Preliminary Findings of Feasibility of a Wearable Soft-robotic Glove
Supporting Impaired Hand Function in Daily Life
A Soft-robotic Glove Supporting ADL of Elderly People
B. Radder
1
, G. B. Prange-Lasonder
1,2
, A. I. R. Kottink
1,3
, L. Gaasbeek
4
, J. Holmberg
5
, T. Meyer
6
,
J. H. Buurke
1,3
and J. S. Rietman
1,2
1
Roessingh Research & Development, Roessingsbleekweg 33b, Enschede, the Netherlands
2
Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
3
Department of Biosystems and Signals, University of Twente, Enschede, the Netherlands
4
National Foundation for the Elderly, Regulierenring 2D, Bunnik, the Netherlands
5
Eskilstuna Kommun Vård- och omsorgsförvaltningen, Eleonoragatan 18, Eskilstuna, Sweden
6
terzStiftung, Seestrasse 112, Berlingen, Switzerland
Keywords: Assistive Technology, Assistive Device, Hand, Activities of Daily Living.
Abstract: Elderly people frequently encounter difficulties in independently performing activities of daily living (ADL)
due to a reduced hand function. Robotic assistive devices have the potential to provide the assistance that is
necessary to perform ADL independently without the need of personal assistance. Therefore, the objective of
the present study was to explore feasibility of a wearable soft-robotic glove (ironHand (iH) system) that can
support hand function of elderly people in daily life. Thirty elderly people (>56 years) with a reduced hand
function resulting in difficulties in performing ADL were recruited to perform six functional tasks three times
with and without the iH system. Evaluation measurements consisted of functional tasks performance times
and user-acceptance of the iH system, measured by the System Usability Scale (SUS). Participants improved
their functional task performance after multiple attempts either with and without the glove, but performed
significantly faster without the glove (p0.032). Besides, the mean of the SUS score for the iH system was
70.1%. Although this indicates a good probability for acceptance in the field, several design adaptations are
necessary to have a user-friendly and accepted assistive device.
1 INTRODUCTION
In general, the elderly population frequently
experiences a decline in hand function due to
deterioration of handgrip strength (Carmeli et al.,
2003; Ranganathan et al., 2001). The decline in hand
function can lead to a negative effect on the ability to
grip and manipulate an object (Kinoshita and Francis,
1996). This results in difficulties in independently
performing activities of daily living (ADL), such as
holding (heavy) objects, writing and manipulating
small objects (Hackel et al., 1992; Shiffman, 1992).
These limitations often have an impact on elderly’s
quality of life (Ranganathan et al., 2001).
To overcome limitations in ADL, elderly often
need personal assistance and/or assistive devices to
carry out ADL. However, personal assistance results
in an increased dependency in performing ADL for
the elderly person him/herself, while assistive devices
do have the potential to contribute to functional
independence (Hoenig et al., 2003). There are several
assistive devices available that people can use to
compensate for the loss of functionality in hand motor
function (Maciejasz et al., 2014). However, the
functionality of simple assistive devices (e.g., a knife
with adapted handle) is limited to the specific
application (e.g. cutting), whereas fully robotic
assistive devices (e.g., a robotic arm and gripper
(JACO)) are often expensive, not portable and not
easy to use in daily life (Frappier, 2011, Maciejasz et
al., 2014). Other robotic hand devices are aimed at
rehabilitation (Balasubramanian et al., 2010), not to
support the hand directly during ADL over prolonged
periods at home.
180
Radder, B., Prange-Lasonder, G., Kottink, A., Gaasbeek, L., Holmberg, J., Meyer, T., Buurke, J. and Rietman, J.
Preliminary Findings of Feasibility of a Wearable Soft-robotic Glove Supporting Impaired Hand Function in Daily Life - A Soft-robotic Glove Supporting ADL of Elderly People.
In Proceedings of the International Conference on Information and Communication Technologies for Ageing Well and e-Health (ICT4AWE 2016), pages 180-185
ISBN: 978-989-758-180-9
Copyright
c
2016 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
Therefore, an easy to use wearable soft-robotic
glove is being developed in the ongoing ironHand
(iH) project, namely the iH system, that can support
hand function in a wide range of ADL. By adding a
personalized computer gaming environment, specific
training exercises can be provided as well. As a first
step, this study explores whether use of such an
assistive glove during functional tasks can enhance
task performance. Since this device should be usable
independently during daily life, user acceptance is
assessed as well.
