28 research outputs found

    Three-dimensional head and trunk movement characteristics during gait in children with spastic diplegia

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    This study uses a recently developed trunk model to determine which head and trunk kinematic parameters differentiate children with spastic diplegia from typically developing (TD) children while walking. Differences in head and trunk parameters in relation to the severity of the motor involvement (GMFCS levels) were additionally examined. The trunk model consisted of five segments (pelvis, thorax, head, shoulder line, spine). Discrete kinematic parameters (ROM, mean position) and angular waveforms were compared between 20 children with spastic diplegia (age 9.8 years±2.9 years; GMFCS I: n=10, GMFCS II: n=10) and 20 individually age-matched TD children (9.7 years±3 years). A new measure for overall trunk pathology, the trunk profile score (TPS), was proposed and included in the comparative analysis. Compared to TD children, children with GMFCS II showed a significantly higher TPS and increased ROM for pelvis tilt, for thorax and head in nearly all planes, and the angle of kyphosis. In children with GMFCS I, only ROM of thorax lateral bending was significantly increased. Sagittal ROM differentiated best between GMFCS levels, with higher ROM found in children with GMFCS II. Current results provide new insights into head and trunk kinematics during gait in children with spastic diplegia.sponsorship: Lieve Heyrman received a PhD fellowship of the Research Foundation Flanders (FWO), Belgium. (Research Foundation Flanders (FWO), Belgium)status: Publishe

    Reliability of head and trunk kinematics during gait in children with spastic diplegia

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    This study describes the reliability of a clinically oriented model for three-dimensional movement analysis of head and trunk movements in children with spastic diplegia. The model consists of five rigid segments (head, thorax, pelvis, shoulder line, spine) and includes a detailed analysis of spinal segmental movements. Within and between session reliability during gait was tested in 10 children with spastic diplegia (6-14yrs). Reliability of discrete parameters was assessed with the intraclass correlation coefficient (ICC) and similarity of thorax and pelvis waveforms with the coefficient of multiple correlation (CMC). Measurement errors were calculated for all parameters (SEM, σ). Results indicated acceptable within and between session reliability of discrete parameters for thorax, pelvis, shoulder line, angle of kyphosis and the majority of the spinal segmental angles, reflected by low SEMs (0.60. Within and between session waveform errors were below 4°. CMCs ranged from poor to very good, with highest values for movements in the frontal and transversal planes. The angle of lordosis showed lower between session reliability for several discrete parameters, although waveform errors were still below 5°. Head parameters showed lower overall reliability. The results of this study support the reliability of the proposed model. Head kinematic parameters should be interpreted with caution, due to difficulties in standardization. Accurate palpation of the spinal markers, especially the lumbar spine, is critical and demands thorough training of the assessor.sponsorship: Lieve Heyrman received a PhD fellowship of the Research Foundation Flanders (FWO), Belgium. The authors wish to thank Prof. Alberto Leardini from the Istituto Ortopedico Rizzoli of Bologna (Italy) for his collaboration on the development of the trunk model. (Research Foundation Flanders (FWO), Belgium)status: Publishe

    Altered trunk movements during gait in children with spastic diplegia: compensatory or underlying trunk control deficit?

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    Altered trunk movements during gait in children with CP are considered compensatory due to lower limb impairments, although scientific evidence for this assumption has not yet been provided. This study aimed to study the functional relation between trunk and lower limb movement deficits during gait in children with spastic diplegia. Therefore, the relationship between trunk control in sitting, and trunk and lower limb movements during gait was explored in 20 children with spastic diplegia (age 9.2 ± 3 yrs; GMFCS level I n=10, level II n=10). Trunk control in sitting was assessed with the Trunk Control Measurement Scale (TCMS), a clinical measure that reflects the presence of an underlying trunk control deficit. Trunk movements during gait were measured with a recently developed trunk model including the pelvis, thorax, head, shoulder line and spine. Lower limb movements were assessed with the Plug-in-Gait model (Vicon(®)). Range of motion (ROM) of the different trunk segments was calculated, as well as the Trunk Profile Score (TPS) and Trunk Variable Scores (TVSs). Similarly, the Gait Profile Score (GPS) and Gait Variable Scores (GVSs) were calculated to describe altered lower limb movements during gait. Correlation analyses were performed between the presence of impaired trunk control in sitting (TCMS) and altered trunk movements during gait (ROM, TPS/TVSs) and between these altered trunk movements and lower limb movements (GPS/GVSs) during gait. A poorer performance on the TCMS correlated with increased ROM and TPS/TVSs, particularly for the thorax, indicating the presence of an underlying trunk control deficit. No significant correlation was found between the TPS and GPS, suggesting that overall trunk and lower limb movement deficits were not strongly associated. Only few correlations between specific lower limb deficits (GVSs for hip ab/adduction, knee flexion/extension and ankle flexion/extension) and TVSs for thorax lateral bending and rotation were found. This study provided first evidence that the altered trunk movements observed during gait should not be solely considered compensatory due to lower limb impairments, but that these may also partially reflect an underlying trunk control deficit. A better understanding of underlying trunk control deficits in children with CP may facilitate targeted therapy planning and ultimately can optimize a child's functionality.status: Publishe

