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Amsterdam-Zuidoost, Netherlands

Van Schooten K.S.,VU University Amsterdam | Pijnappels M.,VU University Amsterdam | Rispens S.M.,VU University Amsterdam | Elders P.J.M.,EMGO Institute | And 4 more authors.
PLoS ONE | Year: 2016

Falls can have devastating consequences for older people. We determined the relationship between the likelihood of fall incidents and daily-life behavior. We used wearable sensors to assess habitual physical activity and daily-life gait quality (in terms of e.g. stability, variability, smoothness and symmetry), and determined their predictive ability for time-to-first-and-second-falls. 319 older people wore a trunk accelerometer (Dynaport MoveMonitor, McRoberts) during one week. Participants further completed questionnaires and performed grip strength and trail making tests to identify risk factors for falls. Their prospective fall incidence was followed up for six to twelve months. We determined interrelations between commonly used gait characteristics to gain insight in their interpretation and determined their association with time-to-falls. For all data -including questionnaires and tests- we determined the corresponding principal components and studied their predictive ability for falls. We showed that gait characteristics of walking speed, stride length, stride frequency, intensity, variability, smoothness, symmetry and complexity were often moderately to highly correlated (r > 0.4). We further showed that these characteristics were predictive of falls. Principal components dominated by history of falls, alcohol consumption, gait quality and muscle strength proved predictive for time-to-fall. The cross-validated prediction models had adequate to high accuracy (time dependent AUC of 0.66-0.72 for time-to-first-fall and 0.69-0.76 for -second-fall). Daily-life gait quality obtained from a single accelerometer on the trunk is predictive for falls. These findings confirm that ambulant measurements of daily behavior contribute substantially to the identification of elderly at (high) risk of falling. © 2016 van Schooten et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source


van Duijvenbode D.,Medisch Centrum Alkmaar Center for Orthopaedic Research Alkmaar | Stavenuiter M.,Medisch Centrum Alkmaar Center for Orthopaedic Research Alkmaar | Burger B.,Medisch Centrum Alkmaar Center for Orthopaedic Research Alkmaar | van Dijke C.,Medisch Centrum Alkmaar | And 2 more authors.
International Orthopaedics | Year: 2016

Purpose: The objective of this study was to evaluate the inter-observer reliability and the intra-observer reliability of four patellar height ratios: Insall-Salvati (IS), modified Insall-Salvati (MIS), Blackburne-Peel (BP) and Caton-Deschamps (CD). Methods: The patellar height ratios were assessed by four independent examiners using weight-bearing lateral knee radiographs in 30° flexion. Intra-class correlation coefficients and Fleiss’ kappa’s were determined. Results: The inter-observer reliability was excellent for the IS and moderate for the other ratios. When the ratio values were categorized, the inter-observer reliability was strong for the IS, moderate for the MIS and BP, and poor for the CD. The intra-observer reliability was excellent for the IS, MIS and CD, and strong for the BP. When the ratio values were categorized, the intra-observer reliability was strong for the IS and MIS, and moderate for the other ratios. Conclusion: Although the IS showed best reliability, we advise to use the MIS as it showed the second best reliability but is, according to the literature, associated with better validity. © 2015, SICOT aisbl. Source


Webb R.,Merri Community Health Services | Cofre Lizama L.E.,MOVE Research Institute Amsterdam | Galea M.P.,Royal Melbourne Hospital
Evidence-based Complementary and Alternative Medicine | Year: 2013

Objective. To investigate the effects of Feldenkrais Method classes on gait, balance, function, and pain in people with osteoarthritis. Design. Prospective study with pre-/postmeasures. Setting. Community. Participants. Convenience sample of 15 community-dwelling adults with osteoarthritis (mean age 67 years) attending Feldenkrais Method classes. Intervention. Series of Feldenkrais Method classes, two classes/week for 30 weeks. Main outcome measures: Western Ontario and McMaster Universities osteoarthritis scale, Human Activity Profile, stair climbing test, 6-minute walk test, timed up-and-go test, Four Square Step Test (4SST), gait analysis, and assessment of quality of life (AQoL). Results. Participants improved on the 4SST and on some gait parameters. They also reported a greater ease of movement. Conclusions. A 30-week series of Feldenkrais classes held twice per week was feasible in the community setting. The lessons led to improvements in performance of the four square step test and changes in gait. © 2013 Robert Webb et al. Source


