Development and validation of the first robotic scale for the clinical assessment of upper extremity motor impairments in stroke patients

Purpose: We aimed to develop and validate the first robotic-based instrument and procedure for assessing upper extremity motor impairments in patients with stroke and to test its discriminative power. Methods: The ReoGo robotic rehabilitation platform was used to design a novel, upper limb functionality assessment tool, the Reo Scale Assessment (RSA). We used the RSA to evaluate 100 patients with stroke. The RSA items were tested for internal consistency and submitted to factor analysis. The Fugl-Meyer (FM) motor test, the Wolf Motor Function Test (WMFT), and the Action Research Arm Test (ARAT) were used to examine the validity of the RSA. RSA scores were compared and correlated with the scores of the 3 scales. The discriminative power of the RSA was tested against the FM impairment levels by analysis of variance. Results: The total RSA score correlated closely with the upper extremity scores of the FM, WMFT, and ARAT (r = 0.95, 0.93, and 0.90, respectively). The RSA was able to discriminate between low, moderate, and high functioning patients (86% agreement with FM). Principal component analysis revealed that the RSA coefficients loaded on 3 tested components: proximal, distal, and force. Conclusions: Our results provide strong evidence that the validity of the RSA is comparable with that of the FM, WMFT, and ARAT. The objective measuring and scoring systems of the robotic RSA make it an efficient tool for assessing motor function of stroke patients in clinical and research settings. Additional studies are needed to test the reliability and sensitivity of the RSA.