    Performance Evaluation of Polymer Modified Bitumens on a Heavily Trafficked Test Road

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    In asphalt paving, polymer modified bitumens (PMBs) have more potential for use and can clearly demonstrate the value of their initial higher cost. To further assess the sustainable benefits of using PMBs, a test road was constructed on a highway in Sweden. In this paper, the asphalt binders used were investigated extensively using rheological and chemical methods, and asphalt field cores characterized with respect to permanent deformation and fatigue. It was found that the modified binders, particularly with SBS polymers, retain better rheological properties in comparison with conventional ones, even after several years in the field; these include higher strain recovery and lower non-recoverable compliance at high temperatures, and lower stiffness at low temperatures. The SBS modified binders also demonstrate good aging resistance, shown by both laboratory aging tests and field aging. the high resistance to aging for the SBS modified binders was also evident in the stiffness measurement made on asphalt field cores. Moreover, the modified binders with SBS polymers significantly enhance fatigue behaviour.</p

    Evaluation of test sections with Polymer Modified Bitumens

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    It has been recognized that Polymer Modified Bitumens (PMB) have more potential for use in asphalt paving and can clearly demonstrate the value of their initial higher cost. To further assess sustainable benefits on heavy trafficked roads, test sections using various PMBs were built on highway E6 in Sweden during 2003-2006. The main objective of this paper is to study the aging and rheological properties of the binders used. A large number of cores were drilled and characterized with respect to stiffness, fatigue and permanent deformation. The binders (original, lab aged and recovered) were investigated extensively with rheological and chemical methods. It was found that PMBs, particularly SBS modified, demonstrate better rheological properties as compared to unmodified bitumens, even after several years in the field. These include higher strain recovery and lower non-recoverable compliance at high temperatures, and lower stiffness at low temperatures. For the SBS modified binders, good aging resistance was observed. The high resistance to aging for the SBS modified binders was also evident in the stiffness measurement made on asphalt field cores. Although significant differences have not yet been seen between the test sections (all the sections are in good condition after six years of traffic), the observed improvements for the modified binders are expected to be confirmed by a longer follow-up of the test road.</p

    Clinical characteristics of impaired trunk control in children with spastic cerebral palsy

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    This study aimed to identify clinical characteristics of impaired trunk control in hundred children with spastic CP (mean age 11.4 ± 2.1 years, range 8–15 years). Assessment of trunk control was performed with the Trunk Control Measurement Scale (TCMS). Trunk control was clearly impaired, indicated by a median total TCMS score of 38.5 out of 58 (66%). Median subscale scores were 18 out of 20 (90%) for the subscale static sitting balance, 16 out of 28 (57%) for the subscale selective movement control and 6 out of 10 (60%) for the subscale dynamic reaching. Total TCMS and subscale scores differed significantly between topographies and severity of motor impairment according to the Gross Motor Function Classification System (GMFCS). Children with hemiplegia obtained the highest scores, followed by children with diplegia and children with quadriplegia obtained the lowest scores. TCMS scores significantly decreased with increasing GMFCS level. In conclusion, trunk control is impaired in children with CP to a various extent, depending on the topography and severity of the motor impairment. The findings of this study also provide specific clues for treatment interventions targeting trunk control to improve their functional abilities.status: Publishe

    Creep-recovery behavior of bituminous binders and its relation to asphalt mixture rutting

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    Rutting is one of the main distress modes of asphalt pavements, especially after prolonged warm periods, and thus a great deal of research has been focused on the development of a rheological parameter that would address the rutting susceptibility of both unmodified and modified bituminous binders. In this study the Multiple Stress Creep Recovery (MSCR) test method is used to investigate the creep-recovery behavior of various bituminous binders and its relation to asphalt mixture rutting. Frequency sweep and MSCR tests were conducted on three unmodified and six elastomer and/or wax modified binders, and the resulting data were used to calculate the values of various binder rutting parameters. These binders were also used to manufacture asphalt slabs for mixture rutting simulations in the LPC wheel tracking device. It was found that the non-recoverable creep compliance parameter (Jnr3200) and the accumulated strain at the end of the MSCR test (γacc) correlate very strongly with each other and that they both have a superior capability of predicting asphalt mixture rutting compared to other rheological binder rutting indicators. An effort was made to explain the manifested nonlinear viscoelastic properties of the modified binders with their expected microstructural characteristics. The use of the MSCR test in the rutting characterization of bituminous binders is highly recommended based on the results of this research.</p
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