One of the main sequelae of stroke is partial loss of strength or partial paralysis. This condition means that patients who have suffered a stroke must undergo long rehabilitation processes to recover their balance and gait. The traditional techniques used in exercise-based assessments are not entirely objective, as they largely depend on the person carrying them out. So professionals from Gorliz Hospital suggested a need to objectify this assessment and systematize the evolution of patients during the rehabilitation process.

So the UPV/EHU’s COMPMECH research group, which has expertise in mechatronics (a multidisciplinary branch of engineering that develops devices and technologies combining the branches of systems, electronics, mechanics, control and robotics), has developed a new prototype to “assess, exercise and rehabilitate a person's balance when standing on a surface by measuring his or her centre of pressure,” explained Francisco Campa, a researcher in the group.

“Let’s imagine we are standing while travelling on a bus,” explained Campa. “When the bus moves off or brakes, the body, in order to balance itself, distributes its weight forwards and backwards supported by the soles of the feet against the floor. The resultant point of this force is known as the centre of pressure, and the study of its movement enables a person's balance to be assessed.”

Control over balance stimulation

The prototype recently patented by the COMPMECH group has a platform on which the person with balance problems stands, and has two functions. The first is to stimulate the patient’s balance, in other words, to provoke a reaction in order to see how he or she responds. “The mechanism we have designed raises the platform vertically or tilts it forward, from side to side or in any direction, with a certain amplitude and speed that is determined by the physiotherapist who is programming the machine,” he pointed out. And the second function is to measure the patient's response: “The platform rests on four sensors that enable the force the patient is exerting on the platform to be measured. And on the basis of that force, the movement of the centre of pressure is determined,” he added.

What is new about this prototype is that “it has been designed to make reliable and repeatable measurements. The same stimulus is always introduced. It is always going to be a movement of a certain amplitude and speed, so that it can be better traced, and the patient's evolution can be better monitored over time. This allows us to be more effective in finding out what has caused the patient to move in a certain way,” he pointed out. 

Once the design had been validated by the medical team at Gorliz Hospital, the prototype entered the clinical trial phase: “We have started testing the prototype on actual patients and volunteers,” said Campa. The researcher pointed out that “this machine is promising, because balance problems are not only experienced by stroke patients, but also by patients with other conditions, such as amputees who need to get used to a prosthesis, people with vertigo problems, etc.”

Campa is delighted with the level of collaboration they have had with the team of professionals at Gorliz Hospital: “Their involvement has been invaluable. They have opened the doors of the hospital to us, and we have worked side by side with professionals from many different fields.”

Additional information

Francisco Javier Campa lectures in the Department of Mechanical Engineering on the Degree course in Industrial Technology Engineering at the Faculty of Engineering -  Bilbao.