Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

A method of modelling a system consisting of a cylindrical coil with its axis perpendicular to a metal plate of finite thickness, and a simple electrical circuit for producing a transient current in the coil, is discussed in the context of using such a system for de-icing aircraft surfaces. A transmission line model of the coil and metal plate is developed as the heart of the system model. It is shown that this transmission model is central to calculation of the coil impedance, the coil current, the magnetic fields established on the surfaces of the metal plate, and the resultant total force between the coil and the plate. FORTRAN algorithms were developed for numerical calculation of each of these quantities, and the algorithms were applied to an experimental prototype system in which these quantities had been measured. Good agreement is seen to exist between the predicted and measured results

Electro-impulse de-icing testing analysis and design

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided

Mortality of People with Parkinson's Disease in a Large UK-Based Cohort Study: Time Trends and Relationship to Disease Duration

BACKGROUND: Parkinson's disease (PD) is associated with increased mortality, but little is known about changes over time, and relationship to disease progression. OBJECTIVES: To explore how PD mortality rates have changed over time and their relationship to disease duration and demographics using a large population-based cohort in the UK. METHODS: We included individuals aged 50+ years with a first recording of PD diagnosis and at least two prescriptions of any antiparkinsonian drug actively registered within a general practice from 2006 to 2016 and up to six frequency-matched controls from The Health Improvement Network (THIN) database. We estimated adjusted mortality rates using multivariable Poisson regression. RESULTS: A total of 10,104 people with a diagnosis of PD and 55,664 people without PD were included. Overall, PD was associated with slightly increased mortality compared to non-PD controls (adjusted mortality rate ratio: 1.14; 95% CI: 1.03 to 1.19). Adjusted mortality rates per 1000 person-years at risk for people with PD approximately doubled in the 5 years following diagnosis from 43 (95% CI: 38 to 48) to 75 (95% CI: 64 to 85). Following adjustments for age, gender, and time since diagnosis, mortality rates between 2007 and 2016 declined more slowly for people with PD (2% per year; 95% CI: 0%–4%) compared to people without PD (5% per year; 95% CI: 3%–6%). CONCLUSIONS: Whilst mortality in PD is only slightly increased overall, it gradually increases with advancing disease. There has been a decline in mortality in PD over time, but this decrease was less pronounced than that in the general population. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society

Rate of Hospitalizations and Underlying Reasons Among People with Parkinson's Disease: Population-Based Cohort Study in UK Primary Care

BACKGROUND: Hospitalization in Parkinson's disease (PD) is associated with reduced quality of life, caregiver burden and high costs. However, no large-scale studies of rate and causes of hospitalizations in patients with PD have been published. OBJECTIVE: To investigate the rate and reasons for hospitalization and factors associated with hospitalization among people with PD compared to the general population. METHODS: We examined rate and causes of admission in PD patients and matched controls in The Health Improvement Network from 2006 to 2016. Multivariable Poisson regression was used to explore the effects of age, gender, social deprivation, urbanicity and practice geographic location on hospitalization. RESULTS: In longitudinal data from 9,998 newly diagnosed individuals with PD and 55,554 controls without PD aged≥50years, 39%of PD patients and 28%of controls were hospitalised over a median follow-up 5.1years. The adjusted incidence rate ratio(IRR) of hospitalization in PD compared to controls was 1.33(95%CI:1.29-1.37) and rose with increased follow-up duration. Hospitalization rate was overall higher in the older age groups, but the adjusted IRR of hospitalization compared to controls was highest in the youngest age group. PD patients were more often admitted with falls/fractures, infections, gastrointestinal complications, PD, dementia, psychosis/hallucinations, postural hypotension, electrolyte disturbances, stroke and surgical procedures and slightly less often due to hypertension. CONCLUSION: People with PD have an increased hospitalization rate compared to controls, particularly in the younger age groups, and it increases with longer disease duration. The complications of motor and non-motor features of PD are amongst the main reasons for admission, some of which could be managed preventatively to avoid admissions

Prediagnostic presentations of Parkinson's disease in primary care: a case-control study

