6. Cells in PPRF
Burst Cell-sends
pulse step to
move the eye
Pause Cell-
inhibits firing of
burst cell allowing
burst cell to
initiate saccade
Tonic Cell –
maintain the eye
position
9. Vestibulocerebellar system-
Important input of gaze system
Modulate eye movements
Stabilize eye against the gravitatinal & accelerational
force
Maintaining clear vision
10. Cerebellum-
Eye movements
Fixation accuracy
Suppress the vestibulo-ocular reflex
Controls smoothness of pursuit movements
Accuracy of saccades
11. Lesion of Supranuclear oculomotor
pathways -
Based on anatomical location-
Lesions of internuclear system
Immediate premotor structure in the brain
PPRF
Posterior commisure
Rostral mesencephalon
Cerebral hemisphere
Descending pathway from cerebral hemisphere
Superior colliculus
Thalamus
14. Oculocephalic maneuvers-
Dolls eye reflex
Tilt the head 30 degree forward & fixate a distant
target
Rotate the head in direction opposite to gaze palsy
Direct projection from vestibular system to ocular
motor nuclei
Prenuclear,nuclear infranuclear reflex does not
overcome
Lesion in cerebral cortex overcome by VOR
15. Vestibular ocular reflex -
Tilt the head by 60 degree & irrigate external auditary
meatus with cool/warm water
In normal subject/supranuclear gaze palsy eye deviate
towards the irrigated side- nystagmus with fast phase
to opposite side
Fast phase towards the stimulated eye when warm
water is used
18. Parinaud syndrome-
Dorsal midbrain syndrome
Lesion of posterior commisure & MRF
Cause- compression by mass in pineal region
Dilatation of third ventricle
Midbrain infarction
multiple sclerosis
AV malfomation
Poor to absent upgaze
Convergence retraction nystagmus in upgaze
Colliers sign
Setting sun sign
19. Parinaud syndrome-
EMG shows co-contraction of occulomotor innervated
muscles- retraction of globe
Neuroimaging scan
Surgical treatment causes resolution of ocular
findings
20.
21.
22. Progressive supranuclear palsy-
Lesion of mesencephalic structure-
Steele-Richardson-Olszewski syndrome
Onset –after 40 years
Disorder of basal ganglia
Marked rigidity –trunk & neck
Little tremor
Difficulty with vertical eye movements down > up
Progresses to horizontal gaze disorder
End stage – global ophthalmoplegia
23. Progressive supranuclear palsy-
Vertical direction more severely affected initially
Voluntary saccades affected first, convergence, and
smooth pursuit later
Slowing of saccade velocity
Supranuclear movements primarily affected (vestibulo-
ocular reflex spared)
Square wave jerks
Gait abnormalities
Nuchal rigidity
30. Monoocular elevation paresis-
No ocular deviation in primary gaze
Inability to elevate one eye
Prenuclear congenital unilateral midbrain lesion
Oculocephalic maneuver is normal
Lesion in pretectum
Connection of riMLF to the occulomotor nuclei
Forced duction & tensilon test are negative
32. Skew deviation-
Skew deviation is a vertical divergence
“prenuclear” lesion of the vertical vestibulo-ocular
pathways in the brainstem or cerebellum.
Comitant, associated with cyclotorsion of one or both
eyes.
Noncomitant it can mimic a partial third or fourth
cranial nerve palsy
33. Skew deviation-
Occur most commonly with vascular lesions of the
pons or lateral medulla (Wallenberg's syndrome)
lesions of the midbrain or upper pons
Alternating skew deviation, the hypertropia changes
with the direction of gaze. The adducting eye usually
is hypotropic,mimick superior oblique overaction.
35. Ocular tilt reaction-
cyclotorsion of both eyes, and paradoxical head tilt,
all to the same side – that of the lower eye
A tonic (sustained) ocular tilt reaction occurs with
lesions of the ipsilateral utricle, vestibular nerve or
nuclei, or a lesion in the region of the contralateral
interstitial nucleus of Cajal and medial thalamus
A phasic (paroxysmal) ocular tilt reaction occurs with
lesions of the ipsilateral interstitial nucleus of Cajal
and may respond to baclofen.
36. Horizontal gaze palsy-
More common
Vary from
Gaze evoked nystagmus
Dysmetria of movements
Total inability to move the eye
Commonly occur in CVA patients
37. Internuclear ophthalmoplegia-
Lesion in MLF
Between the abducens nucleus and C/L medial rectus
subnucleus of the oculomotor nerve
Impairs adducting saccades of the ipsilateral eye,
which become either slow or absent
Dysmetria
Disconjugate nystagmus.
38.
39. Internuclear ophthalmoplegia-
If INO is bilateral
abduction saccades also may be slow
Upward beating and torsional nystagmus
Other clinical features
skew deviation
defective vertical smooth pursuit
impairment of the vertical VOR
impaired ability to suppress or cancel the vertical VOR.
40. Internuclear ophthalmoplegia-
Occur with a variety of disorders of brainstem
Vascular
Demyelinating
Metastatic
Must be differentiated from the pseudo-INO of
myasthenia or a long-standing exotropia.
41.
42. One & half syndrome-
Damage to the caudal pons
Ipsilateral MLF and either the ipsilateral PPRF or the
abducens nucleus
It results in an ipsilateral gaze palsy with an ipsilateral
INO
Intact horizontal movement is abduction of the
contralateral eye
43. One & half syndrome-
If the facial nerve nucleus or fasciculus is involved,
oculopalatal myoclonus may develop
Most common causes
multiple sclerosis and
brainstem stroke
followed by metastatic
primary brainstem tumors
Ocular myasthenia may cause a pseudo-one-and-a-
half syndrome
44. Ocular motor apraxia-
Loss of or severely diminished volitional saccades
Retention of the fast phases of vestibular nystagmus
• Difficult horizontal saccades
• Head thrust towards desired
direction
Congenital
• Balint syndrome
• Both Horizontal & Vertical
• Simutagnosia/optic ataxia
Acquired
45. Convergence paralysis-
Midbrain lesions ,dorsal midbrain syndrome.
Cerebellar degeneration, Parkinson's disease, and
progressive supranuclear palsy, are associated with
poor convergence.
Lack of pupillary constriction on attempted
convergence may differentiate psychogenic
convergence paralysis from organic disease.
46. Divergence paralysis-
Uncrossed horizontal diplopia
Intermittent or constant esotropia
Abduction is full.
Break in fusion later in life
Treated easily with base-out prisms for the distance
correction
Divergence paralysis is a controversial entity, difficult
to differentiate from divergence insufficiency and
bilateral sixth cranial nerve palsies.
47. Functional gaze palsies-
Horizontal gaze palsy – miosis during attempted gaze
Saccades-VOR should be stimulated (oculocephalic
maneuvers,calorics,chair rotation ), OKN test
Pursuit