Feasibility of Adapting a Classroom Balance Training Programto a Video Game Platform for People with Parkinson’s Disease

Glenna A. Dowling, RN, PhD, FAAN,1 Robert Hone, MS, MJ,2

Charles Brown, BS,2 Judy Mastick, RN, MN,1

and Marsha Melnick, PhD3

1Departments of Physiological Nursing and 3Physical Therapy andRehabilitation, University of California, San Francisco, SanFrancisco, California.

2Red Hill Studios, San Rafael, California.

AbstractObjective: Decreased postural stability in people with Parkinson’s

disease (PD) is a major component of disability. Rehabilitation inter-

ventions are therefore targeted to improve balance, mobility, and

strength. Virtual environment and gaming platforms can encourage

therapeutic activity in the home and be challenging and fun. The aims

of the project were to demonstrate the technical feasibility of adapting a

classroom-based gait-and-balance training program to a video game

platform. Ease of use, appeal, and safety of the proposed games were

tested for both clinic and in-home use. Subjects and Methods: This

cross-sectional observational study was carried out in three phases.

Modifications in the game platform were made in an iterative fashion

based on feedback from subjects and the observations of clinical and

design team members. The first two phases of testing were performed in

a laboratory setting, and the final phase was carried out in subjects’

homes. Results: Subjects (n = 20) scored the primary ‘‘Rail Runner’’

game 3.6 for ease of use (1 = hard, 5 = easy) and 3.9 for appeal (1 = did

not like at all, 5 = liked very much). There were no safety issues en-

countered, and the games performed without technical flaws in the

final phase of testing. Conclusions: A computer-based video game that

incorporates therapeutic movements to improve gait and balance for

people with PD was appealing to subjects and feasible for home use.

Key words: e-health, home health monitoring, telemedicine

Introduction

Parkinson’s disease (PD) is characterized by tremor, rigidity,

bradykinesia/akinesia, postural instability, and impaired

gait (decreased velocity and stride length).1–4 These gait

abnormalities place people with PD at high risk for falling.5,6

Physical rehabilitation interventions are frequently prescribed to

improve balance, mobility, strength, and activities of daily living.7–12

These interventions may be prescribed on an individual or group basis.

Computer-mediated virtual environment platforms have been

used for motor rehabilitation for decades. Movements learned by

people with disabilities in virtual environments transfer to real-world

equivalent motor tasks in most cases and even generalize to other

untrained tasks in some cases.13 The Nintendo� Wii� system (Nin-

tendo of America, Redmond, WA) offers a low-cost alternative to

high-end head-mounted virtual environment systems. Players in-

teract with the Wii system by making normal motions (i.e., swinging

an arm) that control the movements of virtual objects on the screen.

The input device, the Wiimote, detects acceleration in three dimen-

sions as well as rotations about the two axes perpendicular to the

force of gravity. The rapid response of the system provides a smooth,

easy-to-learn, human–computer interface that is much less expen-

sive than high-end virtual environment systems.

There is increasing interest in the use of games within the health

field. One of the benefits of games is that they can adapt to the

patient’s actions to maintain a high level of engagement. Adaptive

computer games evolve as players learn new skills by increasing the

difficulty of challenges, thereby allowing the player to stay within an

‘‘area of maximal engagement,’’ which is similar to Vygotsky’s ‘‘zone

of proximal development.’’14,15 In educational situations, the zone of

proximal development is where maximum learning occurs. In

physical training or rehabilitation situations, being in the ‘‘zone’’

fosters continued and mindful effort on the training goals.

Developing games for people with disabilities involves unique

design challenges because the ‘‘area of maximal engagement’’ for this

type of player is likely to be different from that of an unaffected

person. Game developers use a combination of usability testing and

‘‘tuning’’ approaches when targeting players with disabilities to

properly calibrate the game difficulty to the players’ abilities.16–18

Observation and rapid, iterative changes are essential for success.

