Horizontal pendular nystagmus in upgaze and downgaze becoming horizontal jerk nystagmus on lateral gaze.
https://www.youtube.com/watch?v=nJwbazlakws&t=1s
https://www.youtube.com/watch?v=FrlsK4MF3Ao&t=8s
https://www.youtube.com/watch?v=5vPCL7MaSDk&t=1s
https://www.balancemd.net/nystagmus.html
https://collections.lib.utah.edu/details?id=188527
Right beating horizontal jerk nystagmus in all positions of gaze, increasing in
amplitude on right gaze.
