| 1. |
- Grinberg, Adam, 1980-, et al.
(författare)
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An electroencephalography-based approach to evaluate movement-related anxiety in physically active adults and following anterior cruciate ligament injury
- 2022
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Konferensbidrag (refereegranskat)abstract
- Background: Psychophysiological consequences often persist following musculoskeletal trauma and can result in vastly decreased quality of life. Re-injury anxiety is particularly common among individuals following anterior cruciate ligament (ACL) injury. Existing assessments of re-injury anxiety are, however, restricted to subjective suboptimal questionnaires, which may result in under-reporting and thus poorer injury management. We propose a novel approach to objectively quantify arousal response to movement-related anxiety. A new experimental paradigm was implemented to induce and record a conditioned electrophysiological response to a sudden perturbation, experienced to be potentially injurious.Objective: To explore the feasibility of detecting anxiety-associated electrocortical response and to evaluate its discriminative ability between asymptomatic individuals and those who had experienced an ACL injury.Methods: Physically-active asymptomatic persons and individuals post-ACL reconstruction stood blindfolded on a perturbation platform capable of generating high-acceleration translations (1.5 m/s2). Auditory stimuli were repeatedly presented in four-second intervals, as either low- or high-frequency tones. Half of the high-frequency tones were followed 1.5 seconds later by a destabilizing perturbation in one of eight randomized directions. The two tone conditions were thus termed ‘Neutral’ and ‘Anxiety’, as the high-frequency tone was intended to invoke an arousal response in anticipation of a potential perturbation. Event-related potentials (ERP) were computed for nine electrodes by averaging 100 Neutral and 100 Anxiety trials. Significant ERP components were identified using functional data analysis. Paired difference-waves’ amplitudes (Neutral - Anxiety) were compared between groups.Results: ERP correlates of anxiety were detected for both groups in frontal and central midline locations, with an observable contingent negative variation (CNV) from 500 ms post-stimulus in Anxiety compared with Neutral trials. This ERP component is reflective of a threat-induced arousal response, associated with attention and expectancy of an anxiety-relevant event. Preliminary data indicate no group differences in CNV amplitudes.Conclusions: Objective evaluation of an arousal response to movement-related anxiety was found to be feasible, resulting in a threat-induced CNV. Further investigation will elucidate the discriminative power of such an approach to differentiate between individuals with high and low re-injury anxiety, as well as potential associations with existing patient-reported outcome measures.
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| 2. |
- Grinberg, Adam, 1980-, et al.
(författare)
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An electroencephalography-based approach to evaluate movement-related anxiety in physically-active persons
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Psychological consequences often persist following musculoskeletal trauma and can result in vastly decreased quality of life. Re-injury anxiety is reported to hinder return to sports and can itself be a precursor for secondary injuries. Existing assessments of re-injury anxiety are restricted to subjective questionnaires, which may result in under-reporting and thus poorer injury management. In the current study, we introduced an experimental approach to objectively quantify movement-related anxiety using a threat-conditioning paradigm. We aimed to explore the feasibility of such an approach among non-injured persons.Ten physically-active individuals stood blindfolded on a platform capable of generating high-acceleration translations in eight different directions. Consecutive auditory stimuli were presented (four-second intervals), as either high- (conditioned stimulus; CS+) or low- (neutral stimulus; CS–) tones. Half of the CS+ trials were followed by a perturbation in a pseudo-random order. Event-related potentials were computed for nine electrodes by averaging 100 X CS– and 100 X CS+ trials. Significant latencies for CS– – CS+ comparisons were identified using interval-wise testing. Mean-amplitudes for significant intervals were used to detect a channel effect.Large negative CS+ waveforms were observed from 302-627ms post-stimulus and continuing until the end of the trials, most prominently over frontal and central midline locations (p ≤ 0.025). This effect, inferred as a contingent negative variation wave (CNV), may be reflective of threat-induced arousal response.Our test paradigm was found to be feasible, with a CNV suggested as a potential biomarker for re-injury anxiety. Further validation is needed, as well as exploring the discriminative power of such an approach between individuals with and without previous injury.
