Daniel Simonsen

Effect of Early and Late Rehabilitation Onset in a Chronic Rat Model of Ischemic Stroke— Assessment of Motor Cortex Signaling and Gait Functionality Over Time

The aim of the present study was to investigate the effects of ischemic stroke and onset of subsequent rehabilitation of gait function in rats. Nine male Sprague-Dawley rats were instrumented with a 16-channel intracortical (IC) electrode array. An ischemic stroke was induced within the hindlimb area of the left motor cortex. The rehabilitation consisted of a repetitive training paradigm over 28 days, initiated on day one (“Early-onset”, 5 rats) and on day seven, (“Late-onset”, 4 rats). Data were obtained from IC microstimulation tests, treadmill walking tests, and beam walking tests. Results revealed an expansion of the hindlimb representation within the motor cortex area and an increased amount of cortical firing rate modulation for the “Early-onset” group but not for the “Late-onset” group. Kinematic data revealed a significant change for both intervention groups. However, this difference was larger for the “Early-onset” group. Results from the beam walking test showed functional performance deficits following stroke which returned to pre-stroke level after the rehabilitative training. The results from the present study indicate the existence of a critical time period following stroke where onset of rehabilitative training may be more effective and related to a higher degree of true recovery.

Validation and Test of a Closed-Loop Tele-rehabilitation System Based on Functional Electrical Stimulation and Computer Vision for Analysing Facial Expressions in Stroke Patients

The aim of the present study was to validate and test a closed-loop tele-rehabilitation system for training of hand function and analyzing facial expressions in stroke patients. The paper presents the methods for controlling functional electrical stimulation (FES) to assist hand opening and grasping. The main outcome of the FES control was time differences in grip detections performed by the automatic system and by analysis of the output from force sensing resistors. This time difference was in the range of 0 to 0.8 s. Results from analysis of facial expressions were very variable showing that subjects were disgusted, happy and angry during the exercises, which were not in agreement with the observations made during the experimental sessions.

Design and test of a Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during training of upper limb movement

The present paper describes the design and test of a low-cost Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during the execution of an upper limb exercise. Eleven sub-acute stroke patients with varying degrees of upper limb function were recruited. Each subject participated in a control session (repeated twice) and a feedback session (repeated twice). In each session, the subjects were presented with a rectangular pattern displayed on a vertical mounted monitor embedded in the table in front of the patient. The subjects were asked to move a marker inside the rectangular pattern by using their most affected hand. During the feedback session, the thickness of the rectangular pattern was changed according to the performance of the subject, and the color of the marker changed according to its position, thereby guiding the subject’s movements. In the control session, the thickness of the rectangular pattern and the color of the marker did not change. The results showed that the movement similarity and smoothness was higher in the feedback session than in the control session while the duration of the movement was longer. The present study showed that adaptive visual feedback delivered by use of the Kinect sensor can increase the similarity and smoothness of upper limb movement in stroke patients.

Kinect-based tele-rehabilitation system for hand function

In an ongoing study (part of a 3-year PhD project) conducted in collaboration with a Danish rehabilitation unit, a tele-rehabilitation system is being tested on stroke patients with hand function deficits, in order to validate the accuracy of the system and assess its functional value. Further development and testing of the tele-rehabilitation system will be accomplished.

Design and Test of a Closed-Loop FES System for Supporting Function of the Hemiparetic Hand Based on Automatic Detection Using the Microsoft Kinect Sensor

This paper describes the design of a FES system automatically controlled in a closed loop using a Microsoft Kinect sensor, for assisting both cylindrical grasping and hand opening. The feasibility of the system was evaluated in real-time in stroke patients with hand function deficits. A hand function exercise was designed in which the subjects performed an arm and hand exercise in sitting position. The subject had to grasp one of two differently sized cylindrical objects and move it forward or backwards in the sagittal plane. This exercise was performed with each cylinder with and without FES support. Results showed that the stroke patients were able to perform up to 29% more successful grasps when they were assisted by FES. Moreover, the hand grasp-and-hold and hold-and-release durations were shorter for the smaller of the two cylinders. FES was appropriately timed in more than 95% of all trials indicating successful closed loop FES control. Future studies should incorporate options for assisting forward reaching in order to target a larger group of stroke patients.

Tele-Rehabilitation of Upper Limb Function in Stroke Patients using Microsoft Kinect

Stroke is a major cause of death and disability worldwide. The damage or death of brain cells caused by a stroke affects brain function and leads to deficits in sensory and/or motor function. As a consequence, a stroke can have a significantly negative impact on the patient’s ability to perform activities of daily living and therefore also affect the patient’s quality of life. Stroke patients may regain function through intensive physical rehabilitation, but often they do not recover their original functional level. The incomplete recovery in some patients might be related to e.g. stroke severity, lack of motivation for training, or insufficient and/or non-optimal training in the initial weeks following the stroke.

Design and test of an automated version of the modified Jebsen test of hand function using Microsoft Kinect

BackgroundThe present paper describes the design and evaluation of an automated version of the Modified Jebsen Test of Hand Function (MJT) based on the Microsoft Kinect sensor.MethodsThe MJT was administered twice to 11 chronic stroke subjects with varying degrees of hand function deficits. The test times of the MJT were evaluated manually by a therapist using a stopwatch, and automatically using the Microsoft Kinect sensor. The ground truth times were assessed based on inspection of the video-recordings. The agreement between the methods was evaluated along with the test-retest performance.ResultsThe results from Bland-Altman analysis showed better agreement between the ground truth times and the automatic MJT time evaluations compared to the agreement between the ground truth times and the times estimated by the therapist. The results from the test-retest performance showed that the subjects significantly improved their performance in several subtests of the MJT, indicating a practice effect.ConclusionsThe results from the test showed that the Kinect can be used for automating the MJT.

Microsoft Kinect-based system for automatic evaluation of the Modified Jebsen Test of Hand Function

The design and test of a Microsoft Kinect-based system for automatic evaluation of the Modified Jebsen Test of Hand Function (MJT) is presented. The MJT was administered to 11 chronic stroke patients (both the dominant and non-dominant hand). MJT completion times were evaluated by a therapist using a stopwatch and automatically by use of the Kinect-based system. The ground truth times were assessed based on visual inspection of video-recordings. Analysis of the agreement between the MJT times estimated by the two methods generally showed better agreement between the ground truth times and the times estimated by the Kinect-based system compared to the agreement between the ground truth times and the times obtained by the therapist.