Ocular Static Fixation as a Sign of Delirium

Ocular motor behavior (OMB) has been proposed as a delirium marker.

To analyze the discriminant value of ocular static fixation (OSF) and saccadic eye movements (SEM) in delirium diagnosis and their relationship to delirium phenomenology using the Delirium Rating Scale-Revised-98 (DRS-R98).

Cross-sectional bedside evaluation of OSF and four SEM tests in 223 consecutive geriatric inpatients, with or without DSM-5-TR delirium. Logistic regressions assessed performance of OMB for delirium diagnosis while controlling for clinical confounds and contribution of OMB to delirium and its three core domains. Correlational analysis assessed the relationship between OMB and DRS-R98 core domains and overall severity.

All OMB tests had higher specificity than sensitivity, with better positive than negative likelihood ratios. OSF, saccadic initiation delay and hypometria, as well as saccadic initiation failure, were delirium discriminants in logistic models with age, neuroleptics and drowsiness as control variables. The logistic model for OSF had the highest area under the receiver operating characteristic curve (AUC 91.6%). Only OSF contributed to delirium diagnosis when identified together with each of three core delirium symptoms (sleep-wake cycle, attention, thought process; 90.1%-93.7% logistic models' AUC). OMB were not correlated with delirium motor subtypes or core domains. Saccadic initiation failure's (n=16) association with delirium was a nonspecific inability to be tested.

OSF had the best performance for delirium presence. It is easily assessed at the bedside and simpler than SEM for patient cooperation. Its high specificity suggests a role to combine it with high sensitivity brief delirium tools.