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J.H. de Groot

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8 records found

Journal article (2025) - K.E. Rodriguez Hernandez, J.H. de Groot, Eveline R. M. Grootendorst-Heemskerk, Frank Baas, M. Stijntjes, S.K. Schiemanck, F.C.T. van der Helm, H. van der Kooij, W. Mugge
Background/Objectives: “Hermes” is an ankle–foot orthosis (AFO) with negative stiffness designed to mechanically compensate the symptomatic increase in plantarflexion (PF) torque (i.e., ankle joint torque resistance to dorsiflexion, DF) in patients with spastic paresis. Methods: The effectiveness of “Hermes” was evaluated in twelve patients with chronic unilateral spastic paresis after stroke. Using a robotic ankle manipulator, stiffness at the ankle joint was assessed across three conditions: ankle without Hermes (𝐴A), ankle with Hermes applying no torque compensation (𝐴+𝐻0%A+H0%), and ankle with Hermes tuned to compensate 100% of the patients’ ankle joint stiffness (𝐴+𝐻100%A+H100%). Results: A significant reduction in PF torque was found with Hermes applying compensation (𝐴+𝐻100%A+H100%) compared to the conditions without Hermes (𝐴A) and with Hermes applying no compensation (𝐴+𝐻0%A+H0%). Furthermore, a significant reduction in positive dorsiflexion work was found with Hermes applying compensation (𝐴+𝐻100%A+H100%) compared to the condition with Hermes applying no compensation (𝐴+𝐻0%A+H0%). Hermes did not significantly contribute to additional PF torque or positive work when applying no compensation (𝐴+𝐻0%A+H0%). Conclusions: The reductions in PF torque achieved with Hermes are comparable to those seen with repeated ankle stretching programs and ankle robot training. Thus, Hermes is expected to assist voluntary dorsiflexion and improve walking in patients with spastic paresis. ...
Journal article (2024) - Jules J.M. Kraaijkamp, Marjon Stijntjes, Jurriaan H. De Groot, Niels H. Chavannes, Wilco P. Achterberg, Eléonore F. van Dam van Isselt
The aim of this study was to quantify physical activity and sedentary behavior in older adults recovering from hip fracture and to identify groups based on movement patterns. In this cross-sectional cohort study, older adults (≥70 years) were included 3 months after surgery for proximal femoral fracture. Patients received an accelerometer for 7 days. Demographics and outcomes related to physical function, mobility, cognitive functions, quality of life, and hip fracture were assessed. In total, 43 patients with sufficient accelerometer wear time were included. Across all groups, participants engaged in very low levels of physical activity, spending an average of 11 hr/day in prolonged sedentary behavior. Based on the extracted components from a principal component analysis, three groups with substantial differences in levels of physical activity and sedentary behavior could be distinguished. ...
Individuals with an upper motor neuron syndrome, e.g., stroke survivors, may have a pathological increase of passive ankle stiffness due to spasticity, that impairs ankle function and activities such as walking. To improve mobility, walking aids such as ankle-foot orthoses and orthopaedic shoes are prescribed. However, these walking aids generally limit the range of motion (ROM) of the foot and may therewith negatively influence activities that require a larger ROM. Here we present a new ankle-foot orthosis 'Hermes', and its first experimental results from four hemiparetic chronic stroke patients. Hermes was designed to facilitate active ankle dorsiflexion by mechanically compensating the passive ankle stiffness using a negative-stiffness mechanism. Four levels of the Hermes' stiffness compensation (0%, 35%, 70% and 100%) were applied to evaluate active ROM in a robotic ankle manipulator and to test walking feasibility on an instrumented treadmill, in a single session. The robotic tests showed that Hermes successfully compensated the ankle joint stiffness in all four patients and improved the active dorsiflexion ROM in three patients. Three patients were able to walk with Hermes at one or more Hermes' stiffness compensation levels and without reducing their preferred walking speeds compared to those with their own walking aids. Despite a small sample size, the results show that Hermes holds great promise to support voluntary ankle function and to benefit walking and daily activities. ...

