The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy
Stretch reflex hyperactivity in the gastrocnemius of children with spastic cerebral palsy (CP) is commonly evaluated by passively rotating the ankle joint into dorsiflexion at different velocities, such as applied in conventional clinical spasticity assessments. However, surface electromyography (sE...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-10-01
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| Series: | Frontiers in Pediatrics |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fped.2018.00259/full |
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| author | Lynn Bar-On Lynn Bar-On Barbara M. Kalkman Francesco Cenni Simon-Henri Schless Guy Molenaers Constantinos N. Maganaris Alfie Bass Gill Holmes Gabor J. Barton Thomas D. O'Brien Kaat Desloovere |
| author_facet | Lynn Bar-On Lynn Bar-On Barbara M. Kalkman Francesco Cenni Simon-Henri Schless Guy Molenaers Constantinos N. Maganaris Alfie Bass Gill Holmes Gabor J. Barton Thomas D. O'Brien Kaat Desloovere |
| author_sort | Lynn Bar-On |
| collection | DOAJ |
| description | Stretch reflex hyperactivity in the gastrocnemius of children with spastic cerebral palsy (CP) is commonly evaluated by passively rotating the ankle joint into dorsiflexion at different velocities, such as applied in conventional clinical spasticity assessments. However, surface electromyography (sEMG) collected from the medial gastrocnemius (MG) during such examination reveals unexplained heterogeneity in muscle activation between patients. Recent literature also highlights altered muscle tensile behavior in children with spastic CP. We aimed to document MG muscle and tendon lengthening during passive ankle motion at slow and fast velocity and explore its interdependence with the elicited hyperactive stretch reflex. The ankle of 15 children with CP (11 ± 3 years, GMFCS 9I 6II, 8 bilateral, 7 unilateral) and 16 typically developing children (TDC) was passively rotated over its full range of motion at slow and fast velocity. Ultrasound, synchronized with motion-analysis, was used to track the movement of the MG muscle-tendon junction and extract the relative lengthening of muscle and tendon during joint rotation. Simultaneously, MG sEMG was measured. Outcome parameters included the angular and muscle lengthening velocities 30 ms before EMG onset and the gain in root mean square EMG during stretch, as a measure of stretch reflex activity. Compared to slow rotation, the muscle lengthened less and stretch reflex activity was higher during fast rotation. These velocity-induced changes were more marked in CP compared to TDC. In the CP group, muscle-lengthening velocity had higher correlation coefficients with stretch reflex hyperactivity than joint angular velocity. Muscles with greater relative muscle lengthening during slow rotation had earlier and stronger stretch reflexes during fast rotation. These initial results suggest that ankle angular velocity is not representative of MG muscle lengthening velocity and is less related to stretch reflex hyperactivity than MG muscle lengthening. In addition, muscles that lengthened more during slow joint rotation were more likely to show a velocity-dependent stretch reflex. This interdependence of muscle lengthening and stretch reflexes may be important to consider when administering treatment. However, muscle and tendon lengthening properties alone could not fully explain the variability in stretch reflexes, indicating that other factors should also be investigated. |
| first_indexed | 2024-12-17T01:51:20Z |
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| id | doaj.art-221b84ab0a0a4e489e26e55ebfde1a15 |
| institution | Directory Open Access Journal |
| issn | 2296-2360 |
| language | English |
| last_indexed | 2024-12-17T01:51:20Z |
| publishDate | 2018-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Pediatrics |
