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Applying Stretch to Evoke Hyperreflexia in Spasticity Testing

Velocity vs. Acceleration

Journal article - Lizeth H. Sloot, Lizeth H. Sloot, Guido Weide, Guido Weide, Marjolein M. van der Krogt, K. Desloovere, J. Harlaar, J. Harlaar, Annemieke I. Buizer, Annemieke I. Buizer, Lynn Bar-On, Lynn Bar-On

In neurological diseases, muscles often become hyper-resistant to stretch due to hyperreflexia, an exaggerated stretch reflex response that is considered to primarily depend on the muscle's stretch velocity. However, there is still limited understanding of how different biomechan ...

In neurological diseases, muscles often become hyper-resistant to stretch due to hyperreflexia, an exaggerated stretch reflex response that is considered to primarily depend on the muscle's stretch velocity. However, there is still limited understanding of how different biomechanical triggers applied during clinical tests evoke these reflex responses. We examined the effect of imposing a rotation with increasing velocity vs. increasing acceleration on triceps surae muscle repsonse in children with spastic paresis (SP) and compared the responses to those measured in typically developing (TD) children. A motor-operated ankle manipulator was used to apply different bell-shaped movement profiles, with three levels of maximum velocity (70, 110, and 150°/s) and three levels of maximum acceleration (500, 750, and 1,000°/s2). For each profile and both groups, we evaluated the amount of evoked triceps surae muscle activation. In SP, we evaluated two additional characteristics: the intensity of the response (peak EMG burst) and the time from movement initiation to onset of the EMG burst. As expected, the amount of evoked muscle activation was larger in SP compared to TD (all muscles: p < 0.001) and only sensitive to biomechanical triggers in SP. Further investigation of the responses in SP showed that peak EMG bursts increased in profiles with higher peak velocity (lateral gastrocnemius: p = 0.04), which was emphasized by fair correlations with increased velocity at EMG burst onset (all muscles: r > 0.33–0.36, p ≤ 0.008), but showed no significant effect for acceleration. However, the EMG burst was evoked faster with higher peak acceleration (all muscles p < 0.001) whereas it was delayed in profiles with higher peak velocity (medial gastrocnemius and soleus: p < 0.006). We conclude that while exaggerated response intensity (peak EMG burst) seems linked to stretch velocity, higher accelerations seem to evoke faster responses (time to EMG burst onset) in triceps surae muscles in SP. Understanding and controlling for the distinct effects of different biological triggers, including velocity, acceleration but also length and force of the applied movement, will contribute to the development of more precise clinical measurement tools. This is especially important when aiming to understand the role of hyperreflexia during functional movements where the biomechanical inputs are multiple and changing.@en

Comprehensive evaluation of gait, spasticity, and muscle morphology

A case report of a child with spastic paresis treated with Botulinum NeuroToxin-A, serial casting, and physiotherapy

Journal article - Guido Weide, Guido Weide, Lizeth Sloot, Laura Maria Oudenhoven, Richard T. Jaspers, J. Harlaar, J. Harlaar, Annemieke I. Buizer, Lynn Bar-On, Lynn Bar-On

Comprehensive instrumented muscle and joint assessments should be considered when prescribing Botulinum NeuroToxin-A (BoNT-A) treatment in spastic paresis. In a child with spastic paresis, comprehensive evaluation following treatment with BoNT-A, serial casting, and physiotherapy ...

Personalisation of Plantarflexor Musculotendon Model Parameters in Children with Cerebral Palsy

Journal article - Kirsten Veerkamp, Kirsten Veerkamp, Kirsten Veerkamp, Marjolein M. van der Krogt, Marjolein M. van der Krogt, J. Harlaar, J. Harlaar, Thomas D. O’Brien, Barbara Kalkman, A. Seth, Lynn Bar-On, Lynn Bar-On, Lynn Bar-On

Neuromusculoskeletal models can be used to evaluate aberrant muscle function in cerebral palsy (CP), for example by estimating muscle and joint contact forces during gait. However, to be accurate, models should include representative musculotendon parameters. We aimed to estimate ...