2 METHODS
2.1 Participants
In this study, elderly (55 years) with hand function
problems resulting in difficulties in performing ADL
were included across four clinical sites: National
Foundation for the Elderly (NFE), Bunnik and
Roessingh Research & Development (RRD),
Enschede in the Netherlands, Eskilstuna Kommun
Vård- och omsorgsförvaltningen (ESK), Eskilstuna in
Sweden and terzStiftung (TERZ), Berlingen in
Switzerland.
Participants had to meet the following inclusion
criteria: (1) at least 10 degrees of active flexion and
extension movement of the fingers; (2) sufficient
cognitive status to understand two-step instructions;
(3) having (corrected to) normal vision; (4) living at
home; (5) and provided written informed consent
prior to the start of the study.
Exclusion criteria for this study were: (1) severe
sensory problems of the hand; (2) severe acute pain
of the hand; (3) wounds on their hands that may create
problems when using the glove; (4) severe
contractures limiting passive range of motion; (5) co-
morbidities limiting functional use/performance of
the arms/hands; (6) insufficient knowledge of the
Dutch, Swedish or Swiss-German language to
understand the purpose or methods of the study; (7)
and participation in other studies that can affect
functional performance of upper limb.
This study was approved by the local Medical
Ethical Committees (MEC) in the Netherlands,
Sweden and Switzerland.
2.2 ironHand System
The iH system encompasses an iH Assistive System
(iH AS), consisting of the glove and a control unit to
support functional performance in a wide range of
ADL directly; and an iH Therapeutic System (iH TS)
with additional computer-game-like exercises to
provide a specific training context (see Figure 1). This
study focuses on the iH AS only.
The iH AS is based on the concept of the SEM™
glove (Nilsson et al., 2012) that provides support for
grip of the thumb, middle finger and ring finger in a
natural and intuitive way, but only if the user initiates
the movement actively. Additionally, the iH AS
provides support for hand opening via leaf springs
attached to the top (dorsal side) of the glove fingers.
The support of grasping is controlled by touch
sensors on the finger tips. These sensors send a signal
to the control unit which pulls the artificial tendons,
placed along the length of the fingers in the glove,
such that the grip force is augmented. The extra force
applied by the glove is in proportion to the force
applied by the user. The amount of extra force can be
tuned for the individual user. Further details can be
found in Nilsson et al. (Nilsson et al., 2012).
2.3 Procedure
2.3.1 Study Design
A multicentre cross-sectional study design was used
for this feasibility study, consisting of executing tasks
with and without the iH AS.
These tests were performed in a simulated ADL
environment at NFE, ESK and TERZ supervised by
the researchers of NFE, ESK and TERZ and
coordinated by RRD.
2.3.2 Experimental Protocol
Before the evaluation session started, demographic
characteristics including age (years), gender,
dominant hand and most-affected hand were
collected.
Next, the sensitivity level and maximum force of
the iH AS and the amount of leaf springs in the iH AS
Figure 1: The ironHand system.
Preliminary Findings of Feasibility of a Wearable Soft-robotic Glove Supporting Impaired Hand Function in Daily Life - A Soft-robotic
Glove Supporting ADL of Elderly People
181
were tuned for each participant, based on ability/need
and the experienced comfort. Furthermore,
instructions needed for proper use of the iH system
were provided by the researchers, if necessary.
Thereafter, the participant was asked to
independently perform six functional tasks with and
without the iH AS. The functional tasks were based
on real life situations and consisted of drinking,
eating, household, reading (and writing), (un)dressing
and door opening tasks (see section 2.4.1 for more
details). All functional tasks were standardized to
ensure uniformity in task execution within and
between participants. Each activity was performed
three times with and three times without the iH AS to
observe the differences between both conditions in
functional performance. From those three repetitions,
the first two were dedicated to getting used to the
system, and only the last repetition was used to
compare the performance time between conditions
with and without iH AS. For each participant, the
order of functional tasks with and without the glove
was randomized by using sealed envelops.
At the end of the evaluation session, the
participant was asked about his or her experiences
and perceived ability of using the iH system. For this
purpose the System Usability Scale (SUS) was
assessed (see section 2.4.2 for more details).
2.4 Evaluation
2.4.1 Functional Task Performance Test
Before the start of each functional task, the execution
of the functional task was demonstrated by the
researchers to the participants. In addition, the
researchers provided verbal instructions about the
execution of each task during its performance.
The six selected functional tasks were performed
as described below:
1. Drinking Task: The participant opens a bottle of
water (0.5L), pours some water in a cup, closes
the bottle of water, takes a sip of water and returns
the bottle and cup to the starting position.
2. Eating Task: The participant takes a knife,
cucumber and plate to prepare 3 slices of
cucumber. After cutting 3 slices of cucumber, the
participants returns the knife, cucumber and plate
to the starting position.
