NeuroTeach 28 - Nystagmus Part VII (seesaw & hemi-seesaw nystagmus)

Nystagmus series – Part VII

(seesaw & hemi-seesaw nystagmus)

“Maddox rod, double prism Maddox, red glass Maddox, Maddox cross, and Maddox wing”

British ophthalmologist Ernest Edmund Maddox (1863–1933) (first report)

2) Definition “one half-cycle of elevation&intorsion of one eye and synchronous depression&extorsion of the other eye. Next half-cycle, vertical&torsional components are reversed” - waveform: pendular (seesaw) & jerk (hemi-seesaw) - hemi-seesaw: only one half-cycle

3) Pathophysiology

Jerk (hemi-seesaw) - lesion in the interstitial nucleus of Cajal Pendular (seesaw) - parasellar (midbrain compression & visual field defects) - calibration lesion

4) Fixation

Fixation in central vestibular nystagmus “poorly suppressed by fixation of a visual target” - abnormal smooth-pursuit system

5) Associated symptoms

Hemi-seesaw nystagmus - contralateral ocular tilt reaction - central otolithic imbalance Seesaw nystagmus - visual field defect

6) Considerations

Reversed congenital form - elevation & extorsion - dissociated vertical deviation

7) Seesaw nystagmus – features

i) 🔄 elevation&intorsion w/ depression&extorsion ii) no suppress by visual fixation

8) Seesaw nystagmus

9) Seesaw nystagmus

10) Seesaw nystagmus

11) Seesaw nystagmus

12) Seesaw nystagmus

13) Seesaw nystagmus

14) Seesaw nystagmus

15) Seesaw nystagmus

16) Seesaw nystagmus

17) Seesaw nystagmus

18) Hemi-seesaw nystagmus – features

i) elevation&intorsion w/ depression&extorsion ii) only one half-cycle iii) no suppress by visual fixation

19) Hemi-seesaw nystagmus

20) Hemi-seesaw nystagmus

21) Hemi-seesaw nystagmus

22) Hemi-seesaw nystagmus