A1 Journal article (refereed)
Revising the stretch reflex threshold method to measure stretch hyperreflexia in cerebral palsy (2022)

Valadão, P., Bar-On, L., Cenni, F., Piitulainen, H., Avela, J., & Finni, T. (2022). Revising the stretch reflex threshold method to measure stretch hyperreflexia in cerebral palsy. Frontiers in Bioengineering and Biotechnology, 10, Article 897852. https://doi.org/10.3389/fbioe.2022.897852

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Publication details

All authors or editorsValadão, Pedro; Bar-On, Lynn; Cenni, Francesco; Piitulainen, Harri; Avela, Janne; Finni, Taija

Journal or seriesFrontiers in Bioengineering and Biotechnology


Publication year2022

Publication date23/11/2022


Article number897852

PublisherFrontiers Media SA

Publication countrySwitzerland

Publication languageEnglish


Publication open accessOpenly available

Publication channel open accessOpen Access channel

Publication is parallel published (JYX)https://jyx.jyu.fi/handle/123456789/85120


Hyper-resistance is an increased resistance to passive muscle stretch, a common feature in neurological disorders. Stretch hyperreflexia, an exaggerated stretch reflex response, is the neural velocity-dependent component of hyper-resistance, and has been quantitatively measured using the stretch reflex threshold (i.e., joint angle at the stretch reflex electromyographic onset). In this study, we introduce a correction in how the stretch reflex threshold is calculated, by accounting for the stretch reflex latency (i.e., time between the stretch reflex onset at the muscle spindles and its appearance in the electromyographic signal). Furthermore, we evaluated how this correction affects the stretch reflex threshold in children and young adults with spastic cerebral palsy. A motor-driven ankle dynamometer induced passive ankle dorsiflexions at four incremental velocities in 13 children with cerebral palsy (mean age: 13.5 years, eight males). The stretch reflex threshold for soleus and medial gastrocnemius muscles was calculated as 1) the joint angle corresponding to the stretch reflex electromyographic onset (i.e., original method); and as 2) the joint angle corresponding to the electromyographic onset minus the individual Hoffmann-reflex latency (i.e., latency corrected method). The group linear regression slopes between stretch velocity and stretch reflex threshold differed in both muscles between methods (p < 0.05). While the original stretch reflex threshold was velocity dependent in both muscles (p < 0.05), the latency correction rendered it velocity independent. Thus, the effects of latency correction on the stretch reflex threshold are substantial, especially at higher stretch velocities, and should be considered in future studies.

Keywordscerebral palsyneuromuscular activityreflexesneurophysiologyelectromyography

Free keywordshyperreflexia; neurophysiology; stretch reflex; electromyography; cerebral palsy

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Ministry reportingYes

Reporting Year2022

JUFO rating1

Last updated on 2024-15-06 at 00:46