The effect of botulinum toxin-A on neural and non-neural components of wrist hyper-resistance in adults with stroke or cerebral palsy.
Aukje Andringa, Erwin van Wegen, Ingrid van de Port and 4 others
PMID 33811454WHAT IT FOUND
Botulinum toxin reduced the neural component of wrist stiffness in adults with stroke or cerebral palsy, but did not change non-neural tissue stiffness.
Clinical function scores showed minimal improvement, and the study lacked a control group.
Key findings
01The neural component of wrist hyper-resistance significantly decreased 6 and 12 weeks after botulinum toxin treatment, while the non-neural elastic and viscous components did not change significantly.
02There was no significant correlation between the reduction in neural resistance and improvements in clinical scales like the Modified Ashworth Scale or Fugl-Meyer Assessment.
03The study was a small, non-blinded pre-experimental cohort without a control group, limiting conclusions about efficacy.
STILL TO COME
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What it does not show
The study was a small, non-blinded pre-experimental cohort with no control group, making it impossible to determine if changes were due to the treatment or natural variation. The population had severe motor impairments, leading to floor effects on functional measures like the ARAT, which limits the ability to detect functional improvements. Most participants had received multiple previous botulinum toxin treatments, which may influence the response to the current injection compared to first-time users. The NeuroFlexor device requires at least 40 degrees of passive wrist extension, which excluded patients with severe contractures and may limit generalizability.
Declared interests
Funding was provided by the European Research Council, Ipsen Fund, and ZonMw. The authors reported no conflicts of interest.
The easy way to misread this
Do not conclude that botulinum toxin improves functional hand use based on this study. The neural component of stiffness decreased, but functional scores like the Action Research Arm Test showed no significant improvement, and the study lacked a control group to confirm that the observed changes were due to the treatment.