Using smells to help predict recovery in comatose or unresponsive ICU patients

Consciousness Prognosis Evaluation Using Olfactory Stimulations in Comatose Patients

Not applicable Interventional Centre Hospitalier St Anne · NCT07127224

This will test whether brief smell challenges and a patient's 'sniff' response can help predict neurological and functional status three months later for adults who remain unresponsive after stopping sedation in the neuro-ICU.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment96 (estimated)
Ages18 Years and up
SexAll
SponsorCentre Hospitalier St Anne Academic / other
Locations1 site (Paris, GHU Psychiatrie Et Neurosciences)
Trial IDNCT07127224 on ClinicalTrials.gov

What this trial studies

This is an observational protocol that adds standardized olfactory stimulation to routine neurophysiological evaluation in adult neuro-ICU patients with persistent disorders of consciousness after sedation withdrawal. Investigators will record the presence or absence of a bedside 'sniff' response and compare olfactory-evoked signals with somatosensory and auditory evoked responses. Participants are followed at three months for clinical, neurological, and functional outcomes to determine whether the olfactory response provides additional prognostic information. No experimental treatment is given; the procedure consists of extra sensory testing performed during the hospital stay.

Who should consider this trial

Good fit: Adults (≥18) admitted to the neuro-ICU who remain unresponsive with a CRS-R score <16 at 72 hours after sedation withdrawal and are breathing spontaneously, with consent from a legal representative or emergency waiver.

Not a fit: Patients with brain death, known ENT/olfactory pathway damage, neurodegenerative disease, or other conditions that prevent olfactory perception are unlikely to benefit from this olfactory prognostic test.

Why it matters

Potential benefit: If successful, this could provide a simple, noninvasive bedside marker to improve early prognostication and help guide clinical decisions for unresponsive ICU patients.

How similar studies have performed: Use of olfactory stimulation for prognostication is relatively novel compared with somatosensory and auditory tests, with some preliminary data suggesting promise but limited definitive evidence to date.

Eligibility criteria

Show full inclusion / exclusion criteria
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)

Where this trial is running

Paris, GHU Psychiatrie Et Neurosciences

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Disorders of Consciousness Due to Severe Brain Injury
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.