Clinical assessment of motor and sensory deficits is still today largely based on tests that
do not permit any precise quantification. However, robotic technologies, coupled with
neuroimaging techniques constitute new tools to assess sensorimotor functions that could
allow to conceive neurorehabilitation protocols better adapted to the neurological impairment
of each patient and to her/his specific recovery profile.
The goal of this project is to contribute identifying the factors that determine functional
recovery in stroke patients presenting upper-limb motor deficits. Here, we will focus our
research on two factors that contribute in a complementary way to motor control: 1) the
processing of proprioceptive informations, and 2) the processing of movement-execution
errors. In this purpose, we will combine psychophysical methods that allow to precisely
quantify sensorimotor deficits with functional and anatomical neuroimaging techniques. More
specifically, we will exploit experimental protocols that have been developed in basic
research, that use a robotic exoskeleton coupled with a virtual reality device, to precisely
quantify motor and proprioceptive deficits in stroke patients. Then, we will link these
behavioral data to electroencephalographic (EEG) signals recorded during a motor adaptation
task, as well as to anatomical data, namely conventional magnetic resonance imaging (MRI)
completed by diffusion tensor images (DTI) in order to achieve a finer description of the
The present study will include two experimental parts, respectively centered on the
proprioceptive deficits (Part 1) and the anomalies in the processing of movement-execution
errors (Part 2).
Proprioceptive deficits in stroke patients : We will test the hypothesis that, when present,
deficits in kinaesthesia and troubles in unconscious proprioception contribute substantially
to motor deficits in stroke patients ; with as a corollary hypothesis, that deficits in "
proprioception for action " are more determinant than deficits in the conscious sense of
position (classically tested in clinics). In this purpose, we will collect three sets of
behavioral data, in chronic stroke patients and healthy control participants, respectively
intended to assess a) motor deficits, b) troubles in conscious sense of position, and c)
deficits in "proprioception for action". To better document the neuronatomical substrates of
these different types of deficits. In this purpose, we will link the obtained behavioral data
with the results of detailed analyses of the lesions of the tested stroke patients.
Anomalies in the processing of movement-execution errors in stroke patients : We will assess
movement-execution error processing in stroke patients, in order to test the idea that
anomalies in error processing might contribute to motor deficits in stroke patients. In this
purpose, we will record an electrophysiological correlate (ERP) of movement-error processing
during a motor adaptation task. We will analyse the relation between the modulation of this
ERP and motor performance. We will also examine the relation between these two sets of data
(behavioral and electrophysiological) and the behavioral data collected during the first part
of the study (Proprioceptive deficits). This will provide us with insight into the
relationship between proprioceptive deficits and cinematic error processing. As in the first
part of the study, we will link the observed electrophysiological and behavioral anomalies
with the results of a detailed analysis of the anatomical lesions of the tested patients.