Stroke
is a leading cause of long-lasting disability. As many as 41.5 million
new cases occur yearly in Europe, and 3.7 million survivors experience
long-lasting impairments, whereas less than 15% of patients achieve full
poststroke recovery [1].
It
is estimated that 80% of stroke patients have upper-limb deficits and
have decreased activity and use of the paretic hand in daily life [2];
the involvement of the more affected hand in activities of daily living
(ADLs) depends on the severity of the deterioration and is associated
with a decrease in health-related quality of life (HRQoL) and
restrictions on social participation [3, 4].
Most
of the functional recovery after diagnosis occurs in the first three
months, although neural repair processes and behavioral improvements
continue to show slight plasticity in later phases of the rehabilitation
process [5, 6].
Therefore, it is crucial that hand rehabilitation begin early;
treatment should start within this window of opportunity for functional
recovery, when the brain is especially receptive to sensorimotor
interaction [7,8,9].
Rehabilitative
treatment of the upper limb is recognized by consensus among survivors,
caregivers and health professionals as one of the top ten research
priorities for poststroke recovery [10, 11].
In addition to the rehabilitation of the upper limb, other priorities
should also be taken into account for the development of
neurorehabilitation programs and the design of the corresponding
studies, such as minimizing patients’ mobility disability, poststroke
fatigue and difficulty in fulfilling responsibilities in the family and
work environments; improving patients’ response to the demands of
society; and ensuring exhaustive, well-structured monitoring of their
clinical evolution after treatment.
During poststroke hand
treatment, special attention must be paid to restoring the different
biomechanical movements and curvature of the hand in order to provide a
stable base and correct alignment as a prerequisite for dexterity
training and modulation of reaching movements [12,13,14].
It is crucial to remember that restoring the selective voluntary
movements of the upper limb in stroke patients also relies on the
postural control that is necessary for reaching movements—scapula
stabilization, shoulder stability more broadly, and selective muscle
recruitment [15,16,17,18,19,20].
Various
therapies based on a conventional approach have been demonstrated to be
useful, achieving good results in terms of hand rehabilitation: motor
imagery training seems to improve the precision and accuracy of
movement, as well as the reception of sensory signals, by fostering
activation of dormant synapses and accelerating reperfusion of the
ischemic penumbra [21].
Mirror therapy can reduce asymmetric hemisphere activation, stimulate
the primary motor cortex in both the lesioned (ipsilateral) hemisphere
and the opposite (contralateral) hemisphere, widely activate the mirror
neuron system and induce partial pathways for motor neurons on the side
affected by stroke, which facilitates the remodeling of brain function [22, 23].
Constraint-induced movement therapy focuses on intensive, gradual
training of the paretic upper limb to improve its use in specific tasks,
limit the use of the less affected upper limb, and, in the context of
behavior-changing methods for improving adherence, transfer the clinical
achievements into the patient’s real life [24]
by relating the therapeutic intervention components to the improvement
of motor function and the use and skill of the paretic hand in daily
life [25].
Forced use, which is meant to maximize daily use of the paretic hand,
seems to yield improvements in motor function after intervention, and
these improvements persist for three months after poststroke
intervention [26].
Last but not least, active sensory therapies focus on active sensory
training in the context of practice with goals involving multiple areas
of the brain; pursuing neural reorganization in this manner enhances the
motor recovery of the paretic upper limb (e.g., practicing nonvisual
identification of common objects increases stereognosis) [27].
Another important aspect of hand-focused therapy programs is the use of a generous dose of intense repetition [28]. Lang et al. [27]
determined by means of meta-regression that from 24 to 57 h, the effect
size increased by 0.034 for every ten extra hours of therapy,
independent of the specific poststroke intervention. In a conventional
therapy session at an ordinary hospital rehabilitation unit, a patient
can achieve 30 repetitions of an exercise involving the upper limbs,
whereas specific technological systems allow more than 300 repetitions
in 34 min of action per session [29, 30].
Recent
years have witnessed an increased use of technology-based and
especially virtual reality–based neurorehabilitation approaches, which
have allowed the creation of effective simulated environments and
provided multimodal, controllable and customizable stimulation [31]. The re-creation of objects in virtual form maximizes visual feedback [32].
In addition, high intensity and a large number of repetitions are key
factors influencing neuroplasticity and functional improvement in
patients [33].
Rehabilitation based on virtual reality offers the possibility of
addressing individual treatment needs and simultaneously standardizing
evaluation and training protocols [34, 35].
