Circle drawing as evaluative movement task in stroke rehabilitation: an explorative study

<p>Abstract</p> <p>Background</p> <p>The majority of stroke survivors have to cope with deficits in arm function, which is often measured with subjective clinical scales. The objective of this study is to examine whether circle drawing metrics are suitable objective outcome measures for measuring upper extremity function of stroke survivors.</p> <p>Methods</p> <p>Stroke survivors (n = 16) and healthy subjects (n = 20) drew circles, as big and as round as possible, above a table top. Joint angles and positions were measured. Circle area and roundness were calculated, and synergistic movement patterns were identified based on simultaneous changes of the elevation angle and elbow angle.</p> <p>Results</p> <p>Stroke survivors had statistically significant lower values for circle area, roundness and joint excursions, compared to healthy subjects. Stroke survivors moved significantly more within synergistic movement patterns, compared to healthy subjects. Strong correlations between the proximal upper extremity part of the Fugl-Meyer scale and circle area, roundness, joint excursions and the use of synergistic movement patterns were found.</p> <p>Conclusions</p> <p>The present study showed statistically significant differences in circle area, roundness and the use of synergistic movement patterns between healthy subjects and stroke survivors. These circle metrics are strongly correlated to stroke severity, as indicated by the proximal upper extremity part of the FM score.</p> <p>In clinical practice, circle area and roundness can give useful objective information regarding arm function of stroke survivors. In a research setting, outcome measures addressing the occurrence of synergistic movement patterns can help to increase understanding of mechanisms involved in restoration of post stroke upper extremity function.</p

A reaching hand:towards an active therapeutic device for the upper extremity following stroke

The majority of stroke survivors have to cope with permanent disability and around 85 % of these people have deficits in arm- and hand function. After stroke, rehabilitation training is started to re-learn (partly) lost functions and to achieve the highest possible degree of physical and psychological performance. The repetitive nature of rehabilitation training has led to training devices such as robotics and electrical stimulators. The aim of this thesis is to contribute to the development of a therapeutic rehabilitation robot used in post stroke upper extremity rehabilitation training. The intended use of the robot is to train both arm and hand function by actively supporting the arm against gravity and support hand opening by means of multichannel functional electrical stimulation. To be able to support hand opening, differences and commonalities of muscle activation patterns of muscles involved in reaching and grasping, were studied in a group of stroke patients and healthy elderly. For this purpose, an autonomous EMG burst detector has been developed and applied to EMG data measured in both groups. In an explorative study, the instantaneous effect of arm support and electrical stimulation on a functional movement task was assessed. Stroke patients performed the Box and Block test while the arm was supported against gravity and opening of the hand was supported by electrical stimulation. In a longitudinal experiment, the effect of training in a gravity compensated environment on unsupported arm function was studied. Arm function was assessed before and after the 6 week training period. Arm function was assessed by a circle drawing tasks, a forward reaching task and by EMG obtained while performing these movement tasks. Answers on the research question presented and discussed in this thesis, contributed to the development of an Active Therapeutic Device, intended to train both the proximal and distal arm after stroke. The circle metrics and the method to autonomously detect bursts of EMG and generate muscle onset and offset profiles can be used to objectively quantify upper extremity function in stroke patients. It is expected that the algorihms used in the burst detector can be easily adapted to work in real-time to detect the intention of the user and control active assistive devices

Influence of gravity compensation training on synergistic movement patterns of the upper extremity after stroke, a pilot study

Abstract Background The majority of stroke patients have to cope with impaired arm function. Gravity compensation of the arm instantaneously affects abnormal synergistic movement patterns. The goal of the present study is to examine whether gravity compensated training improves unsupported arm function. Methods Seven chronic stroke patients received 18 half-hour sessions of gravity compensated reach training, in a period of six weeks. During training a motivating computer game was played. Before and after training arm function was assessed with the Fugl-Meyer assessment and a standardized, unsupported circle drawing task. Synergistic movement patterns were identified based on concurrent changes in shoulder elevation and elbow flexion/extension angles. Results Median increase of Fugl-Meyer scores was 3 points after training. The training led to significantly increased work area of the hemiparetic arm, as indicated by the normalized circle area. Roundness of the drawn circles and the occurrence of synergistic movement patterns remained similar after the training. Conclusions A decreased strength of involuntary coupling might contribute to the increased arm function after training. More research is needed to study working mechanisms involved in post stroke rehabilitation training. The used training setup is simple and affordable and is therefore suitable to use in clinical settings.</p

The MIRIAM Robot: A Novel Robotic System for MR-Guided Needle Insertion in the Prostate

Early prostate cancer detection and treatment are of major importance to reduce mortality rate. magnetic resonance (MR) imaging provides images of the prostate where an early stage lesion can be visualized. The use of robotic systems for MR-guided inter-ventions in the prostate allows us to improve the clinical outcomes of procedures such as biopsy and brachytherapy. This work presents a novel MR-conditional robot for prostate interventions. The minimally invasive robotics in an magnetic resonance imaging environment (MIRIAM) robot has 9 degrees-of-freedom (DoF) used to steer and fire a biopsy needle. The needle guide is positioned against the perineum by a 5 DoF parallel robot driven by piezoelectric motors. A 4 DoF needle driver inserts, rotates and fires the needle during the procedure. Piezoelectric motors are used to insert and rotate the needle, while pneumatic actuation is used to fire the needle. The MR-conditional design of the robot and the needle insertion controller are presented. MR compatibility tests using T2 imaging protocol are performed showing a SNR reduction of 25% when the robot is operational within the MR scanner. Experiments inserting a biopsy needle toward a physical target resulted in an average targeting error of 1.84 mm. Our study presents a novel MR-conditional robot and demonstrated the ability to perform MR-guided needle-based interventions in soft-tissue phantoms. Moreover, the image distortion analysis indicates that no visible image deterioration is induced by the robot