An Willems

Effects of external rhythmical cueing on gait in patients with Parkinson's disease: a systematic review

Objective: To critically review studies evaluating the effects of external rhythmical cueing on gait in patients with Parkinsons disease. Methods: Articles published from 1966 to January 2005 were searched by two physiotherapists in MEDLINE, PiCarta, PEDRo, Cochrane, DocOnline, CINAHL and SUMSEARCH. To be included, articles had to investigate the effects of external rhythmical cueing (i.e., auditory, visual or tactile cueing) on gait parameters in patients with idiopathic Parkinsons disease. Both controlled and noncontrolled studies were included. Based on the type of design and methodological quality a meta-analysis or best-evidence synthesis was applied. Results: Twenty-four studies (total number of patients = 626) out of the 159 screened studies were evaluated in this systematic review. Two out of 24 were randomized controlled trails (RCT), both of high methodological quality. One RCT did not focus specifically on external rhythmical cueing of individual patients with Parkinsons disease, but on group exercises in general, including walking with cues. All other studies were pre-experimental studies. Best-evidence synthesis showed strong evidence for improving walking speed with the help of auditory cues. Insufficient evidence was found for the effectiveness of visual and somatosensory cueing. Conclusion: Only one high-quality study, specifically focused on the effects of auditory rhythmical cueing, suggesting that the walking speed of patients with Parkinsons disease can be positively influenced. However, it is unclear whether positive effects identified in the laboratory can be generalized to improved activities of daily living (ADLs) and reduced frequency of falls in the community. In addition, the sustainability of a cueing training programme remains uncertain.

Picture Frame Test of Woven Composite Reinforcements with a Full-Field Strain Registration:

Results of picture frame shear tests with optical registration of the strain fields are presented for glass (plain and twill, three types) and glass/PP woven (plain and twill) fabric reinforcements for composite materials. Four problems were investigated. (1) How does the shear diagram vary with differences in test conditions? The major factor is the sample pretension, which is influenced by its gripping, removing/preserving yarns near the grips and “conditioning” in the shear cycles. (2) Does the shear of the fabric differ from the pure shear prescribed by the frame? The differences are normally negligible. (3) How large are the variations of the local fabric shear? The scatter of the local fabric shear does not exceed 2°. (4) How is shear of the fabric translated into deformations of the yarns on the micro-scale? Different stages of the fabric deformation are identified: rotation of the yarns followed by their lateral compression.

Picture frame shear tests on woven textile composite reinforcements with controlled pretension

This paper presents in‐plane shear tests on a picture frame of a glass‐PP textile weave in three different biaxial tensile states. Aim of these tests is to study the influence of tensile load in the yarn direction on the shear resistance for this textile family and the repeatability of the current test method. Digital image correlation (DIC) is used to assess the local deformation of the fabric during the shear tests. The shear deformation of the fabric deviates significantly from the frame shear, but is not affected by the tensile state. During the shear deformation sideways sliding of the yarns and an overall rigid body rotation take place. Despite the ill‐conditioned nature of the shear test, significant tensile‐shear interaction was observed. However, it is difficult to assess the importance of this interaction as large data scatter exists between shear tests performed according to different test methods (frame and fabric size, clamping and sample preparation) or by different labs.

Measurement of local deformations on thermoformed composite parts under different process conditions

The growing use of thermoplastic composites demands tools to analyze the deformed parts accurately. Intraply shear is the most pronounced deformation mode that occurs when a 2D fabric is draped into a complex 3D shape. The paper uses a 3D image correlation method to investigate the intraply shear deformation of a woven fabric reinforced composite. The thickness distribution of the formed ply is determined by using a dial indicator. The fabric is deformed by non‐isothermal stamping into a matched “half‐salami” shaped mould. The influence of processing conditions, especially pre‐heating temperature, stamp speed and the blankholder force is investigated. The effect of the ply‐orientation on the shear angle distribution is discussed. The measured shear angles are compared with a kinematical drape model. It was concluded that the local deformations are not influenced by the processing conditions. For 0 and 90° ply‐orientation, the draping model adequately predicts the shear angle up to about 40°; for higher an...