A Serious Game Development and Usability Test for Blood Phobia

Treatment - PHOBOS

João Petersen

, Vítor Carvalho

1,2 b

, João Tiago Oliveira

and Eva Oliveira

2Ai Laboratory, School of Technology, IPCA, Barcelos, Portugal

Algoritmi Research Center, University of Minho, Guimarães, Portugal

CIPsi - Psychology Research Center, School of Psychology, University of Minho, Portugal

Keywords: Serious Games, Blood-Injection-Injury Phobia, Virtual Reality, Virtual Reality Exposure Therapy, Biometric

Sensors.

Abstract: This paper addresses the development of the serious game PHOBOS, a virtual reality exposure therapy game

for the treatment of blood-injection-injury phobia, also known as hemophobia. The virtual reality game which

incorporates biometric sensors was upgraded from a 2018 version to perform usability tests to get the game

ready for clinical trials. With this project we expect to contribute to the development of a framework that can

be used by physiologists in the treatment of their patients with hemophobia.

1 INTRODUCTION

Serious games have been used for treatment of

phobias, social anxiety disorder, amongst other

disorders (Li, S. et al., 2022). While about 10% of the

worldwide population suffer from a specific phobia,

there have been further improvements on the

development of VRET (Virtual Reality Exposure

Therapy) and ARET (Augmented Reality Exposure

Therapy) for its treatment (Albakri, G., et al., 2022;

Freitas, J.R.S., et al., 2021; Jiang, M., et al., 2020, Li,

S. et al., 2022). The technological evolution on game

engines, virtual reality and biometric sensors provides

new possibilities for the work as we can get more

realistic graphics with a higher framerate producing a

more immersive experience and therefore providing

the user a more focused therapy (Bond, A. et al.,

2017).

With this project we aim to improve the research

and development of VRET serious games. The game

will be combined with biometric sensors for data

acquisition that will have impact in the game

mechanics allowing to implement and control the

exposure to blood in a dynamic and player adapted

way. The aim is to develop a solid serious game for

https://orcid.org/0000-0002-0441-7992

https://orcid.org/0000-0003-4658-5844

https://orcid.org/0000-0001-6624-8816

https://orcid.org/0000-0001-8394-7088

the treatment of the blood-injection-injury phobia by

exposing the player to progressive and dynamic blood

stimuli controled by the players’ heart rate and stress

levels. The player will be taught on how to avoid

fainting by using applied tension exercises when

he/she recognises that his/her blood pressure is

getting lower (Vögele, C., et al. 2003). This game is

PHOBOS, a photorealistic serious game for VRET,

which addresses this specific issue, (Petersen, J. et al.,

2019). This project started in 2018 having reached a

demonstration version.

This paper is organized in five sections. Section 2

presents the related work which describes the work

done on the subject so far, from serious games for

VRET on disorders and phobias, to the specific-

phobia, blood-injection-injury phobia. Section 3

describes the project development section with the

funcional and non-funcional requirements sub-

section, where we highlight the features of the project

and its atributes, the storyboard sub-section which has

a description of the narrative and the example steps

the user can take on the playthrough, followed by the

hardware used sub-section. Section 4 details the

usability questionnaire section with the questions for

Petersen, J., Carvalho, V., Oliveira, J. and Oliveira, E.

A Serious Game Development and Usability Test for Blood Phobia Treatment - PHOBOS.

DOI: 10.5220/0011924900003414

In Proceedings of the 16th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2023) - Volume 5: HEALTHINF, pages 723-728

ISBN: 978-989-758-631-6; ISSN: 2184-4305

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

723

usability tests that we intend to do. Finally, section 5

adresses the final remarks and future work.

2 RELATED WORKS

Phobias are excessive or irrational fear of an object or

a situation, which can be divided in two categories,

social phobias, and specific phobias. In the case of

specific phobias, the irrational fear is caused by a

specific object or situation (Singh, J., Singh, J., 2016).

BII (Blood-injection-injury) phobia, also known as

hemophobia, is a specific phobia that is characterized

by the fear of blood, injury, and injections, interfering

with a person’s ability to function in their daily life

on more severe cases (Abado, E. et al., 2021). There

is a unique physiologic response pattern with this

phobia, which is the rise of heart rate and blood

pressure followed by the sudden fast drop which leads

to faint due to the low oxygen supply to the brain

(Vögele, C., et al. 2003).