Studies in patients with stroke,19–21 traumatic brain injury,22,23

cerebral palsy,24 and PD25,26 have shown successful motor rehabili-

tation using interactive technology. Esculier et al.26 reported high

functioning subjects with PD improved their balance, mobility, and

functional ability playing preselected off-the-shelf Wii games.

However, many commercially available games are not suitable for

people with marked disability who require specifically targeted ex-

ercises and routines to achieve therapeutic goals. Neurorehabilitation

usability studies have found that off-the-shelf games may actually

provide negative auditory and visual feedback because patients are

not fast enough or efficient enough to perform the movements re-

quired to successfully play the game.27,28 Because of these user

limitations, researchers are now developing games specifically tar-

geted for rehabilitation in particular populations.

After successfully offering a 1-hour group class for gait and bal-

ance training for people with PD8 at the University of California, San

298 TELEMEDICINE and e-HEALTH APRIL 2013 DOI: 10.1089/tmj .2012.0055

Francisco (UCSF), training program developers G.A.D. and M.M.

sought to broaden access by providing a home-based program. In late

2007, Red Hill Studios (RHS), a developer of educational and health

games, suggested building a set of games that would utilize the re-

cently released Nintendo Wii motion-sensing system to detect pa-

tients’ movements as they performed the training exercises. RHS and

the UCSF clinicians partnered to obtain National Institutes of Health

funding through the Small Business Technology Transfer grant

program. The goal of this Phase I study was to test the feasibility of

creating a comprehensive computer game-based training program,

demonstrate safety for clinic and home use, and test usability and

appeal with end users. The team also sought to develop a remote data

capture transmission system with the ultimate goal of enabling

healthcare professionals to remotely prescribe personalized gaming

regimens and monitor progress.

The specific aims of the study were to demonstrate:

1. Technical feasibility of adapting the classroom training pro-

gram to a computer-based platform

2. Safety of the proposed program for clinic and in-home use

3. Ease of use of the proposed program and

4. Appeal of the proposed program.

Subjects and MethodsSAMPLES AND SETTINGS

The innovative nature of the program required extensive iterative

development with several rounds of evaluation:

1. The operational evaluation used a small sample (n = 3) to

gather initial data about the user interface and identify ther-

apeutic physical movements to be incorporated into the

computer-based games and took place at the UCSF Physical

Therapy Health and Wellness Center to enable the use of a

suspended safety harness.

2. The preliminary evaluation occurred in two stages (Stage 1,

n = 3; Stage 2, n = 4), again at the UCSF Physical Therapy

Health and Wellness Center. Subjects played the prototype

games, and the clinical and design teams in conjunction with

the subjects identified bugs and difficulties and assessed po-

tential safety issues.

3. In the in-home evaluation, we evaluated the final version of

the Phase I prototype games that had been redesigned based on

the findings of the preliminary evaluation, with subjects

(n = 10) in their homes.

In total, 20 subjects were enrolled in this study. Inclusion criteria

were consistent with the guidelines for idiopathic PD,29,30 and sub-

jects met criteria for Hoehn and Yahr disease Stage 1 (unilateral

disease) to 3 (bilateral disease, physically independent).31 Exclusion

criteria included persons with features of atypical PD30 or significant

other neurologic, orthopedic, or cardiac problems, cognitive im-

pairment as evidenced by five or more errors on the Mini Mental State

Examination,32 or visual or hearing impairments serious enough to

interfere with the ability to interact with the computer-based training

program. All subjects consented, and the study was approved by the

UCSF Committee on Human Research. At all evaluations, subjects

were tested 1–2 h after taking their routine dose of anti-parkinsonian

medication to facilitate being in the ‘‘on’’ state.

MEASUREMENTS/INSTRUMENTS

Demographics and functional status. Demographic, general

health information, and functional status ratings on the Unified

Parkinson’s Disease Rating Scale (Parts 2 and 3)31 and the Hoehn and

Yahr disease staging31 were collected on all subjects to characterize

the sample.

Perception of exertion. To determine subjective assessment of

physical activity intensity during game play, the Borg Rating of

Perceived Exertion Scale33 was administered upon completion of the

gaming session.

