[Comp-neuro] Post-doc position - Montpellier, France

[Christine Azevedo]

Post doctoral position

Active compensation of pathological TREMOR using FES

Environnement
Tremor is defined as the involuntary rhythmic or semi rhythmic 
oscillation of a body part resulting from alternating of simultaneous 
contractions of antagonistic muscle groups. The tremor frequency may 
change but motion is always sinusoidal. Tremor is the most common 
abnormal motion encountered in human pathology. It is classified 
depending on the source and can be a rest tremor or an action tremor 
(kinetic or postural). The origin, the functional consequences and the 
treatment may change depending on the pathology. Pathological tremor 
affects 5-9% of the population age 40 and above. Common causes of 
pathological tremor include Parkinson’s disease or cerebellar 
dysfunctions (e.g. multiple sclerosis, stroke, etc.). Not only does this 
involuntary movement impair the activities of daily living of many 
patients, it also often leads to social embarrassment and even 
isolation. The lifetime economical and social cost as a result of a 
reduction in independence is an enormous burden to an individual, as 
well as the society.
The main objective of the project is then to propose an alternate 
solution to actual pharmacological or surgical therapies that may have 
limited results. This alternate solution is based on the active tremor 
compensation of the upper limbs via functional electrical stimulation. 
The TREMOR project is composed of 4 subsections (two scientific, one 
technological and one clinical) which are successively i) modeling of 
pathological tremor, ii) synthesis of algorithms for active tremor 
compensation, iii) design of a prototype for a wearable orthosis and iv) 
clinical evaluation.
It involves a research laboratory (LIRMM) through the research teams 
DEXTER and DEMAR, a company (MXM) expert in functional electrical 
stimulation and two clinical partners (CHU of Montpellier, Neurology 
Department, and Propara Rehabilitation Center).

Missions
Currently, tremor modelling and filtering algorithms have been developed 
to better understand the physiological phenomenon of tremor and to 
separate voluntary motion from disturbed motion subject to tremor. We 
are now in the phase of developing closed loop control algorithms and 
testing clinically all the proposed algorithms.

Activities
Within the duration of the post-doctoral position, the main goals to be 
achieved are then:
•To evaluate first the feasibility and efficiency of FES to reduce upper 
limb tremor in open loop. The outcome of this will be a set of 
strategies in terms of stimulated muscles and FES parameters adapted to 
given patient profiles.
•To implement new closed loop control algorithms for compensating tremor 
based on inertial sensors (e.g. accelerometers) and physiological 
sensors (e.g. EMG),
•To evaluate clinically the filtering and control algorithms in closed 
loop on a large set of patients
All experiments have been submitted to the authorization of the ethical 
committee obtained in September 2009.

Keywords
Control theory - modeling of biological system - Experiments

Complementary Information
C programming

Contacts :
Philippe.poignet at lirmm.fr
Christine.Azevedo at lirmm.fr