Reliability and sensitivity of a wrist rig to measure motor control and spasticity in poststroke hemiplegia.
BACKGROUND
Objective assessment of impairments after stroke is vital for evidence-based therapy and progress monitoring.


OBJECTIVE
This study determines the utility of outcome measures obtained from an instrumented wrist rig for future rehabilitation trials. The tests undertaken were evaluated in terms of sensitivity to detect differences between normal and impaired participants, test-retest repeatability (repeatability coefficient and intraclass correlation coefficient [ICC]), and interrater agreement (Bland and Altman limits of agreement).


METHODS
Twelve participants with chronic poststroke hemiparesis (mean 5.6 years); and 12 unimpaired volunteers performed a series of tasks in the rig. The hemiparetic arm (impaired group) and dominant arm (unimpaired group) were tested in 3 sessions on the same day by 2 assessors. Signals were analyzed to derive a tracking index (motor control), stretch index (spasticity), flexor modulation index (FMI) (muscle activation), force angle index (FAI) (stiffness), range of movement, and isometric force.


CONCLUSIONS
The means of all tests differed between impaired and unimpaired participants except for range of movement into flexion, the FAI, and the FMI. Repeatability coefficients for each test are presented as benchmark values for use in future trials in which the wrist rig tests may be used to detect change. Test-retest reliability was excellent in the impaired group (ICC = 0.88-0.98) and poor to excellent in the unimpaired group (ICC = 0.06-0.89). The Bland-Altman ranges showed no bias between assessors, and that the interassessor variability was similar to that between repeats by the same assessor for most tests.
Turk
Ruth
R
School of Health Professions and Rehabilitation Sciences, University of Southampton, Southampton, UK. r.turk@soton.ac.uk
Notley
Scott V
SV
Pickering
Ruth M
RM
Simpson
David M
DM
Wright
Philip A
PA
Burridge
Jane H
JH
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004185:Disability Evaluation; D005260:Female; D006429:Hemiplegia / Q000209:etiology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D009119:Muscle Contraction / Q000502:physiology; D009128:Muscle Spasticity / Q000209:etiology / Q000534:rehabilitation*; D017063:Outcome Assessment, Health Care; D011434:Proprioception; D011597:Psychomotor Performance / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012026:Reflex, Stretch / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000150:complications; D000071939:Stroke Rehabilitation; D014953:Wrist / Q000294:innervation*