Feature Extraction based on Touch Interaction Data in Virtual
Reality-based IADL for Characterization of Mild Cognitive
Impairment
Yuki Kubota
1
, Takehiko Yamaguchi
2
, Takuya Maeta
1
, Yosuke Okada
2
, Yoshihito Miura
2
,
Niken Prasasti Martono
3
, Hayato Ohwada
3
and Giovannetti Tania
4
1
Department of Applied Electronics, Graduated of Tokyo University of Science, Katsushika-ku, Tokyo, Japan
2
Department of Applied Electronics, Tokyo University of Science, Katsushika-ku, Tokyo, Japan
3
Department of Industrial Administration, Tokyo University of Science, Noda-shi, Chiba, Japan
4
Department of Psychology, Temple University, 1701 N. 13
th
Street, Philadelphia, U.S.A.
Keywords: Dementia, MCI, Screening, VR-IADK, Characterization.
Abstract: The aim of this study was to explore the feature pattern of Mild Cognitive Impairment (MCI) in Virtual Reality
based Instrumental Activities of Daily Living (VR-IADL) which runs on a tablet PC as well as requires
participants a touch interaction to complete the task. Twelve participants (MCI: 4, history of MCI: 2, healthy
elderly: 6) were recruited from the region of Philadelphia in USA to perform a VR-IADL task. We found that
Non Touch Time (NTT) which is time interval during not touching screen on tablet was longer than that of
MCI patients as well as healthy older adults with having history of MCI. Several types of feature patterns
were extracted from the NTT such as … Based on the feature pattern, Support Vector Machine (SVM) was
performed to calculate the accuracy of the feature patter for characterization of MCI. As the result, the
identification rate was 75%.
1 INTRODUCTION
The population of older adults is increasing, placing
a burden on health care resources. According to
World Alzheimer’s Report (2016), the world’s
dementia population included approximately 47
million in 2016 and is expected to increase to 131
million by 2050. Dementia is an irreversible
condition that includes symptoms that disturb daily
living due to degeneration of the brain and impaired
cognitive abilities. Mild Cognitive Impairment (MCI)
is the prodromal stage of dementia that is associated
with mild cognitive and functional difficulties. MCI
may be reversible; therefore, screening for MCI may
promote prevention of Alzheimer’s disease through
early intervention. Recent research has turned to the
characterization of early behavioral dysfunction in
MCI and cognitive aging (Seligman et al., 2013).
People with MCI have been shown to perform more
inefficiently than healthy older adults on
performance-based tests of instrumental activities of
daily living (IADL; i.e., learned, sequential, object-
oriented behaviour in the service of everyday goals
like meal preparation) (Schmitter-Edgecomb et al.,
2012). In several studies, neuropsychologists view
video recordings of the everyday action performance
of participants and code behaviour according to an
error taxonomy that includes micro-error and overt
error subtypes, such as omission error and various
types of commission (Giovannetti et al., 2008). The
method has been used with the Naturalistic Action
Test (NAT), a performance-based test of IADL.
IADL performance analysis of MCI participants must
include indicators of subtle errors or inefficient
behaviour. Some investigators have shown that time
to complete IADL tasks distinguish people with MCI
from healthy older adults (Wadley et al., 2008). Long
completion times in people with MCI may be the
result of slowed thinking and/or slowed movements;
however, to date investigators have not evaluated
motor vs. cognitive IADL speed in MCI. Virtual
Reality (VR)-based technology has been introduced
for environmental assistive technology and to assist
in diagnostic decision making. Yamaguchi et al.
developed the Virtual Kitchen application with VR-
based technology for assessment Alzheimer’s disease
152
Kubota Y., Yamaguchi T., Maeta T., Okada Y., Miura Y., Martono N., Ohwada H. and Tania G.
Feature Extraction based on Touch Interaction Data in Virtual Reality-based IADL for Characterization of Mild Cognitive Impairment.
