Supranuclear disorders of ocular motility

1. SUPRANUCLEAR AND
INTERNUCLEAR DISORDERS OF
OCULAR MOTILITY
DR ARPITA

2. • Extraocular muscles are supplied by 3,4,6 th
cranial nerves which have their nuclei in the
brainstem
• Centres controlling the nuclei – Supranuclear
• Pathways connecting the nuclei – Internuclear
• Nerves supplying the EOM - Infranuclear

3. • The eyes move in SIX WAYS
FAST EYE
MOVEMENTS
(300°-600°/SEC)
1)SACCADES
2)NYSTAGMUS
SLOW EYE MOVEMENTS
(5°-50°/SEC)
1) SMOOTH PURSUIT
2) OPTOKINETIC
3) VESTIBULAR
4) VERGENCE

4. SACCADES
• Derived from french word “Saquer” which
means to pull or tug
• REDIRECT eyes from one target to another
• Voluntary or reflex ( in response to visual ,
auditory or pain stimulus )

5. • Always conjugate
• Ballistic – once initiated they cannot be stopped
or modified
• Speed of saccade is directly proportional to size
of movement Velocity of a larger saccade is
faster than the velocity of a slow saccade , this is
known as Main sequence
• Visual suppression occurs - even though the
visual world is sweeping across retina , there is no
sense of a blurred image

6. Pathways for saccades

7. CROSSED
PATHWAY

8. Synthesis of a saccade- “pulse step”

10. Clinical examination
Thefixation objects should be presented at an angular separation
of about 20 to 30°.

11. Clinical examination
• SPEED - slowing of saccades can be seen in
AIDS dementia complex , Lipid storage
disorders , PSP , drug intoxications
• SMOOTHNESS – affected in cerebellar
diseases
• ACCURACY – Hypometric or Hypermetric ,
affected in cerebellar diseases

12. SMOOTH PURSUIT
• Slow eye movements that permits the eyes to
conjugately follow/track a target during
movements of the target or observer or both
• Have the capcity for compensation unlike
saccades - when speed of target is varied
after initiation of the movement , speed of
pursuit can be varied.

13. • Initiated by a slow moving target across the
fovea
• Visual fixation holds the image of a stationary
object on the fovea

14. Pathway for pursuit movements
DOUBLE
DECUSSATION

15. • Parieto – occipito – temporal region is the
confluence of Brodman areas 19, 37 and 39
• A pure occipital lobe lesion will not affect
smooth pursuit movements
• Deep parietal lobe lesions disrupt smooth
pursuit to ipsilateral side

19. VESTIBULAR REFLEX
• Coordinates eye movements with head
movements, holds image steady during brief
head rotations
• Stimulation of Ampulla of horizontal
semicircular canal conjuate movement
towards contralateral side
• Information from anterior and posterior
semicircular canals - combination of vertical
and torsional eye movements

20. “COWS”

22. OPTOKINETIC REFLEX
• Stimulus – sustained head rotation
• With sustained head rotation at a constant
velocity , vestibular response fades and
optokinetic response takes over
• OKN prevents a continuous blur from relative
motion of the moving visual field .

23. Turning the drum to the right elicits an ipsilateral pursuit movement to the right and a
contralateral saccade to the left.

24. VERGENCE
• Allows bifoveation of an object moving in Z
axis
• Stimuli –
• Retinal blur – accomodative vergence
• Disparity of location of images- fusional
vergence
• Pathway : Occipital cortex – midbrain reticular
formation – 3rd nerve nucleus

25. INTERNUCLEAR PATHWAYS

27. • Vertical saccades require simultaneous
activation of both FEF
• Unilateral activation of the riMLF generates
torsional eye movements
• Right riMLF – clockwise movements
• Left riMLF – anticlockwise movements

28. Supranuclear disorders...
• Affect both eyes
• Do not produce diplopia
• Dolls eye phenomenon and Bells
phenomenon remain intact

29. DISORDERS OF HORIZONTAL GAZE
A) SACCADIC DISORDERS
• INABILITY TO PRODUCE SACCADES
1) Frontal lobe lesions - Injury
• Cannot generate contralateral saccades
• Preferential gaze to affected side
• Pursuit , OKN ,VOR are normal
• Recovers after several weeks due to activation
of projections from ipsilateral FEF to PPRF

