30 research outputs found

    Direct regularized reconstruction for the three-dimensional Calder\'on problem

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    Electrical Impedance Tomography gives rise to the severely ill-posed Calder\'on problem of determining the electrical conductivity distribution in a bounded domain from knowledge of the associated Dirichlet-to-Neumann map for the governing equation. The uniqueness and stability questions for the three-dimensional problem were largely answered in the affirmative in the 1980's using complex geometrical optics solutions, and this led further to a direct reconstruction method relying on a non-physical scattering transform. In this paper, the reconstruction problem is taken one step further towards practical applications by considering data contaminated by noise. Indeed, a regularization strategy for the three-dimensional Calder\'on problem is presented based on a suitable and explicit truncation of the scattering transform. This gives a certified, stable and direct reconstruction method that is robust to small perturbations of the data. Numerical tests on simulated noisy data illustrate the feasibility and regularizing effect of the method, and suggest that the numerical implementation performs better than predicted by theory.Comment: 23 pages, 5 figue

    The Bayesian approach to inverse Robin problems

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    In this paper we investigate the Bayesian approach to inverse Robin problems. These are problems for certain elliptic boundary value problems of determining a Robin coefficient on a hidden part of the boundary from Cauchy data on the observable part. Such a nonlinear inverse problem arises naturally in the initialisation of large-scale ice sheet models that are crucial in climate and sea-level predictions. We motivate the Bayesian approach for a prototypical Robin inverse problem by showing that the posterior mean converges in probability to the data-generating ground truth as the number of observations increases. Related to the stability theory for inverse Robin problems, we establish a logarithmic convergence rate for Sobolev-regular Robin coefficients, whereas for analytic coefficients we can attain an algebraic rate. The use of rescaled analytic Gaussian priors in posterior consistency for nonlinear inverse problems is new and may be of separate interest in other inverse problems. Our numerical results illustrate the convergence property in two observation settings

    Factors associated with discharge destination from acute care after moderate-to-severe traumatic injuries in Norway: a prospective population-based study

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    Background - Previous studies have demonstrated that the trauma population has needs for rehabilitation services that are best provided in a continuous and coordinated way. The discharge destination after acute care is the second step to ensuring quality of care. There is a lack of knowledge regarding the factors associated with the discharge destination for the overall trauma population. This paper aims to identify sociodemographic, geographical, and injury-related factors associated with discharge destination following acute care at trauma centers for patients with moderate-to-severe traumatic injuries. Methods - A multicenter, population-based, prospective study was conducted with patients of all ages with traumatic injury [New Injury Severity Score (NISS) > 9] admitted within 72 h after the injury to regional trauma centers in southeastern and northern Norway over a 1-year period (2020). Results - In total, 601 patients were included; a majority (76%) sustained severe injuries, and 22% were discharged directly to specialized rehabilitation. Children were primarily discharged home, and most of the patients ≥ 65 years to their local hospital. Depending on the centrality of their residence [Norwegian Centrality Index (NCI) 1–6, where 1 is most central], we found that patients residing in NCI 3–4 and 5–6 areas sustained more severe injuries than patients residing in NCI 1–2 areas. An increase in the NISS, number of injuries, or a spinal injury with an Abbreviated Injury Scale (AIS) ≥ 3 was associated with discharge to local hospitals and specialized rehabilitation than to home. Patients with an AIS ≥ 3 head injury (RRR 6.1, 95% Confidence interval 2.80–13.38) were significantly more likely to be discharged to specialized rehabilitation than patients with a less severe head injury. Age  Conclusions - Two-thirds of the patients sustained severe traumatic injury, and 22% were discharged directly to specialized rehabilitation. Age, centrality of the residence, preinjury comorbidity, injury severity, length of hospital stay, and the number and specific types of injuries were factors that had the greatest influence on discharge destination

    Functional Outcomes at 6 and 12 Months Post-Injury in a Trauma Centre Population with Moderate-to-Severe Traumatic Injuries

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    This study aims to evaluate the global functional outcomes after moderate-to-severe traumatic injury at 6 and 12 months and to examine the sociodemographic and injury-related factors that predict these outcomes. A prospective cohort study was conducted in which trauma patients of all ages with a New Injury Severity Score > 9 who were discharged alive from two regional trauma centres in Norway over a one-year period (2020) were included. The Glasgow Outcome Scale Extended (GOSE) score was used to analyse the functional outcomes. Regression analyses were performed to investigate the predictors of the GOSE score. Follow-up assessments were obtained from approximately 85% of the 601 included patients at both time points. The mean (SD) GOSE score was 6.1 (1.6) at 6 months and 6.4 (1.6) at 12 months, which corresponds to an upper-moderate disability. One-half of the patients had a persistent disability at 12 months post-injury. The statistically significant predictors of a low GOSE score at both time points were more pre-injury comorbidity, a higher number of injuries, and higher estimated rehabilitation needs, whereas a thorax injury with an Abbreviated Injury Scale ≥ 3 predicted higher GOSE scores. A high Glasgow Coma Scale score at admission predicted a higher GOSE score at 6 months. This study strengthens the evidence base for the functional outcomes and predictors in this population

    Adherence to Guidelines for Acute Rehabilitation in the Norwegian Trauma Plan.