DOI: 10.5220/0006265201520157
In Proceedings of the 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2017), pages 152-157
ISBN: 978-989-758-229-5
Copyright
c
2017 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
(Yamaguchi et al., 2012, Allain et al., 2015). The
Virutal Kitchen includes VR-based IADL tasks (VR-
IADL) to assess functional ability of people with
Alzheimer’s disease by comparing frequency of
omission error and commission error. Martono et al.
classified the error pattern based on the acceleration
changes of finger movement in a touch-screen version
of the Virtual Kitchen (Martono et al., 2016).
However, effective feature patterns that could clearly
classify MCI vs. healthy elderly remain elusive. The
aim of this study was to investigate the feature pattern
of MCI with behavioral data such as touching
interaction data in VR-IADL task. Because previous
studies have shown that people with MCI
demonstrate longer decision making times and slower
cognitive processing speed, we hypothesized that
MCI participants would show greater cognitive
slowing than older adults on IADL. By contrast, we
expected motor speed would be relatively spared.
Thus, we predicted that MCI participants would
spend more time not touching the screen (i.e., Non-
Touch Time; NTT) than healthy elderly.
2 EXPERIMENT AND METHOD
2.1 Participants
Table 1: Neuropsychological test.
Domain Test
Language
Category fluency;
Boston Naming Test
Executive
function
WAIS-R digit span backward;
Trail Making Test version B
Memory-
Immediate
Rey Figure in recall; WMS-R:
logical memory Story A
Episodic
Memory ability
Rey Figure copy; WAIS-R:
picture completion
Attention
TMT part A, WAIS-R:
digit span forward
Processing
speed
TMT part A, crossing-off test
The participants aged 60 years and older were
recruited from the region of Philadelphia in the USA.
Participants included 6 healthy elderly, 4 elderly with
MCI, and 2 elderly with a history of MCI but who no
longer met MCI diagnostic criteria at the time of
testing. Participants were classified with several test
such as MMSE (score > 24), GDS: (Geriatric
Depression Scale < 10) and neuropsychological tests
of specific abilities (Seelye, 2015) as shown in Table
1 (Kaye, 2011).
2.2 Apparatus
2.2.1 Experimental Setup
Figure 1: The experimental setup for the VR-IADL task.
Figure 1 shows the experimental setup for the task.
It included one tablet device, web camera for video
recording during the task, and the Virtual Kitchen
Challenge application, which is VR-IADL
assessment tool. Participants were seated in front of
the tablet device, which was placed on the table. They
were asked to use their finger to complete the task.
The finger enabled them to move virtual objects by
touching on the object with their finger and then
dragging the object to the desired position in the plane.
In this study, we used the Virtual Kitchen
Challenge (VKC), which is visually developed 3D
environment in order to improve reality. VKC could
record several types of data such as the objects the
participant touched and dragged in time series. Firure
2 shows an example of the structure of each task. This
application consists of two IADL tasks: (1) Toast and
coffee task, (2) Lunch box task. Each task has two
or three main tasks, and main task has several sub task
which is action to complete main task. For example,
Toast and coffee task has 2 main task: (1) Toast task,
(2) Coffee task. Toast task has 8 sub task, and coffee
task has 8 sub task, too.
Before performing the task, we introduced the
goal of task, and operation of VK and we were sure
that participants understood (Giovannetti, 2008).
2.2.2 Toast and Coffee Task
The toast and coffee task included 14 objects, 10
target objects and 4 distractor objects. Two of the
distractors were related (salt shaker, ice-cream scoop)
to the target objects and the other two distractors were
unrelated to the targets (paintbrush, ash tray). The
placement of the distractors was evenly distributed
within right/left and proximal/distal positions on the
Feature Extraction based on Touch Interaction Data in Virtual Reality-based IADL for Characterization of Mild Cognitive Impairment
153
screen. Figure 3 shows the screen shot of toast and
coffee task.
Figure 2: The example of the task structure.
Figure 3: Screen shot of the Toast and Coffee Task.
Participants were required to perfom 13 steps to
make toast with butter and jelly and instanct coffee
with cream and sugar. The steps included: (1) place a
slice of bread into the toaster; (2) turn on the switch
to toast; (3) remove toast and place on the plate; (4)
take butter; (5) spread butter on the toast; (6) open the
jelly jar; (7) place jelly on the toast with knife; (8)
open the coffee jar; (9) take a spoonful of coffee
powder with spoon and into the cup; (10) open the
suger pot jar;(11) place suger into cup with spoon;
(12) pour milk into the cup; (13) stir cup of coffee
with spoon.
