Supranuclear Palsy and Moebius Syndrome

Question 1

Why do we have eye movements?

Answer 1

To maximize vision, hold images still on the retina, analyze objects optimally, compensate for head movements, and achieve binocular vision.

Question 2

Two principal types of eye movements:

Answer 2

Steady image on retina: Vestibular, optokinetic, smooth pursuit.

Change line of sight: Saccades, pursuit, vergences.

Question 3

What is a supranuclear palsy?

Answer 3

A lesion in the eye movement control pathways above the cranial nerve nuclei, leading to gaze palsies.

Question 4

Horizontal saccades pathway:

Answer 4

From FEF through internal capsule, decussates in midbrain and terminates in PPRF. Parietal pathway decussates to the superior colliculus before PPRF.

Question 5

Vertical saccades pathway:

Answer 5

Requires bilateral stimulation of FEF and passes through the rostral interstitial nucleus of the MLF (riMLF).

Question 6

Lesion effects on horizontal saccades:

Answer 6

Before decussation: Loss of conjugate gaze to contralateral side.
At decussation: Loss of movement to both sides.
Below decussation (pons): Ipsilateral gaze loss.

Question 7

Global paralysis (Roth Bielschowsky syndrome):

Answer 7

Total loss of saccades and pursuit, but intact VOR and vestibular nystagmus, due to a lesion in the upper midbrain.

Question 8

Frontal lobe lesions (unilateral):

Answer 8

Loss of saccades to the contralateral side and visual hemifield neglect.

Question 9

Occipital lobe lesions:

Answer 9

Unilateral lesions cause contralateral hemianopia and search saccades when attempting to look into the affected field.

Question 10

Parieto-occipital lesions:

Answer 10

Unilateral lesions lead to failure of smooth pursuit on the affected side and cogwheel pursuit.

Question 11

Progressive Supranuclear Palsy (PSP):

Answer 11

Affects vertical saccades (upgaze/downgaze), eventually causes complete ophthalmoplegia, and presents with balance issues and swallowing difficulties.

Question 12

Parkinson’s disease:

Answer 12

Defective upgaze and slow vertical saccades with impaired vergences (particularly divergence).

Question 13

Huntington’s chorea:

Answer 13

Causes defective saccades, especially during the early part of upgaze.

Question 14

Parinaud’s syndrome:

Answer 14

Loss of upgaze, Collier’s sign (lid retraction), convergence-retraction nystagmus, and skew deviation.

Question 15

Hydrocephalus:

Answer 15

Vertical upgaze palsy with the “setting sun sign” due to increased intracranial pressure.

Question 16

Key clinical observations:

Answer 16

Check gait, facial weakness, head thrusts, AHP, and consciousness.

Question 17

Ocular observations:

Answer 17

Eye position, pupil abnormalities, ptosis, nystagmus types, globe position (proptosis or enophthalmos).

Question 18

Eye movement assessments:

Answer 18

Test saccades, smooth pursuit, VOR, OKN, and uniocular movements.

Question 19

Caloric testing:

Answer 19

Warm water causes eye deviation to the same side; cold water causes deviation to the opposite side.

Question 20

Bells phenomenon:

Answer 20

Elevation of eyes during forced lid closure indicates intact 3rd nerve and superior rectus.

Question 21

Orthoptic treatment

Answer 21

Monitor condition, prism therapy, manage AHP, occlusion for diplopia, and ptosis props.

Question 22

Multidisciplinary approach:

Answer 22

Collaborate with ophthalmology, neurology, and medical teams to assess progress and adjust care.

Question 23

Definition of Moebius syndrome:

Answer 23

A congenital, non-progressive disorder with bilateral 6th and 7th cranial nerve palsies, often part of the congenital cranial dysinnervation disorders (CCDD).

Question 24

Etiology of Moebius syndrome:

Answer 24

Developmental defects, hypoxic/traumatic insult in utero, vascular malformations, or genetic predisposition.

Question 25

Clinical features of Moebius syndrome:

Answer 25

Lack of facial expression, poor lid closure, esotropia, and abduction limitation.

Question 26

Associated systemic features:

Answer 26

Limb defects (e.g., clubfoot, syndactyly), hearing loss, feeding difficulties, delayed speech, and microstomia.

Question 27

6th cranial nerve involvement:

Answer 27

Marked esotropia, cross-fixation, impaired convergence, and V pattern strabismus.

Question 28

7th cranial nerve involvement:

Answer 28

Bilateral facial palsy with absent facial expression and poor lid closure.

Question 29

Vertical gaze in Moebius syndrome:

Answer 29

Intact in most cases, but 25% may have impairments.

Question 30

Exposure keratitis management:

Answer 30

Use lubricants and lid taping at night to prevent corneal abrasions.

Question 31

Differentiating moebius syndrome from other conditions:

Answer 31

Infantile myotonic dystrophy, Duane’s syndrome, congenital ocular motor apraxia, and horizontal gaze palsy.

Question 32

What is congenital ocular motor apraxia (COMA):

Answer 32

Absence of voluntary horizontal saccades with head thrusting maneuvers to initiate fixation.

Question 33

Why is refractive correction used:

Answer 33

To address astigmatism and amblyopia early to optimize vision.

Question 34

Which surgery is used

Answer 34

Bilateral medial rectus recessions for esotropia and vertical muscle transpositions for improved cosmesis.

Question 35

What does the MDT approach include

Answer 35

Include genetic counseling and developmental monitoring for comprehensive care.

Question 36

Prognosis in Moebius syndrome:

Answer 36

Stable over time with tailored interventions for ocular and systemic complications.

Question 37

PSP progression:

Answer 37

Gradual decline, loss of vertical and later horizontal movements, with significant mortality within 6 years.

Question 38

Improvement with age (e.g., COMA):

Answer 38

Some patients develop compensatory strategies and gain better control over time.

Question 39

Imaging techniques:

Answer 39

MRI/CT for identifying structural lesions, such as hydrocephalus or pinealoma.

Question 40

Electrodiagnostic tools use:

Answer 40

Eye movement recordings for documenting saccadic latency, accuracy, and nystagmus waveforms.