Treatment methods for the treatment of BII

phobia include cognitive therapy with graded

desensitization, in vivo and imaginal exposure, and a

combination of exposure therapy with relaxation

(Vögele, C., et al. 2003). The most used treatment for

this phobia is exposure therapy with applied tension,

consisting of exposing the patient to the phobic

stimuli followed by applied tension exercises

(Hellström, K., et al., 1996; Öst, L., et al., 1991,). The

applied tension exercise is composed by tensing their

major body muscles when they detect a drop in blood

pressure (Hellström, K., et al., 1996; Öst, L., et al.,

1991; Vögele, C., et al. 2003).

The advances of virtual reality paved the way for

VRET for the treatment of phobias, allowing a more

controlled environment and exposure to the phobia

(Krzystanek, M., et al., 2021) like the in vivo

exposure therapy. There are ongoing studies on

VRET, such as the virtual environment for treating

multiple types of phobias by VRET on a handheld

virtual reality headset (Jashwanth, K., et al., 2020),

and the case study for one session treatment of BII

phobia which suggests improvements in their fears

(Jiang, M., et al., 2020). Following these trends, we

consider that the development of a VR game with

interactable objects, movement, immersion, and an

adequate storyboard that measures biometric signals

can improve the treatment of patients with

hemophobia and be a better alternative to the virtual

reality experiences done so far.

3 PROJECT DEVELOPMENT

3.1 Functional and Non-Functional

Requirements

The game will be a 3D virtual reality single-player

first-person game, where the player, as the user who

will play the game, will be allowed to move freely

through the game scenario with the rigid body of the

VR set which the player controls. There will be

collisions between the VR rigid body and game

objects, that could be static, interactive, and movable

objects. The sensor must register data with its ECG

(Electrocardiography) data acquisition for future

dynamic control over the phobic stimuli. There will

be spatial sound objects placed on specific objects to

increase immersion, for instance, the sound of the air

conditioners when the player gets near them. The

game will have mechanics to unlock doors, to solve

puzzles made of paintings, or to grab and inspect

objects. And the game must have blood objects for

phobic stimuli, distributed gradually over the various

rooms of the scene for gradual exposure.

For the non-functional requirements, the main

requirement is that the player feels that the blood is

realistic enough to trigger the phobia, followed by the

immersion, so that the player can be fully committed

to the exposure therapy. The game must have medium

to high frames per second, preferably above 30, the

sensor must have a continuous connection to the

computer, the area for the VR system must be

unobstructed to reduce the possibility of accidents.

3.2 Storyboard

To create a narrative that included blood it was

selected, amongst other studied possibilities, a crime

scene due to its probable blood/agressive character.

We priviledge this option instead of others studied in

the process for its logical creation of an environment

that will likely show a blood exposure situation which

will create a more immersive and even a surprise

effect to the player.

The player is a police officer who is called to go

to the game scene, a penthouse, because the

neighbours reported screamings after a stranger

entered the house.

The player exits the elevator, and arrives in the

entryway of the house where he/she has to find a spare

key hidden in one of the plant vases. In this area there

is no blood stimuli, and is a place where the player

can get aquainted with the controllers.

The player opens the now unlocked door and

he/she sees an interactable landline phone on a

WHC 2023 - Special Session on Wearable HealthCare

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cabinet with a voice message to his/her right, the

living room in his/her front, two doors to his/her left

and one to his/her right behind a bar counter. If the

player chooses he/she can interact with the phone to

hear the message and then enter the living room,

Figure 1, exploring it and finding a broken glass, a

small bloodstain on the carpet and a mobile phone

between the couch and the center table. The level of

phobic stimuli on this room is very low having only

the small blood-stain. The player can interact with

paintings on the left side of the room which drop

another key that unlocks the next room.

Figure 1: Phobos’ living room.

As the player opens the door to the bedroom

he/she is met with bloodied sheets, in the bed in front

of him/her and a bloodied handprint on the sliding

door of the closet to the right.

From here the player can open another door to the

left which opens the bathroom where he/she is

exposed to a bloodied mirror, soap and sink. There is

also a key in this room that unlocks the last room, the

kitchen which is the door behind the bar in the living

room.