2.2.3 Lunch Box Task
Lunch box task included 13 objects, 9 target objects
and 4 distractor objects. Two of the distractors were
related (fork, cup) to the target objects and the other
two distractors were unrelated to the targets (razor,
spray bottle). The placement of the distractors was
evenly distributed within right/left and
proximal/distal positions on the screen. Figure 4
shows the screen shot of the lunch task. The lunch
task required participants to make, wrap and pack a
peanut butter and jelly sandwich, prepare a thermos,
and wrap and pack cookies. The task included 16
steps: (1) take bread; (2) open the jelly jar; (3) place
jelly on the bread with knife; (4) open the peanut
butter jar; (5) place peanut butter on bread with knife;
(6) take another piece of bread to close sandwich; (7)
take a sheet of foil to wrap the sandwich; (8) pack the
wrapped sandwich into the lunchbox; (9) take cookies
(one by one); (10) take a sheet of foil then wrap the
cookies; (11) pack the wrapped cookies into the
lunchbox; (12) pour the juice into the themos; (13)
seal the thermos with lid; (14) seal the thermos with
cap; (15) pack thermos into the lunch box; (16) close
the lunch box (Martono, 2016).
Figure 4: Screen shot of the Lunch Box Task.
3 DATA AND METHODS
3.1 Movie Analysis
Video recordings of performances were reviewed for
error coding. As a result, we realized difference
between the Touch Time (TT) and Non Touch Time
(NTT). Figure 5 shows the flow of acquire several
data and definition of dragging time and not dragging
time.
Figure 5: Classification of behaviour.
In this study, we defined TT as the time
participants had contact with the screen. NTT was the
time when participants were not touching the screen;
see Figure 5. TT and NTT behaviour could be
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154
classified as shown in
Figure 6.
When participants
touched the screen, they make two types of actions:
(1) move object appropriately to complete task (2)
move object inappropriately (i.e., error). NTT
included three types of action: (1) no movement
(possibly resting or thinking), (2) movements above
tablet (possibly scanning and searching for object),
(3) reaching error.
Figure 6: Classification of behaviour.
We hypothesized that MCI participants would
show larger NTT times than healthy elderly, because
we hypothesized that people with MCI demonstrate
longer decision making times and slower processing
speed.
3.2 Touch Time Data
We hypothesized that the rate of touching time
( 

) would be higher in healthy elderly
people compared to people with MCI, including those
with a history of MCI. We calculated RTT, using the
following mathematical formula (1).







(1)
RTT was calculated with 

\ and∈

. The Rate of Not Touching Time (

)
was calculated with the following mathematical
formula (2).
 1 
(2)
4 RESULT AND DISCUSSION
4.1 VR-IADL Analysis
The number of times the participant touched the
screen, the sum of TT and NTT, mean and variance
of TT and NTT, RTT and RNTT, which is showed
formula (1) and (2), were calculated for both IADL
tasks for the healthy elderly group and MCI groups
(i.e, MCI + history of MCI). Mann-Whitney tests for
the toast and coffee task showed significant
differences between the healthy and MCI participants
for variance of NTT (p < 0.05), mean of NTT (p <
0.1), the sum of NTT (p < 0.05), and RNTT and RTT
(p < 0.05). Also in lunch box task, there were
significant differences on two types of variance of
NTT (p < 0.05), the sum of NTT (p < 0.05) and RNTT
and RDT (p < 0.05).The mean NTT in the toast and
coffee task was longer for MCI participants than the
healthy group. Also, the sum of NTT and RNTT of
MCI group in both tasks is larger than that of healthy
group.
The results suggest that NTT could reflect slowed
cognitive speed and may be a behavioural feature that
reliably distinguishes MCI from healthy elders. The
variance of NTT was larger for the MCI group;
therefore, it is possible that the MCI group may be
experiencing more cognitive slowing at specific
points in the IADL (i.e., main task vs. subtask). In
next section, we analysed NTT and TT in different
IADL task segments.
