Ocular Motor Abnormalities in Functional Neurological Disorder: A Video‐Oculography Study

Background Functional neurological disorders (FND) can include various sensory, motor or cognitive symptoms. Eye movement recordings, measured through video‐oculography, could serve as biomarkers for characterizing these dysfunctions in FND. Objective To identify oculomotor patterns that may help to support a positive diagnosis of FND. Methods We conducted a retrospective analysis of video‐oculography recordings performed between 2011 and 2023 in 149 patients with FND, focusing on horizontal and vertical prosaccades, smooth pursuit, and antisaccades. These data were compared with those obtained from 132 age and gender‐matched healthy volunteers and 43 patients diagnosed with multiple sclerosis (MS). Results FND patients exhibited significantly increased mean saccade latencies in both horizontal and vertical prosaccade tasks compared to controls (t‐test, P < 0.0001). Additionally, variability in horizontal and upward saccade latency was substantially greater in the FND group than in the control and MS groups ( P < 0.0001). Vertical saccades in FND patients were hypometric ( P < 0.0001) with increased variability of upward saccade amplitude ( P < 0.0001). Both MS and FND patients had higher antisaccade error rates than controls ( P < 0.0001). Conclusion These findings suggest that video oculography may be useful in understanding the pathophysiology of FND and highlight its potential as a complementary tool to support diagnostic reasoning in complex clinical presentations.