Experience feedback survey. Table 1 gives the survey used.

Computer platform. The PC-based games were developed using a

computer programming platform, Unity 3D (Unity Technologies, San

Francisco), and incorporated the Nintendo Wiimote controller, which

Table 1. Experience Feedback Survey

EVALUATION, QUESTION, SCALE

Operational evaluation

1. How difficult or easy was it to use the Wiimote? (scale from 1 to 5, with

1 = difficult and 5 = easy)

2. How difficult or easy were the instructions? (scale from 1 to 5, with

1 = difficult and 5 = easy)

3. How difficult or easy was it to perform the gestures? (scale from 1 to 5,

with 1 = difficult and 5 = easy)

4. Do you have any suggestions about the types of games you would like to

play with the Wiimote?

Preliminary evaluation and in-home evaluation

1. How enjoyable were the games? (scale of 1 to 5, with 1 = not enjoyable and

5 = very enjoyable)

2. How appealing were the graphics? (scale of 1 to 5, with 1 = not enjoyable

and 5 = very enjoyable)

3. How easy was it to play the games? (scale of 1 to 5, with 1 = not enjoyable

and 5 = very enjoyable)

4. How helpful was the audio? (scale of 1 to 5, with 1 = not enjoyable and

5 = very enjoyable)

5. How appropriate was the duration of one game? (scale of 1 to 5, with

1 = not enjoyable and 5 = very enjoyable)

6. Is there anything else that you would like to add?

Questions were developed for each stage of the testing.

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detects acceleration in three dimensions

(x,y,z) through the use of low-cost acceler-

ometers. The PC-based platform provided

greater flexibility in developing the proto-

type games (as opposed to the closed system

of the Nintendo Wii console). In addition,

the computer programming environment

allowed us to capture engineering data

necessary to properly tune the system for

the intended audience. Data from the Wii-

mote were acquired through the computer’s

Bluetooth� (Bluetooth SIG, Kirkland, WA)

receiver and sent to the Unity real-time

three-dimensional programming environ-

ment. The short transmission and response

time (tenths of a second) between the Wii-

mote and the computer minimized signal

latency creates a fluid interface in which the

user quickly learns to act through the in-

terface instead of acting with the inter-

face.34 This allows the user to focus on how

he or she is manipulating the virtual objects

on the screen, as opposed to how to operate

the interface device (Wiimote).

Procedures. There was close collabora-

tion between the RHS and UCSF teams

during development of the game proto-

types. The steps in the process of translating

the classroom training to a gaming format

are depicted in the flowchart given in Figure

1. The operational and preliminary evalua-

tion feedback enabled several rounds of it-

erative game redesign (Figs. 2 and 3). First,

the clinical team (UCSF) identified a set of

five therapeutic movements that could be

the focus of potential games. The design team (RHS) defined a set of

‘‘game gestures’’ designed to elicit the therapeutic movements se-

lected by the clinical team. The design team narrowed the number of

game gestures to three possible options (because of budget con-

straints of the Small Business Technology Transfer Phase I grant) and

developed algorithms to identify the game gestures based on the data

provided by the Wiimote. For example, in one game, the game ges-

ture consisted of the subject standing up and then sitting down. When

the game program detected that the game gesture had been suc-

cessfully performed, it provided feedback in the form of a game

action. For the standing up/sitting down gesture, the game action

involved propelling a railroad handcar down the track. Given the

exploratory nature of this research, we took advantage of production

efficiencies to develop rough prototypes for two other games. The

two other games provided different technical challenges, which al-

lowed us to expand our knowledge of gesture-based games. For the

second game, trunk rotation movement was developed into a

Fig. 1. Workflow chart showing the iterative design/evaluate/revise/re-evaluate process.

Fig. 2. Operational evaluation. (Left) First the subject was testedwith the support of a harness for safety. The apparatus did notallow for free range of motion; subsequent subjects were testedwith a gait belt. (Right) Subjects initially had the Wiimotesplaced on the ankle and forearm.

