A Portable Biomedical Device for Post-Stroke Spasticity Assessment: Development and Preliminary Analysis

Spasticity is a common and disabling consequence of stroke, leading to impaired motor control and functional limitations. The Modified Ashworth Scale (MAS) is the most widely used clinical tool for assessing spasticity, although its subjectivity and inter-examiner variability limit measurement precision. This study aimed to conduct a preliminary evaluation of a portable, sensor-based biomedical device for assessing post-stroke spasticity by measuring resistance force and angular displacement during passive movement. Twenty-one individuals with chronic post-stroke hemiparesis were evaluated. MAS scoring and device measurements were performed simultaneously to ensure consistent biomechanical conditions and minimize variations in muscle tone or flexibility. The device recorded force and angular displacement during passive movements of the shoulder adductors, elbow flexors, and wrist flexors. Strong positive correlations with MAS scores were observed for the shoulder adductors (r = 0.79, p < 0.001) and elbow flexors (r = 0.80, p < 0.001), as well as a moderate but significant correlation for the wrist flexors (r = 0.47, p = 0.003). These findings indicate that the device reliably captures resistance patterns associated with increasing spasticity severity. It can be concluded the portable-sensor-based device is a valuable and potential adjunct tool into comparison to conventional assessments. As a preliminary validation study, the findings support the feasibility of the proposed device while indicating the need for future large-scale reliability analyses.