Detecting Elementary Arm Movements by Tracking Upper Limb Joint Angles With MARG Sensors

This paper reports an algorithm for the detection of three elementary upper limb movements, i.e., reach and retrieve, bend the arm at the elbow and rotation of the arm about the long axis. We employ two MARG sensors, attached at the elbow and wrist, from which the kinematic properties (joint angles, position) of the upper arm and forearm are calculated through data fusion using a quaternion-based gradient-descent method and a two-link model of the upper limb. By studying the kinematic patterns of the three movements on a small dataset, we derive discriminative features that are indicative of each movement; these are then used to formulate the proposed detection algorithm. Our novel approach of employing the joint angles and position to discriminate the three fundamental movements was evaluated in a series of experiments with 22 volunteers who participated in the study: 18 healthy subjects and four stroke survivors. In a controlled experiment, each volunteer was instructed to perform each movement a number of times. This was complimented by a seminaturalistic experiment where the volunteers performed the same movements as subtasks of an activity that emulated the preparation of a cup of tea. In the stroke survivors group, the overall detection accuracy for all three movements was 93.75% and 83.00%, for the controlled and seminaturalistic experiment, respectively. The performance was higher in the healthy group where 96.85% of the tasks in the controlled experiment and 89.69% in the seminaturalistic were detected correctly. Finally, the detection ratio remains close (±6%) to the average value, for different task durations further attesting to the algorithms robustness

A water-based training program that include perturbation exercises to improve stepping responses in older adults: study protocol for a randomized controlled cross-over trial

<p>Abstract</p> <p>Background</p> <p>Gait and balance impairments may increase the risk of falls, the leading cause of accidental death in the elderly population. Fall-related injuries constitute a serious public health problem associated with high costs for society as well as human suffering. A rapid step is the most important protective postural strategy, acting to recover equilibrium and prevent a fall from initiating. It can arise from large perturbations, but also frequently as a consequence of volitional movements. We propose to use a novel water-based training program which includes specific perturbation exercises that will target the stepping responses that could potentially have a profound effect in reducing risk of falling. We describe the water-based balance training program and a study protocol to evaluate its efficacy (Trial registration number #NCT00708136).</p> <p>Methods/Design</p> <p>The proposed water-based training program involves use of unpredictable, multi-directional perturbations in a group setting to evoke compensatory and volitional stepping responses. Perturbations are made by pushing slightly the subjects and by water turbulence, in 24 training sessions conducted over 12 weeks. Concurrent cognitive tasks during movement tasks are included. Principles of physical training and exercise including awareness, continuity, motivation, overload, periodicity, progression and specificity were used in the development of this novel program. Specific goals are to increase the speed of stepping responses and improve the postural control mechanism and physical functioning. A prospective, randomized, cross-over trial with concealed allocation, assessor blinding and intention-to-treat analysis will be performed to evaluate the efficacy of the water-based training program. A total of 36 community-dwelling adults (age 65–88) with no recent history of instability or falling will be assigned to either the perturbation-based training or a control group (no training). Voluntary step reaction times and postural stability using stabiliogram diffusion analysis will be tested before and after the 12 weeks of training.</p> <p>Discussion</p> <p>This study will determine whether a water-based balance training program that includes perturbation exercises, in a group setting, can improve speed of voluntary stepping responses and improve balance control. Results will help guide the development of more cost-effective interventions that can prevent the occurrence of falls in the elderly.</p