DOWLING ET AL.

300 TELEMEDICINE and e-HEALTH APRIL 2013

zoetrope game, where a movie would play at the correct speed if the

rotation was done at optimal speed and radius. For the third game,

diagonal reach across midline movement was developed into a

clothes toss game (Table 2).

For the in-home evaluations, subjects were outfitted with two

Wiimotes: one on the wrist and the other on the opposing thigh using

polychloroprene (Neoprene; DuPont�, Wilmington, DE) straps and

Velcro� (Velcro USA, Manchester, NH). Clinical team spotters were

situated on either side of the subject for safety. The subjects were

oriented to the equipment and to study procedures and were en-

couraged to ask questions along the way. Researchers reinforced the

fact we were testing the equipment, not the subject. Subjects

were prompted with the tutorial start screen that explained the

movement verbally and visually with a simple jointed figure as their

avatar (Fig. 4). Subjects practiced the game movements while

watching an on-screen avatar that mirrored their movements, pro-

viding real-time feedback on performance. Subjects also received

audio feedback that provided suggestions for improvement and en-

couragement. If subjects were having difficulty achieving the correct

movement, a clinical team member demonstrated and guided their

movement until the desired movement was achieved. After suc-

cessfully completing the tutorial, the subject then played the ‘‘Rail

Runner’’ prototype game several times. A design team member

monitored the subject’s level of engagement and/or frustration and

made adjustments to the speed and difficulty of the game manually

on the computer. The same process was carried out for the rough

tutorials and prototypes for the other two ‘‘back up’’ game concepts.

Fig. 3. Preliminary evaluation tutorial screen shots. ‘‘Gesturescreens’’ were originally developed for the operationalevaluation. With feedback from subjects, the screen shots wereexpanded, and audio cues were added for better instructionand guidance.

Table 2. Game Descriptions

GAME DESIRED MOVEMENT ACTIVITY GRAPHIC

‘‘Rail Runner’’ Sit to stand The player propels the forward mo-

tion of the rail car by the sit to stand

motion. The reward is a pot of gold

coins.

‘‘Virtual Zeotrope’’ Trunk rotation The player rotates trunk in even,

large circles to move the wheel and

see the film progress in the center.

‘‘Musical Garments’’ Diagonal reach across midline The player reaches down and to one

side to pick up clothes, then reaches

across the midline and up to toss the

clothes over the screen.

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Rest breaks were given as desired by subjects or if the clinical team

perceived the subject was experiencing fatigue. After completion of

game play, subjects rated their perceived exertion and answered

questions regarding their subjective sense of ease of use and appeal of

the games.

ResultsSample characteristics are described in Table 3. Operational and

preliminary testing subject feedback results and the game revisions

are described in Table 4 and depicted in Figures 1 and 2. During the

in-home testing, the games performed without technical bugs or

flaws during the in-home evaluations, and there were no falls or

injuries. After subjects played the ‘‘Rail Runner’’ game, their mean

ease-of-use rating score was 3.6 (standard deviation [SD] 1.3) (from

1 = very hard to use to 5 = very easy to use), and mean appeal score

was 3.9 (SD 1.1) (from 1 = did not like to 5 = liked very much). After

subjects played the ‘‘back up’’ game ‘‘Virtual Zoetrope,’’ their mean

rating score for ease of use was 2.7 (SD 1.6) (from 1 = very hard to use

to 5 = very easy to use), and mean appeal score was 2.8 (SD 1.6) (from

1 = did not like to 5 = liked very much). After subjects played the less

developed ‘‘back up’’ game ‘‘Musical Garments,’’ their mean rating

score for ease of use was 3.6 (SD 0.7) (from 1 = very hard to use to

5 = very easy to use), and mean appeal score was 3.1 (SD 1.2) (from

1 = did not like to 5 = liked very much).