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    Objective: To evaluate adherence to 3 central operational recommendations for acute rehabilitation in the Norwegian trauma plan. Methods: A prospective multi-centre study of 538 adults with moderate and severe trauma with New Injury Severity Score >9. Results: Adherence to the first recommendation, assessment by a physical medicine and rehabilitation physician within 72 h following admission to the intensive care unit (ICU) at the trauma centre, was documented for 18% of patients. Adherence to the second recommendation, early rehabilitation in the intensive care unit, was documented for 72% of those with severe trauma and ≥2 days ICU stay. Predictors for early rehabilitation were ICU length of stay and spinal cord injury. Adherence to the third recommendation, direct transfer of patients from acute ward to a specialized rehabilitation unit, was documented in 22% of patients, and occurred more often in those with severe trauma (26%), spinal cord injury (54%) and traumatic brain injury (39%). Being employed, having head or spinal chord injury and longer ICU stay were predictors for direct transfer to a specialized rehabilitation unit. Conclusion: Adherence to acute rehabilitation guidelines after trauma is poor. This applies to documented early assessment by a physical medicine and rehabilitation physician, and direct transfer from acute care to rehabilitation after head and extremity injuries. These findings indicate a need for more systematic integration of rehabilitation in the acute treatment phase after trauma

    Rehabilitation Needs, Service Provision, and Costs in the First Year Following Traumatic Injuries: Protocol for a Prospective Cohort Study

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    Background: Traumatic injuries, defined as physical injuries with sudden onset, are a major public health problem worldwide. There is a paucity of knowledge regarding rehabilitation needs and service provision for patients with moderate and major trauma, even if rehabilitation research on a spectrum of specific injuries is available. Objective: This study aims to describe the prevalence of rehabilitation needs, the provided services, and functional outcomes across all age groups, levels of injury severity, and geographical regions in the first year after trauma. Direct and indirect costs of rehabilitation provision will also be assessed. The overarching aim is to better understand where to target future efforts. Methods: This is a population-based prospective follow-up study. It encompasses patients of all ages with moderate and severe acute traumatic injury (New Injury Severity Score >9) admitted to the regional trauma centers in southeastern and northern Norway over a 1-year period (2020). Sociodemographic and injury data will be collected. Upon hospital discharge, rehabilitation physicians estimate rehabilitation needs. Rehabilitation needs are assessed by the Rehabilitation Complexity Scale Extended–Trauma (RCS E–Trauma; specialized inpatient rehabilitation), Needs and Provision Complexity Scale (NPCS; community-based rehabilitation and health care service delivery), and Family Needs Questionnaire–Pediatric Version (FNQ-P). Patients, family caregivers, or both will complete questionnaires at 6- and 12-month follow-ups, which are supplemented by telephone interviews. Data on functioning and disability, mental health, health-related quality of life measured by the EuroQol Questionnaire (EQ-5D), and needs and provision of rehabilitation and health care services are collected by validated outcome measures. Unmet needs are represented by the discrepancies between the estimates of the RCS E–Trauma and NPCS at the time of a patient’s discharge and the rehabilitation services the patient has actually received. Formal service provision (including admission to inpatient- or outpatient-based rehabilitation), informal care, and associated costs will be collected. Results: The project was funded in December 2018 and approved by the Regional Committee for Medical and Health Research Ethics in October 2019. Inclusion of patients began at Oslo University Hospital on January 1, 2020, and at the University Hospital of North Norway on February 1, 2020. As of February 2021, we have enrolled 612 patients, and for 286 patients the 6-month follow-up has been completed. Papers will be drafted for publication throughout 2021 and 2022. Conclusions: This study will improve our understanding of existing service provision, the gaps between needs and services, and the associated costs for treating patients with moderate and major trauma. This may guide the improvement of rehabilitation and health care resource planning and allocation

    One-year prevalence and the impact of migraine and tension-type headache in Turkey: a nationwide home-based study in adults

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    Several studies have shown that the prevalence of migraine and tension-type headache (TTH) varied between different geographical regions. Therefore, there is a need of a nationwide prevalence study for headache in our country, located between Asia and Europe. This nationwide study was designed to estimate the 1-year prevalence of migraine and TTH and analyse the clinical features, the impact as well as the demographic and socio-economic characteristics of the participant households in Turkey. We planned to investigate 6,000 representative households in 21 cities of Turkey; and a total of 5,323 households (response rate of 89%) aged between 18 and 65 years were examined for headache by 33 trained physicians at home on the basis of the diagnostic criteria of the second edition of the International Classification of Headache Disorders (ICHD-II). The electronically registered questionnaire was based on the headache features, the associated symptoms, demographic and socio-economic situation and history. Of 5,323 participants (48.8% women; mean age 35.9 ± 12 years) 44.6% reported recurrent headaches during the last 1 year and 871 were diagnosed with migraine at a prevalence rate of 16.4% (8.5% in men and 24.6% in women), whereas only 270 were diagnosed with TTH at a prevalence rate of 5.1% (5.7% in men and 4.5% in women). The 1-year prevalence of probable migraine was 12.4% and probable TTH was 9.5% additionally. The rate of migraine with aura among migraineurs was 21.5%. The prevalence of migraine was highest among 35–40-year-old women while there were no differences in age groups among men and in TTH overall. More than 2/3 of migraineurs had ever consulted a physician whereas only 1/3 of patients with TTH had ever consulted a physician. For women, the migraine prevalence was higher among the ones with a lower income, while among men, it did not show any change by income. Migraine prevalence was lower in those with a lower educational status compared to those with a high educational status. Chronic daily headache was present in 3.3% and the prevalence of medication overuse headache was 2.1% in our population. There was an important impact of migraine with a monthly frequency of 5.9 ± 6, and an attack duration of 35.1 ± 72 h, but only 4.9% were on prophylactic treatment. The one-year prevalence of migraine estimated as 16.4% was similar or even higher than world-wide reported migraine prevalence figures and identical to a previous nation-wide study conducted in 1998, whereas the TTH prevalence was much lower using the same methodology with the ICHD-II criteria
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