NeuroTeach 26 - Nystagmus Part V (torsional/rotatory nystagmus)

 Nystagmus series – Part V

(torsional/rotatory nystagmus)

“the only ophthalmologist 'who practiced ophthalmology' to win a Nobel Prize”

Swedish ophthalmologist Allvar Gullstrand (1862–1930) (dioptrics of the eye)

2) Pathophysiology

“lesions in midbrain and medulla” Central - pure torsional: medulla (pontomedullary junction) - up/down: midbrain (rostral interstitial nucleus of the medial longitudinal fasciculus) Peripheral - horizontal: anterior and posterior semicircular canals

3) Fixation in central vestibular nystagmus

“poorly suppressed by fixation of a visual target” - abnormal smooth-pursuit system

4) Making torsional nystagmus more noticeable

Modulated by vertical smooth pursuit movements Bedside maneuvers - change head position - vigorous head-shaking

5) Obs

a) minimal vertical&horizontal components, in pure torsional b) slow-phase without specific waveform c) may be suppressed by convergence d) often, ocular tilt reaction or unilateral internuclear ophthalmoplegia

6) Obs

e) most useful technique for seeing primary positional torsional nystagmus is fundoscopy - ectoscopy, look conjunctival vessels f) torsional components in peripheral vestibular, congenital, and seesaw nystagmus (lateral gaze)

7) Torsional nystagmus – features

i) no suppress by visual fixation ii) may be suppressed by convergence iii) modulated by vertical smooth pursuit

8) Torsional nystagmus

- jerk torsional nystagmus

9) Torsional nystagmus

- pendular torsional nystagmus

10) Torsional nystagmus

- congenital torsional nystagmus

11) Torsional nystagmus

- jerk torsional nystagmus (BPPV)

12) Torsional nystagmus

- pure torsional nystagmus

13) Torsional nystagmus

14) Torsional nystagmus

15) Torsional nystagmus

16) Torsional nystagmus

17) Torsional nystagmus