Lecture 31 supranuclear and internuclear

Question 1

What is congenital ocular motor apraxia?
when is the onset?
what will parents notice?

Answer 1

-saccadic initiation failure
(affects horizontal voluntary gaze saccades)

-from a few months old

-lack of attention
-delayed milestones

Question 2

what are the characteristics of congenital OMA?

Answer 2

*Head thrusts (uses VOR) to gain fixation
*Eye movements follows head movement until the target fixated
*Head then moves slowly back to mid line
*Repetitive blinking to break fixation
*Head thrusts decrease as age increases due to child developing better coping strategies

Question 3

What is acquired OMA?

Answer 3

*Inability to execute voluntary saccades
*Still able to perform some reflexive saccades
*Difficulty making horizontal and vertical saccades to command

Question 4

What are the associations of acquired OMA?

Answer 4

• Huntington’s disease
• Multiple sclerosis
• Wilson’s disease
• Iatrogenic (aortic surgery)
• Damage possibly occurs in the frontal eye field parietal cortex

Question 5

What are the signs of vergence system failure?

Answer 5

Convergence paralysis
*Head trauma
*XOT larger at near

Divergence paralysis
*Stroke or head trauma
*SOT larger in distance

Spasm of the near reflex
*Often psychogenic
*Rarely due to disease processes

Question 6

What are the signs of failure of vestibular system?

Answer 6

*causes skew deviations
*Vertical strabismus
*Incyclotosion in higher eye
*Usually associated with brainstem or cerebellar disease
*Deviation improves when lying down by about 50% (Agnes Wong test)

Question 7

What is the aetiology of unilateral gaze palsy?

what are the signs?

Answer 7

*Aetiology: lesion in the pons at the level of the 6th nerve nucleus
* demyelinating disease like MS, vascular, tumour

*Mild damage: slow ipsilateral saccades with sparing of pursuit and VOR

*Severe damage:
- complete palsy of ipsilateral horizontal gaze (both pursuit & saccadic)
-Large lesions affect vestibular nuclei therefore VOR also affected usually associated with gaze evoked nystagmus

Question 8

What is the aetiology of Dorsal midbrain syndrome?

what is this syndrome also called?

Answer 8

-pineal tumuor
-vascular
-trauma

parinaud’s syndrome

Question 9

What are the features of parinaud’s syndrome?

Answer 9

*Initial loss of upward saccades despite normal smooth pursuit
*OKN drum rotated downwards absence of re-fixation (no upward saccade)
*Upward drum rotation normal response (upward pursuit maintained)
*Convergence retraction nystagmus (eyes converge & retract on attempted up gaze)
*Upper eyelid retraction (Colliers sign)
*Pupils dilated (demonstrate light near dissociation) pupils wont strict to light but will restrict in accommodation and convergence.
*Sometimes papillodema (space occupying lesion)

Question 10

What is the aetiology of Steele-Richardson syndrome?

what are the features?

Answer 10

*Degeneration of the brainstem reticular formation

*Initially slowing of the vertical saccadic velocity
*First down gaze then complete vertical saccadic paralysis
*Horizontal gaze problems late feature
*Difficulty opening lids
Problems with:
* Speech
* Swallowing
* Balance
* Seeing food on plate
* Walking downstairs

• Progressive dementia
• Mortality after 10 years

Question 11

What are the features of parkinsons disease?

Answer 11

*Impaired up gaze
*Usually, down gaze normal
*Convergence insufficiency

Question 12

What are the types of internuclear disorders?

Answer 12

*Internuclear ophthalmoplegia (INO)
*One and a half syndrome
*Bilateral INO