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| 3. |
- Grinberg, Adam, 1980-, et al.
(författare)
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Electrocortical activity associated with movement-related fear : a methodological exploration of a threat-conditioning paradigm involving destabilising perturbations during quiet standing
- 2024
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Ingår i: Experimental Brain Research. - : Springer Nature. - 0014-4819 .- 1432-1106. ; 242:8, s. 1903-1915
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Tidskriftsartikel (refereegranskat)abstract
- Musculoskeletal trauma often leads to lasting psychological impacts stemming from concerns of future injuries. Often referred to as kinesiophobia or re-injury anxiety, such concerns have been shown to hinder return to physical activity and are believed to increase the risk for secondary injuries. Screening for re-injury anxiety is currently restricted to subjective questionnaires, which are prone to self-report bias. We introduce a novel approach to objectively identify electrocortical activity associated with the threat of destabilising perturbations. We aimed to explore its feasibility among non-injured persons, with potential future implementation for screening of re-injury anxiety. Twenty-three participants stood blindfolded on a translational balance perturbation platform. Consecutive auditory stimuli were provided as low (neutral stimulus [CS–]) or high (conditioned stimulus [CS+]) tones. For the main experimental protocol (Protocol I), half of the high tones were followed by a perturbation in one of eight unpredictable directions. A separate validation protocol (Protocol II) requiring voluntary squatting without perturbations was performed with 12 participants. Event-related potentials (ERP) were computed from electroencephalography recordings and significant time-domain components were detected using an interval-wise testing procedure. High-amplitude early contingent negative variation (CNV) waves were significantly greater for CS+ compared with CS– trials in all channels for Protocol I (> 521-800ms), most prominently over frontal and central midline locations (P ≤ 0.001). For Protocol II, shorter frontal ERP components were observed (541-609ms). Our test paradigm revealed electrocortical activation possibly associated with movement-related fear. Exploring the discriminative validity of the paradigm among individuals with and without self-reported re-injury anxiety is warranted.
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| 4. |
- Grinberg, Adam, 1980-
(författare)
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Sensorimotor function following anterior cruciate ligament injury : movement control, proprioception and neuropsychological perspectives
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The high incidence of anterior cruciate ligament (ACL) injuries in sports suggests an involvement of both biomechanical and neurocognitive risk factors. Athletes are constantly exposed to challenging sports scenarios, which are often characterised by high-intensity movements combined with a multi-stimuli environment and continuous psychological pressure. Post-injury loss of knee proprioception and long-term injury-associated neuroplasticity arguably place an athlete in a disadvantage when coping with such situations when returning to sports (RTS). This is postulated to contribute to a high rate of re-injuries, seen despite achieving RTS eligibility. Psychological factors such as re-injury fears and anxieties are also suggested to influence central sensorimotor processing and to therefore play a role in the generation and control of functional movements. Their assessment is however based on suboptimal tools, particularly when administered to the athletic population. In general, current clinical assessments focus primarily on coarse outcome measures while disregarding aspects such as multi-joint control and the influence of psychological aspects on motor performance. This thesis focuses on the role of proprioception and re-injury anxiety on functional movement control following ACL injury and reconstruction (ACLR), with implications for risks of re-injury.Methods: This thesis is comprised