Background: We aimed to validate three widely used scales in stroke research in a multiethnic Brazilian population. Methods: The National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS) and Barthel Index (BI) were translated, culturally adapted and applied by two independent investigators. The mRS was applied with or without a previously validated structured interview. Interobserver agreement (kappa statistics) and intraclass correlation coefficients were calculated. Results: 84 patients underwent mRS (56 with and 28 without a structured interview), 57 BI and 62 NIHSS scoring. Intraclass correlation coefficient was 0.902 for NIHSS and 0.967 for BI. For BI, interobserver agreement was good (kappa = 0.70). For mRS, the structured interview improved interobserver agreement (kappa = 0.34 without a structured interview; 0.75 with a structured interview). Conclusion: The NIHSS, BI and mRS show good validity when translated and culturally adapted. Using a structured interview for the mRS improves interobserver concordance rates.

Objective: To validate a quality of life scale, EuroQoL, on stroke patients. Method: 67 patients were scored simultaneously for EuroQoL-5 Dimensions (EQ-5D), NIH Stroke Scale (NIHSS) and modified Barthel Index (mBI). Pearson test was used to correlate each scale. Additionally, 31 patients were examined by two independent evaluators on the same day through application of EQ-5D. Kappa statistics were used to evaluate interobserver agreement. Results: EQ-5D showed good correlation with both stroke severity (NIHSS, r= -0.404, P<0.001) and degree of impairment on activities of daily living (mBI, r=0.512, P<0.001). We noticed a good interobserver agreement (k>0.60) in all dimensions evaluated (P<0.01). Conclusion: We demonstrated that EQ-5D is reproducible and valid on evaluation of quality of life in patients post stroke in Brazil.

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The hand trajectory of motion during the performance of one-dimensional point-to-point movements has been shown to be marked by motor primitives with a bell-shaped velocity profile. Researchers have investigated if motor primitives with the same shape mark also complex upper-limb movements. They have done so by analyzing the magnitude of the hand trajectory velocity vector. This approach has failed to identify motor primitives with a bell-shaped velocity profile as the basic elements underlying the generation of complex upper-limb movements. In this study, we examined upper-limb movements by analyzing instead the movement components defined according to a Cartesian coordinate system with axes oriented in the medio-lateral, antero-posterior, and vertical directions. To our surprise, we found out that a broad set of complex upper-limb movements can be modeled as a combination of motor primitives with a bell-shaped velocity profile defined according to the axes of the above-defined coordinate system. Most notably, we discovered that these motor primitives scale with the size of movement according to a power law. These results provide a novel key to the interpretation of brain and muscle synergy studies suggesting that human subjects use a scale-invariant encoding of movement patterns when performing upper-limb movements.