title: Upper-extremity H-reflex measurement post-stroke: reliability and inter-limb differences.
abstract: OBJECTIVE
  To establish test-retest reliability of flexor carpi radialis (FCR) H-reflexes in non-disabled and stroke participants. We also investigated inter-limb differences and effects of chronicity post-stroke compared to non-disabled group and age-related effects in the non-disabled group.
  
  
  METHODS
  Sixteen chronic stroke and twenty-two non-disabled participants were recruited. Bilateral FCR H-reflexes were tested on two separate days by stimulating the median nerve and recording surface electromyography responses. FCR recruitment curves were plotted for H-reflex (H) and motor (M) waves and normalized as a percentage of maximal M-wave (ordinate) and motor threshold (abscissa).
  
  
  METHODS
  Intraclass correlation coefficients [two-way mixed model-ICC (1, 2)], one-way ANOVA, Bland-Altman plots, standard error of measurement (SEM), and smallest real difference (SRD).
  
  
  RESULTS
  ICCs ranged from 0.55 to 0.95 (stroke) and 0.69-0.88 (non-disabled). SEM% (% of the mean) ranged from 9% to 24% (stroke) and 18-38% (non-disabled); SRD% ranged from 18% to 66% (stroke) and 6% to 50% (non-disabled). H-reflex amplitude and slope were greater in the paretic vs. non-paretic arm post-stroke (p=0.07 and 0.01, respectively) and the paretic arm vs. non-disabled participants (p=0.007 and 0.002, respectively). Stroke participants with longer chronicity (mean 9.4 years) revealed a significantly greater Hslp/Mslp on the paretic side compared to shorter chronicity (2.5 years; p=0.05). Mean Hslp/Mslp was significantly greater in the young (mean 29 years) compared to the older group (62 years; p=0.045).
  
  
  CONCLUSIONS
  These results establish reliability of FCR H-reflexes in stroke and non-disabled participants. SEM and SRD measurements can be used to interpret recovery patterns and longitudinal effects of therapeutic interventions.
  
  
  CONCLUSIONS
  FCR H-reflex amplitude and slope can be reliably measured and used to investigate neurophysiological mechanisms of motor recovery post-stroke.
authors.affiliation: Neural Control of Movement Laboratory - Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, Gainesville, FL 32608, USA.
authors.forename: Chetan P
authors.initials: CP
authors.lastname: Phadke
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Robertson
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Condliffe
authors.forename: Carolynn
authors.initials: C
authors.lastname: Patten
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001132:Arm / Q000502:physiology*; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015203:Reproducibility of Results; D020521:Stroke / Q000503:physiopathology*