Natural Interface Game
Designing natural user interface games for stroke rehabilitation
Stroke rehabilitation necessitates repetitive physical exercises to regain functionality in affected limbs. Games are vital in this process, as they keep patients engaged in hard-to-perform exercises. However, existing games typically require users to hold controllers or wear specialized equipment, while hands are often last to recover. These controllers cause discomfort and are found to demotivate the users.
Therefore, the goal of this project was to design a Natural User Interface (NUI) game to support rehabilitation exercises while eliminating the need for handling devices.
Unity, kinect 360
Design of the game prototype
User testing and analysis
8 weeks (June - July 2019)
Team of two
To truly grasp the essence of rehabilitation exercises and uncover the pain points associated with the current methods, we visited two rehabilitation centers. Through field studies, we observed and interviewed stroke victims, to empathize and understand their needs, mindset, and constraints. We also talked to the doctors to gain their perspective on the pain points.
What are the pain points in current methods of performing rehabilitation exercises?
Not interesting to everyone
Existing games were unable to connect with individuals from diverse age groups. Particularly the elder population lacked motivation towards themes that captivated children.
Lack of continued motivation
Users easily become demotivated due to the physical strain associated with the exercises. A continuous need for motivation was recognized to support users in executing challenging limb movements.
What are the key characteristics needed in rehabilitation games?
Gameplay movements must accurately correspond to the required exercises and postures for rehabilitation. This entails focusing on specific movements such as moving elbow or shoulder in vertical and horizontal directions.
Low cognitive load
The game should be designed to impose a low cognitive load on the users, taking into consideration their current mental state. Game's tasks and interactions should be simple and easy to understand, minimizing mental effort or strain.
How Might We Design a More Ideal Game?
How might we make the game play appealing to users of varied age groups?
How might we enable appropriate movements for the rehabilitation needs without handling controllers ?
How might we perpetuate motivation throughout the game?
A pilgrimage experience to famous temples in India, a culturally motivating theme
In addition to motivation, it brings a form of hope and support
The majority of the users trust in God and hope to visit places of worship
A grid-based item collection
The vertical and horizontal movement of elbow or shoulder
Navigate in horizontal or vertical directions over the grid to collect items
For instance, a horizontal motion is achieved by collecting items from a single row with other rows frozen. Similarly, for vertical motion items are collected from a single column
To advance the level, the user can choose to collect from any grid
Set hierarchical goals
The user gets easily demotivated as the exercise is physically straining
Low - Collect appropriate items to fill the health bar -> unlocks a temple
Middle - Visit a temple -> see a replica of the real diety
High - Repeat to visit all the temples
Immediate visual feedback upon item collection. Colour based on right or wrong object
Wide spacing between the grids to allow enough hand movement
A white handball to indicate the current hand position
Hold the hand for 2 seconds at a single grid to collect an item - improve hand stability
Alternate colored grids for easy differentiation - reduces visual strain
User testing - Iteration I
We demonstrated the game to the head physician at a rehabilitation center and conducted user studies with two stroke victims. Participants were asked to visit a single temple by completing the following tasks.
Collect items to fill the health bar
Unlock a temple and walk inside to worship the Idol
Need for furhter simplification of gameplay.
Initially, the grid consisted of three different types of items. Health items to increase health points, prayer items for bonus points and restricted items to decrease health points. However, it was observed that the user needs high concentration to perform the physical movement and more item categories induced difficulty rather than encouragment.
Solution: Removed Prayer items. Items are only of two types, appropriate for worship or not. Simplicity is priority.
Repositioning the grid to accomodate movement for both the hands.
Users have motor impairment on left or right sides. Since the perpendicular hand position (start point) is calibrated to last column of the grid, it faltered the left hand movement and required the user to move from side to side.
Solution: The start position has been aligned with centre of the grid, with two columns of matrix to right and two to the left allowing similar movement for both the hands from a static position. This also ensures that the user has elbow movement in both the directions.
Facilitate gradual improvement by allowing increase of range.
To encourage users to increase their range of hand movement during the game, an option was added to increase or decrease the maximum width and height recorded during calibration through the keyborad.
Logging the user performance to monitor.
The data of patient’s performance such as maximum range of hand movement in horizontal and vertical directions, time taken to fill health bar and the mode played are automatically stored into an excel sheet for the doctor's analysis.
User testing - Iteration II
After implementing all the improvements from first iteration we re-conducted the usability testing for the first part of the game. The participant details along with their performance data were recorded.
Task: Collect relevant items to fill the health bar
The participants were comfortable with the gameplay. They stated that the game was involving and were willing to replay.
It was observed that the users needed more time to interpret and move from one grid to another. Thus the duration of an item in a grid was increased from 6 seconds to 15 seconds.
The users mentioned that they preferred some form of hand support(for instance a table) for a longer duration of play to avoid the possibility of pain in the shoulder.
The physical movement required for controls in the game has a vital role in determining user's interest.
A gameplay with a realistic scenario, made it relatable and appealing to the users.
Obtaining a credit(collect an item -> health points) with small movement of hand(from one grid to another) kept the user engaged throughout.
Some rehabilitation centers would need additional arrangements to facilitate the game setup due to hardware or space constraints. In the physician's words, "If more similar games were developed, it would encourage rehabilitation centers to buy them as a package"
Scope to improve design for hand movement
As I understand the importance of the design process in ideating good designs, reflecting back on the project, I would try to add improvements to the grid-based item collection for hand movement. Address the issue of pain for longer play and make it more involving using ideas such as drag and drop action etc
Importance of user testing
The user testing phase helped me learn and analyze the design from different perspectives of the user. In-depth user research, in the beginning, could have helped in pointing out the majority of the issues observed in iteration I. These learnings from the project encouraged me to develop a foundation in UX.
Unity for prototyping
I was able to learn Unity from scratch and develop the game within the project duration. I learned the need to decide on how detailed the features in the prototype should be for better user testing