3. Household Task: The participant takes a cloth,
wrings the cloth for three times and cleans the
table.
4. Reading (and Writing) Task: The participant
holds a book in the most-affected hand for 30
seconds and if possible, he/she writes the last
word on the left page of the book on a paper and
returns the book to the starting position.
5. Dressing Task: The participant takes jacket off
the coat hanger, puts jacket on, closes the
zippers/button, opens jacket and returns it to the
coat hanger.
6. Door Task: The participant takes the key of the
door from a seat, puts the key in the door,
closes/opens the door and returns the key to the
seat next to the door.
The researchers assessed the performance time for
each activity by using a stopwatch.
2.4.2 System Usability Scale
The SUS is a simple ten-item questionnaire to assess
system usability. It uses a 5 point Likert scale ranging
from ‘strongly disagree’ till ‘strongly agree’. The
scores of the ten items were multiplied by 2.5, so that
the total score is between 0-100% (Brooke, 1996).
A total score of <50% indicates that the system
will almost certainly have usability difficulties in the
field; 50-70% is a promising score, but guarantees no
high acceptability in the field and more improvement
is necessary; >70% indicates a high probability of
acceptance in the field (Bangor et al., 2008).
2.4.3 Data Analysis
The data of the outcomes were analysed using the
IBM SPSS Statistics software package version 23.0.
The performance times of the functional tasks were
checked for normal distribution by visual inspection
of the q-q plot, the box plot, histogram plot and by the
Shapiro-Wilks test, prior to the statistical analysis.
Descriptive statistics were used for all outcomes
measures.
In order to assess the direct influence of
performance with and without the iH AS, a Wilcoxon
signed rank test or a paired sample t-test was
performed, depending on normal distribution of the
outcome measures. The overall level of significance
was set at p< 0.05.
3 RESULTS
3.1 Participants
In total, 30 elderly were included in this feasibility
study with the current prototype of the iH system
across the Netherlands (n=10), Sweden (n=10) and
Switzerland (n=10). There were two drop outs in the
Netherlands as a result of too much pain in their
ICT4AWE 2016 - 2nd International Conference on Information and Communication Technologies for Ageing Well and e-Health
182
hand/fingers, which prevented the participant to be
able to use the glove. Table 1 shows the
characteristics of the remaining 28 individuals at
baseline.
Table 1: Characteristics of participants at baseline.
Participants (n=28)
Age (years)
a
72 ± 8 (56-84)
Gender (male/female) 9/19
Living at home (yes/no) 28/0
Affected body side (right/left/both) 14/8/6
Dominant hand (right/left/both) 25/2/1
a
Mean ± standard deviation (range
3.2 Functional Task Performance Test
The dressing task was excluded from analysis,
because of many missing values. This task was
difficult to perform due to the bulkiness of the iH AS.
Furthermore, data of the reading (and writing) and
door tasks were not complete. Both tasks have
missing data of the third attempt with and without the
glove for one participant and the door task is not
executed at all by one participant.
Figure 2 shows the performances times of the 3
repetitions of each functional task with and without
using the glove (data only available from NFE and
ESK; n=18), respectively. This figure shows that the
participants improved their performance time over
the three repeated attempts either with or without the
iH system (p0.045), except for the reading task
without the glove.
Figure 2: Performance times of the functional tasks.
*
significant difference between repeated attempts.
The last attempt of all five functional tasks with
and without the glove are presented in figure 3 (n=28)
to compare the performance time between conditions
with and without iH AS. The participants performed
significantly faster on all five functional tasks without
the iH AS (p0.032).
Figure 3: Performance times of the last attempt of the
functional tasks.
*
significant differences.
During the performance of the functional tasks,
researchers observed that participants had some
difficulties when using the iH AS. The most
frequently mentioned and observed issues with the iH
AS during the performance of the functional tasks
were difficulties with grasping the cap of the bottle,
opening and closing the bottle, writing, grabbing the
plate, grasping the pen and picking up the key.
However, most participants mentioned that they
felt support of the iH AS during grasping the bottle,
cutting food, wringing the cloth, turning the key
(pinch grip well supported) and holding the book.
They considered the support as helpful. In addition,
they noticed that their performance with the iH AS
improved after multiple attempts.
3.3 System Usability Scale
There was one missing SUS resulting in 27 completed
SUS for the iH AS. The mean score on the SUS is
70.1% (SD=14.1) and only 7% of the participants
scored lower than 50% (see figure 4).