of four cross-sectional studies (Papers I-IV), that stem from two data collections performed in a motion analysis laboratory. Paper I introduces a novel obstacle clearance test aimed to functionally assess proprioception and sensorimotor control. The goal of the test was to cross an obstacle, downward vision occluded, aiming for minimal foot clearance. Individuals following ACLR and rehabilitation were compared to both mildly active uninjured persons (CTRL) and elite athletes (ATH). A kinematic analysis, using 3D motion capture, included estimates of lower limb movement accuracy, variability and symmetry. Paper II evaluates knee proprioception among the same individuals using a weight-bearing knee joint position sense (JPS) test, and outcomes were compared with associated outcomes from the obstacle clearance test. Paper III explores whether self-reported fear of re-injury is manifested in the biomechanics (kinematics and electromyography) of a standardised rebound side-hop test (SRSH). An ACLR group was stratified into high-fear and low-fear subgroups based on one discriminating question, and compared also to uninjured controls. In Paper IV, a threat-conditioning test paradigm is introduced, aiming to invoke and measure a neurophysiological arousal response to movement-related fear, among uninjured individuals. Conditioned auditory stimuli were occasionally followed by unexpected perturbations of the base of support, and compared with neutral stimuli. Electroencephalography was continuously registered and event-related potentials were explored as potential anxiety biomarkers.Results: Kinematic asymmetry was observed for the ACLR group during obstacle crossing, both for individual joints and for multi-joint movement and velocity curves. In addition, trailing leg trajectory variability during higher obstacle crossings was lower for ACLR compared to both control groups. The less physically-active CTRL group demonstrated less crossing accuracy (larger obstacle distances and JPS errors) compared to both ACLR and ATH. Moderate positive correlations were observed between knee JPS absolute errors and obstacle distances, for the injured leg of the ACLR group only. Individuals with ACLR, classified as having high fear, demonstrated higher biceps femoris amplitudes and anterior-posterior co-contraction index during landing. Side-hop performance was also distinguishable for ACLR (regardless of fear allocation) with greater hip and knee flexion, while high-fear individuals also had more trunk flexion. Perturbation-related fearful response was reflected as a high-amplitude contingent negative variation (CNV) wave in response to conditioned compared to neutral stimuli. The CNV wave was observed over all electrode cites but most significantly over frontal and central cortical areas.Conclusions: Even following rehabilitation, individuals with ACLR showed unique sensorimotor function, characterised by less trajectory variability and greater multi-joint asymmetry when proprioception was challenged (i.e., downward vision occluded). However, knee JPS did not seem to be deficient among these individuals, but instead more related to physical activity, than to the ACLR history. Correlations to JPS errors, seen exclusively for the ACLR leg might suggest a tendency to focus attention more internally when crossing an obstacle (generally an external focus task), though this should be investigated further. Higher levels of self-reported fear of re-injury were manifested in the biomechanics of side hops, with seemingly stiffer landings and protective neuromuscular strategy. This has potential implications for joint degeneration hastening as well as reduced motor adaptability, implying a risk for re-injury. Finally, the balance-perturbation test paradigm seemed to provoke threat-associated arousal in the form of a CNV wave among uninjured individuals. The CNV wave should further be explored as a potential biomarker for re-injury anxiety. Future research should implement this paradigm on individuals with different levels of self-reported movement-related fears and anxieties, striving for a more holistic approach in rehabilitation following ACLR.
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| 5. |
- Grip, Helena, et al.
