The effect of spasticity on cortical somatosensory-evoked potentials: changes of cortical somatosensory-evoked potentials after botulinum toxin type A injection

Arch Phys Med Rehabil. 2002 Nov;83(11):1592-6. doi: 10.1053/apmr.2002.34623.


Objective: To evaluate the changes in cortical somatosensory-evoked potentials (SEPs) after botulinum toxin type A injection to determine what effect spasticity has on cortical SEPs.

Design: Intervention study and before-after trial.

Setting: University-affiliated hospital in Korea.

Participants: Twelve children with spastic hemiplegic cerebral palsy (CP), 7 children with spastic diplegic CP, and 8 patients with traumatic brain injury.

Intervention: All participants had botulinum toxin type A injected into the muscles of the spastic limb.

Main outcome measures: SEPs were recorded before and 7 days after the botulinum toxin type A injection. Spasticity of the affected spastic limb was also measured. The short latency and amplitude of waves in SEPs were measured. The SEP results were divided into 3 groups: flat (no evoked potential), abnormal (evoked but delayed in latency), and normal (clear waveform with normal latency).

Results: The normal response of cortical SEP increased after injection. The SEPs exhibited more frequent improvement in the limbs, with greater improvement of spasticity in grade (>1.0 grade) and in patients of younger age (<3y) after injection (P<.05).

Conclusion: The observed improvement of cortical SEPs with associated reduction of spasticity that occurred after the botulinum toxin type A injection indicates that spasticity itself can be considered a factor affecting cortical SEPs.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Botulinum Toxins, Type A / pharmacology
  • Botulinum Toxins, Type A / therapeutic use*
  • Brain Injuries / complications*
  • Cerebral Palsy / complications*
  • Child
  • Child, Preschool
  • Electric Stimulation
  • Evoked Potentials, Somatosensory / drug effects*
  • Female
  • Hemiplegia / complications*
  • Humans
  • Infant
  • Injections, Intramuscular
  • Magnetic Resonance Imaging
  • Male
  • Muscle Spasticity / classification
  • Muscle Spasticity / diagnosis
  • Muscle Spasticity / drug therapy*
  • Muscle Spasticity / etiology
  • Neuromuscular Agents / pharmacology
  • Neuromuscular Agents / therapeutic use*
  • Reaction Time / drug effects
  • Severity of Illness Index
  • Treatment Outcome


  • Neuromuscular Agents
  • Botulinum Toxins, Type A