1,720,959 research outputs found
Effect of gait cycle selection on EMG analysis during walking in adults and children with gait pathology
No full textThis paper presents the results of a project to evaluate different methods of gait cycle selection on the analysis of electromyography recorded during gait. Electromyography (EMG) describes the electrical activity associated with the muscle and is often interpreted in gait analysis using a simultaneously obtained signal to identify phases of the gait cycle. Phase transitions are often selected manually from reference signals derived from additional instrumentation, such as pressure platforms, footswitches and video cameras. We propose two methods (automatic and semi-automatic) as an alternative to the more traditional manual selection, and analyse how the gait cycle selection affects the EMG analysis. To quantify the differences between the gait cycles obtained using each method and to classify each cycle, three indices have been introduced. The effect of the gait cycle selection has been evaluated with respect to the EMG step profiles and temporal gait descriptors. An asymptomatic adult, an asymptomatic child and two children with cerebral palsy were examined using telemetric EMG devices and pressure footswitches. The results obtained showed that the method of gait cycle selection did not have a major influence for the adult, but it altered considerably the analysis in the case of the children with cerebral palsy
Enforcing cyclic movements of the upper limb for movement analysis systems
No full textAnalysing the movement of the upper limb is difficult due to the variability and complexity of the mechanics available to complete any given task. When combining a clinical hand function assessment with the analysis of cyclic movement patterns clinicians are able to generate an independent assessment of function, in conjunction with waveforms of movement during a prehensile task, which is clinically relevant.Applying repetitive tasks to facilitate movement analysis is quite common and usually incorporates the use of Activities of Daily Living (ADL) [1,2] or reach-to-grasp tasks [3,4]. In 2001, Fowler, et al., employed an adapted version of a hand function test in order to provide more stable movement patterns [5]
Application of complex wavelets for EMG analysis during gait of asymptomatic and pathological subjects
No full textThe wavelet transform seems particularly suited to analyse the electromyographic signal (EMG) during gait of asymptomatic and pathological subjects. Firstly, because physiologically the electrical activity generated by the muscles derives from a weighted sum of individual physiological components having limited support in time and in frequency. Secondly, because it is important to analyze muscle activity during specific phases of the cycle, and finally, because specific ranges of frequency are important pathological discriminators. In this paper we report the preliminary results of a project aimed at classifying asymptomatic and pathological subjects by analysing the complex wavelet transform of the EMG signal derived from two muscles (Tibialis Anterior and Lateral Gastrocnemius) during gait. An asymptomatic adult, an asymptomatic child and two pathological (cerebral palsy) children were examined using telemetric EMG devices and pressure footswitches. The results showed that the indices derived from the coefficient amplitudes (Gastrocnemius) and from frequency distribution (Tibialis) are capable of classifying the subjects into three groups. Despite the small number of cases analyzed, we believe that the relevance of the results deserves particular attention because of the novelty of the use of the wavelet transform for this application and of the potential application to monitor patients during interventions aimed at improving muscle behavior, particularly antispasticity treatment such as Botulinum Toxin injections
Complex wavelet transform for EMG analysis during walking of children suffering of Cerebral Palsy
No full textEvaluation of orthoses used in the management of children with cerebral palsy and who walk with frames
No full textObjective: The aim of this study was to evaluate the effect that
orthoses have on the gait and energy expenditure of a group of children with cerebral palsy (CP) and who walk with the assistance of frames. The study complemented a qualitative
investigation to examine the views and opinions of the children
about their orthoses.Method: Fifteen children were recruited to the investigation from physiotherapy departments located in a residential school and two child development centres. All children recruited were aged between 5 and 16 years, had CP, wore orthoses, and walked with the assistance of a frame. The children took part in one assessment which comprised of an interview followed by biomechanical data collection. They walked around a 20m course using their walking frame for a period of 5 minutes during which time data were recorded using a video camera filming in the sagittal plane and a heart rate monitor. Children were assessed with and without their orthoses, in random order. Video was analyzed to provide sagittal plane joint angles, walking velocity, stride length, and stance/swing phase timing. Energy expenditure was evaluated using the Physiological Cost Index (PCI).Results: There were mixed results with the orthotics having positive effects in some children, negative in others, and in many children no changes occurred. Consequently the orthoses did not improve joint angles, PCI, and temporal/spatial parameters across the board. In some children PCI, temporal, or spatial parameters improved but joint kinematics did not (and vice versa). Eight of the children showed consistent results. Four participants consistently improved with orthoses, and four showed no change. Although ankle kinematics improved in many of the children only three showed improvement at either the knee or hip.Conclusion: In light of the findings it would seem important that careful consideration is given to identifying the specific aim of prescribing orthoses, and selection of the correct type. Following prescription it would also be useful, although not always possible, to use gait analysis to evaluate whether those goals have been achieved
Validation and application of a computational model for wrist and hand movements using surface markers
Full text linkA kinematic model is presented based on surface marker placement generating wrist, metacarpal arch, fingers and thumb movements. Standard calculations are used throughout the model and then applied to the specified marker placement. A static trial involving eight unimpaired participants was carried out to assess inter-rater reliability. The standard deviations across the data were comparable to manual goniometers. In addition, a test retest trial of ten unimpaired participants is also reported to illustrate the variability of movement at the wrist joint, metacarpal arch, and index finger as an example of model output when repeating the same task many times. Light and heavyweight versions of the tasks are assessed and characteristics of individual movement strategies presented. The participant trial showed moderate correlation in radial/ulnar deviation of the wrist ( = 0 65), and strong correlation in both metacarpal arch joints ( = 075 and = 085), the MCP ( = 079), and PIP ( = 087) joints of the index finger. The results indicate that individuals use repeated strategies of movement when lifting light and heavyweight versions of the same object, but showed no obvious repeated pattern of movement across the population
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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