Background: Parkinson’s disease (PD) has an insidious onset and is diagnosed when typical motor features occur. A number of motor and non-motor features may occur during a “pre-diagnostic” phase, reflecting the early disease process. Previously there has been no comprehensive analysis in the general population of the relative magnitude and timing of their association with PD diagnosis. Aim: To assess the association of first presentation of several pre-diagnostic features in primary care with a subsequent diagnosis of PD, and to chart the timeline of these first presentations before diagnosis of PD. Methods: 8,166 individuals with a first diagnosis of PD and 46,755 individuals without PD were identified from 1st January 1996 to 31st December 2012 from The Health Improvement Network, United Kingdom primary care database. Codes were extracted for a wide range of possible pre-diagnostic or early symptoms comprising motor features (tremor, rigidity, balance impairment, neck pain and shoulder pain), autonomic features (constipation, hypotension, dizziness, erectile dysfunction, urinary dysfunction), mental disturbances (memory problems, depression, anxiety) and additional features (fatigue, insomnia) in the years prior to diagnosis. Incidence rates for symptoms recorded in more than 1% of cases per 1000 person years and incidence risk ratio (RR) were calculated and compared for individuals with and without PD at two, five and ten years before diagnosis. Findings: At two years before PD diagnosis the incidence of all examined pre-diagnostic features except neck pain was higher in patients (n=7,232) than in controls (n=40,541). At five years before diagnosis, patients with PD (n=4,769) had higher incidence rates of tremor (RR 13.70 (95%CI 7.82-24.31), balance impairment (RR, 2.19 (95%CI 1.09-4.16), depression (RR 1.76 (95%CI 1.41-2.17), anxiety (RR 1.41 (95%CI 1.09-1.79), constipation (RR 2.24 (95%CI 2.04-2.46), postural hypotension (RR 3.23 (95%CI 1.85-5.52), dizziness (RR 1.99 (95%CI 1.67-2.37), erectile dysfunction (RR 1.30 (95%CI 1.11-1.51), fatigue (RR 1.56 (95%CI 1.27-1.91), and urinary dysfunction (RR 1.96 (95%CI 1.34-2.80) than controls (n=25,544). At ten years before diagnosis of PD the incidence of constipation (RR 2.01 (95%CI 1.62-2.49) and tremor (RR 7.59 (95%CI 1.1-44.8) was already higher in those with later diagnosis with PD (n=1,680) than in controls (n=8,305). Interpretation: This study for the first time provides evidence for a range of pre-diagnostic features that can be detected several years before diagnosis of PD in primary care, estimating the comparative magnitude of risk for each and where they fit in the prodromal timeline. These data on the pre-diagnostic symptoms of PD can be incorporated into ongoing efforts to identify individuals at the earliest stages of the disease in future trials and help understand progression in the earliest phase of PD

Factors associated with hospitalisation among people with Parkinson's disease – A systematic review and meta-analysis

INTRODUCTION: Parkinson's disease (PD) is associated with an increased risk of admission to hospital, however data on the main reasons for admission is lacking. Our objective was to determine the pooled prevalence of the most common factors leading to admissions among people with Parkinson's disease. METHODOLOGY: MA systematic literature search was conducted in 11 electronic databases. We included all studies providing reasons for admissions among PD patients without restrictions to diagnostic criteria of PD, language or year of study. In the included studies, methodological quality, publication bias and heterogeneity were assessed. Meta-analysis was performed using random-effects models to calculate the pooled estimates of the identified top factors that lead to admission among people with PD. RESULTS: A total of 7283 studies were identified of which nine studies including 7162 people with PD were included in this review. There was a high degree of heterogeneity between studies regarding reasons for hospitalisation. The pooled prevalence of the topmost reasons for hospitalisation among people with PD was 22%(95%CI 16.0%-30.0%) for infections (mainly urinary tract infections and pneumonia); 19%(95%CI 13.0%-27.0%) for worsening motor manifestations of PD; 18%(95%CI 14.0%-21.0%) for falls/fractures; 13%(95%CI 9.0%-18%) for cardiovascular co-morbidities; 8%(95%CI 4.0%-13.0%) for neuropsychiatric and 7%(95%CI 4.0%-11.0%) gastrointestinal complications. CONCLUSION: The main reasons for hospitalisation among people with PD are infections, worsening motor features, falls/fractures, cardiovascular co-morbidities, neuropsychiatric and gastrointestinal complications. Further research is needed in targeting and implementing preventative strategies

Experiences of advance care planning in Parkinson’s disease and atypical Parkinsonian disorders: a mixed methods systematic review

