How Do I Examine for a Supranuclear Gaze Palsy?

Classically, a supranuclear gaze palsy ( SNGP ) is a conjugate gaze limitation that can be overcome (i.e., corrected) by the vestibulo‐ocular reflex ( VOR ). It involves vertical eye movement most commonly. In practice, SNGP can be encountered as a limitation in excursion of self‐generated conjugate saccades (fast eye movements) that can be improved or overcome with verbal command, visual targets, or VOR . Thus, mild SNGP s may be overcome with verbal commands (e.g., “look down”) or visual targets (e.g., “look down at my hand”), whereas moderate SNGP s may be overcome by smooth pursuit mechanisms and following a visual target (e.g., “look at my pen as it moves”) and severe SNGP s can only be overcome with the VOR (i.e., fixating straight ahead while the head is passively rotated). So, it is best to assess for an SNGP in a hierarchical fashion; initially assessing saccades to command, then saccades to visual targets, then smooth pursuit of a target, and finally with the VOR .