Assessments of upper extremity performance typically include qualitative rather than quantitative measures of functional ability. Kinematic analysis is an objective, discriminative measure that quantifies movement biomechanics; however, the use within the poststroke impaired upper extremity is not well established. The purpose of this study was to examine the reliability of upper extremity kinematics in 18 individuals with stroke and 9 healthy controls. Participants performed reaching and grasping tasks over 2 separate days and metrics included movement time, peak velocity, index of curvature, trunk displacement, maximum aperture, and percentage of the movement cycle where maximum aperture occurred. The results showed moderate to high intraclass correlation and low standard error of measurement values for most variables, demonstrating that kinematic analysis may be a feasible and useful tool to quantify upper extremity movement after stroke.

Background The objective of this study was to determine movement variability in the more-affected upper-extremity in chronic stroke survivors. We investigated two hypotheses: (1) individuals with stroke will have increased amount of variability and altered structure of variability in upper-extremity joint movement patterns as compared to age-matched controls; and (2) the degree of motor impairment and joint kinematics will be correlated with the temporal structure of variability. Methods Sixteen participants with chronic stroke and nine age-matched controls performed three trials of functional reach-to-grasp. The amount of variability was quantified by computing the standard deviation of shoulder, elbow, wrist and index finger flexion/extension joint angles. The temporal structure of variability was determined by calculating approximate entropy in shoulder, elbow, wrist and index finger flexion/extension joint angles. Findings Individuals with stroke demonstrated greater standard deviations and significantly reduced approximate entropy values as compared to controls. Furthermore, motor impairments and kinematics demonstrated moderate to strong correlations with temporal structure of variability. Interpretation Changes in the temporal structure of variability in upper-extremity joint angles suggest that movement patterns used by stroke survivors are less adaptable. This knowledge may yield additional insights into the impaired motor system and suggest better interventions that can enhance upper-extremity movement adaptability.

Study Design Quasi-experimental design Introduction Although the effectiveness of constraint induced movement therapy (CIMT) in upper extremity (UE) rehabilitation post stroke is well known, the efficacy of CIMT to enhance the temporal structure of variability in upper extremity movement is not known. Purpose The purpose of this study was to investigate whether CIMT could enhance temporal structure of variability in upper extremity movement in individuals with chronic stroke. Methods Six participants with chronic stroke underwent CIMT for 4 hours/day for 2 weeks. Participants performed three trials of functional reach-to-grasp before and after CIMT. Temporal structure of variability was determined by calculating approximate entropy (ApEn) in shoulder, elbow and wrist flexion/extension joint angles. Results ApEn increased post CIMT, however, statistical significance was not achieved (p > 0.0167). Conclusion Future studies with larger sample size are warranted to investigate the effect of CIMT upon temporal structure of variability in UE movement.

Temporal structure reveals the potential adaptive strategies employed during upper extremity movements. The authors compared the temporal structure of upper extremity joints under 3 different reaching conditions: preferred speed, fast speed, and reaching with rhythmic auditory cues in 10 individuals post-stroke. They also investigated the temporal structure of these 3 reaching conditions in 8 healthy controls to aid in the interpretation of the observed patterns in the poststroke cohort. Approximate entropy (ApEn) was used to measure the temporal structure of the upper extremity joints. ApEn was similar between conditions in controls. After stroke, ApEn was significantly higher for shoulder, elbow, and wrist both at fast speed and with rhythmic cues compared with preferred speed. ApEn at index finger was significantly higher only with rhythmic cues compared with preferred speed. The authors propose that practice reaching at faster speed and with rhythmic cues as a component of rehabilitation interventions may enhance adaptability after stroke. Keywords nonlinear; rhythm; stroke; temporal structure; upper extremity Stroke is the leading cause of adult-onset disability in the United States (American Heart Association, 2016). Up to 85% of individuals with stroke exhibit upper extremity (UE) paresis immediately poststroke (Kwakkel & Kollen, 2007;Kwakkel, Kollen, van der Grond, & Prevo, 2003;Olsen, 1990). Recent advances in our understanding of the principles of neuroplasticity provide motivation for development of interventions enhancing UE function in stroke survivors (Jang et al., 2003;Liepert, Graef, Uhde, Leidner, & Weiller, 2000; Correspondence address: Amit Sethi, Assistant Professor, Department of Occupational Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, 5019 Forbes Tower, Pittsburgh, PA 15260, USA. asethi@pitt.edu. HHS Public AccessAuthor manuscript J Mot Behav. Author manuscript; available in PMC 2018 January 01. Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript Sawaki et al., 2008;Wolf et al., 2006). Regrettably, despite advanced rehabilitation approaches, residual UE impairments still persist. Current clinical assessment tools do not sensitively quantify the underlying motor impairments, limiting the ability to detect clinically important change in response to rehabilitation interventions. Insights provided by contemporary analyses are needed to better detect motor impairments and develop potentially more targeted and effective rehabilitation interventions after stroke.While clinical and biomechanical (kinematic) assessments of UE movements are typically used to characterize motor impairments, measures that quantify movement variability offer a unique advantage to assess motor adaptability during performance of everyday tasks (Stergiou & Decker, 2011). However, these approaches have received less attention in clinical motor assessment and rehabilitation studies. Variability in reaching movements, which is characterized by the ability to u...