This last room is the one with the highest exposure

to blood as there is a bloodied knife and blood drag

marks on the ground that lead to the dispenser,

although it is unusually clean.

There are no bodies so that the exposure is not to

heavy and also not to break immersion because of the

technical dificulties of creating a good photo-realistic

3d model. The main focus is the gradual exposure of

the player to its phobia and it should be followed by

a physician for any questions about the phobia or

about the AT exercise, which if the player should let

physician know if he/she is about to faint, so theres

less risk of injury if the exercise doesn’t work.

3.3 Hardware Used

For the HMD (Head Mounted Display) it was

selected the HTC Vive, Figure 2, due to the graphic

processing power with the 1080x1200 Dual

AMOLED 3.6” screens supporting more realistic

graphics with higher frames per second.

Figure 2: Playthrough with HTC Vive.

The computer has a Nvidia

GeForce

RTX 2080

8gb GDDR6, 32gb RAM (Random Access Memory),

Intel

Core™ i7-8750H CPU (Central Processing

Unit) @ 2.20GHz and the windows 11 OS (Operating

System). The use of headphones while playing the

game for the spatial sound design is recommended,

although the use of the computer embedded speakers

also work.

For the sensors, it was selected the PLUX

Biosignals BITalino ®evolution Board Kit, due to its

capabilities and performance versus the standards

(Batista, D., et al., 2019), where for the moment we

are only using the ECG sensor as seen in Figure 3, but

the board has the capability of performing the

following data acquisitions opening the possibility of

multi-modal signal acquisition (da Silva, H. P., et al.,

2014) for more accurate measures of the phobias’

reaction, EMG (Electromyography), EDA

(Electrodermal Activity), EEG

(Electroencephalography), ACC (Accelerometer) &

LUX (Light) sensors.

After some more testing it was possible to find

that the placement of the ECG sensor in the wrist was

causing unnecessary noise and that it provided more

accurate readings when placing the sensor on the

chest of the player because of the muscles activated

during gameplay.

A Serious Game Development and Usability Test for Blood Phobia Treatment - PHOBOS

725

Figure 3: First location of the ECG sensor.

4 USABILITY QUESTIONNAIRE

To gather results, usability tests will be driven

followed by self-report questionnaires after multiple

relevant questionnaires on user engagement and

experience satisfaction combined with some

questions that we consider relevant. The main

questionnaire studied was the questionnaire of a

similar virtual reality project for HRC (Heart-Rate

Controlled) interaction game, (Houzangbe, S., et al.,

2020), the UES (User Engagement Scale) (Wiebe, E.

N., et al., 2014) and GUESS (Game User Experience

Satisfaction Scale) (Phan, M. H., et al., 2016).

The self-report questionnaires are subdivided in

four categories.

The first category, as seen in table 1, is

information about the user who did the test, for

demographic segmentation. This information is

relevant because it’s the baseline to make the

necessary adjustments in the game, from the

information shown to the player, be it more technical

or more common written, to minor tweaks in game

mechanics to improve the playability and usability of

the game.

The second category, as seen in table 2, gathers

information about the previous experience of the user

with playing digital games, and VR games. This

follow-up of the baseline will inform us if some of the

difficulties found in the game were due to the lack of

experience, or the opposite, if the game is in a state of

usability that even a person without prior experience

can easily learn to play.

The third category, as seen in table 3, gathers

information about the equipment, both the sensor and

the VR set. This information will lead us to adapt the

hardware used depending on the answers, we might

change to a wireless HMD or even one with less

weight.

The fourth and final category, as seen in table 4,

gathers information about the gameplay, in this

category the usability of the game, the intuitiveness

of the game mechanics, the visibility of the objects

and features by the user are measured as well as the

discomfort, if any, felt whilst playing the game.

This questionnaire will allow us to assess the

scope of the player, the friendliness of the sensor, the

comfortability of the virtual reality head mounted

device and the usability factors of the game.

The usability tests are of the upmost importance,

as they provide feedback to improve the game to a

state where the players will feel comfortable and

natural in the virtual environment. They will also aid

us in fixing motion sickness related issues, which are

very common in virtual reality games but are not

acceptable for phobia treatment since they are an

external factor that the patients shouldn’t have to

experience for their treatment.

