Faculty of Physical Education
and Physiotherapy
Exam Commission:
Prof. dr. Bart Roelands - chairman
Department of Human Physiology,
Faculty of Physical Education and
Physiotherapy, Vrije Universiteit Brussel,
Belgium
Prof. dr. ir. Heike Vallery
Department of Biomechanical
Engineering, Faculty of Mechanical
Engineering, Delft University of
Technology, the Netherlands
Prof. dr. Jacques Duysens
Movement Control & Neuroplasticity
Research Group, Faculty of Kinesiology
and Rehabilitation Sciences, Katholieke
Universiteit Leuven, Belgium
Prof. dr. Maria Francesca Piacentini
Department of Human Movement and
Sport Sciences, University of Rome,
Italy; Department of Human Physiology,
Faculty of Physical Education and
Physiotherapy, Vrije Universiteit Brussel,
Belgium
Prof. dr. Nicole Pouliart
Department of Orthopaedics and
Traumatology, University Hospital
Brussels, Belgium; Department of Human
Anatomy, Vrije Universiteit Brussel,
Belgium
Prof. dr. ir. Guy Nagels
Department of Internal Medicine
Specializations, Faculty of Medicine
and Pharmacy, Vrije Universiteit Brussel,
Belgium
Promoters:
Prof. dr. Romain Meeusen
Department of Human Physiology,
Faculty of Physical Education and
Physiotherapy, Vrije Universiteit Brussel,
Belgium
We cordially invite you to the public defence
of the doctoral dissertation in fulfilment
of the requirements for the degree of
DOCTOR IN REHABILITATION SCIENCE
AND PHYSIOTHERAPY
Of miss KRISTEL KNAEPEN
Which will take place on
Friday, June 19 at 17:00 in “U-Residence” located
near the athletics track on the campus of Etterbeek,
followed by a walking dinner at 19:00
HUMAN-ROBOT INTERACTION IN REHABILITATION
AND ASSISTANCE OF LOCOMOTION
Promotor: Prof. dr. Romain Meeusen
Prof. dr. ir. Dirk Lefeber
Prof. dr. E. Kerckhofs
Dean of the Faculty of Physical Education and Physiotherapy
Please confirm your presence by June 10 to [email protected]
Prof. dr. ir. Dirk Lefeber
Robotics & Multibody Mechanics
Research Group, Department of
Mechanical Engineering, Faculty of
Engineering, Vrije Universiteit Brussel,
Belgium
How to reach the Vrije Universiteit Brussel
http://www.vub.ac.be/infoover/campussen/index.html
Pleinlaan 2 – 1050 Brussel
[T] 02/629 27 19 - 27 26 - 27 27 – 39 57
[F] 02/629 27 01
[E] [email protected]
Presentation of the Dissertation
Recently, technological advancements have led to the use of robotic devices to facilitate
gait rehabilitation and assistance in subjects with lower limb impairments and gait
disorders. Robot-assisted gait training has a large potential to improve motor function
and facilitate walking recovery, while robotic devices for the assistance of gait can
augment walking performance, and thus mobility and independency of disabled
patients. Yet, to date it is not entirely clear how humans interact with robotic devices
for rehabilitation and assistance of the lower limbs and how we can, based on that
interaction, maximize their effectiveness. Until now, emphasis has often been put
on the mechanical development and control design of robotic systems. Furthermore,
conclusions on its effectiveness are mostly drawn from experiments measuring system
performance on one or two subjects. However, in order to optimize these systems, it
is imperative to determine how humans respond to and interact with them from a
biomechanical and physiological point of view.
Aim of the Dissertation
The purpose of this work was to study the assessment and effects of human-robot
interaction (HRI) between a healthy human motor system and robotic devices for
rehabilitation and assistance of gait. HRI was studied in terms of biomechanical and
(electro)physiological parameters. All studies were carried out in the framework of the
ALTACRO (i.e., Automated Locomotor Training using an Actuated Compliant Robotic
Orthosis) and CYBERLEGs project (i.e., The Cybernetic Lower Limb Cognitive OrthoProsthesis).
Studies
Several studies were performed to examine the assessment and effects of HRI on a
healthy human motor system. First, a literature review was performed to provide an
overview of the state-of-the-art in the assessment of HRI and the effects of robot-aided
assistance and rehabilitation of gait on the human body. Next, a first study on HRI, in
terms of muscle activity, kinematics and gait parameters, with a unilateral powered knee
exoskeleton (KNEXO) at different levels of compliant assistance was performed. The
study revealed that healthy subjects can walk with KNEXO in patient-in-charge mode
with some slight constraints in kinematics and muscle activity primarily due to inertia
of the device. Yet, during robot-in-charge walking the muscular constraints are reversed
by adding positive power to the leg swing. No significant differences in the human
response to the interaction with KNEXO in low and high compliant assistance could be
pointed.
As motor intentions and high-level adaptations of motor patterns originate at the
supraspinal level, a measure to assess the effects of HRI on this level was introduced,
i.e., electroencephalography (EEG). EEG is a non-invasive technique with a high temporal
resolution, which renders it ideal to record intrastride changes in brain activity. However,
it is prone to movement artifacts. Therefore, the feasibility of using EEG to record brain
activity during walking was investigated in a second study.
The results showed that it is feasible to measure EEG during human gait. Moreover, a
characteristic temporal pattern of positive and negative potentials related to the phases
of the gait cycle was observed over the cortical leg representation area.
In a third study, HRI was assessed in terms of cortical activity during robot-assisted
treadmill walking with the Lokomat-system. The study revealed three active clusters
located in the sensorimotor cortex during treadmill walking and robot-assisted treadmill
walking in healthy subjects. These clusters demonstrated gait-related modulations in
the mu, beta and low gamma bands over the sensorimotor cortex related to specific
phases of the gait cycle (i.e., event-related spectral perturbations). Moreover, mu and
beta rhythms were suppressed (i.e., event-related desynchronisations) in the primary
sensory cortex during treadmill walking compared to robot-assisted treadmill walking,
indicating a larger involvement of the sensorimotor area during treadmill walking.
In a last study, the feasibility of using physiological parameters as a measure of cognitive
workload during walking was examined. The study indicated that heart rate, heart
rate variability and breathing frequency as well as gait parameters are sensitive to
detect changes in cognitive workload during walking. As such, these parameters are
good candidates to feed back to the control loop of a bio-cooperative assistive device
(e.g., lower limb prosthesis) in order to detect the cognitive workload and give robotic
assistance as needed.
Conclusion
This dissertation showed that biomechanical and (electro)physiological parameters are
adequate to assess different aspects of HRI, such as human performance and active
participation. Furthermore, the different neural correlates closely related to the phases
of the gait cycle during walking and robot-assisted walking indicate that there is a
cortical contribution to the motor control of human gait.
Curriculum Vitae
Kristel Knaepen graduated as master in Rehabilitation Science and Physiotherapy at
the Vrije Universiteit Brussel in 2005, magna cum laude. From 2006 until 2008 she
worked, respectively, at the department of Rehabilitation Research and the department
of Movement Education and Sports Training of the Vrije Universiteit Brussel. In 2008, she
started her PhD at the department of Human Physiology of the Vrije Universiteit Brussel,
on the ALTACRO project. In 2012 she joined the FP7 European project, CYBERLEGs. Kristel
published 5 full-text papers as first author and 8 full-text papers as co-author in peerreviewed international journals and presented her findings at several (inter)national
scientific conferences.