4 DISCUSSION
After the identification of user requirements for the
iH system (Radder et al., 2015), the current study
examined the feasibility of the iH system by applying
a user centred approach. It is important that end-users
are involved early in the design and development
process of new assistive technology to increase the
probability of getting assistive technology adopted by
users (Demain et al., 2013). From the present
feasibility tests it became clear that the concept of the
iH system is well received and appreciated to support
ADL, but practical usability and performance of the
current prototype should be improved further. These
findings are in line with the study of Polygerinos et
al. (Polygerinos et al., 2015).
Preliminary Findings of Feasibility of a Wearable Soft-robotic Glove Supporting Impaired Hand Function in Daily Life - A Soft-robotic
Glove Supporting ADL of Elderly People
183
Figure 4: Individual SUS scores with the group mean score
(black line).
The results of the functional task performance test
showed that participants substantially improved task
performance either with or without the glove within 3
attempts. However, at this moment, all functional tasks
were performed faster without the glove than with the
glove. During the current feasibility tests, some issues
were observed that could explain these results.
First of all, elderly used the iH system only for a
few minutes in which three repetitions of the
functional task were done. During these three
repetitions, participants showed improvements in
their functional performance indicating a fast learning
effect (see figure 2). The steep learning curve is
promising because participants have probably not
reached their plateau yet. This suggests that more
progression is possible if participants have a longer
time to get used to iH system (Prasad et al., 2002).
The reason for having relatively short time for getting
acquainted with iH AS, was to get a good idea of
feasibility and usability for independent use. If too
many instructions and repetitions are provided, no
information about intuitive use is available. Future
user tests should ideally include a longer
acquaintance period.
Secondly, it is possible that the current functional
tasks were not the most appropriate. In case of stroke
patients, the most-affected hand is mainly used to
support the other hand during the performance of
ADL, instead of using the most-affected hand as
primary hand for manipulating objects during ADL
(Prange et al., 2015). However, the participating
elderly performed the functional tasks with the glove
worn on the hand they perceived as most affected,
which was in most cases their dominant hand. Instead
of using the gloved hand as supporting hand during
functional tasks, the elderly attempted to perform
finer motor activities with their gloved hand. Due to
a limited sensation of the covered dominant fingers,
the functional task performance may have been
affected. Therefore, the role of the gloved, more
affected hand in (bi-manual) functional tasks should
be taken into account more specifically in subsequent
studies with elderly participants.
Thirdly, several usability issues hindered
functional task performance with the glove,
indicating that the current iH prototype should be
improved. For instance, the current fabric of the glove
decreased the sensation of the fingertips during the
performance of functional tasks with the glove, which
made it very difficult for participants to perform fine
motor activities such as grasping a cap of a bottle,
opening and closing a bottle, writing etc.. Further
design adaptations are needed to fulfil the expectation
of participants that such robotic devices are easy to
use and not too bulky to use unobtrusively in a wide
range of ADL (Maciejasz et al., 2014). It is likely that
an improved sensation will result in a better
performance of the functional tasks relative to the
performance without the glove.
Although some very important aspects for
improvement of the iH system were formulated by the
participants, averaged SUS score was 70.1%, which
indicates good probability for acceptance in the field
(Bangor et al., 2008). Other studies using the SUS for
other types of technology showed similar or higher
SUS scores (Ambrosini et al., 2014, Nijenhuis et al.,
2015, Ni, 2013). The one study addressing actual use
at home in addition to usability, where the mean SUS
score was 67%, showed that people were able to
independently use a robotic training device at home
for on average 15 min/day over 6 weeks (Nijenhuis et
al., 2015). This suggests that the iH AS could be
usable at home.
In summary, the current results on user acceptance
are promising for developing a user-friendly and
acceptable assistive device. However, several design
changes based on the results of the feasibility study
are necessary to further enhance the chance for uptake
of the iH system in daily life. This should also
improve functional task performance with the glove
beyond performance without the glove, before actual
use of such assistive system will be beneficial for (and
adopted by) elderly. In future studies, a next version
of the iH system will be tested in daily life situations
of elderly persons as part of the iterative, user-centred
design process.
ACKNOWLEDGEMENTS
This feasibility study of the iH project is partly
fundedby the Ambient Assisted Living joint
ICT4AWE 2016 - 2nd International Conference on Information and Communication Technologies for Ageing Well and e-Health
184
programme (grant AAL-2013-6-134) via ZonMw
(the Netherlands), Vinnova (Sweden) and SERI
(Switzerland). Furthermore, we would like to thank
our iH project partners for the provided iH systems
and their technical support during the study: Bioservo
Technologies AB and Hocoma AG.
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