Mobile Game-based Virtual Reality Program for Upper Extremity Stroke Rehabilitation

Summary

Here, we present a protocol to develop and apply a mobile game-based virtual reality program for the recovery of upper limb dysfunction in patients with stroke. The present study shows that the mobile program is feasible and effectively promotes upper limb recovery in stroke patients.

Abstract

Stroke rehabilitation requires repetitive, intensive, goal-oriented therapy. Virtual reality (VR) has the potential to satisfy these requirements. Game-based therapy can promote patients' engagement in rehabilitation therapy as a more interesting and a motivating tool. Mobile devices such as smartphones and tablet PCs can provide personalized home-based therapy with interactive communication between patients and clinicians. In this study, a mobile VR upper extremity rehabilitation program using game applications was developed. The findings from the study show that the mobile game-based VR program effectively promotes upper extremity recovery in patients with stroke. In addition, patients completed two weeks of treatment using the program without adverse effects and were generally satisfied with the program. This mobile game-based VR upper extremity rehabilitation program can substitute for some parts of the conventional therapy that are delivered one-on-one by an occupational therapist. This time-efficient, easy to implement, and clinically effective program would be a good candidate tool for tele-rehabilitation for upper extremity recovery in patients with stroke. Patients and therapists can collaborate remotely through these e-health rehabilitation programs while reducing economic and social costs.

Introduction

Stroke is one of the most common causes of neurological impairment in adults. Recovery from impairment after a stroke is usually incomplete, and approximately 50% of patients are left with disabilities, making them dependent on others¹. In particular, upper limb dysfunction makes stroke survivors dependent on others for assistance with activities of daily living (ADL)². Regaining the lost function in the upper extremities may be more difficult to achieve than returning the normal function of ambulation to the lower extremities. Although bilateral lower extremity movement is indispensable for locomotion, patients can perform ADL with unilateral upper extremity movement. This leads to a learned non-use phenomenon of the affected limb³. This phenomenon is an obstacle to the rehabilitation of the upper extremity in stroke survivors. Therefore, a tremendous amount of research is focused on the upper limb function recovery. Studies have highlighted the importance of extensive practice and repetitive task-specific training^4,5,6.

Virtual reality (VR) technology has recently been introduced into the field of rehabilitation⁷. VR allows users to interact with a simulated environment and receive continuous, immediate feedback related to performance. VR has the potential to apply basic concepts of neurorehabilitation in stroke patients, such as intensive, repetitive, and task-oriented training⁸. Specifically, non-immersive VR does not require high-level graphics performance or special hardware. Therefore, non-immersive VR is a good candidate for providing a low-cost, ubiquitous, and interesting treatment program. Previous studies used computers, monitors, and special devices, such as consoles, sensor gloves, joy-sticks, and commercial gaming systems for non-immersive VR⁹. Higher start-up costs and sufficient space were mandatory for using such systems. Recently, low-cost tools, such as commercial gaming devices, have been utilized to develop new rehabilitation systems^10,11. However, the consoles with sensors in those devicesare not sufficiently small and lightweight for carrying. Nevertheless, to improve the popularity of non-immersive VR as a post-stroke upper extremity treatment method and to create a ubiquitous rehabilitation environment for stroke survivors, portable and inexpensive tools are needed.

Furthermore, game-based therapy can be a good option for stroke rehabilitation. Many patients complain that conventional occupational therapy (OT) for upper limb function recovery is boring and monotonous^12,13. A more interesting and motivating tool for the therapy is, therefore, necessary to promote patients' engagement in rehabilitation training. Many studies that involve the use of commercial games have been conducted^14,15,16. However, the games used do not target the desired movement of the upper extremity in patients with stroke, and they lack special consideration for the spasticity that may be present after a stroke.

This paper describes the development of a mobile game-based VR program and its use for patients who have experienced a stroke and suffer from upper limb dysfunction (Figure 1).

Protocol

The study was approved by the Seoul National University Bundang Hospital Institutional Review Board, and all participants gave written informed consent before screening.