30. • 2) Congenital ocular motor apraxia (COMA)
• Cannot initiate voluntary horizontal saccades
• Vertical saccades are normal
• “ Head thrusting occurs ”
• Becomes less prominent with age

31. • 3) Acquired ocular motor apraxia
• Aka Balints syndrome
• Seen in extensive B/L cerebral disease (parieto
– occipital)
• Simultagnosia – inability to perceive more
than one object at a time
• Optic ataxia – inaccurate arm pointing
• Dementia
• Visual field defects

32. • SLOWING OF SACCADES
1) Progressive supranuclear palsy
• Aka Steel – Richardson – Olszewski syndrome
• Progressive conjugate paresis of gaze in all
directions especially downward
• Associated neurological symptoms include
dementia , dysarthria , nuchal and axial
rigidity
• Recurrent falls early in course
• Death within several years of diagnosis

33. • 2) Olivopontocerebellar degeneration
• Presents early in adulthood
• Ataxia , slurred speech and dementia
• Eye movements in all directions are
progressively affected
• Eventually leads to total ophthalmoplegia

35. • Dysmetric saccades
• Hypometric saccades are not necessarily
pathological;they can be the product of
inattention or poor cooperation.
• Hypermetric saccades on the contrary are
always pathological and strongly suggest the
presence of a lesion in the cerebellar vermis.

36. • UNWANTED SACCADES
• Square wave jerks – named for their
appearance of eye movement recordings
• Sporadic saccades that return to fixation
within 100-200 msec
• Greater than 1 degree = pathologic
• Associated with cerebellar disease
• Called as “ sed rate of CNS “ as more than
10/min is a non specific indicator of CNS
disease

37. • Ocular flutter
• Intermittent brief volley of horizontal
oscillations aroud fixation
• No intersaccadic interval unlike square wave
jerks

38. • Opsoclonus
• Chaotic saccades occuring randomly in any
direction
• Aka saccadomania
• Causes – cerebellar disease , post viral
encephalopathy , paraneoplastic sign , drug
toxicity

40. • Internuclear ophthalmoplegia
• Lesion of the MLF

41. • INO is named for the side of the MLF lesion
• Posterior INO – convergence is preserved
• Anterior INO – absence of convergence
• WEBINO – bilateral INO
• Myaesthenia can present similarly – pseudo
INO

42. • One and a half syndrome – PPRF lesion plus
ipsilateral MLF lesion
• Only movement left is contralateral abduction
• “Paralytic pontine exotropia”- transient
phenomenon seen during first few days of one
and a half syndrome – due to unopposed
action of contralateral PPRF

43. DISORDERS OF VERTICAL GAZE
• Downgaze palsy –
• Occlusion of posterior thalamo-subthalmic
artery which enters from anterior part of
midbrain (Percheron's artery),
• Upgaze palsy – lesion in rostral midbrain
(posterior comissure)

44. • Dorsal midbrain syndrome
• Aka Parinauds syndrome / Sylvian aqueduct
syndrome
• Paresis of vertical gaze –mainly upward
• Light near dissociation of pupils
• Convergence retraction nystagmus
• Lid retraction – Colliers sign
• Spasm / paresis of convergence
• Spasm / paresis of accomodation

45. • Skew deviation
• Acquired vertical and torsional deviation
• May be comintant or incomitant
• Due to imbalance of otolithic inputs from
utricule and saccule to ocular motor neurons
• With lower brainstem lesions the ipsilateral
eye tends to be hypotropic , with pontine and
midbrain lesions the eye tends to be
hypertropic

46. • Ocular tilt reaction
• Due to lesion affection central or peripheral
otolithic pathways
• Destructive lesion of INC leads to :
• Contralateral head tilt
• Depression and extorsion of contralateral eye
• Elevation and intortion of ipsilateral eye

47. • 4th nerve palsy extortion of hypertropic eye
• OTR intortion of hypertropic eye

48. • Tonic downward deviation of gaze, or forced
downgaze, is associated with medial thalamic
hemorrhage, acute obstructive hydrocephalus,
severe metabolic or hypoxic encephalopathy,
or massive subarachnoid hemorrhage.
• When associated with lid retraction, the
corneas can be buried below the lower lid
(sundowning).
• In this setting, elevated intracranial pressure is
a major concern.