Posts Tagged kinematic analysis
[ARTICLE] Effects of robot therapy on upper body kinematics and arm function in persons post stroke: a pilot randomized controlled trial – Full Text
Robot-based rehabilitation for persons post-stroke may improve arm function and daily-life activities as measured by clinical scales, but its effects on motor strategies during functional tasks are still poorly investigated. This study aimed at assessing the effects of robot-therapy versus arm-specific physiotherapy in persons post-stroke on motor strategies derived from upper body instrumented kinematic analysis, and on arm function measured by clinical scales.
Forty persons in the sub-acute and chronic stage post-stroke were recruited. This sample included all those subjects, enrolled in a larger bi-center study, who underwent instrumented kinematic analysis and who were randomized in Center 2 into Robot (R_Group) and Control Group (C_Group). R_Group received robot-assisted training. C_Group received arm-specific treatment delivered by a physiotherapist. Pre- and post-training assessment included clinical scales and instrumented kinematic analysis of arm and trunk during a virtual untrained task simulating the transport of an object onto a shelf. Instrumented outcomes included shoulder/elbow coordination, elbow extension and trunk sagittal compensation. Clinical outcomes included Fugl-Meyer Motor Assessment of Upper Extremity (FM-UE), modified Ashworth Scale (MAS) and Functional Independence Measure (FIM).
R_Group showed larger post-training improvements of shoulder/elbow coordination (Cohen’s d = − 0.81, p = 0.019), elbow extension (Cohen’s d = − 0.71, p = 0.038), and trunk movement (Cohen’s d = − 1.12, p = 0.002). Both groups showed comparable improvements in clinical scales, except proximal muscles MAS that decreased more in R_Group (Cohen’s d = − 0.83, p = 0.018). Ancillary analyses on chronic subjects confirmed these results and revealed larger improvements after robot-therapy in the proximal portion of FM-UE (Cohen’s d = 1.16, p = 0.019).
Robot-assisted rehabilitation was as effective as arm-specific physiotherapy in reducing arm impairment (FM-UE) in persons post-stroke, but it was more effective in improving motor control strategies adopted during an untrained task involving vertical movements not practiced during training. Specifically, robot therapy induced larger improvements of shoulder/elbow coordination and greater reduction of abnormal trunk sagittal movements. The beneficial effects of robot therapy seemed more pronounced in chronic subjects. Future studies on a larger sample should be performed to corroborate present findings.
Stroke is a primary cause of long-term disability worldwide  with nearly 1.1 million persons in Europe suffering a stroke each year . Importantly, this number is expected to increase to more than 1.5 million cases per year in 2025, mainly due to an aging population .
Approximately 70–85% of persons post-stroke present with impairment of an upper limb [4, 5] that persists even after 3–6 months from stroke , leading to a significant reduction of independence and quality of life . Consequently, improving upper limb functionality is a core element of stroke rehabilitation to reduce disability and increase the capacity to perform the activities of daily living (ADLs) . Different rehabilitative approaches have been proposed [9, 10], including constraint induced movement therapy , functional electrical stimulation [12, 13], virtual reality [14, 15] and robot therapy [16, 17]. Regarding the latter approach, two recent reviews [16, 17] indicated that robot-based rehabilitation is effective in improving ADLs, arm function and muscle strength in persons post-stroke. Previous studies suggested that the advantage of robotic devices, when compared with other physiotherapy approaches, may be the capability of these systems to provide rehabilitation paradigms enabling a strict application of some motor learning principles [18,19,20] indispensible to promote neural plasticity and reorganization [21,22,23]. In particular these principles include (1) the provision of highly intensive training involving a large number of goal-directed movements (e.g. center-out reaching of peripheral targets aimed at improving the coordination between shoulder and elbow) [21, 24], (2) the promotion of active participation by the person, also when severely impaired , and (3) the provision of real-time sensory feedback (visual and haptic) and quantitative summary feedback that can be used by the participant to correct his/her movement [14, 26]. Importantly, as previously discussed [27, 28], further investigation is needed to evaluate if the application of these motor learning principles can enhance the transfer of the rehabilitation effects also to non-trained tasks and contexts typical of ADLs.
The effects of motor rehabilitation on upper limb function are commonly assessed with clinical scales  that are mainly focused on task accomplishment, but do not give quantitative, objective and sensitive information on underlying changes in neuromotor control strategies involving inter-joint coordination and/or compensatory movements [30,31,32,33]. As discussed by Levin et al. , the main goal of motor rehabilitation is to lead the person to accomplish a task. However, also the assessment of how the task is performed is of paramount importance to evaluate whether the person has regain the ability to execute the task with a more physiological upper limb motor pattern (recovery), or he/she has developed compensatory strategies, such as abnormal trunk rotations (compensation) [30, 31, 34,35,36,37]. Instrumented motion analysis may provide this information and complement clinical assessment [31,32,33, 38, 39].
Instrumented analysis is usually performed using quantitative robot-based indexes describing a number of trained and non-trained tasks [28, 40,41,42,43,44]. As summarized in a review by Nordin et al. , the most common robot-based parameters describing upper limb movement and sensation include the amplitude of robot-generated forces [40, 41], temporal and speed metrics [40, 43, 44, 46, 47], response latency [46, 47], accuracy indexes [40, 43, 44, 46, 47], path length and range of motion [41, 42, 46, 47], and movement smoothness [40,41,42,43,44, 46, 47]. The test-retest reliability, the discriminant ability and the concurrent validity of these robot-based indexes have been analyzed in a large number of studies. Among these studies, those including the largest samples of persons post-stroke [41, 46,47,48,49] found good to excellent reliability [41, 48], good discriminant ability [41, 47], and moderate to high concurrent validity with clinical scales [41, 46, 47, 49]. The main advantage of the robot-based indexes is that they can be easily obtained during the course of the robotic training, thus providing indications about the gradual progression of the participants’ performance . By contrast, the main drawback is that these parameters mainly describe the trajectory of the end-effector during planar tasks executed within the robot workspace that is different from the typical daily living contexts.