Electromyographic biofeedback-driven gaming to alter calf muscle activation during gait in children with spastic cerebral palsy

Journal article - Eline Flux, Eline Flux, Lynn Bar-On, Lynn Bar-On, Lynn Bar-On, Annemieke I. Buizer, Annemieke I. Buizer, Annemieke I. Buizer, J. Harlaar, J. Harlaar, J. Harlaar, Marjolein M. van der Krogt, Marjolein M. van der Krogt

Background: Children with cerebral palsy often show deviating calf muscle activation patterns during gait, with excess activation during early stance and insufficient activation during push-off. Research question: Can children with cerebral palsy improve their calf muscle activat ...

Background: Children with cerebral palsy often show deviating calf muscle activation patterns during gait, with excess activation during early stance and insufficient activation during push-off. Research question: Can children with cerebral palsy improve their calf muscle activation patterns during gait using one session of biofeedback-driven gaming? Methods: Eighteen children (6–17 y) with spastic cerebral palsy received implicit game-based biofeedback on electromyographic activity of the calf muscle (soleus or gastrocnemius medialis) while walking on a treadmill during one session. Biofeedback alternately aimed to reduce early stance activity, increase push-off activity, and both combined. Early stance and push-off activity and the double-bump-index (early stance divided by push-off activity) were determined during baseline and walking with feedback. Changes were assessed at group level using repeated measures ANOVA with simple contrast or Friedman test with post-hoc Wilcoxon signed rank test, as well as individually using independent t-tests or Wilcoxon rank sum tests. Perceived competence and interest-enjoyment were assessed through a questionnaire. Results: Children successfully decreased their electromyographic activity during early stance feedback trials (relative decrease of 6.8 ± 12.2 %, P = 0.025), with a trend during the combined feedback trials (6.5 ± 13.9 %, P = 0.055), and increased their electromyographic activity during push-off feedback trials (8.1 ± 15.8 %, P = 0.038). Individual improvements were seen in twelve of eighteen participants. All children experienced high levels of interest-enjoyment (8.4/10) and perceived competence (8.1/10). Significance: This exploratory study suggests that children with cerebral palsy can achieve small within-session improvements of their calf muscle activation pattern when provided with implicit biofeedback-driven gaming in an enjoyable manner. Follow-up gait training studies can incorporate this method to assess retention and long-term functional benefits of electromyographic biofeedback-driven gaming.@en

Spasticity assessment in cerebral palsy

Book chapter - Lynn Bar-On, Lynn Bar-On, J. Harlaar, J. Harlaar, K. Desloovere

Spasticity is an important, but not the only, component contributing to the increased joint resistance experienced by children with spastic cerebral palsy. Conventional clinical spasticity scales, based on physical examination of the passive muscle, are easy to apply in pediatric ...

Gastrocnemius Medialis Muscle Geometry and Extensibility in Typically Developing Children and Children With Spastic Paresis Aged 6–13 Years

Journal article - Guido Weide, Guido Weide, Peter A.J.B.M. Huijing, Lynn Bar-On, Lynn Bar-On, Lizeth Sloot, Annemieke I. Buizer, Jules G. Becher, J. Harlaar, J. Harlaar, Richard T. Jaspers

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim ...