DiscussionThe technical performance of the games was high, with no tech-

nical flaws occurring during the final prototype evaluation. In the

process of ‘‘getting under the hood’’ of the Wiimote system, we

identified two key limitations of the device. First, bias error and

sampling noise from the accelerometers quickly produced unac-

ceptably large error values for derived velocity and position (due to

single and double integration of force data). Gesture recognition

software typically used for the Wiimote (e.g., AILive) relies on rec-

ognizing sequences of relatively large, short-duration impulses in the

acceleration signature, which are suitable for detecting vigorous

gestures such as shaking or ‘‘batting.’’ However, the motions of in-

terest for this project were generally slower motions, lacking these

large, short-duration impulses. Second, although the accelerometers

produce relatively accurate limb orientation estimations when used

as three-axis ‘‘tilt meters,’’ they are unable on their own to discrim-

inate rotation purely around the vertical axis. This makes them less

reliable in detecting motions such as trunk rotation. We overcame these

limitations by focusing on the relatively accurate ability to deter-

mine limb orientation combined with the constraints of human body

mechanics and developed specific criteria to determine when game

gestures were successfully completed. For example, using the acceler-

ometer as a tilt meter (deviations from vertical force of gravity), we

Fig. 4. In-home evaluation, using a well-lighted room with a sturdystraight-backed chair for the ‘‘Rail Runner’’ game.

Table 3. Demographic and Functional Characteristicsof the Sample

EVALUATION,SUBJECT NUMBER

AGE(YEARS) GENDER

DIAGNOSIS(YEARS)a H&Yb

Operational

1 60 F 3 2.5

2 73 M 11 2

3 72 M 11 3

Preliminary Stage 1

4 75 F 6 2

5 83 M 16 3

6 68 M 6 2.5

Preliminary Stage 2

7 51 M 0.67 2

8 74 M 12 2.5

9 60 F 9 2

10 69 F 5 2.5

In-home

11 55 F 15 2.5

12 51 F 13 3

13 56 M 13 2.5

14 63 M 28 3

15 72 M 1.5 2

16 60 F 10 2.5

17 65 F 2 2

18 70 M 6 2

19 63 F 10 2.5

20 59 f 11 2

aDiagnosis is how many years have lapsed since the subject has been

diagnosed with PD.bH&Y is the Hoehn and Yahr score, on a scale of 1–5, with a higher number

reflecting more disability.

F, female; M, male.

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302 TELEMEDICINE and e-HEALTH APRIL 2013

calculated the deflection of the subject’s trunk and thigh from vertical

and used the combined signature of these values as they changed over

time to detect the ‘‘standing up’’ and ‘‘sitting down’’ movements.

The limitations of systems based solely on accelerometers will be

avoided moving forward by replacing the Wiimote with an enhanced

motion-sensing system that uses gyroscopes and a digital magne-

tometer to augment the three accelerometers. This modification

will allow far superior estimation of limb orientation in three-

dimensional space and thus a greater breadth of detectable gestures.

There were no falls or safety issues encountered in any of the three

Phase I evaluations. This can be attributed to the close collaboration

between UCSF and RHS that produced games suitable for the target

audience that did not foster dangerous situations or elicit overexer-

tion. It should be noted, however, that the UCSF team had to closely

monitor several subjects while they were playing to ensure safety.

Thus, safety strategies and close monitoring will be key components

in the subsequent phases of game testing.

The prototype game was challenging for subjects to play because it

required them to interact with a computer in a totally new way. The

fact that subjects were able to play the prototype game and rated it

highly is encouraging. However, each new game will present new user

interface challenges because this novel interface requires subjects to

physically interact with the game (as opposed to a simple Web activity).

