Nystagmus series – Part IV
(upbeat nystagmus)
“Bruns ataxia, Bruns syndrome, Bruns law, Bruns nystagmus”
2) Pathophysiology
3) Fixation in central vestibular nystagmus
“poorly suppressed by fixation of a visual target”
- abnormal smooth-pursuit system
4) Making upbeat nystagmus more noticeable
5) Obs
a) slow-phase without specific waveform
b) convergence does not specific change nystagmus
c) sometimes increased by looking down
- slow-phase shows increasing velocity
d) different
- gaze-holding failure: myasthenia gravis
- mixed upbeat-torsional: BPPV – posterior canal
6) Bow-tie nystagmus
abnormal:
- vertical vestibular
- smooth-pursuit responses
- saccadic intrusions (square-wave jerks)
marked saccadic hypermetria
8) Upbeat nystagmus
9) Upbeat nystagmus
10) Upbeat nystagmus
- sometimes increased by looking down (slow-phase shows increasing velocity)
11) Upbeat nystagmus
12) Upbeat nystagmus
13) Upbeat nystagmus
14) Upbeat nystagmus
15) Upbeat nystagmus
16) Upbeat nystagmus
17) Upbeat nystagmus
- sometimes increased by looking down (slow-phase shows increasing velocity)