A systematic review on outcomes after nonsurgical management and tendon transfer surgery

Review (2023) - Timon H. Geurkink, Hamez Gacaferi, Perla J. Marang-van de Mheen, Jan W. Schoones, Jurriaan H. de Groot, Jochem Nagels, Rob G.H.H. Nelissen
Background: Scapular winging is a rare condition of the shoulder girdle that presents challenging treatment decisions for clinicians. To inform clinical practice, clinicians need guidance on what the best treatment decision is for their patients, and such recommendations should be based on the total evidence available. Therefore, the purpose of this review was to systematically review the evidence regarding nonsurgical management and tendon transfer surgery of patients with neurologic scapular winging due to serratus anterior (SA) or trapezius (TP) palsy. Methods: PubMed, Embase, Web of Science, Cochrane Library, Emcare, and Academic Search Premier were searched up to April 5, 2022, for studies reporting on clinical outcomes after nonsurgical management and tendon transfer surgery of scapular winging due to weakness of the SA or TP muscle. The Integrated quality Criteria for Review Of Multiple Study (ICROMS) tool was used to classify the quality of the studies. Primary outcomes were the fraction of patients with spontaneous recovery after nonsurgical management and improvement in shoulder function, pain scores, and shoulder scores after tendon transfer surgery. Data were pooled if data on the same outcome were available for at least 3 studies, using random-effects meta-analysis. Results: Twenty-three (10 moderate-quality [MQ] and 13 low-quality) studies were included. Six studies (3 MQ; 234 shoulders) reported on outcomes after nonsurgical management of SA palsy, whereas 12 (6 MQ; 221 shoulders) and 6 studies (1 MQ; 80 shoulders) evaluated the outcomes of tendon transfer for SA or TP palsy (1 study addressed both). Spontaneous recovery of scapular winging with nonsurgical management varied between 21% and 78% across studies after a median follow-up of 72 months. For surgical management of SA palsy, pooling data in a meta-analysis showed that patients on average improved by 47° (95% confidence interval [CI]: 34-61, P ≤ .001) in active forward flexion, had lower visual analog scale scores for pain (mean difference [MD]: −3.0, 95% CI: −4.9 to −1.0, P = .003), and had substantial improvements in American Shoulder and Elbow Surgeons (MD: 24, 95% CI: 9-39, P = .002) and Constant scores (MD: 45, 95% CI: 39-51, P ≤ .001). Patients with TP palsy on average improved by 36° (95% CI: 21-51, P ≤ .001) in active forward flexion after tendon transfer. Statistical pooling was not possible for other outcome measures as insufficient data were available. Conclusion: A substantial part of nonsurgically managed patients with scapular winging seem to have persistent complaints, which should be part of the information provided to patients. Data pooling demonstrated significant improvements in shoulder function, pain scores, and shoulder scores after tendon transfer surgery, but higher quality evidence is needed to allow for more robust recommendations and guide clinical decision-making on when to perform such functional surgery. ...
Journal article (2023) - Timon H. Geurkink, Celeste L. Overbeek, Perla J. Marang-van de Mheen, Jochem Nagels, Rob G.H.H. Nelissen, Jurriaan H. de Groot
Purpose: This study aimed to quantify the extent to which age was associated with joint position sense (JPS) of the asymptomatic shoulder as measured by joint position reproduction (JPR) tasks and assess the reproducibility of these tasks. Methods: 120 Asymptomatic participants aged 18–70 years each performed 10 JPR-tasks. Both contralateral and ipsilateral JPR-tasks were evaluated on accuracy of JPR under active- and passive conditions at two levels within the shoulder forward flexion trajectory. Each task was performed three times. In a subgroup of 40 participants, the reproducibility of JPR-tasks was assessed one week after initial measurement. Reproducibility of JPR-tasks was evaluated by both reliability (intra-class correlation coefficients (ICC's)) and agreement (standard error of measurement (SEM)) measures. Results: Age was not associated with increased JPR-errors for any of the contralateral or ipsilateral JPR-tasks. ICC's ranged between 0.63 and 0.80 for contralateral JPR-tasks, and from 0.32 to 0.48 for ipsilateral tasks, except for one ipsilateral task where the reliability was similar to contralateral tasks (0.79). The SEM was comparable and small for all JPR-tasks, ranging between 1.1 and 2.1. Conclusion: No age-related decline in JPS of the asymptomatic shoulder was found, and good agreement between test and re-test measurements for all JPR-tasks as indicated by the small SEM. ...
