Journal of Rehabilitation Medicine 51-4inkOmslag | Page 65

UE performance with a soft-robotic glove in elderly patients
of user acceptance and usability) (14, 15) and its ef-
fect on functional performance (13, 15, 16), showing
promising results on user acceptance and usability.
Although pinch strength increased significantly, ADL,
such as picking up, and moving, objects, were perfor-
med slower with the ironHand glove compared with
without the glove (15, 16). Clinical scales that score
performance time may be less suitable to assess the
direct effect of a soft-robotic glove on hand function,
since aspects other than performance time can be in-
fluenced by use of such a glove, which was developed
to support grip strength. For instance, small changes
in movement execution can make a difference in fun-
ctional use of the hand in daily life (17, 18).
Assessing functional tasks through kinematic ana-
lysis is useful for evaluating actual functioning of the
upper limb in daily life, since kinematics movement
analysis is seen as a sensitive and objective method
to assess differences in movement execution (19).
Therefore, the goal of the present study was to explore
differences in movement duration of a reach-and-grasp
task with and without the assistance of the ironHand
glove. Secondly, the influence of the glove on duration
of movement phases, movement smoothness, trunk
displacement, peak hand velocity, hand opening and
joint excursion of the elbow and wrist were explored.
METHODS
Participants
A subgroup of 8 participants who also participated in an earlier
cross-sectional study, investigating the overall orthotic effect of
the ironHand glove (13), were included in this explorative study
at Roessingh Research and Development (RRD), Enschede, the
Netherlands. Inclusion criteria for participation in this study
were: at least 55 years of age; experienced difficulties with
performing ADL involving the hand; the most-affected hand is
the dominant hand; able to perform at least 10° of active flexion/
extension movement of the fingers; sufficient cognitive function
to understand 2-step instructions; (corrected to) normal vision;
and living at home. Exclusion criteria were: severe sensory
problems; pain or wounds on the hand that may create problems
when wearing the glove; severe contractures limiting passive
range of motion; co-morbidities limiting functional use of the
arms/hands; insufficient knowledge of the Dutch language to
understand the purpose or methods of the study. All participants
gave their written informed consent prior to the start of the study.
The study was approved by the Medical Ethics Committee in
Twente, the Netherlands (CCMO-number NL56746.044.16).
ironHand system
The ironHand glove was developed to support grip strength of the
thumb, middle finger and ring finger (Fig. 1) (13). The ironHand
system consisted of a 3-fingered wearable soft-robotic glove
(Fig. 1A) and a control unit (Fig. 1B) that contains the embedded
software to control the amount of force needed to support grip
299
Fig. 1. The ironHand system. A: Glove. B: Control unit (14).
strength and the batteries. The control unit was attached at the belt
of the participant (Fig. 1B). Sensory input from pressure sensors
(Interlink Electronics, Camarillo, CA, USA) at the fingertips is
used to control the amount of extra grip that is regulated by a
tendon-driven mechanism. An intention detection logic ensures
that the grip is activated in a natural and intuitive way with more
grip support supplied when a stronger grip is applied on the object.
The gain of the control mechanism (i.e. sensitivity) and maximal
amount of support from the glove can be tuned for each indivi-
dual. In this study, the maximal amount of grip strength support
was set at 20 N for each participant and the gain of the control
mechanism was tuned for each patient between 2 preprogramed
modes based on the participants’ needs and experienced comfort.
Study design
Prior to performance of a standardized reach-and-grasp task,
maximal handgrip strength was measured (without the glove) to
describe the degree of functional limitations of the present sample
(20, 21). In addition, information about the participants, such as
sex, age, affected body side, dominant side and handgrip strength,
was gathered. Next, participants performed a standardized reach-
and-grasp task with various weighted cylindrical objects during
a cross-sectional evaluation session. Both tasks were performed
with the most-affected hand, once with and once without the
ironHand glove, to evaluate differences in movement between
both conditions with use of a 3D motion analysis systems. Sealed
envelopes were used to randomize the order of glove use (first
with or without the glove). The primary focus was placed on
total movement duration. Secondarily, the effect of the glove on
movement duration of movement phases, movement smoothness,
trunk displacement, peak hand velocity, hand opening and joint
excursion of the elbow and wrist were explored.
J Rehabil Med 51, 2019