title: Reorganization of multi-muscle and joint withdrawal reflex during arm movements in post-stroke hemiparetic patients.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: University of Rome La Sapienza, Polo Pontino, Latina, Italy. mariano.serrao@uniroma1.it
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.forename: Alberto
authors.initials: A
authors.lastname: Ranavolo
authors.forename: Ole Kaeseler
authors.initials: OK
authors.lastname: Andersen
authors.forename: Romildo
authors.initials: R
authors.lastname: Don
authors.forename: Francesco
authors.initials: F
authors.lastname: Draicchio
authors.forename: Carmela
authors.initials: C
authors.lastname: Conte
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Fabio
authors.forename: Armando
authors.initials: A
authors.lastname: Perrotta
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Bartolo
authors.forename: Luca
authors.initials: L
authors.lastname: Padua
authors.forename: Valter
authors.initials: V
authors.lastname: Santilli
authors.forename: Giorgio
authors.initials: G
authors.lastname: Sandrini
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
mesh_terms: D001132:Arm / Q000294:innervation*; D001696:Biomechanical Phenomena / Q000502:physiology; D004525:Efferent Pathways / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007596:Joints / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology; D010291:Paresis / Q000209:etiology / Q000503:physiopathology*; D012018:Reflex / Q000502:physiology*; D020521:Stroke / Q000150:complications*; D013647:Task Performance and Analysis