The goal of this observational study is to determine whether the clinical response to olfactory stimulation (known as the "sniff" response) can help predict 3-month neurological outcomes in ICU patients with persistent disorders of consciousness after sedation withdrawal, regardless of the reason for admission or the initial severity.

The main questions this study aims to answer are:

• Can the "sniff" response to olfactory stimulation predict neurological outcomes at 3 months?
• Is this response a better prognostic indicator than commonly used neurophysiological tests? Researchers will compare the results obtained from olfactory stimulation with those from somatosensory and auditory stimulations to determine whether the olfactory method provides additional or superior prognostic value.

Participants will receive additional olfactory stimuli as part of the neurophysiological evaluation for prognostic purposes and be followed up at 3 months for clinical, neurological, and functional evaluation

Inclusion Criteria:

• Admission to neuro-intensive care unit (neuro-ICU)
• Age ≥ 18 years
• Patients with persistent disorders of consciousness defined by an abnormal CRS-R score (<16) at 72 hours after sedation withdrawal and spontaneous ventilation
• Consent obtained from legal representatives or activation of emergency waiver
• Patient covered by or affiliated with a social security system

Exclusion Criteria:

• Pregnancy
• Brain death
• Pre-existing ENT or olfactory bulb pathologies that may affect olfactory functions
• Acute or chronic peripheral neurological diseases that may alter evoked potentials
• Known neurodegenerative diseases (e.g., Parkinson's disease, Alzheimer's disease)
• Patients under legal guardianship or protective supervision (safeguard or protection measures)