Validity of Robot-based Assessments of Upper Extremity Function

Objective To examine the validity of 5 robot-based assessments of arm motor function post-stroke. Design Cross sectional. Setting Outpatient clinical research center. Participants Volunteer sample of 40 participants, age \u3e18 years, 3-6 months post-stroke, with arm motor deficits that had plateaued. Intervention None. Main Outcome Measures Clinical standards included the Fugl-Meyer Arm Motor Scale (FMA), and 5 secondary motor outcomes: hand/wrist subsection of the FMA; Action Research Arm Test (ART); Box & Blocks test (B/B); hand subscale of Stroke Impact Scale-2 (SIS); and the Barthel Index (BI). Robot-based assessments included: wrist targeting; finger targeting; finger movement speed; reaction time; and a robotic version of the (B/B) test. Anatomical measures included percentage injury to the corticospinal tract (CST) and primary motor cortex (M1, hand region) obtained from MRI . Results Subjects had moderate-severe impairment (arm FMA scores = 35.6±14.4, range 13.5-60). Performance on the robot-based tests, including speed (r=0.82, p\u3c0.0001), wrist targeting (r=0.72, p\u3c0.0001), and finger targeting (r=0.67, p\u3c0.0001) correlated significantly with the FMA scores. Wrist targeting (r=0.57 - 0.82) and finger targeting (r=0.49 - 0.68) correlated significantly with all 5 secondary motor outcomes and with percent CST injury. The robotic version of the B/B correlated significantly with the clinical B/B test but was less prone to floor effect. Robot-based assessments were comparable to FMA score in relation to percent CST injury and superior in relation to M1 hand injury. Conclusions The current findings support using a battery of robot-based methods for assessing the upper extremity motor function in subjects with chronic stroke