Eye-Tracking Assessment in Patients with Disorders of Consciousness: A Systematic Review

Area of Science:

• Neuroscience
• Medical Technology
• Clinical Diagnostics

Background:

• Disorders of consciousness (DOC), including vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state (MCS), pose significant diagnostic challenges.
• Misdiagnosis rates for DOC approach 40% due to limitations in detecting subtle behavioral responses via clinical observation.
• Eye-tracking technology provides objective, quantitative assessment of visual behaviors, potentially revealing covert signs of consciousness.

Purpose of the Study:

• To evaluate the diagnostic accuracy of eye-tracking technology compared to the Coma Recovery Scale-Revised (CRS-R) for detecting visual responses and consciousness signs in patients with DOC.
• To examine the effects of different stimuli on eye-tracking responses.
• To assess the prognostic value of eye-tracking in patients with DOC.

Main Methods:

• A systematic literature search was conducted across multiple databases (SciSpace, Google Scholar, PubMed) following PRISMA 2020 guidelines.
• Included studies involved patients with prolonged DOC assessed using eye-tracking technology.
• Data extraction, risk of bias assessment, and GRADE certainty evaluation were performed systematically.

Main Results:

• Fifteen studies (n=4-123 patients) were included, published between 2012-2025.
• Eye-tracking detected visual responses in significantly more patients (46.2%) than clinical observation (18.1%).
• Mirror stimuli showed the highest detection sensitivity (97%). Affectively salient stimuli elicited stronger responses in MCS patients. Advanced VR systems demonstrated high diagnostic accuracy (100% sensitivity, 88.9% specificity) and prognostic value.

Conclusions:

• Eye-tracking offers an objective and sensitive method for assessing visual behaviors in patients with DOC, potentially reducing misdiagnosis.
• A conditional recommendation supports its use as a supplementary tool alongside CRS-R.
• Methodological heterogeneity, small sample sizes, and lack of blinding limit current certainty, necessitating large-scale prospective studies.