(författare)
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Kinematic analyses including finite helical axes of drop jump landings demonstrate decreased knee control long after anterior cruciate ligament injury
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 14:10
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to evaluate the dynamic knee control during a drop jump test following injury of the anterior cruciate ligament injury (ACL) using finite helical axes. Persons injured 17-28 years ago, treated with either physiotherapy (ACLPT, n = 23) or reconstruction and physiotherapy (ACLR, n = 28) and asymptomatic controls (CTRL, n = 22) performed a drop jump test, while kinematics were registered by motion capture. We analysed the Preparation phase (from maximal knee extension during flight until 50 ms post-touchdown) followed by an Action phase (until maximal knee flexion post-touchdown). Range of knee motion (RoM), and the length of each phase (Duration) were computed. The finite knee helical axis was analysed for momentary intervals of ~15° of knee motion by its intersection (ΔAP position) and inclination (ΔAP Inclination) with the knee's Anterior-Posterior (AP) axis. Static knee laxity (KT100) and self-reported knee function (Lysholm score) were also assessed. The results showed that both phases were shorter for the ACL groups compared to controls (CTRL-ACLR: Duration 35±8 ms, p = 0.000, CTRL-ACLPT: 33±9 ms, p = 0.000) and involved less knee flexion (CTRL-ACLR: RoM 6.6±1.9°, p = 0.002, CTRL-ACLR: 7.5 ±2.0°, p = 0.001). Low RoM and Duration correlated significantly with worse knee function according to Lysholm and higher knee laxity according to KT-1000. Three finite helical axes were analysed. The ΔAP position for the first axis was most anterior in ACLPT compared to ACLR (ΔAP position -1, ACLPT-ACLR: 13±3 mm, p = 0.004), with correlations to KT-1000 (rho 0.316, p = 0.008), while the ΔAP inclination for the third axis was smaller in the ACLPT group compared to controls (ΔAP inclination -3 ACLPT-CTRL: -13±5°, p = 0.004) and showed a significant side difference in ACL injured groups during Action (Injured-Non-injured: 8±2.7°, p = 0.006). Small ΔAP inclination -3 correlated with low Lysholm (rho 0.391, p = 0.002) and high KT-1000 (rho -0.450, p = 0.001). Conclusions Compensatory movement strategies seem to be used to protect the injured knee during landing. A decreased ΔAP inclination in injured knees during Action suggests that the dynamic knee control may remain compromised even long after injury.
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| 6. |
- Liebermann, Dario G., et al.
(författare)
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Spatiotemporal lower-limb asymmetries during stair descent in athletes following anterior cruciate ligament reconstruction
- 2024
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Ingår i: Journal of Electromyography & Kinesiology. - : Elsevier. - 1050-6411 .- 1873-5711. ; 75
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study evaluated motor control recovery at different times following anterior cruciate ligament reconstruction (ACLR) by investigating lower-limb spatiotemporal symmetry during stair descent performances.Methods: We used a cross-sectional design to compare asymptomatic athletes (Controls, n = 18) with a group of people with ACLR (n = 49) divided into three time-from-ACLR subgroups (Early: <6 months, n = 17; Mid: 6–18 months, n = 16; Late: ≥18 months, n = 16). We evaluated: “temporal symmetry” during the stance subphases (single-support, first and second double-support) and “spatial symmetry” for hip-knee-ankle intra-joint angular displacements during the stance phase using a dissimilarity index applied on superimposed 3D phase plots.Results: We found significant between-group differences in temporal variables (p ≤ 0.001). Compared to Controls, both Early and Mid (p ≤ 0.05) showed asymmetry in the first double-support time (longer for their injured vs. non-injured leg), while Early generally also showed longer durations in all other phases, regardless of stepping leg. No statistically significant differences were found for spatial intra-joint symmetry between groups.Conclusion: Temporal but not spatial asymmetry in stair descent is often present early after ACLR; it may remain for up to 18 months and may underlie subtle intra- and inter-joint compensations. Spatial asymmetry may need further exploration.
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| 7. |
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| 8. |
- Markström, Jonas, 1985-, et al.