The collaborative team’s experience in designing and developing

the ‘‘Rail Runner’’ game as well as the ‘‘back up’’ games ‘‘Virtual

Zoetrope’’ and ‘‘Musical Garments’’ reinforced the need to follow a

highly iterative design/evaluate/revise/re-evaluate process moving

forward as we design new games. The development of the two ‘‘back

up’’ games gave us the opportunity to test a broader range of motions

than would have been possible with just one game and anticipate

potential technical issues in new game designs. For example, the hip-

rotation game involved a continuous movement (rotating the hips) as

opposed to a sequence of discrete movements with specific end points

as in the ‘‘Rail Runner’’ game (sit, stand, sit, etc.). Some of the subjects

decreased the amplitude of rotation over time, finally reaching a

point where the system did not recognize the motion. Given that

progressive decrement in amplitude with repetitive motion is com-

mon in people with PD, this issue is likely to emerge with any

game that does not have specific end points. Our plan is to ensure

that the system continues to recognize the movements while

also encouraging subjects to exaggerate their motions to achieve

therapeutic benefit.

Overall, subjects were intrigued by and enthusiastic about the

possibility of using games to perform gait and balance training. The

preliminary nature of the Phase I prototype, in terms of graphics, au-

dio, and supporting material, may have affected the subjects’ rating of

appeal in the final in-home evaluation. Several subjects commented

specifically that they would have liked more tutorial/instructional

material about the games, which supports the findings of Robertson35

and the needs of ‘‘silver gamers.’’ Based on these results, we will in-

crease resources for instructional support moving forward.

Instructions were presented to the subjects as both audio prompts

and on-screen text instructions. In some cases, the text was not large

enough to be read clearly by all subjects. We will establish a mini-

mum text size (number of inches on screen) and dynamically adjust

the size of the type based on the subject’s system.

One of the issues with the ‘‘Virtual Zoetrope’’ game was that some

of the subjects did not know what a zoetrope was (an old-fashioned

mechanical device that rotates to display a sequence of images as a

movie). The project team assumed, incorrectly, that this device would

be familiar to subjects, but for some subjects it clearly was not, and

this impacted their performance. Moving forward, we will review

potential game concepts with typical end users at an early stage in

development.

Summary and ConclusionsThis study demonstrated the feasibility of using computer-based

games to provide gait and balance training to people with PD. As could

be expected when exploring innovative uses of technology, the study

involved a fair amount of experimentation and refinement. The ability

of the collaborative team of RHS and UCSF to respond to interim

challenges and find creative solutions bodes well for future develop-

ment. The design and production capabilities of the collaborative team

were also demonstrated by the ‘‘extra’’ development of two additional

prototype games. The inclusion of these games in the Phase I program

allowed us to gain valuable information that will greatly inform the

Phase II study. Finally, the moderately high variability in the sample

population in terms of game appeal, desired difficulty level, and per-

sonal abilities has directly informed the design of future games. We

will increase the number of games and increase the difficulty range to

customize the game challenge to individual abilities.

Table 4. Early Testing Design Iterations Based on Subjectand Team Feedback

TESTINGSTAGE

SUBJECTFEEDBACK REVISIONS

Operational evaluation

(n = 3)

Enjoyed experience, able

to understand how to

interact with game by

moving body, wanted

more instruction on what

to do.

Added more visual feed-

back. Graphic displays

were developed that

would respond to actions.

Preliminary evaluation

Stage 1 (n = 3) Subjects continue to de-

sire more introduction

and more feedback. Ease-

of-use average score 2.0.

Games appeal average

score 2.0.

Integrated audio

prompts, added the

original movements as a

tutorial.

Stage 2 (n = 4) Scores for ease of use

appeal improved. Ease-

of-use average score 3.8.

Games appeal average

score 4.3.

Detection of sit/stand

improved by placing

Wiimote at the lateral

thigh instead of on the

ankle for better move-

ment detection.

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Disclosure StatementR.H. and C.B. are employees of Red Hill Studios. G.A.D., J.M., and

M.M. declare no competing financial interests exist.

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Address correspondence to:

Glenna A. Dowling, RN, PhD, FAAN

Department of Physiological Nursing

University of California, San Francisco

2 Koret Way, Room 631J

San Francisco, CA 94143-0610

E-mail: glenna.dowling@nursing.ucsf.edu

Received: February 27, 2012

Revised: July 15, 2012

Accepted: July 19, 2012

DOWLING ET AL.

304 TELEMEDICINE and e-HEALTH APRIL 2013