Nystagmus

Question 1

Idiopathic downbeat nystagmus - treatment

Answer 1

GABA agonist - clonazepam. Potassium channel blockers - 4-aminopyridine and 3,4-diaminopyridine. selective activator of calcium-activated potassium channel - chlorzoxazone

Question 2

Periodic alternating nystagmus - treatment

Answer 2

Baclofen 5mg 3x1. If refractory - Memantine

Question 3

Alexander’s law

Answer 3

nystagmus increases in intensity (amplitude and frequency) as the eyes are moved in the direction of the fast phase

Question 4

Downbeat nystagmus - where localizes? Causes?

Answer 4

Cerebellum and craniocervical junction. cerebellar degenerations from spinocerebellar ataxia, posterior fossa vascular lesions, sporadic onset adult ataxia, craniocervical malformations, Chiari malformation

Question 5

Seesaw nystagmus - movement

Answer 5

one eye elevates and intorts while the other depresses and extorts

Question 6

Seesaw nystagmus - where localizes?

Answer 6

Sellar/diencephalic region (thalamus, hypothalamus, third ventricule)

Question 7

Bruns’ nystagmus - movement

Answer 7

low-frequency , large-amplitude nystagmus when looking towards the side of the lesion and a high-frequency, small-amplitude nystagmus when looking away from the lesion

Question 8

Bruns’ nystagmus - where localizes?

Answer 8

Cerebellopontine angle tumor (meningiomas or schwannomas of the vestibulocochlear nerve)

Question 9

Oculopalatal myoclonus - movement

Answer 9

vertical pendular nystagmus and synchronous rhythmic movements of the palate

Question 10

Oculopalatal myoclonus - cause

Answer 10

hypertrophy of the inferior olivary nucleus. develops several months after brainstem or cerebellar infarction

Question 11

Infantile nystagmus syndrome - features

Answer 11

jerk or pendular, uniplanar (remains horizontal in upgaze and downgaze), null point, increasing velocity of slow phase, worsened by distant fixation, abolished in sleep

Question 12

Infantile nystagmus syndrome - treatment

Answer 12

The Kestenbaum-Anderson procedure is a surgical treatment that moves the attachments of the extra ocular muscles so that the new null point corresponds to each eye’s new central position. gabapentin and memantine, prisms that result in increased convergence (eg. 7D base-out with -1D sphere to compensate for accommodation), and prisms that shift the null point