PMC9462393_01
Video-oculography (VOG) recording of central fixation. The patient has a primary gaze, low-amplitude downbeat nystagmus with a slow phase velocity of 2 deg/sec and a frequency of 2 Hz, and this nystagmus increases in amplitude and velocity in right and left gaze.
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F1
Furthermore, she had direction-changing horizontal (h) nystagmus in right and left gaze with a downward and oblique direction; she had saccadic h and vertical (v) pursuit (Supplementary Video 1, Figure 1), mostly associated with DBN (Table 1); she had failed to suppress the VOR with visual fixation (VFX).
Microscopic examination of the hemispheric cerebellar cortex. H&E x20. (A) Normal cerebellar cortex, the arrow points to morphologically intact Purkinje cells. (B) Similar section inpatient 1 shows absent Purkinje cells, note absent of acute inflammation. In this patient, the deep nuclei were normal.
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F2
The autopsy was significant for extensive cerebellar folia atrophy and loss of PCs in the midline and lateral cerebellar hemispheres (Figure 2).
PMC9462393_02
Video head impulse test (vHIT) of the horizontal VOR. Gain: 0.57 right and 0.89 left. Note catch-up saccade. There is a catch-up saccade 100 m sec after the end of the left head impulse (arrow).
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F3
We found DBN superimposed on the horizontal and downward pursuit and poor VFX of rotational nystagmus, and he had decreased VOR gain and overt corrective saccades in response to a left head impulse test (Figure 3).
PMC9462393_03