1. Game Contents Development

NOTE: The mobile game-based upper extremity virtual reality program for patients with stroke (MoU-Rehab) consists of mobile game applications.

1. Install the studio and environment for development using a programing language.
2. Collect data on x, y and z-axis locations of patients' movements through the built-in sensors of the smartphone.
3. Allocate storage for data on the motion, location, and velocity with the following source code:
   float[ ] gravity_data = new float[3];
   float[ ] accel_data = new float[3];
   float[ ] m_acc_data = new float[3];
   final float alpha = (float)0.8;
   Gather data measured by the built-in sensor with the following source code.
   SensorManager sm = (SensorManager) getSystemService(SENSOR_SERVICE);
   Sensor mSensor = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
4. Send the data to the tablet PC after image processing through the short-distance wireless connection to display x, y, and z-coordinates as images on the screen.
5. Design all game applications to improve the strength, endurance, range of motion, control, speed, and accuracy of movement in the upper extremity.
   NOTE: Board-certified physiatrists (rehabilitation medicine doctors) and occupational therapists gathered and discussed what therapeutic maneuvers would be appropriate to transform into game programs. Movements in each joint was targeted based on the conventional occupational therapy methods that promote the recovery of upper limb function and improve the strength, endurance, range of motion, control, speed, and accuracy of movement in the upper extremity
6. Recommend game applications to each patient according to their upper extremity function measured by the Brunnström stage.
   NOTE: The Brunnström stage (B-stage) for the arm and hand evaluates the upper extremity recovery stages (1=flaccid, no voluntary movements; 7= normal function)¹⁶. For example, patients categorized as Brunnström stage 1 used applications that induce shoulder flexion/extension movements with the assistance of the unaffected arm. Patients categorized as Brunnström stage 5 used applications that require precise control of movements.
7. Adjust the level of difficulty of the game applications individually, by changing the speed, maintenance time for the specific posture, and range of motion according to the severity of the upper extremity dysfunction. Refer to the examples with detailed information as below (Figure 2).

2. Study Design

NOTE: A quasi-randomized, double-blind, controlled trial was conducted to evaluate the program's feasibility and effectiveness. Participants who (1) were diagnosed with ischemic stroke; (2) had the ability to follow a one-step command; (3) had the medical stability to participate in active rehabilitation, and (4) had upper extremity impairment, were included. Patients were excluded if they (1) had delirium, confusion, or other severe consciousness problems, (2) suffered from uncontrolled medical conditions, (3) were unable to follow commands because of severe cognitive impairment, (4) had a visual disturbance, and (5) had poor sitting balance. Participants were recruited at the university hospital.

1. To make the participants completely blinded to the group assignment, assign them to either control or experimental group by admission period because participants needed to share the OT room.
2. Ensure that the patients in the intervention group received 30 min of conventional OT and 30 min of the mobile game-based VR upper extremity rehabilitation program using a smartphone and a tablet PC.
3. Ensure that the patients in the control group received conventional OT alone for 1 h per day.
   NOTE: The rehabilitation program for both groups consisted of 10 sessions of therapy, 5 days per week, for 2 weeks.
4. Educate the patients in the intervention group on how to use the program in the first treatment session, although each game application provided brief instructions at the beginning. Ensure that the patients used the program for 30 min on their own during the study.
5. Assess the outcome measurements at the beginning, at the end of the treatment and at a one-month follow-up.
6. Let a single blinded evaluator who is an experienced occupational therapist perform all the clinical assessments during all the testing sessions.
   NOTE: The primary outcome measure was the Fugl-Meyer Assessment of the upper extremity (FMA-UE), which measures the motor function of the patients' hemiparetic arm (0 = lowest score; 66 = highest score).¹⁷ The secondary outcome was evaluated by the Brunnström stage (B-stage) for the arm and hand and manual muscle testing (0–5).

