Severe traumatic brain injuries are common and can lead to major long-term disability. Patients with severe brain injury often require admission to critical care. For relatives, this period is highly distressing: during and after an ICU stay, family members frequently experience anxiety, depression, and post-traumatic stress symptoms.

In recent years, family involvement in critical care has been associated with better communication with the healthcare team and fewer psychological difficulties among relatives. In parallel, findings from neuroscience suggest that early multisensory stimulation (engaging the five senses) may help support brain recovery by promoting neuronal connections during the awakening phase.

This study evaluates whether a standardized neurosensory stimulation program, delivered by trained relatives of brain-injured patients hospitalized in critical care, can reduce post-traumatic stress symptoms in those relatives. We hypothesize that involving relatives in a structured, supervised multisensory stimulation protocol during the patient's awakening phase (before transfer to rehabilitation) will decrease relatives' post-traumatic stress symptoms at 3 months after critical care discharge (or after the patient's death). We also expect potential secondary benefits on patients' awakening and recovery trajectory.

Traumatic brain injury is a major public health issue, with a substantial number of severe cases requiring critical care management. Beyond the patient's neurological prognosis, critical care admission for brain injury exposes relatives to intense stressors and is associated with anxiety, depressive symptoms, and post-traumatic stress symptoms. Published studies have reported wide but consistently high rates of post-traumatic stress symptoms among relatives of ICU patients.

Family-centered approaches in intensive care have been increasingly promoted. Prior research has suggested that involving family members in care processes can improve communication with the clinical team and may reduce psychological distress among relatives. Building on this rationale, the present study aims to integrate relatives of brain-injured patients into an early, structured care activity: standardized neurosensory stimulation.

The intervention is grounded in neuroscientific principles supporting early stimulation during the awakening phase, with the intent to provide repeated sensory inputs that may help maintain and strengthen neuronal networks. To translate these principles into critical care practice, a standardized protocol of multisensory stimulation by relatives of brain-injured patients has been developed.

The study is conducted in a surgical and trauma ICU setting, with patient trajectories potentially including step-down surgical high-dependency care. Participants (i.e. patients and their relatives willing to participate) are enrolled shortly after cessation of sedation, during the early awakening period. Participants are randomized to one of two parallel groups: (1) usual care, where stimulation occurs according to standard clinical practice led by the care team and relatives follow standard visiting procedures; or (2) a standardized family-delivered neurosensory stimulation program. In the intervention group, the program includes several key components: an interview with relatives to identify the reference family member(s) and to collect relevant information on the patient's habits and preferences; presentation of the standardized stimulation protocol and training of the relative(s) in practical methods to stimulate the five senses, with an emphasis on adapting stimulation to the patient's condition; structured traceability of stimulation activities performed during visits.

Relatives are followed up after the critical care period to assess psychological outcomes, and patients' level of awakening is monitored during critical care stay and discharge. Overall, the study evaluates whether a standardized, supervised, family-delivered neurosensory stimulation approach can reduce relatives' post-traumatic stress symptoms and potentially support patient recovery during the transition from awakening in critical care to rehabilitation.

inclusion criteria :

• Age ≥ 18 years
• Relative (family member or close person) of an eligible brain-injured patient hospitalized in critical care
• Able and willing to provide informed consent to participate.
• Available to attend at least three visits during the patient's critical care hospitalization.
• French-speaking (sufficient proficiency to understand study information and complete questionnaires).

exclusion criteria :

• Non-French-speaking or insufficient French proficiency to complete study procedures/questionnaires.
• Insufficient understanding/comprehension of the study procedures, as assessed during the initial interview after explanations by the study nurse.