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim of this study was to compare gastrocnemius medialis (GM) muscle geometry and extensibility in children with SP with those of typically developing (TD) children and assess how GM morphology is related to its extensibility. Thirteen children with SP, of which 10 with a diagnosis of spastic cerebral palsy and three with SP of unknown etiology (mean age 9.7 ± 2.1 years; GMFCS: I–III), and 14 TD children (mean age 9.3 ± 1.7 years) took part in this study. GM geometry was assessed using 3D ultrasound imaging at 0 and 4 Nm externally imposed dorsal flexion ankle moments. GM extensibility was defined as its absolute length change between the externally applied 0 and 4 Nm moments. Anthropometric variables and GM extensibility did not differ between the SP and TD groups. While in both groups, GM muscle volume correlated with body mass, the slope of the regression line in TD was substantially higher than that in SP (TD = 3.3 ml/kg; SP = 1.3 ml/kg, p < 0.01). In TD, GM fascicle length increased with age, lower leg length and body mass, whereas in SP children, fascicle length did not correlate with any of these variables. However, the increase in GM physiological cross-sectional area as a function of body mass did not differ between SP and TD children. Increases in lengths of tendinous structures in children with SP exceeded those observed in TD children (TD = 0.85 cm/cm; SP = 1.16 cm/cm, p < 0.01) and even exceeded lower-leg length increases. In addition, only for children with SP, body mass (r = −0.61), height (r = −0.66), muscle volume (r = − 0.66), physiological cross-sectional area (r = − 0.59), and tendon length (r = −0.68) showed a negative association with GM extensibility. Such negative associations were not found for TD children. In conclusion, physiological cross-sectional area and length of the tendinous structures are positively associated with age and negatively associated with extensibility in children with SP.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Journal article - J. C. van den Noort, J. C. van den Noort, Lynn Bar-On, Lynn Bar-On, J. F. Fleuren, S. Grunt, F. Heinen, H. L. Horemans, C. Jansen, C. Jansen, A. Kranzl, B. K. Krautwurst, M. van der Krogt, M. van der Krogt, S. Lerma Lara, S. Lerma Lara, C. M. Lidbeck, E. Aertbeliën, J. P. Lin, I Martinez, C. Meskers, C. Meskers, D. Metaxiotis, G. Molenaers, D. A. Patikas, O. Rémy-Néris, K Roeleveld, A. P. Shortland, J. Sikkens, M. Bonikowski, LH Sloot, LH Sloot, R. J. Vermeulen, C. Wimmer, A. S. Schröder, S. Schless, Jules G. Becher, K. Desloovere, K. Desloovere, J. Harlaar, J. Harlaar, S. M. Braendvik, S. M. Braendvik, E. W. Broström, Annemieke I. Buizer, J. H. Burridge, A. van Campenhout, B. Dan, B. Dan

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic ...

Background and purpose: To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods: During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results: The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions: A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.@en

SimCP: A simulation platform to predict gait performance following orthopedic intervention in children with cerebral palsy

Journal article - Friedl De Groote, Lorenzo Pitto, Antoine Falisse, Hans Kainz, M.G.H. Wesseling, Sam Van Rossom, Eirini Papageorgiou, Lynn Bar-On, Kaat desloovere, Ilse Jonkers

Gait deficits in cerebral palsy (CP) are often treated with a single-event multi-level surgery (SEMLS). Selecting the treatment options (combination of bony and soft tissue corrections) for a specific patient is a complex endeavor and very often treatment outcome is not satisfyin ...

Gait deficits in cerebral palsy (CP) are often treated with a single-event multi-level surgery (SEMLS). Selecting the treatment options (combination of bony and soft tissue corrections) for a specific patient is a complex endeavor and very often treatment outcome is not satisfying. A deterioration in 22.8% of the parameters describing gait performance has been reported and there is need for additional surgery in 11% of the patients. Computational simulations based on musculoskeletal models that allow clinicians to test the effects of different treatment options before surgery have the potential to drastically improve treatment outcome. However, to date, no such simulation and modeling method is available. Two important challenges are the development of methods to include patient-specific neuromechanical impairments into the models and to simulate the effect of different surgical procedures on post-operative gait performance. Therefore, we developed the SimCP framework that allows the evaluation of the effect of different simulated surgeries on gait performance of a specific patient and includes a graphical user interface (GUI) that enables performing virtual surgery on the models. We demonstrated the potential of our framework for two case studies. Models reflecting the patient-specific musculoskeletal geometry and muscle properties are generated based solely on data collected before the treatment. The patient's motor control is described based on muscle synergies derived from pre-operative EMG. The GUI is then used to modify the musculoskeletal properties according to the surgical plan. Since SEMLS does not affect motor control, the same motor control model is used to define gait performance pre- and post-operative. We use the capability gap (CG), i.e., the difference between the joint moments needed to perform healthy walking and the joint moments the personalized model can generate, to quantify gait performance. In both cases, the CG was smaller post- then pre-operative and this was in accordance with the measured change in gait kinematics after treatment.@en

Physics-Based Simulations to Predict the Differential Effects of Motor Control and Musculoskeletal Deficits on Gait Dysfunction in Cerebral Palsy: A Retrospective Case Study

Journal article - Antoine Falisse, Lorenzo Pitto, Guy Molenaers, Anja Van Campenhout, Friedl De Groote, Ilse Jonkers, Hans Kainz, Hoa Hoang, M.G.H. Wesseling, Sam Van Rossom, Eirini Papageorgiou, Lynn Bar-On, Ann Hallemans, Kaat desloovere

Physics-based simulations of walking have the theoretical potential to support clinical decision-making by predicting the functional outcome of treatments in terms of walking performance. Yet before using such simulations in clinical practice, their ability to identify the main t ...