3. Usage of Mobile Game-based VR Upper Extremity Rehabilitation Program

1. Have the participant sit on the desk.
2. Place the tablet PC on the desk and turn the tablet PC on.
3. Turn the smartphone on and turn on the short-distance wireless connection on the smartphone.
4. Select the game application on the tablet PC by touching the screen of the tablet PC.
5. Enable short-distance wireless connection on the tablet PC and connect to the smartphone.
6. Put the smartphone in the armband and attach the armband to the upper arm or forearm using a commercially available smartphone armband according to the desired movement.
7. Choose either the basic version or the customized version.
8. Select the game speed, time, a number of target movements, and the expected achievement of the game on the touchscreen of the tablet PC on the customized version according to the participants’ ability.
9. Let the participant touch the start button. Ask the participant to take a posture following the commands of the game. Move the maximal range of motion for calibration.
10. Start playing the game and move to the next game when the game ends (generally 5–10 min long).
    1. "Honey Pot Guard" Game
       NOTE: This game targets the elbow flexion and extension motion.
       1. Ask the patients to beat a bear from the honey pot by throwing apples using the movement of the elbow joint.
       2. Let the patient throw apples when the flexed elbow is extended.
       3. Adjust the level of difficulty by the location where the bear appears and the speed at which a new bear appears based on the available range of motion and speed of the motion in the patient's elbow joint.
    2. "Protect the Bunny" Game
       NOTE: This game targets the shoulder abduction and adduction motion.
       1. Ask the patients to protect the bunny by catching stones with a net using the movement of the shoulder joint.
       2. Ensure that the net moves when the adducted shoulder is abducted.
       3. Adjust the level of difficulty by the location where the stone appears and the speed with which a new stone appears based on the available range of motion and speed of motion in the patient's shoulder joint.
    3. "Put out Fire" game
       NOTE: This game targets the shoulder abduction and adduction or shoulder flexion and extension.
       1. Ask the patients to put the fire out with the water hose through the window; the water hose is moved according to the motion of the shoulder.
       2. Ensure that the water hose moves right and left and up and down according to the motion of the shoulder joint; the time needed to put out the fire depends on the size of the fire.
       3. Adjust the level of difficulty by the location where the fire appears, the speed with which a new fire appears, and the size of the fire based on the available range of motion and the speed and endurance of motion of the patient’s shoulder joint.
    4. "Flower Splash" game
       NOTE: This game targets the shoulder abduction and adduction, elbow flexion and extension, or wrist pronation and supination motion.
       1. Ask the patients to water the moving seed with a watering can by the motion of the joint and make the flowers blossom.
       2. Ensure that when the seed moves, the watering follows according to the motion of the joint.
       3. Adjust the level of difficulty by the moving speed of the seed with respect to the accuracy and speed of motion.
11. Track the patients' upper extremity movements by the built-in sensors (accelerometer, gyroscope) of the smartphone, and transfer information about the movement to the tablet PC through the short-distance wireless connection.
12. Provide visual and auditory feedback for patients on their movement with the display on the tablet PC.
13. Demonstrate the real achievement of the game as compared with the expected achievement at the end of the game.

Results

A total of 24 patients were enrolled and assigned to either the control or the experimental group (Table 1). A greater improvement in the FMA-UE, B-stage, and manual muscle testing was found after treatment with the mobile game-based VR upper extremity rehabilitation program than with conventional therapy (Figure 3). The effect was maintained until the one-month follow-up. This means MoU-Rehab was not inferior to the conventional therapy that...

Discussion

Patients with stroke usually have disabilities related to motor impairments due to incomplete motor recovery. Such disabilities, lengthy travel time to a clinic, or socioeconomic difficulties can hinder patients' access to adequate rehabilitation therapy. A ubiquitous healthcare (u-Health) program can be a good option for removing those barriers. As a part of such a u-Health program, a mobile game-based VR rehabilitation program was developed for upper limb recovery after ischemic stroke in the present study. Our fin...

Materials

Name	Company	Catalog Number	Comments
Galaxy Note 10.0	Samsung	Galaxy Note 10.0	Tablet PC
Galaxy S2	Samsung	Galaxy S2	Smartphone
Bluetooth	Bluetooth SIG	Bluetooth	short-distance wireless connection
Java	Oracle	Java	programming language