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SUPRANUCLEAR PATHWAYS
AND LESIONS
Moderator: Dr. Seema Bhosale
Presenter : Shruti Chandra Jain
Overview of the Presentation
A. Fundamentals of Extra-ocular movements
B. Anatomy of cortical and brainstem centers
C. Bas...
FUNDAMENTALS OF EXTRA-OCULAR
MOVEMENTS
FUNDAMENTAL PRINCIPLES OF
OCULAR MOTOR CONTROL
• Detect objects
• Spatial resolution
AFFERENT
visual
system
• Clear and st...
FUNDAMENTAL PRINCIPLES OF
OCULAR MOTOR CONTROL
 Efferent ocular motor system
- Supranuclear pathways : Affect both eyes
s...
FUNDAMENTAL PRINCIPLES OF
OCULAR MOTOR CONTROL
 Moving objects present a special challenge
GAZE
SHIFT
GAZE
STABILIZATION
HIERARCHY OF OCULAR MOTOR
CONTROL
Cortical
Control, BG,
SC, thalamus,
VA, Cerebellum
Brainstem, Ocular
Motor Cranial Nerve...
ANATOMY OF CORTICAL AND
BRAINSTEM CENTERS
CORTICAL CENTRES
BRAINSTEM
CENTRES
VERTICAL SACCADES
HORIZONTAL
SACCADES
BRAINSTEM CENTRES
BRAINSTEM CENTRES
ROLE OF CEREBELLUM
 Cerebellum plays an important role in fine tuning all
eye movements, including modulation and adaptat...
ROLE OF CEREBELLUM
 Two distinct parts of the cerebellum contribute to
ocular motor control:
 (1) the vestibulocerebellu...
BASIC BINOCULAR EYE MOVEMENTS
AND THEIR PATHWAYS
EYE MOVEMENTS
EYE MOVEMENTS
CLASS MAIN FUNCTION
Vestibular Holds retinal image steady during brief head rotation or
translation
Optokine...
1. SACCADES
 Rapid movement to bring object of interest on fovea
 Clinical exam to
Check saccades
SACCADIC SYSTEM
 STIMULUS
 Visually reflexive – Parietal lobe Contralateral
 Memory guided or volitional – Frontal lobe...
SACCADIC PATHWAY- HORIZONTAL
C/l Frontal
cortex
I/l PPRF & VI
n Nu
Via MLF to
C/l IIIn Nu
Created by: Dr. Shruti Chandra
VERTICAL SACCADE PATHWAY
riMLF : upward and
downward eye movements
and for ipsilateral torsional
saccades.
Projects to mot...
VERTICAL SACCADE PATHWAY
SACCADIC SYSTEM – Features of a
saccade
 Latency : duration of stimulus to movement
 Accuracy : arrival of eyes on targe...
SACCADIC DYSFUNCTION
CLINICAL FEATURE SITE OF LESION
Prolonged Latency Degenerative disorders
Hypometric saccades PPRF les...
2. SMOOTH PURSUIT
 Saccade and pursuit have common neural pathway
 Cortical centres Middle Temporal & Medial Superior
Te...
PURSUIT PATHWAY
I/l Posterior
parietal
cortex (PPC)
I/l PPRF
C/l MLF and
VI Nu
Created by: Dr. Shruti Chandra
PURSUIT SYSTEM
 Relatively slow moving target <30 degress per second
 Initiation of pursuit - latency
 Gain of eye move...
PURSUIT DYSFUNCTION
 Low gain -> saccadic pursuit
 Poor initiation -> Frontal / parietal lobe lesions
 Deficits found u...
3. OPTOKINETIC NYSTAGMUS
OKN DYSFUNCTION
 Parietal or temporal lobe lesions -> abnormal OKN
towards the side of lesion
 Locate and define extent ...
4. VESTIBULAR OCULAR REFLEX
 Brief, high frequency rotation of the head
 SCC – angular movements
 Otoliths of utricle &...
SCC PROJECTIONS - EXCITATORY
VESTIBULAR OCULAR REFLEX
 Examination for VOR dysfunction
- Spontaneous nystagmus
- Horizontal head shaking
 VOR gain = ...
5. VERGENCES
 Vergence eye movements drive the eyes in
opposite directions to maintain the image of an
object on the fove...
5. VERGENCES
 Convergence centre : Pretectal area (mesencephalic
reticular formation, just dorsal to the third nerve
nucl...
STEP WISE EVALUATION OF EOMS
EVALUATION OF EOMs
 Q1. Is there a manifest strabismus?
 How to check – Hirschberg, PBCT
 What to look for – Comitant o...
EVALUATION OF EOMs
 Q3. Is there impairment of latency, accuracy or velocity
of voluntary saccade?
 How to check - sacca...
EVALUATION OF EOMs
 Q4. Is their impairment of latency or velocity of
smooth pursuit?
 How to check – Follow a small tar...
EVALUATION OF EOMs
 Q6. Is there impairment of VOR?
 How to check – doll’s head or oculocephalic maneuvers
 What to loo...
EVALUATION OF EOMs
 Q7. Is there impairment of VOR suppression?
 How to check - watching if the patient can keep their
g...
EVALUATION OF EOMs
 Q8. Is there impairment of vergence?
 How to check – Moving object towards bridge of the
nose
 What...
EVALUATION OF EOMs
 Q9. Is there involvement of other cranial nerves?
 How to check – Cranial nerve examination
 What t...
EVALUATION OF EOMs
 Q10. Is the limitation mechanical?
 How to check – FDT, FGT
 What to look for – Restriction vs Para...
SUMMARY
 Supranuclear lesions- BE involvement
 Saccade – Contralateral frontal lobe control
 Pursuit – Ipsilateral pari...
LESIONS OF SUPRANUCLEAR
PATHWAYS
GAZE PALSY
 Symmetric limitation of movement of both eyes in the
same direction.
 Conjugate ophthalmoplegia
HORIZONTAL GAZE PALSY
 Congenital – Mobius Syndrome
 Acquired – Pontine lesions
- Disrupt eye movements towards the side...
HORIZONTAL GAZE PALSY
VERTICAL GAZE PALSY
 Lesions of riMLF or Posterior commissure
INTERNUCLEAR
OPHTHALMOPLEGIA
RIGHT INO
RL
ONE – AND – A HALF SYNDROME
BILATERAL INO
BILATERAL INO
ETIOLOGY OF INO
 - Multiple sclerosis (commonly bilateral): Young
patients
- Brain stem infarction (commonly unilateral):...
PARINAUD SYNDROME
 EPIDEMIOLOGY
 Sporadic
 Causes: obstructive hydrocephalus, mesencephalic
hemorrhage, multiple sclero...
PARINAUD SYNDROME
 SIGNS : MAJOR COMPONENTS
 Vertical gaze disturbance
 Convergence retraction nystagmus
 Light near d...
PARINAUD SYNDROME
PARINAUD SYNDROME
 Differential Diagnoses for Dorsal Midbrain
Syndrome
 Light-near dissociation
 Vertical Gaze Palsy
References
 Neuro- Ophthalmology, American Academy of Ophthalmology,
2010-2011. 5th edition.
 Walsh & Hoyt’s. Clinical N...
THANK YOU
Supranuclear pathways and lesions
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Supranuclear pathways and lesions

