Reorganization of multi-muscle and joint withdrawal reflex during arm movements in post-stroke hemiparetic patients

Mariano Serrao, Alberto Ranavolo, Ole Kaeseler Andersen, Romildo Don, Francesco Draicchio, Carmela Conte, Roberto Di Fabio, Armando Perrotta, Michelangelo Bartolo, Luca Padua, Valter Santilli, Giorgio Sandrini, Francesco Pierelli

Research output: Contribution to journalArticlepeer-review


Objectives: To investigate the behavior of the nociceptive withdrawal reflex (NWR) in the upper limb during reaching and grasping movements in post-stroke hemiparetic patients. Methods: Eight patients with chronic stroke and moderate motor deficits were included. An optoelectronic motion analysis system integrated with a surface EMG machine was used to record the kinematic and EMG data. The NWR was evoked through a painful electrical stimulation of the index finger during a movement which consisted of reaching out, picking up a cylinder, and returning it to the starting position. Results: We found that: (i) the NWR is extensively rearranged in hemiparetic patients, who were found to present different kinematic and EMG reflex patterns with respect to controls; (ii) patients partially lose the ability to modulate the reflex in the different movement phases; (iii) the impairment of the reflex modulation occurs at single-muscle, single-joint and multi-joint level. Conclusions: Patients with chronic and mild-moderate post-stroke motor deficits lose the ability to modulate the NWR dynamically according to the movement variables at individual as well as at multi-muscle and joint levels. Significance: The central nervous system is unable to use the NWR substrate dynamically and flexibly in order to select the muscle synergies needed to govern the spatio-temporal interaction among joints.

Original languageEnglish
Pages (from-to)527-540
Number of pages14
JournalClinical Neurophysiology
Issue number3
Publication statusPublished - Mar 2012


  • Movement analysis
  • Spinal cord
  • Stroke
  • Withdrawal reflex

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Physiology (medical)
  • Sensory Systems


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