David Morley

Young‐ versus older‐onset Parkinson's disease: Impact of disease and psychosocial consequences

The effect of Parkinsons disease (PD) on young patients lives is likely to differ from that in older patients. For this study, 75 patients with onset of PD before the age of 50 and 66 patients with later onset completed a booklet of questionnaires on demographic and clinical variables, quality of life, and psychosocial factors. Apart from a higher rate of treatment‐related dyskinesias in the younger onset group, the two groups did not differ in self‐reported disease severity or disability. A higher percentage of young‐onset patients was unemployed due to disability or had retired early. Quality of life as measured on the PDQ‐39 was significantly worse in young‐onset patients than in older‐onset patients. Young‐onset patients also had worse scores on the stigma and marital satisfaction scales, and were depressed more frequently. Differences between the two groups in their most commonly employed coping strategies and in terms of their satisfaction with emotional support did not reach significance. We conclude that young‐onset patients more frequently experience loss of employment, disruption of family life, greater perceived stigmatization, and depression than do older‐onset patients with PD. In addition to more severe treatment‐related motor complications, social and psychosocial factors may contribute to greater impairment of quality of life in young patients with PD.

The role of cladocerans in tracking long-term change in shallow lake trophic status

Shallow lakes have been affected by a variety of human activities profoundly altering their ecological structure and function. Cladocerans have been used to track change resulting from a variety of drivers at a number of time scales. Aquatic macrophytes are well recognised as reflecting the ecological condition of a lake. Here, we compare the plant macrofossils with the sub-fossil cladoceran assemblages from 20 dated sediment cores. Co-correspondence analysis was used to determine the degree of commonality of change in community composition of the two biological groups through time. This analysis revealed very high levels of agreement in the nature and timing of change at all the sites examined with very high correlation coefficients between the axis 1 scores for macrofossils and cladocerans. Furthermore, at all sites a high proportion of the variance (min 20%, max 54%) in the macrofossil data was explained by the change in the cladoceran assemblage. Sub-fossil macrofossil and cladoceran assemblages, from at least from 1700 AD onwards, were examined in more detail at three sites: Ormesby Great Broad, Felbrigg Lake and Lake Søbygaard. There was very good accord in the main shifts of the cladoceran and macrofossil assemblages at all three sites. This may reflect the long-term shift in the principal focus of primary production from the benthic to the pelagic habitat. We suggest that the combination of their central position in the food-web and the presence of both pelagic and benthic taxa make cladocerans a strong candidate as the single best indicator of (palaeo) ecological condition related to changing trophic status and alteration in food-web structure in shallow lakes.

The self-report Barthel Index: preliminary validation in people with Parkinson's disease.

Background and purpose:u2002 To make a preliminary assessment of the reliability and validity of the self‐report Barthel Index (SRBI) in people with Parkinson’s (PWP) disease.

Risk assessment of vector-borne diseases for public health governance

OBJECTIVESnIn the context of public health, risk governance (or risk analysis) is a framework for the assessment and subsequent management and/or control of the danger posed by an identified disease threat. Generic frameworks in which to carry out risk assessment have been developed by various agencies. These include monitoring, data collection, statistical analysis and dissemination. Due to the inherent complexity of disease systems, however, the generic approach must be modified for individual, disease-specific risk assessment frameworks.nnnSTUDY DESIGNnThe analysis was based on the review of the current risk assessments of vector-borne diseases adopted by the main Public Health organisations (OIE, WHO, ECDC, FAO, CDC etc…).nnnMETHODSnLiterature, legislation and statistical assessment of the risk analysis frameworks.nnnRESULTSnThis review outlines the need for the development of a general public health risk assessment method for vector-borne diseases, in order to guarantee that sufficient information is gathered to apply robust models of risk assessment. Stochastic (especially spatial) methods, often in Bayesian frameworks are now gaining prominence in standard risk assessment procedures because of their ability to assess accurately model uncertainties.nnnCONCLUSIONSnRisk assessment needs to be addressed quantitatively wherever possible, and submitted with its quality assessment in order to enable successful public health measures to be adopted. In terms of current practice, often a series of different models and analyses are applied to the same problem, with results and outcomes that are difficult to compare because of the unknown model and data uncertainties. Therefore, the risk assessment areas in need of further research are identified in this article.

