2025 American Academy of Neurology Abstract Website

Objective:

To examine the relationship between ophthalmological impairments, visual evoked potentials (VEPs), cerebral metabolism, and consciousness levels in patients with severe brain injuries.

Background:

Disorders of consciousness (DoC) such as unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) arise from traumatic brain injuries, cerebrovascular accidents, hypoxic-ischemic events and metabolic disturbances. Diagnosis is based on clinical assessments such as the Coma Recovery Scale-Revised (CRS-R). Misdiagnosis rates remain high, necessitating the integration of neuroimaging such as fluorodeoxyglucose-positron emission tomography (FDG-PET). Visual behavior, particularly pursuit and fixation, plays a critical role in diagnosing MCS and predicting outcomes.

Design/Methods:

Ophthalmological consultation reports and FDG-PET data were analyzed to assess occipital lobe and thalamic metabolism. Prevalence of visual impairments, VEP amplitudes, and hypometabolic voxels in visual regions were compared across diagnostic groups (unresponsive wakefulness syndrome - UWS, minimally conscious state - MCS, and emergence from MCS/locked-in syndrome - EMCS/LIS). A subgroup analysis was conducted between MCS- and MCS+ patients.

Results:

Seventy percent of patients exhibited at least one ophthalmological impairment (100% UWS, 69% MCS, 53% EMCS, 75% LIS), with ocular motility being the most frequent (31%). Abnormal VEPs were more common in UWS (40%) versus MCS (5%) (p=0.03). UWS patients had greater visual network hypometabolism compared to MCS (p=0.020) and EMCS/LIS (p=0.018), with no significant differences between MCS and EMCS/LIS (p=0.861). The right occipital lobe showed similar group differences, with UWS differing from MCS (p=0.020) and EMCS/LIS (p=0.031), but no difference between MCS and EMCS/LIS (p=0.638).

Conclusions:

Visual impairments were present in 70% of patients, and 46% had confirmed ophthalmological diagnoses. UWS patients had greater visual network hypometabolism compared to MCS and EMCS/LIS, with no differences between the latter groups. VEP amplitude and FDG-PET metabolism were linked to fewer ophthalmological impairments, highlighting the role of visual pathways in consciousness recovery and the potential of VEP and FDG-PET in predicting outcomes.