Virtual Reality based Diagnosis System for Visuospatial Neglect
Kais Siala
1
, Mohamed Kharrat
1,3
, Mohamed Belghith
2
, Olfa Boubakri
2
, Sameh Ghroubi
2
,
Mohamed Habib Elleuch
2
and Mohamed Abid
1
1
CES Laboratory, National School of Engineering of Sfax, University of Sfax, Airport Road, Sfax, Tunisia
2
Research Unit UR12ES18, Department of Physical Medecine and Rehabilitation, University of Sfax,
Airport Road, Sfax, Tunisia
3
Higher School of Informatics and Management in Kairouan, Department of Computer Science, University of Kairouan,
Keywords:
Virtual Reality, Health Diagnosis, Visuospatial Neglect, Rehabilitation.
Abstract:
The diagnosis of Visuospatial neglect is generally conducted using paper based manual methods. The obtained
results could be confused with sensory inattention pathology. In this paper we are presenting a new Virtual
Reality based diagnosis method for patients suffering from Visuospatial neglect. For this purpose a Virtual
Reality simulation called Farm Parade has been developed where the patient, after wearing a Virtual Reality
headset, will be guided inside a road crossing a farm like environment where animals at both sides of the road
will slowly move and generate sounds to encourage patients to look at them. The patient head motion will
be then tracked to generate a graph showing his capacity to move his head and judge if he is suffering from
Visuospatial neglect. The strength of the proposed system is the generation of numerical values relative to the
amount of head’s rotation which could be helpful for measuring precisely the degree of recovery.
1 INTRODUCTION
Visuospatial neglect is most commonly the results of
stroke or cranial trauma. It affects up to 80% of pa-
tients in the acute stage (HeilmanKM, 1993)(Barat M,
2000)(PELISSIER J., 2005). It leads that the person
forgets half of his body and mainly the side who is not
relaying on during his daily life activities (Ogourtsova
et al., 2018)(Li and Malhotra, 2015). Since most
people are using their right side, most patients suf-
fers from Visuospatial neglect on the left side of their
body. This affects their daily life activities, in the way
they cannot use their left hand or move normally their
left feet. There are multiple approaches to diagnose
patients suffering from Visuospatial neglect but most
of them are manual. In addition, these approaches
could lead to ambiguities those suffering from sen-
sory inattention. In fact, both pathologies might co-
exist and patient might recover from one before the
other (Li and Malhotra, 2015). Moreover, the classi-
cal tests could not give a precise measure of the re-
covery state of the patient. In the next section we will
review popular methods used today to diagnosis Vi-
suospatial neglect.
2 STATE OF ART
Visuospatial neglect diagnosis is mainly manual and
paper based (Pedroli et al., 2015)(Bergegoc., 1995).
This requires that patient sits in proper position and
has the paper in a fixed position and center it within
his body. This is not always an easy task especially for
patients suffering from serious physical problem or
those trying to cheat during the diagnosis by moving
the paper to the normal side of their body to show that
their fast recovery. Below examples of these tests.
2.1 Bisection Test
In the Bisection test, after sitting in proper position
as described above, patient shall use a pen to mark
the middle of each line. Patients suffering from Visu-
ospatial neglect tend to not marking the line exactly
on the middle. In addition they might not notice the
presence of some line one affected side of their body.
506
Siala, K., Kharrat, M., Belghith, M., Boubakri, O., Ghroubi, S., Elleuch, M. and Abid, M.
Virtual Reality based Diagnosis System for Visuospatial Neglect.
DOI: 10.5220/0007691505060509
In Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2019), pages 506-509
ISBN: 978-989-758-353-7
Copyright
c
 2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved

Figure 1: Bisection Test Example.
Figure 2: Cancellation Test Example.
2.2 Cancellation Test
In the cancellation Test, after sitting in the proper po-
sition, the patient is required to mark a particular type
of image and distinguish it from others. The exercise
complexity could increase with higher number of im-
ages types and by decreasing their size. This is so
far the most efficient test and patients suffering from
Visuospatial neglect tend to mark pictures on the af-
fected side of their body. A percentage of the rec-
ognized objects could be calculated after each test to
track the patient progress.
2.3 Mobility Assessment Course
A work for Dynamic assessment of visual neglect was
proposed by Antonia et al (Brink et al., 2018). In
that work, the patient is moved through a corridor and
has to find and report targets attached in the walls.
This work is compared against classical tests and it
presents sufficient reproducibility. In our proposed
work, the walking through the corridor is replaced
by a Virtual move along a road. The head tracking
we have proposed allows us to precisely measure the
amount of head’s rotation which is a good indicator
of the patient recovery.
3 THE PROPOSED SYSTEM
In the literature, Virtual reality was used to treat
the problem of Visual neglect (Ogourtsova et al.,
2018)(Tsirlin I, 2009)(Klinger E, 2008). A good re-
view is presented in (Pedroli et al., 2015). In our
Figure 3: Simulation setup.
work, we have chosen to develop an immersive con-
tent with head’s interactivity in order to ensure em-
bodiment and ownership. We consider that this con-
straint can help patient to be part of the simulation to
ensure cerabral plasticity which is the first step to re-
covery. The sense of embodiment is well exposed in
(F. Argelaguet, 2016).
A 3D simulation for capturing the angle of head’s
rotation is developed using Unity 3D. The 3D simula-
tion is displayed in the computer’s screen for the ther-
apist to monitor the patient’s behavior. The same con-
tent is displayed in a cardboard manner in the smart-
phone’s screen inside the HMD. We used the Trinus
VR software to ensure the communication between
the PC (Unity plugin) and the smartphone. The same
software (Trinus VR) is used to capture head’s motion
of the patient.
The communication between the Smartphone and
the computer is ensured to be activated prior to the
simulation. The test setup is presented in figure 3.
The functioning of our proposed system is sum-
marized in the organigram in figure 4
In real time, the developed software’s orientation
of the patient, shifts the 3D content according to this
orientation. The particular value of rotation along the
Y-Axis is stored to assess the head’s rotation to right
and left (Y-Angle). Positive values of Y-Angle cor-
respond to rotation into right whereas negative values
correspond to rotation into left. The out performance
of our system is the ability to measure precisely and
in real-time:
• Rotation amount into right and left
• Maximum Y-Angle into right and left
• Angle density into right and left. This density
is the measure of the surface (Y-Angle vs time)
for positive values (right rotation corresponding
Virtual Reality based Diagnosis System for Visuospatial Neglect
507

Figure 4: Simulation organigram.
Figure 5: Density of right and left rotation.
to red surface in figure 5) and for negative val-
ues (left rotation corresponding to green surface
in figure 5)
• Head’s rotation asymmetry, given by equation 1.
It corresponds to the percentage of left rotation
against right rotation. Ideally, for a healthy par-
ticipant, this amount should be 100 % for equal
rotation to right and left.
Figure 6: Simulation Farm Parade.
Asymmetry =
R
end
begin
Angle
le f t
(t)
R
end
begin
Angle
right
(t)
∗ 100 (1)
A the end of the 3D simulation, a graph of Y-
Angle over time is displayed. An excel journal is also
saved for further statistical processing.
We developed the following scenario for measur-
ing head’s rotation:
1. Simulation 1 - Farm Parade : This simulation con-
sists on a navigation inside a farm with animals at
the right and left sides. A patient suffering from
visuospatial neglect could not move his head into
the animals at his left side. This simulation could
be considered as a simple evaluation tool (graph
of head’s position).
4 EXPERIMENTAL RESULTS
We have tested this new diagnosis method on seven
patients at the department of physical medicine and
rehabilitation of Sfax University Hospital. And the
diagnosis method helped us identifying one patient
suffering from Visuospatial neglect. The classical
Visuospatial neglect tests are confirmed by our new
method. In figure 7, corresponding to non visual ne-
glect patient, we see that in the graph is roughly sym-
metric (equal surface for positive and negative val-
ues). The Asymmetry measure for this patient is 84
%. In figure 8, corresponding to visual neglect pa-
tient, we see that the graph is asymmetric (more sur-
face for positive than negative values). The Asymme-
try measure for this patient is 27 %.
HEALTHINF 2019 - 12th International Conference on Health Informatics
508

Figure 7: Non Visuospatial Neglect patient.
Figure 8: Visuospatial Neglect patient.
5 CONCLUSION
The proposed method is innovative, cheap and can be
easily used in medical care centers. The obtained re-
sults are promising since Visuospatial neglect prob-
lem has been successfully identified. The strength of
the proposed method is the ability to measure pre-
cisely the patient’s head movement which is useful
to assess the recovery state across sessions. The pro-
posed system, while developing new scenarios, could
be also used as a treatment for Visuospatial neglect
since the patient is trained to turn his head which can
help him to recover thanks to the neuroplasticity phe-
nomenon. The proposed system will be tried for a
larger group of patients to be validated. In the fu-
ture we are planning to include hand’s motion as a
VR rehabilitation technique for other kinds of stroke
induced disabilities.
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