Journal article (2021) - Aukje Andringa, Carel Meskers, Ingrid van de Port, Sarah Zandvliet, Larissa Scholte, Jurriaan de Groot, Gert Kwakkel, Erwin van Wegen
Patients with poor upper limb motor recovery after stroke are likely to develop increased resistance to passive wrist extension, i.e., wrist hyper-resistance. Quantification of the underlying neural and non-neural elastic components is of clinical interest. This cross-sectional study compared two methods: a commercially available device (NeuroFlexor®) with an experimental EMG-based device (Wristalyzer) in 43 patients with chronic stroke. Spearman's rank correlation coefficients (r) between components, modified Ashworth scale (MAS) and range of passive wrist extension (PRoM) were calculated with 95% confidence intervals. Neural as well as elastic components assessed by both devices were associated (r = 0.61, 95%CI: 0.38-0.77 and r = 0.53, 95%CI: 0.28–0.72, respectively). The neural component assessed by the NeuroFlexor® associated significantly with the elastic components of NeuroFlexor® (r = 0.46, 95%CI: 0.18–0.67) and Wristalyzer (r = 0.36, 95%CI: 0.06–0.59). The neural component assessed by the Wristalyzer was not associated with the elastic components of both devices. Neural and elastic components of both devices associated similarly with the MAS (r = 0.58, 95%CI: 0.34–0.75 vs. 0.49, 95%CI: 0.22–0.69 and r = 0.51, 95%CI: 0.25–0.70 vs. 0.30, 95%CI: 0.00–0.55); elastic components associated with PRoM (r = -0.44, 95%CI: -0.65- -0.16 vs. -0.74, 95%CI: -0.85- -0.57 for NeuroFlexor® and Wristalyzer respectively). Results demonstrate that both methods perform similarly regarding the quantification of neural and elastic wrist hyper-resistance components and have an added value when compared to clinical assessment with the MAS alone. The added value of EMG in the discrimination between neural and non-neural components requires further investigation. ...
Journal article (2017) - Paulina J.M. Bank, L.R.M. Dobbe (student), Carel G M Meskers, Jurriaan H. de Groot, Erwin de Vlugt
Proper understanding of motor control requires insight into the extent and manner in which task performance and control strategy are influenced by various aspects of visual information. We therefore systematically manipulated the visual presentation (i.e., scaling factor and optical flow density) of a visuomotor tracking task without changing the task itself, and investigated the effect on performance, effort, motor control strategy (i.e., anticipatory or corrective steering) and underlying neuromechanical parameters (i.e., intrinsic muscle stiffness and damping, and proprioceptive and visual feedback). Twenty healthy participants controlled the left-right position of a virtual car (by means of wrist rotations in a haptic robot) to track a slightly curved virtual road (presented on a 60” LED screen), while small torque perturbations were applied to the wrist (1.25–20 Hz multisine) for quantification of the neuromechanical parameters. This visuomotor tracking task was performed in conditions with low/medium/high scaling factor and low/high optical flow density. Task performance was high in all conditions (tracking accuracy 96.6%–100%); a higher scaling factor was associated with slightly better performance. As expected, participants did adapt their control strategy and the use of proprioceptive and visual feedback in response to changes in the visual presentation. These findings indicate that effects of visual representation on motor behavior should be taken into consideration in designing, interpreting and comparing experiments on motor control in health and disease. In future studies, these insights might be exploited to assess the sensory-motor adaptability in various clinical conditions. ...
Journal article (2017) - Galia V. Anguelova, Erwin de Vlugt, Alistair N. Vardy, Erik W. Van Zwet, J. Gert van Dijk, Martijn J.A. Malessy, Jurriaan H. de Groot
We suggest short range stiffness (SRS) at the elbow joint as an alternative diagnostic for EMG to assess cocontraction.Elbow SRS is compared between obstetric brachial plexus lesion (OBPL) patients and healthy subjects (cross-sectional study design). Seven controls (median 28. years) and five patients (median 31. years) isometrically flexed and extended the elbow at rest and three additional torques [2.1,. 4.3,. 6.4. N. m] while a fast stretch stimulus was applied. SRS was estimated in silico using a neuromechanical elbow model simulating the torque response from the imposed elbow angle.SRS was higher in patients (250. ±. 36. N. m/rad) than in controls (150. ±. 21. N. m/rad, p = 0.014), except for the rest condition. Higher elbow SRS suggested greater cocontraction in patients compared to controls. SRS is a promising mechanical alternative to assess cocontraction, which is a frequently encountered clinical problem in OBPL due to axonal misrouting. ...