Nina Lefeber

The immediate effects of robot-assistance on energy consumption and cardiorespiratory load during walking compared to walking without robot-assistance: a systematic review

Abstract Purpose: The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. Methods: PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted. Effect sizes were calculated. Results: Fourteen studies were included, concerning 155 participants (85 healthy subjects, 39 stroke and 31 spinal cord injury patients), 9 robots (2 end-effectors, 1 treadmill-based and 6 wearable exoskeletons), and 7 outcome parameters (mostly oxygen consumption and heart rate). Overall, metabolic and cardiorespiratory parameters were lower during RAG compared to walking without robot-assistance (moderate to large effect sizes). In healthy subjects, when no body-weight support (BWS) was provided, RAG with an end-effector device was more energy demanding than walking overground (p > .05, large effect sizes). Conclusions: Generally, results suggest that RAG is less energy-consuming and cardiorespiratory stressful than walking without robot-assistance, but results depend on factors such as robot type, walking speed, BWS and effort. Additional research is needed to draw firm conclusions. Implications for Rehabilitation Awareness of the energy consumption and cardiorespiratory load of robot-assisted gait (RAG) training is important in the rehabilitation of (neurological) patients with impaired cardiorespiratory fitness and patients who are at risk of cardiovascular diseases. On the other hand, the integration of sufficient cardiometabolic stress in RAG training could combine the effects of both RAG and aerobic training. Energy consumption and cardiorespiratory load during walking with robot-assistance seems to depend on factors such as robot type, walking speed, body-weight support or amount of effort. These parameters could be adjusted in RAG rehabilitation to make RAG more or less energy-consuming and cardiorespiratory stressful. Overall, short duration exoskeleton walking seems less energy-consuming and cardiorespiratory stressful than walking without robot-assistance. This might implicate that the exercise intensity is safe for (neurological) patients at risk of cardiovascular diseases. How this changes in extended walking time is unclear.

Motivation, expectations, and usability of a driven gait orthosis in stroke patients and their therapists

Abstract Background: In the development of efficacious driven gait orthoses (DGO), it is an added value to consider patients’ and therapists’ perspectives concerning robot-assisted gait training (RAGT). A better understanding of these issues may improve the process of care and outcome. Objectives: This study aimed to examine stroke patients’ motivation and expectations of RAGT, and therapists’ expectations and perspectives on the usability of RAGT. Additionally, the differences in expectations between stroke patients and their therapists were analyzed. Methods: A cross sectional, multi-center, three-group trial was conducted. Included were (1) stroke patients who have experience with RAGT (i.e. the stroke user group), (2) stroke patients who have no experience with RAGT (i.e. the stroke non-user group), and (3) therapists who have experience with RAGT (i.e. the therapist user group). The Intrinsic Motivation Inventory (IMI), Credibility/Expectancy Questionnaire (CEQ), and Usefulness, Satisfaction and Ease of Use Questionnaire (USE) were used. Descriptive statistics and non-parametric Kruskal–Wallis tests were conducted. Results: In total, 46 subjects were assessed (stroke user group: n = 23, stroke non-user group: n = 14, therapist user group: n = 9). IMI subscale scores ranged from 42 to 88%. Mean credibility and expectancy ranged from 80 to 85% and 57 to 72%, respectively, with no significant differences between groups. USE subscale scores ranged from 61 to 72%. Conclusions: Stroke user group patients seem quite motivated to train with the DGO and both patients and therapists reasonably believe that this training could improve gait functioning. Therapists are moderately satisfied with the usability of the DGO, but there is room for improvement with respect to usefulness and ease of use.

A systematic review investigating the relationship between efficacy and stimulation parameters when using transcutaneous electrical nerve stimulation after knee arthroplasty

Objective: To evaluate the clinical efficacy of transcutaneous electric nerve stimulation in the treatment of postoperative knee arthroplasty pain and to relate these results to the stimulation parameters used. Data Sources: PubMed, Pedro and Web of Knowledge were systematically screened for studies investigating effects of transcutaneous electric nerve stimulation on postoperative knee arthroplasty pain. Review Methods: Studies were screened for their methodological and therapeutical quality. We appraised the influence of the stimulation settings used and indicated whether or not a neurophysiological and/or mechanistic rationale was given for these stimulation settings. Results: A total of 5 articles met the inclusion criteria. In total, 347 patients were investigated. The number of patients who received some form of transcutaneous electric nerve stimulation was 117, and 54 patients received sham transcutaneous electric nerve stimulation. Pain was the primary outcome in all studies. The stimulation settings used in the studies (n = 2) that reported significant effects differed from the others as they implemented a submaximal stimulation intensity. Stimulation parameters were heterogeneous, and only one study provided a rationale for them. Conclusion: This review reveals that an effect of transcutaneous electric nerve stimulation might have been missed due to low methodological and therapeutical quality. Justifying the choice of transcutaneous electric nerve stimulation parameters may improve therapeutical quality.

