How virtual reality affects the brain: mechanisms, benefits and precautions

Immersion in virtual reality triggers three distinct neurological processes: a measurable change in brain waves, the activation of specific brain regions and the emergence of a sense of spatial presence.

Changes in brain waves in a virtual environment

The brain is not passive when faced with a VR headset. In 2019, researchers at Tilburg University used electroencephalograms to measure the brain activity of participants immersed in virtual reality[1]. The result: a notable reduction in alpha waves in the frontal, central and parietal regions. These alpha waves are associated with a state of relaxation and low concentration. Their decrease therefore indicates increased concentration and high cognitive engagement. What the researchers observed was striking: brain activity in VR was similar to that recorded in situations experienced in the real world.

Brain regions activated during the VR experience

Three regions are of particular interest to neuroscientists. The frontal region is involved in the sense of presence, movement control and planning. The central and parietal regions handle engagement, spatial perception and the management of movements in space. During a VR climbing simulation, for example, the frontal region enters a state of intense concentration to plan each movement, while the parietal region becomes active to process spatial information. The stronger the immersion, the more the brain sets aside distractions to focus on the virtual environment.

The sense of presence and embodiment

Embodiment refers to bodily integration into a virtual environment: the feeling that your body belongs in this digital space. A study by Tjon et al. (2019) showed that this sense of spatial presence, meaning the illusion of being physically present in a virtual location, is directly correlated with a significant decrease in alpha waves in the frontal region. When immersion is sufficient, awareness of the real world fades. The brain stops distinguishing between simulation and lived reality.

Three cognitive benefits are now documented: faster assimilation, stimulation of creativity and improved memory retention.

Assimilation up to four times faster

The figures are clear. A PricewaterhouseCoopers study (2024) found that learners using virtual reality assimilate information up to four times faster than those using traditional methods. The explanation lies in the very nature of immersion: VR makes it possible to recreate realistic situations in which learners can practise without risk, particularly for complex or stressful work-related tasks. Medical training, piloting, industrial technical procedures: brain engagement increases and information becomes more memorable. The brain processes a lived experience, not passive content.

Stimulating creativity and innovation

An experiment involving 21 participants compared creative exercises performed in VR and on a standard 2D screen. Participants immersed in VR showed higher levels of immersion, satisfaction and creativity. Their brain activity revealed increased activation of alpha, beta and gamma waves: beta waves reflect a state of active alertness, while gamma waves are involved in complex cognitive processing. Together, they promote a state conducive to generating innovative ideas.

Good to know: The brain does not always distinguish between VR and reality. Brain activity measured during virtual immersion is similar to that observed in situations experienced in real life: a Parisian café to learn French, a Madrid bar to practise Spanish. This neural confusion directly explains the educational effectiveness of virtual reality.

Four categories of adverse effects have been documented: cybersickness, visual disturbances, sleep disturbances and the risk of epileptic seizures.

Cybersickness: nausea and dizziness in virtual environments

Cybersickness is virtual motion sickness. It affects 30 to 50% of users and manifests as nausea, dizziness, sweating, pallor and loss of balance. The mechanism is specific: the brain receives conflicting signals between what the eyes perceive (virtual movement) and what the body feels (actual stillness). This sensory mismatch causes the symptoms. In susceptible individuals, they can appear within the first few minutes of use. The Anses recommendations published in 2021[2] are clear: stop immediately at the onset of any symptom.

Visual disturbances associated with prolonged use

VR screens create an illusion of distance even though the screen is only a few centimetres from the eyes. This discrepancy between perceived and actual distance places unusual demands on the eye muscles. Prolonged use can cause eye strain and temporary visual disturbances. The LED screens in headsets also emit high levels of blue light. According to an Anses survey conducted in 2019, the average session lasts more than an hour, placing most users in a range of prolonged use that requires monitoring. No precise threshold has been defined to date.

Disruptions to the circadian cycle and sleep

Blue light emitted by the LED screens in VR headsets disrupts biological rhythms when exposure occurs in the evening or at night. Documented consequences include delayed sleep onset and impaired sleep quality. Anses recommends avoiding all screen exposure for two hours before bedtime, particularly for children and adolescents, who are more sensitive to blue light. This recommendation is all the more relevant given that sessions last more than an hour on average.

The risk of photosensitive epileptic seizures

The LED screens in VR headsets emit temporally modulated light, a flickering that is sometimes imperceptible to the naked eye. This phenomenon can trigger epileptic seizures in susceptible individuals. The prevalence is 1 in 4,000 people experiencing a seizure in response to flashing lights. Anses recommends avoiding VR use for people with epilepsy, as well as for other populations identified as sensitive: pregnant women, people who experience motion sickness, have balance disorders or are prone to migraines.

Good to know: Anses recommends a rest period of 1 to 2 hours after a VR session before any activity requiring a high level of concentration, such as driving. The body makes a considerable effort to adapt to the virtual world, resulting in real fatigue. Users often overlook this precaution.

Three medical fields have demonstrated the effectiveness of virtual reality, and more specifically of virtual therapy: post-stroke motor rehabilitation, pain management and the treatment of anxiety disorders and phobias.