Refinement and validation of the Parental Illness Impact Scale

OBJECTIVEnTo refine and validate the Parental Illness Impact Scale (PIIS), a questionnaire designed specifically to measure the quality of life of adolescent and adult children of neurologically affected parents.nnnMETHODSnKey informant interviews and a literature review were conducted to ensure all relevant themes were incorporated in the revised PIIS (PIIS-R). Pre-testing was achieved through a 17 member expert panel and cognitive interviews with eight adolescent and adult children. The revised instrument was administered to 169 adolescent and adult children of people with Parkinsons disease, multiple sclerosis and stroke and subjected to psychometric analysis.nnnRESULTSnPrincipal components analysis resulted in eight subscales accounting for 60.6% of explained variance. The PIIS-R showed good concurrent and discriminant validity through correlations with established measures of quality of life and psychosocial well-being. Internal consistency was high (Cronbachs alpha .92), and test-retest reliability values for subscales (r = .59-.74) and total score (r = .79) were moderate to high.nnnCONCLUSIONSnThe PIIS-R is a scientifically robust measurement tool for assessing the impact of parental illness, and currently shows strong psychometric properties. Longitudinal data will be required to assess predictive validity and sensitivity to change. The instrument is available to other investigators, who are encouraged to further evaluate its scientific properties.

Poverty, health and satellite-derived vegetation indices: their inter-spatial relationship in West Africa

BACKGROUNDnPrevious analyses have shown the individual correlations between poverty, health and satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI). However, generally these analyses did not explore the statistical interconnections between poverty, health outcomes and NDVI.nnnMETHODSnIn this research aspatial methods (principal component analysis) and spatial models (variography, factorial kriging and cokriging) were applied to investigate the correlations and spatial relationships between intensity of poverty, health (expressed as child mortality and undernutrition), and NDVI for a large area of West Africa.nnnRESULTSnThis research showed that the intensity of poverty (and hence child mortality and nutrition) varies inversely with NDVI. From the spatial point-of-view, similarities in the spatial variation of intensity of poverty and NDVI were found.nnnCONCLUSIONSnThese results highlight the utility of satellite-based metrics for poverty models including health and ecological components and, in general for large scale analysis, estimation and optimisation of multidimensional poverty metrics. However, it also stresses the need for further studies on the causes of the association between NDVI, health and poverty. Once these relationships are confirmed and better understood, the presence of this ecological component in poverty metrics has the potential to facilitate the analysis of the impacts of climate change on the rural populations afflicted by poverty and child mortality.

Holocene carbon dynamics at the forest – steppe ecotone of southern Siberia

Abstract The forest–steppe ecotone in southern Siberia is highly sensitive to climate change; global warming is expected to push the ecotone northwards, at the same time resulting in degradation of the underlying permafrost. To gain a deeper understanding of long‐term forest–steppe carbon dynamics, we use a highly resolved, multiproxy, palaeolimnological approach, based on sediment records from Lake Baikal. We reconstruct proxies that are relevant to understanding carbon dynamics including carbon mass accumulation rates (CMAR; g C m−2 yr−1) and isotope composition of organic matter (δ 13 CTOC). Forest–steppe dynamics were reconstructed using pollen, and diatom records provided measures of primary production from near‐ and off‐shore communities. We used a generalized additive model (GAM) to identify significant change points in temporal series, and by applying generalized linear least‐squares regression modelling to components of the multiproxy data, we address (1) What factors influence carbon dynamics during early Holocene warming and late Holocene cooling? (2) How did carbon dynamics respond to abrupt sub‐Milankovitch scale events? and (3) What is the Holocene carbon storage budget for Lake Baikal. CMAR values range between 2.8 and 12.5 g C m−2 yr−1. Peak burial rates (and greatest variability) occurred during the early Holocene, associated with melting permafrost and retreating glaciers, while lowest burial rates occurred during the neoglacial. Significant shifts in carbon dynamics at 10.3, 4.1 and 2.8 kyr bp provide compelling evidence for the sensitivity of the region to sub‐Milankovitch drivers of climate change. We estimate that 1.03 Pg C was buried in Lake Baikal sediments during the Holocene, almost one‐quarter of which was buried during the early Holocene alone. Combined, our results highlight the importance of understanding the close linkages between carbon cycling and hydrological processes, not just temperatures, in southern Siberian environments.

FraRI: an algorithm to account for the discontinuity at 60° N in MODIS temperature products

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAs Terra and Aqua satellites conducts continuous monitoring of the Earths land surface and oceans. Recently, a sharp discontinuity (averaging 1.9°C) has been noticed at 60° N in both MODIS daytime and night-time land surface temperature (LST) products. This linear artefact arises because the CO2 high cloud test in the operational code for the generation of the MODIS cloud mask product is used only in the non-polar region (between 60° N and 60° S). The resulting discontinuity clearly has negative implications for any statistical applications of these temperature data. In this technical note we present a new algorithm, which minimizes this discontinuity. The method uses edge detection and elimination based on a mixture of Sobel and non-linear Laplacian filters (edge detection and quantification), cubic splines (edge modelling), and a controllable power function for image restoration. The implementation of this algorithm is demonstrated on an image of average minimum night-time LST between 2001 and 2008.