4.2 Main Task Analysis
The lunch box task consists of three main tasks:
sandwich, snack, and juice. The toast and coffee task
consists of two main tasks: toast and coffee. We
observed how these main tasks were conducted by
analysing timing of subtasks in these main tasks.
Figure 7 shows the sequence in which the main tasks
were conducted. The timing of the sub tasks under
each the main tasks is represented by a different red
marker. This graph was generated automatically with
participant data. The blue, yellow, and green area
respectively represents the section of the main tasks
(i.e. sandwich task, snack task, and juice task).
Figure 8 shows the sequence of the toast and
coffee t main tasks and sub tasks under the main task.
The blue, and green area respectively represents the
section of the main tasks (i.e. toast task, and coffee
task).
In this study, the main task was defined as a set of
completion times of each subtask. The mean of NTT,
variance of NTT, the sum of NTT, the number of
Feature Extraction based on Touch Interaction Data in Virtual Reality-based IADL for Characterization of Mild Cognitive Impairment
155
Figure 7: The sequence of the conducted main task in
lunchbox task.
Figure 8: The sequence of the conducted main task in toast
and coffee task.
touching screen, RTT and RNTT for each task.
Mann-Whitney tests were performed on these
parameters. In lunchbox’s main task, there were
significant differences for NTT variance (p < 0.05,
sandwich and juice task), NTT mean (p < 0.05, only
sandwich task), the sum of NTT (p < 0.05, sandwich
task, p < 0.1, juice task) and RNTT (p < 0.05,
sandwich task). In toast task and coffee task, there
were significant difference for NTT variance (p <
0.05, both task), NTT mean (p < 0.1, both task), the
sum of NTT (p < 0.05, toast task, p < 0.1, coffee task)
and RNTT (p < 0.05, both task). There were no
significant differences for the number of times
participants touched the screen, though there were
significant differences for all data in toast and coffee
task.
The result indicates that NTT of MCI group is
longer and more variable than that of healthy group.
The sandwich and juice tasks were especially difficult
for the MCI group. From the task structure point of
view, the toast and coffee tasks are performed easily
in parallel; therefore, the causal relationship of
subtask of toast and coffee task could be more
complicated to perform.
Summarizing the above, (1) Sandwich and juice
task more difficult for the MCI group. (2) Task
structure could make participant confused. In next
section, we attempted to perform the NTT and TT
analyses on smaller IADL subtasks.
4.3 Sub Task Analysis
We tried to divided main tasks into sub tasks and
calculate NTT in order to find which sub task is
difficult for MCI group. However, it is difficult to
analyse because NTT data is small. We conclude that
we should analyse with another data to explore the
behaviour such as finger velocity data during VR-
IADL.
4.4 Classification with SVM
In order to investigate whether the features is useful
for classifying MCI, Support Vector Machine (SVM)
was performed on eleven parameters: variance and
mean of NTT in both tasks, RNTT in both tasks, NTT
variance in sandwich task, juice task, NTT mean in
sandwich task and variance of toast task and coffee
task. The accuracy of MCI including history of MCI
is 75%. Figure 9 showed that the result of ROC
analysis, which indicate that FPT is 0.5 and FPF is
0.67 and AUC is 0.71. This result suggests that NTT
and several parameters calculated with NTT can
classify MCI group.
Figure 9: ROC analysis.
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156
5 CONCLUSIONS
This study explored the features of IADL behaviours
that effectively distinguish MCI from healthy older
adults. The study focused on identifying cognitive
processing speed and motor processing speed using
time spent touching (TT) or not touching (NTT) the
screen on a VR-based IADL task. We conclude that
NTT was greater in participants with MCI or a history
of MCI. NTT may reflect slowed cognitive
processing speed; however, we were unable to
identify reliable behaviours during NTT did not see a
reliable relation between NTT and IADL subtask.
Therefore, future work is needed to understand why
NTT are longer in MCI. Future studies will include
larger participant samples and analysis with other
methods, including analysis of finger movements
during NTT.
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