Evidence map›Paper›PMID 42012215›Full record

ArticleJournal of rehabilitation medicine2026

Beyond spasticity reduction: botulinum toxin-a injection is associated with changes in abnormal flexor synergies of the upper limb in chronic stroke.

Michiyuki Kawakami, Daisuke Ito, Ken Azuma, Takayuki Kamimoto, Arisa Kawabata, Tetsuya Tsuji

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Article in Journal of rehabilitation medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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2 · The registry

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3 · Its place in the literature

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No citing paper in PubMed yet.

4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Michiyuki Kawakami *Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan. michiyukikawakami@hotmail.com.
Daisuke Ito *Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.
Ken AzumaDepartment of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.
Takayuki KamimotoDepartment of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.
Arisa KawabataDepartment of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.
Tetsuya TsujiDepartment of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectiveThis study aimed to investigate the association between botulinum toxin type A treatment and changes in spasticity and abnormal flexor synergies in patients with chronic stroke. SUBJECTS: Twenty-eight patients with chronic stroke (mean age 56.5 years; mean time since onset 6.3 years) who received botulinum toxin type A injections into upper-arm flexor muscles (biceps brachii, brachialis, or brachioradialis) were enrolled.

methodsThis was a retrospective, single-centre cohort study. Assessments were performed before and approximately 2 months after injection. Primary outcomes were changes in spasticity measured by the Modified Ashworth Scale and the abnormal flexor synergy index based on kinematic analysis. Secondary outcomes included changes in voluntary shoulder flexion angle and subgroup analyses according to baseline upper extremity motor severity and responder/non-responder status based on changes in the Modified Ashworth Scale scores of the elbow flexors.

resultsGeneralized estimating equation analyses showed significant changes in Modified Ashworth Scale elbow flexor scores and the abnormal flexor synergy index after injection. In severity-stratified analyses, significant Time × Severity interactions were observed for Modified Ashworth Scale scores of the elbow and wrist flexors, whereas no significant interaction was found for the abnormal flexor synergy index. In responder/non-responder analyses, a significant Time × Responder-status interaction was observed for the abnormal flexor synergy index. Non-responders showed no significant changes in Modified Ashworth Scale scores or the abnormal flexor synergy index and showed reduced maximum voluntary shoulder flexion angle.

conclusionThis study suggests that botulinum toxin type A treatment was associated with changes in abnormal flexor synergies, in addition to reducing muscle tone. These findings highlight the value of incorporating kinematic assessments such as the abnormal flexor synergy index into the clinical evaluation of botulinum toxin treatment.

Indexed as

Botulinum Toxins, Type AMuscle SpasticityNeuromuscular AgentsStrokeUpper ExtremityAdultAgedChronic DiseaseFemaleHumansInjections, IntramuscularMaleMiddle AgedMuscle, SkeletalRange of Motion, ArticularRetrospective StudiesBotulinum Toxins, Type ANeuromuscular Agents

Identifiers

PMID42012215
PMCPMC13107393

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.