Koolstra J.H.,MOVE Research Institute Amsterdam | Kommers S.C.,VU University Amsterdam | Forouzanfar T.,VU University Amsterdam
Journal of Cranio-Maxillofacial Surgery | Year: 2014

After treatment of fractures in the neck of the mandible by means of immobilization of the dentition, often more or less severe manifestations of malocclusion remain. It was hypothesized that this is caused by an altered articulation in the jaw joint on the affected side. Furthermore, it was hypothesized that an anteriorly displaced condyle, as observed frequently as a side effect of the treatment, is caused by pull of the lateral pterygoid muscle, despite maxillomandibular fixation. Intervention experiments were performed in silico to test these hypotheses. With a biomechanical model of the human masticatory system alterations were applied mimicking a fractured mandibular neck and configurations that had been observed after healing. It was predicted that the altered articulation in the jaw joint caused asymmetrical jaw movements despite symmetrical muscle activation. The jaw was predicted to close with an open bite similar to clinical observations. The predicted laterodeviations, however, were not in accordance with clinical observations. Despite maxillo-mandibular fixation the lateral pterygoid muscle was able to pull the mandibular condyle out of its fossa in anterior direction. Consequently, despite some methodological limitations, in general the predictions corroborated the hypotheses. © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rightsreserved. Source


Blaauboer M.E.,VU University Amsterdam | Blaauboer M.E.,TNO | Boeijen F.R.,VU University Amsterdam | Emson C.L.,Kinemed Inc. | And 6 more authors.
Matrix Biology | Year: 2014

Lung fibrosis is characterized by excessive deposition of extracellular matrix. This not only affects tissue architecture and function, but it also influences fibroblast behavior and thus disease progression. Here we describe the expression of elastin, type V collagen and tenascin C during the development of bleomycin-induced lung fibrosis. We further report in vitro experiments clarifying both the effect of myofibroblast differentiation on this expression and the effect of extracellular elastin on myofibroblast differentiation. Lung fibrosis was induced in female C57Bl/6 mice by bleomycin instillation. Animals were sacrificed at zero to five weeks after fibrosis induction. Collagen synthesized during the week prior to sacrifice was labeled with deuterium. After sacrifice, lung tissue was collected for determination of new collagen formation, microarray analysis, and histology. Human lung fibroblasts were grown on tissue culture plastic or BioFlex culture plates coated with type I collagen or elastin, and stimulated to undergo myofibroblast differentiation by 0-10ng/ml transforming growth factor (TGF)β1. mRNA expression was analyzed by quantitative real-time PCR.New collagen formation during bleomycin-induced fibrosis was highly correlated to gene expression of elastin, type V collagen and tenascin C. At the protein level, elastin, type V collagen and tenascin C were highly expressed in fibrotic areas as seen in histological sections of the lung. Type V collagen and tenascin C were transiently increased. Human lung fibroblasts stimulated with TGFβ1 strongly increased gene expression of elastin, type V collagen and tenascin C. The extracellular presence of elastin increased gene expression of the myofibroblastic markers α smooth muscle actin and type I collagen.The extracellular matrix composition changes dramatically during the development of lung fibrosis. The increased levels of elastin, type V collagen and tenascin C are probably the result of increased expression by fibroblastic cells; reversely, elastin influences myofibroblast differentiation. This suggests a reciprocal interaction between fibroblasts and the extracellular matrix composition that could enhance the development of lung fibrosis. © 2013 International Society of Matrix Biology. Source

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