Anabelle Ayma and Quitterie Legrand study traumatic brain injuries in Geneva; Published in American Journal of Public Health

A friendship, a semester’s project, and a scientific article - EPFL

A friendship, a semester’s project, and a scientific article

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Anabelle Ayma (left) and Quitterie Legrand. 2026 EPFL

Hector Garcia Morales - CC-BY-SA 4.0

Few master’s students see their work published in an international scientific journal. For Anabelle Ayma and Quitterie Legrand, that rare achievement grew out of a friendship formed at EPFL.

During that meeting, Stéphane Joost, Scientist at the EPFL Laboratory for Biological Geochemistry, and Philippe Voruz, psychologist at Geneva University Hospitals (HUG), propose a master’s project on… traumatic brain injury. “I hit my head and the next day someone presented me with a project on traumatic brain injuries. I thought that it must be fate, and I accepted the project,” explains Anabelle.

Given the richness and breadth of the data, the project naturally evolves into two complementary studies. When it came to developing this second line of research, one person immediately comes to Anabelle’s mind: her friend Quitterie. “We had already collaborated on several projects, and each time it had worked out really well,” says Anabelle.

From environmental engineering to public health

The project brings together environmental engineering, geospatial analysis, and public health, an unusual combination that appeals to both students’ interest in spatial data. Yet neither expected to be studying traumatic brain injury through an environmental engineering lens. “I did not know environmental engineering could be applied to this kind of research,” says Anabelle.

The study that led to the publication is divided into two parts. While Anabelle’s work focuses on the general population in Geneva, Quitterie focuses on the impact of traumatic brain injury among older adults. They already know each other’s working styles, and combining the two projects feels natural. “Rather than duplicating efforts, we divided the methodology according to our strengths and priorities,” says Quitterie.

The analysis carried out by Anabelle and Quitterie shows that traumatic brain injuries occur more frequently in some areas than others, and that social and environmental characteristics can help explain these geographic differences.

One interesting fact is that among active people, weekends have the highest incidence due to an increase in physical activities, while for senior population Tuesday is the day with more accidents. “We were wondering why Tuesdays were special. I asked the senior people I knew, and they told me that they go shopping on Tuesdays because they usually have discounts,” says Anabelle.

Over the following months, the two students would spend countless hours discussing methodology, exploring different statistical approaches, and refining their analyses. What began as a semester project gradually became something more ambitious.

A key moment comes when Anabelle presents these results in front of an international conference of neurosurgeons within the neurosurgery service of the HUG attended by specialists in the medical field. “There were lots of white coats. These weren’t young people our age; they were really heads of department,” says Anabelle. The audience showed great interest in the results and actively engaged with the findings.

Encouraged by the response from the medical community, the team submits the study to the American Journal of Public Health , where it is eventually accepted for publication. They start realizing that something serious is happening when they find themselves signing the authorship documentation required for publication. A year after beginning their project, the two students are still getting used to seeing themselves as published researchers.

They do not know where this publication will lead them professionally. They do not even know whether research is their natural path to follow. But what they know for sure is that the journey was worth the effort. The experience introduced them to research and strengthened their confidence. It also showed them that environmental engineering can be used to study public health, not only water resources, rivers and infrastructure.

Yet beyond the publication itself, the project leaves them with something equally valuable: a friendship forged through late-night discussions, shared challenges, and a year of discovery. What began as a meeting in the classroom ultimately became a collaboration that neither had imagined.

Anabelle Ayma, Quitterie Legrand, Noé Fellay, Gabriel Kathari, Dulcinda Delannoy, Aria Nouri, Elena Beanato, Roberta Ronchi, Karl Schaller, Stéphane Joost, Giannina Rita Iannotti, and Philippe Voruz: Spatial Clustering and Multivariate Typologies During Life Span of Hospitalized Traumatic Brain Injury Cases: A Population-Based Study American Journal of Public Health 116, 1272-1275.

