1,721,518 research outputs found
Brain-computer interfacing in rehabilitation
No full textBrain–computer interfacing (BCI) systems involve controlling a computer using brain signals detected by electroencephalography (EEG). Signal processing software uses the EEG signal to control a cursor or application, such as word processing (Birbaumer et al., 1999 and Pfurtscheller et al., 1993). The field of BCI research is at a relatively early stage of producing reliable, robust systems that are widely accessible for everyday use. Several BCI research groups are developing systems to enable communication and environmental control for people with severe disabilities. A more recent area of exploration with BCI is for investigating mechanisms of normal function, dysfunction and recovery, as well as aiding diagnosis and re-training of function. The generation and control of EEG signals for driving a BCI system require training of the user. Methods include imagery tasks, evoked potentials and operant conditioning (for reviews see (Curran and Stokes, 2003 E. Curran and M. Stokes, Brain Cog 51 (2003), pp. 326–335.Curran and Stokes, 2003 and Kübler et al., 2001)). Signal processing techniques continue to be refined (James and Hesse, 2005) and are improving the accuracy and reliability of BCI technology but translation into routine clinical use is limited by several factors influencing accessibility and compliance. Surface or implanted recording devices can be used and for transient use in most areas of rehabilitation, surface electrodes are appropriate. An important aim of BCI research is to bridge the gap between major technological advances and the relatively limited success in practical applications. More clinical disciplines are encouraged to become involved in BCI research to achieve this aim.<br/
Joint loading asymmetries in knee replacement patients observed both pre- and six months post-operation
No full textBackgroundStudies have highlighted asymmetries in knee joint moments during activities of daily living in individuals with osteoarthritis and joint replacements. However, there is a need to investigate the forces at the knee joints in order to establish the extent of loading asymmetry.MethodsTwenty healthy (mean, 62; range, 55-79 years of age) and 34 pre- to post-knee arthroplasty (mean, 64; range, 39-79 years of age) participants performed gait and sit-stand activities in a motion capture laboratory. Testing was conducted 4 weeks pre- and 6 months post- knee arthroplasty. Knee joint forces and moments were predicted using inverse dynamics and used to calculate peak loading and impulse data which were normalized to body weight. Comparisons were made in loading between affected and contralateral limbs, and changes from pre- to post-knee arthroplasty.FindingsPre-knee arthroplasty mean peak vertical knee forces were greater in the contralateral limb compared to the affected limb during both gait 3.5*body weight vs. 3.2*body weight and sit-stand 1.8*body weight vs. 1.5*body weight. During gait, peak knee adduction moment asymmetries significantly changed from pre- to post-knee arthroplasty (-0.3 to 0.8*% Body weight*m*Height), although differences in vertical knee forces remained. The sit-stand activity showed vertical ground reaction asymmetries slightly increased post- knee arthroplasty (from 0.06*body weight pre- to 0.08*body weight post). The healthy participants showed no noteworthy asymmetries.InterpretationThis study showed loading asymmetry of the ground reaction and tibio-femoral forces between affected and contralateral limbs both pre- post-knee arthroplasty. Continued over reliance of the contralateral limb could lead to pathology.<br/
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
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