There
are two major types of virtual reality-based systems used in
neurorehabilitation: nonspecific virtual reality (N-SVR) systems and
specific virtual reality (SVR) systems. These two classes differ in that
systems of the former type use game consoles and video games designed
by the entertainment industry. Such consoles (Wii, Xbox, PlayStation,
etc.) run games that are not designed for adults suffering from a
neurological pathology and do not allow monitoring of movement or other
motor or functional variables of the affected body segments. Thus, N-SVR
systems are not designed for the neurophysiological recovery of the
brain, and they do not focus on the neuronal connections necessary for
the recovery of hand function after stroke. In contrast, SVR systems are
specifically designed to promote motor learning and recovery,
optimizing the acquisition, retention and generalization of motor
skills. SVR systems incorporate key features of virtual reality and add
objective, quantitative movement monitoring and exergames to facilitate
the motor recovery of the hand (regular voluntary movement, arches of
hand curvature, grasping, pinch grips and gross manipulation). In
addition, SVR systems comply with the principles of neurorehabilitation:
mass practice (repetitive training), high dosing (intensive training),
structured practice, task-specific practice (ADL-relevant skills
training), variable practice, multisensory stimulation (training in
which the feedback is not limited to the visual modality), increasing
difficulty (individualized training), explicit feedback (training that
provides knowledge about the results), implicit feedback (training that
provides task-relevant implicit signals), avatar representation
(immersive training) and encouragement of the use of the paretic limb
(training that counteracts compensation) [36].
In
this sense, neurorehabilitation SVR systems allow rehabilitation work
to proceed in a functional way and with specific intervention
objectives, and these systems can easily evaluate and document progress
during sessions [37].
Taking advantage of these characteristics, several authors have used
virtual reality-based therapy (VRBT) to restore motor function after
stroke [38,39,40]. Immersion, presence, and interactivity are three key features of virtual reality [41, 42]. In the course of our study, the exergames of the HandTutor©
glove software made it possible for the user to become the main
character (immersion); users perceived the connection to the virtual
environment through movement (interactivity) and acted inside it as they
received input and responded to the challenges posed by the exergame
(presence).
In this regard, Laver et al. [40]
analyzed studies that compared N-SVR-based therapies with an
alternative intervention or no intervention. In 2017, they updated their
review by adding 35 new studies of N-SVR-based therapies, the majority
of which used commercial games on the Nintendo Wii console. They
concluded that virtual reality alone did not offer statistically
significant improvements, in contrast to conventional treatment.
However, when virtual reality was applied as a complement to common
treatment, this combined treatment outperformed the conventional
treatment alone. In these studies, the experimental group was given more
time for treatment than the control group [41].
Choosing
the appropriate neurorehabilitation strategies to maximize clinical
results in stroke patients takes priority. In this sense, a combination
of more traditional neurophysiological approaches and motion-based
therapies, delivered at a high intensity and in a large dose in
motivating game-related environments where motion can be made, offers an
important advantage in restoring the motor function of the upper limb [29, 31].
Our clinical trial differs from the studies included in the review as follows: (1) it adds SVR technology (HandTutor©
glove), designed for hand motor rehabilitation; (2) it offers the same
amount of time for intervention in both groups (control vs.
experimental); and (3) it combines SVR with conventional treatment
(experimental group). Additionally, many of the studies included in the
review focused on adult patients with chronic stroke (a period of
recovery equal to or greater than six months after diagnosis).
Ikbali and collaborators [39] used the Kinect sensor and the Xbox 360 console from Microsoft Inc.©
to train active movement of the upper limb, focusing on shoulder
abduction and adduction and wrist flexion and extension exercises.
The
Kinect sensor, independent of any specific software for rehabilitation
after stroke, is able to capture gross movement of the upper limb, but
it cannot identify hand motion and does not include exergames designed
for hand motor rehabilitation.
Programs incorporating SVR technology to train distal motor function after cerebrovascular accident remain little known [43, 44], in contrast to programs focusing on proximal motor function [45], robot-assisted hand treatment [30, 46] or improving balance and walking [47, 48].
Therefore, the aim of the present study is to test whether conventional
rehabilitation combined with SVR is more effective than conventional
therapy alone in restoring the motor function and muscle tone of the
hand after stroke.
It was hypothesized that, compared to control
group (CG) participants, adults randomized to the experimental group
(EG) would achieve an increased degree of hand motor function
improvement and have superior results on the Fugl-Meyer Assessment,
Ashworth Scale, and Action Research Arm Test.
More at link.
Wen-Hao Huang
Zu-Lin Dou
Hui-Min Jin
Ying Cui
Xin Li
Qing Zeng4