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

, G. B. Prange-Lasonder

1,2

, A. I. R. Kottink

1,3

, L. Gaasbeek

, J. Holmberg

, T. Meyer

J. H. Buurke

1,3

and J. S. Rietman

1,2

Roessingh Research & Development, Roessingsbleekweg 33b, Enschede, the Netherlands

Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands

Department of Biosystems and Signals, University of Twente, Enschede, the Netherlands

National Foundation for the Elderly, Regulierenring 2D, Bunnik, the Netherlands

Eskilstuna Kommun Vård- och omsorgsförvaltningen, Eleonoragatan 18, Eskilstuna, Sweden

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 (p≤0.032). 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

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)

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

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 (p≤0.045), 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 (p≤0.032).

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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