Physics-based simulations of walking have the theoretical potential to support clinical decision-making by predicting the functional outcome of treatments in terms of walking performance. Yet before using such simulations in clinical practice, their ability to identify the main treatment targets in specific patients needs to be demonstrated. In this study, we generated predictive simulations of walking with a medical imaging based neuro-musculoskeletal model of a child with cerebral palsy presenting crouch gait. We explored the influence of altered muscle-tendon properties, reduced neuromuscular control complexity, and spasticity on gait dysfunction in terms of joint kinematics, kinetics, muscle activity, and metabolic cost of transport. We modeled altered muscle-tendon properties by personalizing Hill-type muscle-tendon parameters based on data collected during functional movements, simpler neuromuscular control by reducing the number of independent muscle synergies, and spasticity through delayed muscle activity feedback from muscle force and force rate. Our simulations revealed that, in the presence of aberrant musculoskeletal geometries, altered muscle-tendon properties rather than reduced neuromuscular control complexity and spasticity were the primary cause of the crouch gait pattern observed for this child, which is in agreement with the clinical examination. These results suggest that muscle-tendon properties should be the primary target of interventions aiming to restore an upright gait pattern for this child. This suggestion is in line with the gait analysis following muscle-tendon property and bone deformity corrections. Future work should extend this single case analysis to more patients in order to validate the ability of our physics-based simulations to capture the gait patterns of individual patients pre- and post-treatment. Such validation would open the door for identifying targeted treatment strategies with the aim of designing optimized interventions for neuro-musculoskeletal disorders.@en

O63: Medial gastrocnemius muscle in children with Spastic Paresis show growth defects for muscle volume and altered normalized muscle and tendon length compared to typically developed children

Abstract - Guido Weide, Guido Weide, Lynn Bar-On, Lynn Bar-On, Lizeth Sloot, Annemieke Buizer, Peter A.J.B.M. Huijing, J. Harlaar, J. Harlaar, Richard T. Jaspers

Typically, Spastic Paresis (SCP) causes morphological changes of m. gastrocnemius medialis (GM) that may change its mechanical characteristics. An enhanced resistance to dorsal flexion may in part be explained by such changes.@en

Effects of Botulinum Toxin-A and casting treatment on assessed spasticity, muscle morphology and gait kinematics in spastic paresis

Abstract - Guido Weide, Guido Weide, Lizeth Sloot, Laura Oudenhoven, Richard T. Jaspers, J. Harlaar, J. Harlaar, Annemieke Buizer, Lynn Bar-On, Lynn Bar-On

Spasticity as part of a central neurological disorder is characterized by a ‘velocity dependent hyperactive stretch-reflex’ [1]. Secondary, morphological adaptations of the muscle-tendon complex reduce the passive joint angle-moment relationship (i.e. passive ROM) [2]. Potentiall ...

Lynn Bar-On

Authored

Applying Stretch to Evoke Hyperreflexia in Spasticity Testing

Velocity vs. Acceleration

Comprehensive evaluation of gait, spasticity, and muscle morphology

A case report of a child with spastic paresis treated with Botulinum NeuroToxin-A, serial casting, and physiotherapy

Personalisation of Plantarflexor Musculotendon Model Parameters in Children with Cerebral Palsy

Electromyographic biofeedback-driven gaming to alter calf muscle activation during gait in children with spastic cerebral palsy

Spasticity assessment in cerebral palsy

Gastrocnemius Medialis Muscle Geometry and Extensibility in Typically Developing Children and Children With Spastic Paresis Aged 6–13 Years

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

SimCP: A simulation platform to predict gait performance following orthopedic intervention in children with cerebral palsy

Physics-Based Simulations to Predict the Differential Effects of Motor Control and Musculoskeletal Deficits on Gait Dysfunction in Cerebral Palsy: A Retrospective Case Study

O63: Medial gastrocnemius muscle in children with Spastic Paresis show growth defects for muscle volume and altered normalized muscle and tendon length compared to typically developed children

Effects of Botulinum Toxin-A and casting treatment on assessed spasticity, muscle morphology and gait kinematics in spastic paresis

Contributed

Calf muscle model parameters in children with cerebral palsy compared to typically developing children