Risk of upper limb complaints due to computer use in older persons: a randomized study

Abstract Background We studied whether the twelve-month use of a standard computer would induce complaints of upper limb pain or functional limitations in older novice computer users. Methods Participants between 64 and 76 of age were randomly assigned to an Intervention group (n = 62), whose members received a personal computer and fast Internet access at their homes, or a No Intervention control group (n = 61), whose members refrained from computer use during the twelve month study period. Results Difference scores between baseline and twelve months assessments on both complaint (SFS) and functional health scales (SF-36) did not differ between groups (all p > .05). Conclusion Prolonged, self-paced use of a standard computer interface does not put older persons at a risk of upper limb complaints or reduce functional health in older adults.</p

Recognition of Handwriting from Electromyography

Handwriting – one of the most important developments in human culture – is also a methodological tool in several scientific disciplines, most importantly handwriting recognition methods, graphology and medical diagnostics. Previous studies have relied largely on the analyses of handwritten traces or kinematic analysis of handwriting; whereas electromyographic (EMG) signals associated with handwriting have received little attention. Here we show for the first time, a method in which EMG signals generated by hand and forearm muscles during handwriting activity are reliably translated into both algorithm-generated handwriting traces and font characters using decoding algorithms. Our results demonstrate the feasibility of recreating handwriting solely from EMG signals – the finding that can be utilized in computer peripherals and myoelectric prosthetic devices. Moreover, this approach may provide a rapid and sensitive method for diagnosing a variety of neurogenerative diseases before other symptoms become clear

Altered Perceptual Sensitivity to Kinematic Invariants in Parkinson's Disease

Ample evidence exists for coupling between action and perception in neurologically healthy individuals, yet the precise nature of the internal representations shared between these domains remains unclear. One experimentally derived view is that the invariant properties and constraints characterizing movement generation are also manifested during motion perception. One prominent motor invariant is the “two-third power law,” describing the strong relation between the kinematics of motion and the geometrical features of the path followed by the hand during planar drawing movements. The two-thirds power law not only characterizes various movement generation tasks but also seems to constrain visual perception of motion. The present study aimed to assess whether motor invariants, such as the two thirds power law also constrain motion perception in patients with Parkinson's disease (PD). Patients with PD and age-matched controls were asked to observe the movement of a light spot rotating on an elliptical path and to modify its velocity until it appeared to move most uniformly. As in previous reports controls tended to choose those movements close to obeying the two-thirds power law as most uniform. Patients with PD displayed a more variable behavior, choosing on average, movements closer but not equal to a constant velocity. Our results thus demonstrate impairments in how the two-thirds power law constrains motion perception in patients with PD, where this relationship between velocity and curvature appears to be preserved but scaled down. Recent hypotheses on the role of the basal ganglia in motor timing may explain these irregularities. Alternatively, these impairments in perception of movement may reflect similar deficits in motor production

Performance-Driven Handwriting Task Selection for Parkinson's Disease Classification

Diagnosing and monitoring Parkinson’s disease (PD) is a topic of current research in many fields, including AI. The innovative challenge is to develop a low-cost, non-invasive tool to support clinicians at the point of care. In particular, since handwriting difficulties in PD patients are well-known, changes in handwriting have emerged as a powerful discriminant factor for PD assessment. A crucial step in designing a decision support system based on handwriting concerns the choice of the most appropriate handwriting tasks to be administered for data acquisition. When data are collected, traditional approaches assume that different tasks, although not with the same impact, are all important for classification. However, not all tasks are likely to be useful for diagnosis, and the inclusion of these tasks may be detrimental to prediction accuracy. This work investigates the potential of an optimal subset of tasks for a more accurate PD classification. The evaluation is carried out by adopting a performance-driven multi-expert approach on different handwriting tasks performed by the same subjects. The multi-expert system is based on similar or conceptually different classifiers trained on features related to the dynamics of the handwriting process. The proposed approach improves baseline results on the PaHaW data set

The relationship between joint mobility and motor performance in children with and without the diagnosis of developmental coordination disorder

<p>Background: The purpose of this study was to determine whether joint mobility is associated with motor performance in children referred for Developmental Coordination Disorder (DCD-group) in contrast to a randomly selected group of children between 3-16 years of age (Random-Group).</p><p>Methods: 36 children with DCD and 352 typically developing children (Random-Group) participated. Hypermobility was classified based on the Beighton score (cut-off >= 5 for 3-9 years and >= 4 for 10-16 years) using goniometry. Motor performance was assessed with the Movement Assessment Battery for Children (MABC).</p><p>Results: The mean Beighton score in the DCD-group was 5.0 versus 2.6 in the Random group. Prevalence of hypermobility was higher in the DCD-group than in the Random Group (64% and 33% respectively; X-2 = 16.09, p <.001). There was a significant [negative] correlation (r(p) = -.38, p = .02) between Beighton score and total MABC scores within the DCD group, but not in the Random Group (r(p) = -0.07, p = .20). More specifically, in the DCD group we found a significant negative correlation between the MABC total score and the degree of hyperextension of the knees.</p><p>Conclusion: The extremely high prevalence of hypermobility when applying the recommended cut-off scores stresses the need for an international agreement on firm cut-off points and the use of standardized measurement of Beighton mobility manoeuvres. The results of this study show that a cut-off of 7 is more appropriate, resulting in a prevalence of 6% in children aged 3-16 years. Although in the general population motor performance and joint mobility are not related, this is the case in children referred for DCD. We argue that more mobility of the joints may be a disadvantage when motor coordination is poorly developed.</p>

Effects of concurrent physical and cognitive demands on muscle activity and heart rate variability in a repetitive upper-extremity precision task

© 2015, Springer-Verlag Berlin Heidelberg. Purpose: Most previous studies of concurrent physical and cognitive demands have addressed tasks of limited relevance to occupational work, and with dissociated physical and cognitive task components. This study investigated effects on muscle activity and heart rate variability of executing a repetitive occupational task with an added cognitive demand integral to correct task performance. Methods: Thirty-five healthy females performed 7.5 min of standardized repetitive pipetting work in a baseline condition and a concurrent cognitive condition involving a complex instruction for correct performance. Average levels and variabilities of electromyographic activities in the upper trapezius and extensor carpi radialis (ECR) muscles were compared between these two conditions. Heart rate and heart rate variability were also assessed to measure autonomic nervous system activation. Subjects also rated perceived fatigue in the neck–shoulder region, as well as exertion. Results: Concurrent cognitive demands increased trapezius muscle activity from 8.2 % of maximum voluntary exertion (MVE) in baseline to 9.0 % MVE (p = 0.0005), but did not significantly affect ECR muscle activity, heart rate, heart rate variability, perceived fatigue or exertion. Conclusion: Trapezius muscle activity increased by about 10 %, without any accompanying cardiovascular response to indicate increased sympathetic activation. We suggest this slight increase in trapezius muscle activity to be due to changed muscle activation patterns within or among shoulder muscles. The results suggest that it may be possible to introduce modest cognitive demands necessary for correct performance in repetitive precision work without any major physiological effects, at least in the short term