Table 1: Demographic segmentation questions of the

usability test questionnaire.

Question Possible answer(s)

What is your

enre?

Female; Male; Prefer not to

disclose; Other.

Choose your

age from the

tions

iven.

<15; 15-20; 21-30; 31-40; 41-50;

51-60; >60.

What are your

academic

qualifications?

Under four years of scholarity; Pre-

school; Middle school; Highschool;

Bachelor; Master; PhD; Prefer not

to disclose.

Table 2: Users’ previous experience questions of the

usability test questionnaire.

Question Possible answer(s)

Do you usually play

digital games?

Yes; No.

Have you ever played a

Virtual Reality game

efore this one?

Yes; No.

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Table 3: Equipment questions of the usability test

questionnaire.

Question Possible answer(s)

Did you find the sensors’

placement invasive?

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

Did the sensors’

placement obstruct your

movements?

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

Did you find the virtual

reality gear

uncomfortable?

Likert scale 1-7

1- Strongly Disagree

–

Stron

ree

If you felt any discomfort

using the virtual reality

gear, choose from the

following answers those

that a

Due to the weight;

Due to the cables;

Due to the lenses;

Due to the controllers;

Other.

Table 4: Gameplay questions of the usability test

questionnaire.

Question Possible answer(s)

Did you find the controls of

the game to be

straightforward?

(

GUESS

)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you always know how

to achieve the

objectives/goals of the

game?

(

GUESS

)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you find the blood

exposure difference evident

etween the various rooms?

Likert scale 1-7

1- Strongly Disagree

–

Stron

ree

Did you feel the game gave

you enough freedom to act

how you want?

(

GUESS

)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you feel that the game’s

audio (e.g., sound effects,

music) enhanced your game

experience?

(

GUESS

)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you think the game was

visually appealing?

(GUESS)

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

When you were playing the

game, you lost track of the

world around you?

(

UES

)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you feel frustrated

playing the game?

(UES)

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

Did you feel like you were

able to interact with the

environment the way you

wanted?

(HRC)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you find that the

environement was

responsible to the actions

that you initiated (or

erformed)? (UES)

Likert scale 1-7

1- Strongly Disagree

7 – Strongly Agree

Did you find the puzzle on

the painting in the living

room?

Yes; No.

Did you find the mobile

phone on the ground in the

living room?

Yes; No.

Did you interact with the

landline

hone?

Yes; No.

Did you feel motion

sickness during the

gameplay session?

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

If you felt motion sickness,

choose the reason from the

following answers.

Due to the graphics;

Due to the movements’

velocity;

Due to the movement

mechanics;

Other.

Would you play this game

again once it’s fully

developed?

Likert scale 1-7

1- Strongly Disagree

–

Strongl

Agree

5 FINAL REMARKS AND

FUTURE WORK

This paper addresses the development of the serious

game PHOBOS, a virtual reality exposure therapy

game for the treatment of blood-injection-injury

phobia, also known as hemophobia, providing the

necessary tools with the safe virtual environment to

overcome the phobia and prevent fainting. The

project started in 2018 and in this paper, we present

the updated version of the game and project progress.

We’ve upgraded the game engine, replaced the

deprecated plugins, and reworked from the ground up

some of the game features to make use of the latest

technology. The game is still in development, close to

the alpha phase to do the usability tests. Although

there are more studies on VRET, ARET and serious

games for phobias and disorders, there is still much

research to be done on BII phobia, that motivates us

to go deeper into this subject.

As future work we intend to do the usability tests,

followed with an iteration of the development

supported by the feedback gathered, making the

adjustments necessary to be able to do clinical trials

to see the viability of the games’ VRET. We also aim

to continue to improve the development of the game

once it reaches the alpha phase as well as the sensor

interplay for it to reach a minimum viable product

A Serious Game Development and Usability Test for Blood Phobia Treatment - PHOBOS

727

stage, where it can be recognized as a viable option

for the treatment of BII phobia.

ACKNOWLEDGEMENTS

This paper was funded by national funds (PIDDAC),

through the FCT – Fundação para a Ciência e

Tecnologia and FCT/MCTES under the scope of the

projects UIDB/05549/2020, UIDP/05549/2020,

NORTE-01-0145-FEDER-000042 and NORTE-01-

0145-FEDER-000045.

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