| spelling | doaj.art-221b84ab0a0a4e489e26e55ebfde1a152022-12-21T22:08:03ZengFrontiers Media S.A.Frontiers in Pediatrics2296-23602018-10-01610.3389/fped.2018.00259387398The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral PalsyLynn Bar-On0Lynn Bar-On1Barbara M. Kalkman2Francesco Cenni3Simon-Henri Schless4Guy Molenaers5Constantinos N. Maganaris6Alfie Bass7Gill Holmes8Gabor J. Barton9Thomas D. O'Brien10Kaat Desloovere11Department of Rehabilitation Sciences, KU Leuven, Leuven, BelgiumAmsterdam UMC, Vrije Universiteit Amsterdam, Department of Rehabilitation Medicine, Amsterdam Movement Sciences, Amsterdam, NetherlandsResearch Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United KingdomDepartment of Mechanical Engineering, KU Leuven, Leuven, BelgiumDepartment of Rehabilitation Sciences, KU Leuven, Leuven, BelgiumDepartment of Rehabilitation Sciences, KU Leuven, Leuven, BelgiumResearch Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United KingdomAlder Hey Children's NHS Foundation Trust, Liverpool, United KingdomAlder Hey Children's NHS Foundation Trust, Liverpool, United KingdomResearch Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United KingdomResearch Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United KingdomDepartment of Rehabilitation Sciences, KU Leuven, Leuven, BelgiumStretch reflex hyperactivity in the gastrocnemius of children with spastic cerebral palsy (CP) is commonly evaluated by passively rotating the ankle joint into dorsiflexion at different velocities, such as applied in conventional clinical spasticity assessments. However, surface electromyography (sEMG) collected from the medial gastrocnemius (MG) during such examination reveals unexplained heterogeneity in muscle activation between patients. Recent literature also highlights altered muscle tensile behavior in children with spastic CP. We aimed to document MG muscle and tendon lengthening during passive ankle motion at slow and fast velocity and explore its interdependence with the elicited hyperactive stretch reflex. The ankle of 15 children with CP (11 ± 3 years, GMFCS 9I 6II, 8 bilateral, 7 unilateral) and 16 typically developing children (TDC) was passively rotated over its full range of motion at slow and fast velocity. Ultrasound, synchronized with motion-analysis, was used to track the movement of the MG muscle-tendon junction and extract the relative lengthening of muscle and tendon during joint rotation. Simultaneously, MG sEMG was measured. Outcome parameters included the angular and muscle lengthening velocities 30 ms before EMG onset and the gain in root mean square EMG during stretch, as a measure of stretch reflex activity. Compared to slow rotation, the muscle lengthened less and stretch reflex activity was higher during fast rotation. These velocity-induced changes were more marked in CP compared to TDC. In the CP group, muscle-lengthening velocity had higher correlation coefficients with stretch reflex hyperactivity than joint angular velocity. Muscles with greater relative muscle lengthening during slow rotation had earlier and stronger stretch reflexes during fast rotation. These initial results suggest that ankle angular velocity is not representative of MG muscle lengthening velocity and is less related to stretch reflex hyperactivity than MG muscle lengthening. In addition, muscles that lengthened more during slow joint rotation were more likely to show a velocity-dependent stretch reflex. This interdependence of muscle lengthening and stretch reflexes may be important to consider when administering treatment. However, muscle and tendon lengthening properties alone could not fully explain the variability in stretch reflexes, indicating that other factors should also be investigated.https://www.frontiersin.org/article/10.3389/fped.2018.00259/fullcerebral palsystretch reflexesspasticitymuscle stiffnessdynamic ultrasoundEMG |
| spellingShingle | Lynn Bar-On Lynn Bar-On Barbara M. Kalkman Francesco Cenni Simon-Henri Schless Guy Molenaers Constantinos N. Maganaris Alfie Bass Gill Holmes Gabor J. Barton Thomas D. O'Brien Kaat Desloovere The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy Frontiers in Pediatrics cerebral palsy stretch reflexes spasticity muscle stiffness dynamic ultrasound EMG |
| title | The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy |
| title_full | The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy |
| title_fullStr | The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy |
| title_full_unstemmed | The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy |
| title_short | The Relationship Between Medial Gastrocnemius Lengthening Properties and Stretch Reflexes in Cerebral Palsy |
| title_sort | relationship between medial gastrocnemius lengthening properties and stretch reflexes in cerebral palsy |
| topic | cerebral palsy stretch reflexes spasticity muscle stiffness dynamic ultrasound EMG |
| url | https://www.frontiersin.org/article/10.3389/fped.2018.00259/full |
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