A perturbation-based balance training program for older adults: study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Previous research investigating exercise as a means of falls prevention in older adults has shown mixed results. Lack of specificity of the intervention may be an important factor contributing to negative results. Change-in-support (CIS) balance reactions, which involve very rapid stepping or grasping movements of the limbs, play a critical role in preventing falls; hence, a training program that improves ability to execute effective CIS reactions could potentially have a profound effect in reducing risk of falling. This paper describes: 1) the development of a perturbation-based balance training program that targets specific previously-reported age-related impairments in CIS reactions, and 2) a study protocol to evaluate the efficacy of this new training program.</p> <p>Methods/Design</p> <p>The training program involves use of unpredictable, multi-directional moving-platform perturbations to evoke stepping and grasping reactions. Perturbation magnitude is gradually increased over the course of the 6-week program, and concurrent cognitive and movement tasks are included during later sessions. The program was developed in accordance with well-established principles of motor learning, such as individualisation, specificity, overload, adaptation-progression and variability. Specific goals are to reduce the frequency of multiple-step responses, reduce the frequency of collisions between the stepping foot and stance leg, and increase the speed of grasping reactions. A randomised control trial will be performed to evaluate the efficacy of the training program. A total of 30 community-dwelling older adults (age 64–80) with a recent history of instability or falling will be assigned to either the perturbation-based training or a control group (flexibility/relaxation training), using a stratified randomisation that controls for gender, age and baseline stepping/grasping performance. CIS reactions will be tested immediately before and after the six weeks of training, using platform perturbations as well as a distinctly different method of perturbation (waist pulls) in order to evaluate the generalisability of the training effects.</p> <p>Discussion</p> <p>This study will determine whether perturbation-based balance training can help to reverse specific age-related impairments in balance-recovery reactions. These results will help to guide the development of more effective falls prevention programs, which may ultimately lead to reduced health-care costs and enhanced mobility, independence and quality of life.</p

The influence of self-efficacy, pre-stroke depression and perceived social support on self-reported depressive symptoms during stroke rehabilitation

Lewin A, Jöbges M, Werheid K. The influence of self-efficacy, pre-stroke depression and perceived social support on self-reported depressive symptoms during stroke rehabilitation. Neuropsychological Rehabilitation. 2013;23(4):546-562.Post-stroke depression (PSD) is the most common mental disorder following stroke; however, little is known about its pathogenesis. We investigated the predictive value and mutual relationship of psychological factors such as self-efficacy and social support and known risk factors such as pre-stroke depression, activities of daily living (ADL), cognitive functioning, and age for the emergence of depressive symptoms in the acute phase after stroke. Ninety-six ischaemic stroke inpatients residing at a rehabilitation centre completed an interview about 6.5 weeks post-stroke. The interview included demographic data, psychiatric anamnesis, the Barthel Index, Mini-Mental State Examination, Social Support Questionnaire, Generalized Self-Efficacy Scale, Stroke Self-Efficacy Questionnaire, and the Geriatric Depression Scale. A multiple regression analysis was performed to ascertain the predictive value of the factors on depressive symptoms. High self-efficacy, no history of pre-stroke depression, and high levels of perceived social support were the strongest protective factors for depressive symptoms. The influence of cognitive functioning on depressive symptoms was fully mediated by general self-efficacy, and general self-efficacy was a stronger predictor than stroke-specific self-efficacy. Neither ADL nor age significantly predicted depressive symptoms. Our findings suggest that consideration of self-efficacy and perceived social support in the inpatient rehabilitation setting may help prevent PSD