Motor rehabilitation after a stroke

The figures illustrate the scale of the challenge. In France, around 140,000 people have a stroke each year, 150,000 sustain a traumatic brain injury, 25,000 new cases of Parkinson's disease are diagnosed and 1,500 cases of cerebral palsy are recorded. Virtual reality supports the restoration of motor function by stimulating brain plasticity, the brain's ability to reorganise itself after an injury.

The Haute Autorité de Santé recommendations published in 2022[3] advocate VR as an adjunct to conventional therapy to improve motor function after a stroke, with a moderate level of evidence. The benefit is tangible: the exercises are engaging and motivating, whereas conventional rehabilitation can become repetitive and discouraging. Sessions help patients regain everyday movements (grasping an object, opening a door), improve balance and walking, or simulate real-life situations such as crossing a street or climbing stairs.

C2Care develops VR solutions for motor rehabilitation, deployed in 350 healthcare facilities in France, with support for medical teams.

Pain management for patients with severe burns and chronic pain

Results in patients with severe burns are among the most extensively documented. During care procedures, which are often very painful, immersion in virtual reality can significantly reduce perceived pain, by up to 60% according to some studies. The mechanism involves attention: virtual immersion engages a large proportion of the brain's cognitive resources. The patient pays less attention to pain signals. Measurements of brain activity confirm this reduction in areas associated with pain perception.

The approach also extends to chronic back pain, neck pain and postoperative pain. Its main advantage is that it is non-pharmacological, limiting side effects and the risk of dependence.

Treatment of anxiety disorders and phobias

Virtual reality exposure therapy (VRET) is based on a simple principle: gradually exposing the patient to a stressor in a safe, controlled environment. This habituation process allows the brain to modify its response to anxiety-provoking stimuli. Fear of flying (from going through security to turbulence), agoraphobia, specific phobias such as spiders, heights or syringes: each situation can be recreated and its intensity precisely adjusted.

VRET is more effective than conventional CBT for certain indications. Psychiatrist Éric Malbos treated patients with tobacco dependence using VRET: 72% had not relapsed after treatment, compared with 50% with CBT. Facilities such as Pitié-Salpêtrière in Paris, hôpital de la Conception in Marseille and CHU de La Réunion use this approach.

C2Care offers a comprehensive suite of therapeutic VR software for phobias and anxiety disorders, with more than 250 exposure situations available, controlled by the practitioner from a single platform. More than 700 practitioners have been trained in this approach.

Controlling a device through thought alone, without any physical movement. This is the principle behind brain–computer interfaces (BCIs). These systems capture the brain's electrical signals via EEG and translate them into commands.

Adding virtual reality to BCI training environments significantly improves brain signal recognition and makes brain–machine interaction smoother. Recent research (Gougeh et al., 2023) shows that people with amputations can control prostheses more precisely through motor imagery in VR: the brain trains to generate the right signals in an immersive environment before transmitting them to the actual prosthesis.

Virtual reality neurofeedback takes this principle further. It is a closed-loop system in which the user's brain activity directly influences what they see and experience in the virtual environment. If the brain reaches a desired state of concentration, the environment becomes brighter or changes positively. Research on virtual reality neurofeedback[4] shows promising applications for anxiety management, ADHD and the optimisation of cognitive performance. Large-scale evidence is still being gathered, but initial results are encouraging.

The recommendations from Anses and feedback from hospital practice point to the same precautions. Here are the rules to follow to limit adverse effects:

• Stop immediately when symptoms appear: nausea, dizziness, sweating, pallor. Do not wait for symptoms to worsen.
• Rest for 1 to 2 hours after each session before any activity requiring sustained concentration, particularly driving. The body makes a real effort to adapt to the virtual world.
• Avoid screens for 2 hours before bedtime, particularly for children and adolescents, who are more sensitive to the blue light from LED screens.
• Do not use VR if you have epilepsy or belong to a group identified as sensitive: pregnant women, people who experience motion sickness, have balance disorders or are prone to migraines.
• Inform users about potential effects through dedicated materials, whether in professional or general-public settings.

The 2019 Anses survey indicates that the average session lasts more than one hour. This finding reinforces the relevance of these precautions. The long-term effects of virtual reality on the brain, whether neurological or developmental, remain insufficiently documented and warrant further research.

Key takeaways on how virtual reality affects the brain

The effects of virtual reality on the brain are documented, measurable and multidimensional.

Brain mechanisms: VR reduces alpha waves in the frontal, central and parietal regions, activates areas involved in planning and spatial perception, and generates a sense of presence measurable by EEG. The brain responds as it would to a real situation.

Cognitive benefits: learning up to 4 times faster, stimulation of creativity, validated therapeutic applications for motor rehabilitation and the treatment of anxiety disorders.

Risks to be aware of: cybersickness in 30 to 50% of users, visual disturbances, sleep disturbances related to blue light, risk of epileptic seizures for 1 in 4,000 people.

Essential precautions: rest after sessions, avoid screens before bedtime, identify at-risk populations. Long-term effects remain to be documented.