Recovering full cognitive function after breast cancer

For some years now, hospitals have been experimenting with virtual reality devices to help patients recover certain faculties impaired by operations or treatments. This may involve, for example, accelerating the recovery of motor functions after a prolonged coma.

At the Inria Center of the University of Rennes, in partnership with the Pontchaillou University Hospital, the ^[1] team develops and evaluates rehabilitation methods by virtual reality in this medical context. Through her thesis^[2] which has just ended, Émilie Hummel has just outlined a new protocol, this time for patients in remission from breast cancer.

Many of these women are young and want to get back to work as soon as possible. But they often suffer from post-cancer cognitive disorders. This complicates their return to work.

Hence the idea of using virtual reality as a complementary tool in clinical rehabilitation programs for these patients.

Estimating acceptability

Until now, nothing like this has ever been done. Everything remains to be built. After a lengthy phase of surveying the state of the art, the next step was to assess the acceptability of such an approach. “With the help of my co-supervisors, Mélanie Cogné, a doctor at Rennes University Hospital and member of the Seamless team, and Marie Lange, a neuro-psychologist at the François Baclesse Centre in Caen, we interviewed 43 patients taking part in a rehabilitation program at these facilities, as well as 19 caregivers.” On this occasion, they were able to don a visiocasque, familiarize themselves with an example of a virtual reality scene and discover its immersive power.

As a result, “some of them were only interested if the exercise presented a precise simulation of their personal work situation. Which, of course, is complicated to set up. Some found it interesting, but more for others than for themselves. Others were ready to take the plunge. They embraced the idea of re-training cognitive functions to facilitate a return to work. Or to regain self-confidence.”

On the basis of these findings, the next step was to start sketching out the outlines of a future application with exercise scenarios. Here too, caregivers were involved in the work.

Three tasks with different functions

“We have defined three tasks that train different cognitive functions. These exercises are similar to what you might do in the office. It's what we call an 'ecological' application in the sense that it's close to everyday life.”

First task: sorting. “Invoices have to be sorted, according to different criteria: date, type of item purchased, price, and so on. This allows us to work on our speed of information processing.”

Second task: planning. “We have to manage the calendar for a community center. There are exhibitions, concerts, activities. You have to fill in the schedule within certain constraints. Some events take place on Wednesdays. Others on weekends. Still others require all available rooms, so we have to avoid scheduling anything else on the same day, etc.”

The third task involves forward memory. “We have to remember that we have something to do later. Picking up the kids at 4 p.m., for example. You have to remember to check the time and then perform the task accordingly. Or perform an action based on an event that occurs. And to do that, I'm going to have to interrupt what I was doing before.”

This virtual environment strives to reproduce the conditions that can exist in real life.  “Through the office window, you can see the street, hear traffic and the sound of construction work. You can also hear colleagues chatting in the corridor. These background volumes of sound vary according to the impact we wish to give them in the exercise. They disrupt attention, and this is something that particularly affects people suffering from these post-cancer cognitive disorders.”

A scripting tool : Xareus

To build these exercises, which include six levels of difficulty, Émilie Hummel relied on Xareus, a scripting tool developed within the Seamless team. “Four engineers^[3]lso helped me with functionalities that didn't yet exist in the software.”

Patients see the scene in the first person. “They have a trigger in their hand. When they close their fist, an object rises up and comes to rest in the avatar's virtual hand. When they release the fist, the object falls back down.”

Integrating psychological states

After all these steps, Émilie Hummel was able to get to the heart of her thesis.

The latter can be defined by the ratio between the available resource and the task at hand. “The more tired I am, the more difficult it seems.

To introduce these factors, two further experiments were conducted. The first was aimed at adapting the difficulty of a task, in this case sorting. “It became harder or easier depending on the action to be performed, but also on the mental load, which we measured via a questionnaire.” The results were convincing. When the algorithm adapted to the mental load, participants felt less tired. “They felt they were doing better and, in fact, they were doing better.”

The second experiment sought to modulate stress levels. How could this be achieved? “Using a haptic interface with thermal feedback. We applied a cooler or warmer temperature to the trapezius muscles to see what effect this had during a difficult and stressful mental arithmetic task. We assumed that a cooler temperature would lead people to be less stressed. The results are mixed, but it would seem to work in people with a preference for cold.” This latter part of the research resulted in a publication^[4] at the Eurohaptics 2024 conference.

The thesis therefore opens up prospects both for the use of virtual reality in the treatment of cognitive disorders after breast cancer, and for the consideration of psychological states in the application. “But this is only the first step. I hope that others will follow suit to one day bring this tool into rehabilitation programs.”

^[1]Seamless est une équipe de recherche Inria, CNRS, Université Rennes et INSA Rennes, commune à l’UMR Irisa.

^[2]Cette thèse a été financée par Inria et l’Inserm, dirigée par Valérie Gouranton et Anatole Lécuyer, encadrée par Mélanie Cogné et Marie Lange. Elle a bénéficié de l’aide de Florence Joly au centre François Baclesse de Caen.

^[3]Florian Nouviale, Alexandre Audinot, Anthony Mirabile et Adrien Reuzeau.

^[4]Cool Me Down: Effects of Thermal Feedback on Cognitive Stress in Virtual Reality.  Philippe, V., Hecquard, J., Hummel, E., Argelaguet, F., Macé, M.J.M., Gouranton, V., Pacchierotti, C., Lécuyer, A. et Saint-Aubert, J., dans Eurohaptics 2024.