity in order to increase understanding of the treatment's potential effectiveness, safety and limitations.</p> <p>Methods</p> <p>We reviewed MEDLINE/PubMed, Ovid, and CENTRAL electronic databases for relevant studies using randomized controlled trials. Studies were included only if a combination of THC and CBD extracts was used, and if pre- and post-treatment assessments of spasticity were reported.</p> <p>Results</p> <p>Six studies were systematically reviewed for treatment dosage and duration, objective and subjective measures of spasticity, and reports of adverse events. Although there was variation in the outcome measures reported in these studies, a trend of reduced spasticity in treated patients was noted. Adverse events were reported in each study, however combined TCH and CBD extracts were generally considered to be well-tolerated.</p> <p>Conclusion</p> <p>We found evidence that combined THC and CBD extracts may provide therapeutic benefit for MS spasticity symptoms. Although some objective measures of spasticity noted improvement trends, there were no changes found to be significant in post-treatment assessments. However, subjective assessment of symptom relief did often show significant improvement post-treatment. Differences in assessment measures, reports of adverse events, and dosage levels are discussed.</p

    Postpandemic rebound of adeno-associated virus type 2 (AAV2) infections temporally associated with an outbreak of unexplained severe acute hepatitis in children in the United Kingdom

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    Over 1000 cases of unexplained severe acute hepatitis in children have been reported to date worldwide. An association with adeno-associated virus type 2 (AAV2) infection, a human parvovirus, prompted us to investigate the epidemiology of AAV in the United Kingdom. Three hundred pediatric respiratory samples collected before (April 03, 2009–April 03, 2013) and during (April 03, 2022) the COVID-19 pandemic were obtained. Wastewater samples were collected from 50 locations in London (August 2021–March 2022). Samples were tested for AAV using real-time polymerase chain reaction followed by sequencing. Selected adenovirus (AdV)-positive samples were also sequenced. The detection frequency of AAV2 was a sevenfold higher in 2022 samples compared with 2009–2013 samples (10% vs. 1.4%) and highest in AdV-positive samples compared with negatives (10/37, 27% vs. 5/94, 5.3%, respectively). AAV2-positive samples displayed high genetic diversity. AAV2 sequences were either very low or absent in wastewater collected in 2021 but increased in January 2022 and peaked in March 2022. AAV2 was detected in children in association with AdV of species C, with a highest frequency in 2022. Our findings are consistent with the expansion of the population of children unexposed to AAV2, leading to greater spread of the virus once distancing restrictions were lifted
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