Radiographic Horizontal Conjugate Gaze Deviation: Clinical Correlates.

Purpose of Review: The potential diagnostic value of radiographic, horizontal, conjugate gaze deviation (Rad h-CGD) was first recognized in 2003 by Simon et al. Thereafter, interest grew related to its potential use as a marker of different neurologic and vestibular disorders. Over the past 20 years, we have identified clinical correlates of Rad h-CGD including those caused by supratentorial and infratentorial lesions. We propose clinicians and radiologists will better diagnose and manage patients by knowing the different diagnostic possibilities for Rad h-CGD. Findings: We report different clinical correlates of Rad h-CGD relevant for localizing and lateralizing lesions. We measured the angle of deviation and correlated it with the clinical findings and underlying mechanisms. We then reviewed important data from the previous literature relevant to the localization of each lesion and combined it with our experience into the design of a practical algorithm to interpret Rad h-CGD. Summary: Using Rad h-CGD provides useful information about the diagnosis and localization and may reveal subtle ocular findings not clear on physical examination. However, Rad h-CGD alone cannot distinguish between supratentorial and infratentorial lesions, and therefore, the clinical context is critical. Moreover, although Rad h-CGD occurs with strokes due to large vessel occlusion, it could also be seen with an acute vestibular syndrome, secondary to a peripheral vestibular neuritis. Other possibilities include ischemic events in the cerebellum, brainstem, and labyrinth.