Background and purpose: Advance care planning allows people to plan for their future care needs and can include medical, psychological and social aspects. However, little is known on the use, experience of and attitudes towards advance care planning in patients with parkinsonian disorders, their family carers and healthcare professionals. Methods: A systematic search of online databases was conducted in April 2019 using a narrative synthesis approach with thematic analysis and tabulation to synthesize the findings. Results: In all, 507 articles were identified and 27 were included. There were five overarching themes: (i) what is involved in advance care planning discussions, (ii) when and how advance care planning discussions are initiated, (iii) barriers to advance care planning, (iv) the role of healthcare professionals and (v) the role of the family carer. This evidence was used to highlight eight effective components to support optimal advance care planning in parkinsonian disorders: advance care planning discussions should be individualized in content, timing and approach; patients should be invited to discuss advance care planning early and regularly; palliative care services should be introduced early; a skilled professional should deliver advance care planning; support to family carers should be offered in the advance care planning process; healthcare professionals should be educated on parkinsonian disorders and palliative care; advance care planning should be clearly documented and shared with relevant services; and healthcare professionals should be enabled to conduct effective advance care planning. Conclusions: These components can inform best practice in advance care planning in patients with parkinsonian disorders

Brain iron deposition is linked with cognitive severity in Parkinson’s disease

Background: Dementia is common in Parkinson’s disease (PD) but measures that track cognitive change in PD are lacking. Brain tissue iron accumulates with age and co-localises with pathological proteins linked to PD dementia such as amyloid. We used quantitative susceptibility mapping (QSM) to detect changes related to cognitive change in PD. Methods: We assessed 100 patients with early-stage to mid-stage PD, and 37 age-matched controls using the Montreal Cognitive Assessment (MoCA), a validated clinical algorithm for risk of cognitive decline in PD, measures of visuoperceptual function and the Movement Disorders Society Unified Parkinson’s Disease Rating Scale part 3 (UPDRS-III). We investigated the association between these measures and QSM, an MRI technique sensitive to brain tissue iron content. Results: We found QSM increases (consistent with higher brain tissue iron content) in PD compared with controls in prefrontal cortex and putamen (p<0.05 corrected for multiple comparisons). Whole brain regression analyses within the PD group identified QSM increases covarying: (1) with lower MoCA scores in the hippocampus and thalamus, (2) with poorer visual function and with higher dementia risk scores in parietal, frontal and medial occipital cortices, (3) with higher UPDRS-III scores in the putamen (all p<0.05 corrected for multiple comparisons). In contrast, atrophy, measured using voxel-based morphometry, showed no differences between groups, or in association with clinical measures. Conclusions: Brain tissue iron, measured using QSM, can track cognitive involvement in PD. This may be useful to detect signs of early cognitive change to stratify groups for clinical trials and monitor disease progression

Heterogeneity in progression of prodromal features in Parkinson’s disease

Background: In the pre-diagnostic phase of Parkinson’s disease (PD), a range of motor and non-motor symptoms can occur. However, there is considerable variability in their onset and currently little information exists on the pattern of progression of clinical features before diagnosis. Methods: We analysed data from a survey amongst patients with PD from 11 European countries by the European Parkinson’s Disease Association. They completed questions on first occurrence of 21 pre-diagnostic features. A principal component analysis (PCA) with varimax rotation was performed to determine the co-occurrence of these features. Findings: 1,467 patients were included. Changes in movement were the most commonly reported features up to 4 years before diagnosis. However, at five or more years before diagnosis loss of sense of smell, sleep problems, fatigue and other non-motor features had been experienced most frequently. PCA of pre-diagnostic features’ duration revealed three factors with eigenvalues over Kaiser’s criterion of 1: a) a neuropsychiatric factor comprised of anxiety, depression, apathy, stress, and sleep problems; b) an axial factor defined by difficulty eating and/or swallowing problems, freezing, and falls/balance problems; and c) a motor factor with additional non-motor features. Bladder/bowel problems and tremor had low factor loadings on all components. However, in those with disease duration less than 5 years the autonomic features were associated with the axial factor and tremor loaded on both the motor and psychiatric symptom factors. Interpretation: The identified symptom complexes in the pre-diagnostic stage of PD may be reflective of a shared pattern of pathological disease progression