(författare)
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Atypical lower limb mechanics during weight acceptance of stair descent at different time frames after anterior cruciate ligament reconstruction
- 2022
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Ingår i: American Journal of Sports Medicine. - : Sage Publications. - 0363-5465 .- 1552-3365. ; 50:8, s. 2125-2133
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Tidskriftsartikel (refereegranskat)abstract
- Background: An anterior cruciate ligament (ACL) rupture may result in poor sensorimotor knee control and, consequentially, adapted movement strategies to help maintain knee stability. Whether patients display atypical lower limb mechanics during weight acceptance of stair descent at different time frames after ACL reconstruction (ACLR) is unknown.Purpose:To compare the presence of atypical lower limb mechanics during the weight acceptance phase of stair descent among athletes at early, middle, and late time frames after unilateral ACLR.Study Design:Controlled laboratory study.Methods:A total of 49 athletes with ACLR were classified into 3 groups according to time after ACLR—early (<6 months; n = 17), middle (6-18 months; n = 16), and late (>18 months; n = 16)—and compared with asymptomatic athletes (control; n = 18). Sagittal plane hip, knee, and ankle angles; angular velocities; moments; and powers were compared between the ACLR groups’ injured and noninjured legs and the control group as well as between legs within groups using functional data analysis methods.Results:All 3 ACLR groups showed greater knee flexion angles and moments than the control group for injured and noninjured legs. For the other outcomes, the early group had, compared with the control group, less hip power absorption, more knee power absorption, lower ankle plantarflexion angle, lower ankle dorsiflexion moment, and less ankle power absorption for the injured leg and more knee power absorption and higher vertical ground reaction force for the noninjured leg. In addition, the late group showed differences from the control group for the injured leg revealing more knee power absorption and lower ankle plantarflexion angle. Only the early group took a longer time than the control group to complete weight acceptance and demonstrated asymmetry for multiple outcomes.Conclusion:Athletes with different time frames after ACLR revealed atypically large knee angles and moments during weight acceptance of stair descent for both the injured and the noninjured legs. These findings may express a chronically adapted strategy to increase knee control. In contrast, atypical hip and ankle mechanics seem restricted to an early time frame after ACLR.Clinical Relevance:Rehabilitation after ACLR should include early training in controlling weight acceptance. Including a control group is essential when evaluating movement patterns after ACLR because both legs may be affected.
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| 9. |
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| 10. |
- Nedergård, Heidi, et al.
(författare)
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Core Sets of Kinematic Variables to Consider for Evaluation of Gait Post-stroke
- 2022
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Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media S.A.. - 1662-5161. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Instrumented gait analysis post-stroke is becoming increasingly more common in research and clinics. Although overall standardized procedures are proposed, an almost infinite number of potential variables for kinematic analysis is generated and there remains a lack of consensus regarding which are the most important for sufficient evaluation. The current aim was to identify a discriminative core set of kinematic variables for gait post-stroke.Methods: We applied a three-step process of statistical analysis on commonly used kinematic gait variables comprising the whole body, derived from 3D motion data on 31 persons post-stroke and 41 non-disabled controls. The process of identifying relevant core sets involved: (1) exclusion of variables for which there were no significant group differences; (2) systematic investigation of one, or combinations of either two, three, or four significant variables whereby each core set was evaluated using a leave-one-out cross-validation combined with logistic regression to estimate a misclassification rate (MR).Results: The best MR for one single variable was shown for the Duration of single-support (MR 0.10) or Duration of 2nd double-support (MR 0.11) phase, corresponding to an 89–90% probability of correctly classifying a person as post-stroke/control. Adding Pelvis sagittal ROM to either of the variables Self-selected gait speed or Stride length, alternatively adding Ankle sagittal ROM to the Duration of single-stance phase, increased the probability of correctly classifying individuals to 93–94% (MR 0.06). Combining three variables decreased the MR further to 0.04, suggesting a probability of 96% for correct classification. These core sets contained: (1) a spatial (Stride/Step length) or a temporal variable (Self-selected gait speed/Stance time/Swing time or Duration of 2nd double-support), (2) Pelvis sagittal ROM or Ankle plantarflexion during push-off, and (3) Arm Posture Score or Cadence or a knee/shoulder joint angle variable. Adding a fourth variable did not further improve the MR.Conclusion: A core set combining a few crucial kinematic variables may sufficiently evaluate post-stroke gait and should receive more attention in rehabilitation. Our results may contribute toward a consensus on gait evaluation post-stroke, which could substantially facilitate future diagnosis and monitoring of rehabilitation progress.
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