Author: Hector Garcia Morales ENAC

Summer holidays. A group of friends meets in Ardèche, in the south of France. During a hike, Anabelle Ayma, a master’s student in environmental engineering at EPFL, trips over a rock and hits her head. She does not lose consciousness, but a cut above her eyebrow leaves blood running down her face. Concerned about the concussion, her friends monitor her throughout the night. Looking back, the incident would take on unexpected significance the following day during a videocall. During that meeting, Stéphane Joost, Scientist at the EPFL Laboratory for Biological Geochemistry, and Philippe Voruz, psychologist at Geneva University Hospitals (HUG), propose a master’s project on… traumatic brain injury. “I hit my head and the next day someone presented me with a project on traumatic brain injuries. I thought that it must be fate, and I accepted the project,” explains Anabelle. Given the richness and breadth of the data, the project naturally evolves into two complementary studies. When it came to developing this second line of research, one person immediately comes to Anabelle’s mind: her friend Quitterie. “We had already collaborated on several projects, and each time it had worked out really well,” says Anabelle. From environmental engineering to public health The project brings together environmental engineering, geospatial analysis, and public health, an unusual combination that appeals to both students’ interest in spatial data. Yet neither expected to be studying traumatic brain injury through an environmental engineering lens. “I did not know environmental engineering could be applied to this kind of research,” says Anabelle. The study that led to the publication is divided into two parts. While Anabelle’s work focuses on the general population in Geneva, Quitterie focuses on the impact of traumatic brain injury among older adults. They already know each other’s working styles, and combining the two projects feels natural. “Rather than duplicating efforts, we divided the methodology according to our strengths and priorities,” says Quitterie. The analysis carried out by Anabelle and Quitterie shows that traumatic brain injuries occur more frequently in some areas than others, and that social and environmental characteristics can help explain these geographic differences. One interesting fact is that among active people, weekends have the highest incidence due to an increase in physical activities, while for senior population Tuesday is the day with more accidents. “We were wondering why Tuesdays were special. I asked the senior people I knew, and they told me that they go shopping on Tuesdays because they usually have discounts,” says Anabelle. Over the following months, the two students would spend countless hours discussing methodology, exploring different statistical approaches, and refining their analyses. What began as a semester project gradually became something more ambitious. Towards scientific publication A key moment comes when Anabelle presents these results in front of an international conference of neurosurgeons within the neurosurgery service of the HUG attended by specialists in the medical field. “There were lots of white coats. These weren’t young people our age; they were really heads of department,” says Anabelle. The audience showed great interest in the results and actively engaged with the findings. Encouraged by the response from the medical community, the team submits the study to the American Journal of Public Health , where it is eventually accepted for publication. They start realizing that something serious is happening when they find themselves signing the authorship documentation required for publication. A year after beginning their project, the two students are still getting used to seeing themselves as published researchers. Paving their future They do not know where this publication will lead them professionally. They do not even know whether research is their natural path to follow. But what they know for sure is that the journey was worth the effort. The experience introduced them to research and strengthened their confidence. It also showed them that environmental engineering can be used to study public health, not only water resources, rivers and infrastructure. Yet beyond the publication itself, the project leaves them with something equally valuable: a friendship forged through late-night discussions, shared challenges, and a year of discovery. What began as a meeting in the classroom ultimately became a collaboration that neither had imagined. This transdisciplinary project involved more than 1,000 patients hospitalized in the Neurosurgery Department of the Geneva University Hospitals (HUG) between 2012 and 2024 with moderate-to-severe traumatic brain injury. The study brought together the complementary expertise of EPFL through the GEOME lab and the HUG through a jointly led consortium involving Karl Schaller, Head of the Neurosurgery Department, and Giannina Rita Iannotti, Coordinator of the HUG NeuroCentre. This project laid the foundations for a broader, long-term research program that intends to move beyond observation with the development and evaluation of preventive interventions aimed at mitigating the effects identified by the study carried out by Anabelle and Quitterie.