Robot-aided therapy on the upper limb of subacute and chronic stroke patients: A biomechanical approach

Abstract

The goal of this study is to propose a methodology for evaluating recovery mechanisms in subacute and chronic post-stroke patients after a robot-aided upper-limb therapy, using a set of biomechanical parameters. Fifty-six post-stroke subjects, thirteen subacute and forty-three chronic patients participated in the study. A 2 dof robotic system, implementing an "assist-as-needed" control strategy, was used. Biomechanical parameters related (i) to the speed measured at the robot's end-effector and (ii) to the movement's smoothness were computed. Outcome clinical measures show a decrease in motor impairment after the treatment both in chronic and subacute patients. All the biomechanical parameters show an improvement between admission and discharge. Our results show that the robot-aided training can contribute to reduce the motor impairment in both subacute and chronic patients and identify neurophysiological mechanisms underlying the different stages of motor recovery.

Assessment of upper limb movement with an autonomous robotic device in a school environment for children with Cerebral Palsy

“…Since this time several other devices have been developed, various control strategies have been devised and several evaluations and studies have been undertaken. This shows that robotic rehabilitation systems show merit and demonstrate effectiveness as an aid to therapy [7,8]. However, studies are ongoing to explore the full efficacy and usage of the systems.…”

Moving on: measuring movement remotely after stroke

“…This resulted in a value of 81.5 for the g parameter and 0.3157 for the peak location. The error between the new found profile and the normalized mean • Normalized reaching speed (NRS) (Mazzoleni et al, 2011):…”

“…A point-to-point reaching movement should have zero velocity both at the beginning and end of the movement, which implies that the mean acceleration over this movement must be zero. However, this was not the case in the referenced studies, suggesting that some aspect of its definition is missing (Mazzoleni et al, 2013(Mazzoleni et al, , 2011. According to the textual description, the metric definition is not face-valid, and it was therefore excluded (criterion E2).…”

“…Reaching Speed (NRS) is the ratio of the difference in peak and mean speed over the peak speed (Mazzoleni et al, 2011). As NRS = 1 -SM, it is a linear transform of the SM metric, and is expected to behave congruently.…”

“…Although a few studies employed additional criteria for peak detection (Casadio et al, 2009;Hussain et al, 2018), the choices for these criteria were not motivated, and they were not considered for the present study. The Acceleration Metric (AM) is the ratio between the mean acceleration and the peak acceleration (Mazzoleni et al, 2011). A point-to-point reaching movement should have zero velocity both at the beginning and end of the movement, which implies that the mean acceleration over this movement must be zero.…”