Predictivity of early depressive symptoms for post-stroke depression

Lewin-Richter A, Volz M, Jöbges M, Werheid K. Predictivity of early depressive symptoms for post-stroke depression. The journal of nutrition, health &amp; aging. 2015;19(7):754-758.Objectives: Depression is a frequent complication after stroke. However, little is known about the predictive value of early self-reported depressive symptoms (DS) for later development of post-stroke depression (PSD) 6 months after discharge. Design: Using a prospective longitudinal design, we investigated the prevalence of DS and examined their predictive value for depressive disorders 6 months after stroke while statistically controlling major established PSD risk factors. Setting and participants: During inpatient rehabilitation, 96 stroke patients were screened for DS. After 6 months, 71 patients were attainable for a follow-up. Measurements: DS was assessed using the 15-item Geriatric Depression Scale (GDS-15). At follow-up a telephone interview that included the Structured Clinical Interview for Psychiatric Disorders (SCID), which is based on DSM-IV criteria, and the GDS-15 was conducted. Patients with major depression (MD) at the follow-up were considered to have PSD. Results: Regression analyses were conducted to examine the influence of early DS on PSD after 6 months while controlling for age, premorbid depression, and functional and cognitive impairments. The percentage of patients who scored above the GDS-15 cut-off for clinically relevant DS increased significantly, from 37% to 44%, after 6 months. According to the SCID, 27% of stroke patients fulfilled the criteria for MD, and another 16% fulfilled those for minor depression. Logistic regression showed that DS at baseline significantly predicted PSD at follow-up (odds ratio: 1.43; 95% CI: 1.15-1.8). Conclusion: Self-reported DS during inpatient rehabilitation are predictive for PSD 6 months after discharge. Assessment of early DS contributes to identifying stroke patients at risk for PSD, thereby facilitating prevention and treatment

Prevalence of mild cognitive impairment in employable patients after acute coronary event in cardiac rehabilitation

Annett Salzwedel,1 Maria-Dorothea Heidler,1,2 Kathrin Haubold,1 Martin Schikora,2 Rona Reibis,3 Karl Wegscheider,4 Michael J&ouml;bges,2 Heinz V&ouml;ller1,5 1Center for Rehabilitation Research, University of Potsdam, Potsdam, 2Brandenburg Klinik, Bernau, 3Cardiological Outpatient Clinic, Am Park Sanssouci, Potsdam, 4Institute for Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, 5Klinik am See, R&uuml;dersdorf, Germany Introduction: Adequate cognitive function in patients is a prerequisite for successful implementation of patient education and lifestyle coping in comprehensive cardiac rehabilitation (CR) programs. Although the association between cardiovascular diseases and cognitive impairments (CIs) is well known, the prevalence particularly of mild CI in CR and the characteristics of affected patients have been insufficiently investigated so far. Methods: In this prospective observational study, 496 patients (54.5 &plusmn; 6.2 years, 79.8% men) with coronary artery disease following an acute coronary event (ACE) were analyzed. Patients were enrolled within 14 days of discharge from the hospital in a 3-week inpatient CR program. Patients were tested for CI using the Montreal Cognitive Assessment (MoCA) upon admission to and discharge from CR. Additionally, sociodemographic, clinical, and physiological variables were documented. The data were analyzed descriptively and in a multivariate stepwise backward elimination regression model with respect to CI. Results: At admission to CR, the CI (MoCA score &lt; 26) was determined in 182 patients (36.7%). Significant differences between CI and no CI groups were identified, and CI group was associated with high prevalence of smoking (65.9 vs 56.7%, P&nbsp;=&nbsp;0.046), heavy (physically demanding) workloads (26.4 vs 17.8%, P&nbsp;&lt;&nbsp;0.001), sick leave longer than 1 month prior to CR (28.6 vs 18.5%, P&nbsp;=&nbsp;0.026), reduced exercise capacity (102.5 vs 118.8&nbsp;W, P&nbsp;=&nbsp;0.006), and a shorter 6-min walking distance (401.7 vs 421.3&nbsp;m, P&nbsp;=&nbsp;0.021) compared to no CI group. The age- and education-adjusted model showed positive associations with CI only for sick leave more than 1&nbsp;month prior to ACE (odds ratio [OR] 1.673, 95% confidence interval 1.07&ndash;2.79; P&nbsp;=&nbsp;0.03) and heavy workloads (OR 2.18, 95% confidence interval 1.42&ndash;3.36; P&nbsp;&lt;&nbsp;0.01). Conclusion: The prevalence of CI in CR was considerably high, affecting more than one-third of cardiac patients. Besides age and education level, CI was associated with heavy workloads and a longer sick leave before ACE. Keywords: cardiac rehabilitation, cognitive impairment, prevalence, acute coronary event, patient educatio