Energy Consumption and Cardiorespiratory Load During Lokomat Walking Compared to Walking Without Robot-Assistance in Stroke Patients: Preliminary Results

Energy consumption and cardiorespiratory load were assessed during 3 different walking conditions (Lokomat, treadmill and overground walking) in stroke patients. Preliminary results demonstrated that Lokomat walking was significantly less oxygen demanding than treadmill, but not overground walking. No significant differences in heart rate and minute ventilation were found. Further research with sufficient sample size and additional analyses will be performed to draw firm conclusions.

Effect of Transcutaneous Electric Nerve Stimulation on Pain after Total Knee Arthroplasty: A Blind Randomized Controlled Trial

Abstract Transcutaneous electric nerve stimulation (TENS) has proven to be effective for postsurgical pain relief. However, there is a lack of well‐constructed clinical trials investigating the effect of TENS after total knee arthroplasty (TKA). In addition, previous investigations reported that low‐ and high‐frequency TENSs produced analgesic tolerance after 4 or 5 days of treatment. The aim of this study is to explore the effect of burst TENS on pain during hospitalization after TKA and to investigate whether burst TENS produces analgesic tolerance after 4 or 5 days of treatment. This stratified, triple blind, randomized controlled trial was approved by the University Hospital Brussels. Sixty‐eight subjects were screened for eligibility before surgery; 54 were found eligible and 53 were included in the analyses. Patients were allocated to either a burst TENS or sham burst TENS group. TENS was applied daily during continuous passive mobilization. Knee pain intensity, knee range of motion, and analgesic consumption were assessed daily. Patients received burst TENS (N = 25) or sham burst TENS (N = 28). No significant differences in knee pain intensity were found between the groups (p > 0.05). Within the TENS and the sham TENS groups, the difference in knee pain before and after treatment did not evolve over time (p > 0.05). This study found no effects of burst TENS compared with sham burst TENS on pain during hospitalization after TKA.

Bilateral, Misalignment-Compensating, Full-DOF Hip Exoskeleton: Design and Kinematic Validation

A shared design goal for most robotic lower limb exoskeletons is to reduce the metabolic cost of locomotion for the user. Despite this, only a limited amount of devices was able to actually reduce user metabolic consumption. Preservation of the natural motion kinematics was defined as an important requirement for a device to be metabolically beneficial. This requires the inclusion of all human degrees of freedom (DOF) in a design, as well as perfect alignment of the rotation axes. As perfect alignment is impossible, compensation for misalignment effects should be provided. A misalignment compensation mechanism for a 3-DOF system is presented in this paper. It is validated by the implementation in a bilateral hip exoskeleton, resulting in a compact and lightweight device that can be donned fast and autonomously, with a minimum of required adaptations. Extensive testing of the prototype has shown that hip range of motion of the user is maintained while wearing the device and this for all three hip DOFs. This allowed the users to maintain their natural motion patterns when they are walking with the novel hip exoskeleton.

Validity and test-retest reliability of the Stride Analyzer in people with knee osteoarthritis

INTRODUCTION Subjects with knee osteoarthritis walk differently compared to healthy subjects. Managing these gait alterations has been proven effective for reducing pain and increasing function. The Stride Analyzer is a low cost gait analysis tool but its clinimetric properties have not been investigated yet in subjects with symptomatic knee osteoarthritis. The aim of this study was to investigate the reliability and validity of the SA compared with the Gold standard (Vicon) in persons with knee OA. METHODS Fifteen subjects with symptomatic knee osteoarthritis were instructed to walk at a self-selected speed in a gait laboratory. Temporospatial (TS) gait parameters were recorded simultaneously by the Stride Analyzer and by a 16-camera-infrared optoelectronic motion capturing system (Vicon). Validity and test-retest reliability of the Stride Analyzer were examined by Bland-Altman plots, intra-class correlation coefficients (ICC) and the standard error of measurement (SEM). RESULTS Test-retest analyses showed good agreement for all TS parameters with ICC values ranging from 0.805 (single limb support right) to 0.949 (velocity) and SEM% values ranging from 0.78% (stance phase right (% of gait cycle)) to 4.52% (double limb support right (% of gait cycle)). Good agreement between Stride Analyzer and Vicon was found for the following TS parameters: velocity (z=1.01), cadence (z=-0.85), stride length (z=1.63) and gait cycle (z=0.86). All other gait parameters showed lower ICC values (<0.689). INTERPRETATION Our results suggest that the Stride Analyzer can be used in the clinical field to perform gait analysis in subjects with symptomatic knee osteoarthritis.

Balance During Bodyweight Supported and Robot-Assisted Walking

Robot-assisted gait rehabilitation improves gait- and balance related outcome measures, but its merit over other gait rehabilitation methods is still insufficiently proven. The trunk and pelvis are important to maintain balance during gait. Despite, scarce research has been presented concerning the importance of the trunk and the pelvis in different types of gait rehabilitation methods. We investigated whether the amount of bodyweight support and the amount of guidance force have an influence on the movements of the trunk and the pelvis during robot-assisted walking (Lokomat-system). The results of this study suggest that walking with the Lokomat-system leads to significant changes in trunk and pelvis movements, which influence the training of the trunk balance during robot-assisted walking. These results should be taken into account in the development of gait rehabilitation robots and gait rehabilitation strategies.