An implant, a programmer, a control system... Put them together and you can help people who have lost the use of their limbs to regain some freedom of movement. The product of a European research project supported by an extremely dynamic, international network of clinics.
Some 300,000 Europeans suffer from paralysis.
Average age: 31. Cause: 65% road accidents and 10% sports injuries.
Medical explanation: the specific nature of the neurons, the cells
which make up the nervous system and which, unlike other cells,
do not regenerate. Each individual is born with a given number of
neurons which, once destroyed, cannot be replaced.
Thus, someone whose spinal cord is damaged at the neck will become quadriplegic and more or less lose the use of all four limbs, whereas other lesions - on the thorax or small of the back - may cause paralysis of the lower limbs (paraplegia).
In this type of accident, however, the muscles which lie underneath the lesions are still alive and connected to the spinal cord by nerves. Their dysfunctional behaviour (contractions, rigidity, etc.) stems from the fact that they are disconnected from the brain. If this could somehow be replaced with another control function, the patient would partly recover the use of his or her limbs.
This theory, which is not new, has led to the development of "functional electrostimulation" techniques: two electrodes, placed on the skin, stimulate the underlying muscles, causing them to contract. "This method clearly has its limitations, however, because putting electrodes on someone, day in, day out, isn't all that easy," comments Pierre Rabischong, professor at the Montpellier faculty of medicine.
... to implants
1984 onwards, as part of the joint research activities funded by
the Commission, European scientists began to devise new solutions,
which were far more promising than electrostimulation. "The
idea was to build an implant, which would be placed inside the body
and controlled by an antenna which would send it radio signals.
This antenna would in turn be connected to a walkman-sized portable
programmer, containing the control system intelligence," continues
Pierre Rabischong, one of the coordinators of the research.
In order to move, patents with paralysed lower limbs would use two crutches incorporating the programmer control buttons (the "brain"). They would be able to choose from a number of very simple commands: start, slow down, accelerate, change direction, etc.
A European network of clinics
Since 1989, the European research team has focused on developing this promising new technology, and in 1992, they formed a network of European clinics bringing together surgeons, rehabilitation experts, engineers, etc. They set up the CALIES project under the EUREKA programme and since 1996, have been receiving support from the Community programme BIOMED2. A new company, Neuromedics, has been set up to coordinate and market the system, working in close partnership with IBM and Thompson. The aim is to place implants in six patients at the beginning of 1998; they will then be monitored in parallel in six countries (France, Italy, Netherlands, Germany, United Kingdom, Denmark).
"The joint project gives Europe an enormous boost in this field of research, particularly with regard to the United States and Japan who are working in similar areas. Thanks to the European projects, we have created a dynamic network of clinics, combining the rigour of the Germans with the imagination of the Italians and the improvisation of the French, to produce a particularly effective, interactive unit," concludes Prof. Rabischong.
A winning formula, which should soon lead to implant-based technologies suitable for large-scale marketing.