This drawback may be partly overcome by using more sophisticated kinematic analysis techniques [32, 33, 38, 51,52,53,54,55,56,57] aimed at characterizing the execution of more ecological activities performed outside the robot workspace, including pointing tasks [34, 37] or reaching forward and touching real objects placed on a table, such as boxes [54, 55], cups , glasses [32, 33, 57], discs , cones  and desk bells [52, 53, 56]. Compared to the robot-based indexes, these analyses may provide a more detailed characterization of the different components of a task (e.g. upper limb and trunk movements), thus adding information about the way a task is performed before and after a rehabilitation treatment. This, in turn, may help in assessing the effects of such treatment in terms of neuromotor recovery and/or compensation [30, 34, 37, 50]. However, with the exception of Cirstea and Levin  who described trunk and arm motion during a 3D pointing tasks, all the above mentioned studies analyzed activities that mainly involved movements in the horizontal plane, with a minimal vertical component against gravity that is, however, a fundamental aspect of ADLs.
Following these considerations, this pilot study had two aims. The first aim was to assess the effects of planar robotic rehabilitation versus arm-specific physiotherapy in persons post-stroke on motor strategies derived from instrumented kinematic analysis of upper limb and trunk during the execution of a non-trained task involving horizontal and vertical arm movements. The second aim was to compare the effects of the two rehabilitation approaches on arm function as measured by clinical scales. We hypothesized that robot therapy provides larger improvements in the coordination between shoulder and elbow joints and in upper limb impairment, since it enables a rigorous application of the motor learning principles described above, in particular administration of high intensity goal-directed training, promotion of active participation, and provision of feedback.
[Abstract] Development of an active and passive finger rehabilitation robot using pneumatic muscle and magnetorheological damper
An FRR is developed for active and passive training using two PMs and an MR damper.
An underactuated mechanism is proposed for independent training of all finger joints.
Modelling of kinematics, statics and dynamics of the FRR is presented.
The motion and force properties of the FRR are experimentally evaluated.
This paper presents the development of a finger rehabilitation robot (FRR) for active and passive training to fulfill the requirements of different rehabilitation stages. In the design, an antagonistic pair of pneumatic muscles (PMs) are utilized to exert a bidirectional force for passive training, and a controllable magnetorheological (MR) damper is used to provide a damping force for active training. In this paper, first, a detailed illustration of the mechanical design of the FRR, including the driving, transmission and actuating mechanisms, and the damping device, is presented. Subsequently, the kinematic analysis and simulation are described, followed by the static and dynamic analysis of the designed FRR. This paper details the static force transfer of the transmission mechanism, and the establishment of dynamic equations for the passive training system. Finally, an experimental set-up is established, and several passive and active training experiments are conducted for the performance evaluation of the FRR prototype. The results validate the feasibility and stability of the developed FRR.
- •Considerable map plasticity occurs spontaneously after an ischemic injury to the motor cortex.
- •Physical rehabilitation impacts on spontaneous neuroplasticity and triggers restoration of function.
- •It is critical to distinguish “true” recovery (i.e. re-establishment of original movement patterns) from compensation.
- •Motor recovery can be boosted by a combination of rehabilitation and plasticizing drugs.
Ischemic injuries within the motor cortex result in functional deficits that may profoundly impact activities of daily living in patients. Current rehabilitation protocols achieve only limited recovery of motor abilities. The brain reorganizes spontaneously after injury, and it is believed that appropriately boosting these neuroplastic processes may restore function via recruitment of spared areas and pathways.
Here I review studies on circuit reorganization, neuronal and glial plasticity and axonal sprouting following ischemic damage to the forelimb motor cortex, with a particular focus on rodent models. I discuss evidence pointing to compensatory take-over of lost functions by adjacent peri-lesional areas and the role of the contralesional hemisphere in recovery. One key issue is the need to distinguish “true” recovery (i.e. re-establishment of original movement patterns) from compensation in the assessment of post-stroke functional gains. I also consider the effects of physical rehabilitation, including robot-assisted therapy, and the potential mechanisms by which motor training induces recovery.
Finally, I describe experimental approaches in which training is coupled with delivery of plasticizing drugs that render the remaining, undamaged pathways more sensitive to experience-dependent modifications. These combinatorial strategies hold promise for the definition of more effective rehabilitation paradigms that can be translated into clinical practice.
[ARTICLE] Experiments and kinematics analysis of a hand rehabilitation exoskeleton with circuitous joints – OPEN ACCESS
Aiming at the hand rehabilitation of stroke patients, a wearable hand exoskeleton with circuitous joint is proposed. The circuitous joint adopts the symmetric pinion and rack mechanism (SPRM) with the parallel mechanism. The exoskeleton finger is a serial mechanism composed of three closed-chain SPRM joints in series. The kinematic equations of the open chain of the finger and the closed chains of the SPRM joints were built to analyze the kinematics of the hand rehabilitation exoskeleton.
The experimental setup of the hand rehabilitation exoskeleton was built and the continuous passive motion (CPM) rehabilitation experiment and the test of human-robot interaction force measurement were conducted. Experiment results show that the mechanical design of the hand rehabilitation robot is reasonable and that the kinematic analysis is correct, thus the exoskeleton can be used for the hand rehabilitation of stroke patients.