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Supranuclear pathways and lesions

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Supranuclear pathways and lesions

  1. 1. SUPRANUCLEAR PATHWAYS AND LESIONS Moderator: Dr. Seema Bhosale Presenter : Shruti Chandra Jain
  2. 2. Overview of the Presentation A. Fundamentals of Extra-ocular movements B. Anatomy of cortical and brainstem centers C. Basic binocular eye movements and their pathways D. Step-wise evaluation of EOMs E. Lesions of Supranuclear Pathways
  3. 3. FUNDAMENTALS OF EXTRA-OCULAR MOVEMENTS
  4. 4. FUNDAMENTAL PRINCIPLES OF OCULAR MOTOR CONTROL • Detect objects • Spatial resolution AFFERENT visual system • Clear and stable vision • Binocular single vision EFFERENT visual system
  5. 5. FUNDAMENTAL PRINCIPLES OF OCULAR MOTOR CONTROL  Efferent ocular motor system - Supranuclear pathways : Affect both eyes simultaneously - Infranuclear pathways : Affect eyes differently
  6. 6. FUNDAMENTAL PRINCIPLES OF OCULAR MOTOR CONTROL  Moving objects present a special challenge GAZE SHIFT GAZE STABILIZATION
  7. 7. HIERARCHY OF OCULAR MOTOR CONTROL Cortical Control, BG, SC, thalamus, VA, Cerebellum Brainstem, Ocular Motor Cranial Nerve Nuclei Ocular motor nerves and Extra- ocular muscles LEVEL 1: SUPRANUCLEAR LEVEL 2:NUCLEAR LEVEL 3: INFRANUCLEAR
  8. 8. ANATOMY OF CORTICAL AND BRAINSTEM CENTERS
  9. 9. CORTICAL CENTRES
  10. 10. BRAINSTEM CENTRES VERTICAL SACCADES HORIZONTAL SACCADES
  11. 11. BRAINSTEM CENTRES
  12. 12. BRAINSTEM CENTRES
  13. 13. ROLE OF CEREBELLUM  Cerebellum plays an important role in fine tuning all eye movements, including modulation and adaptation of vestibulo-ocular responses, saccades, pursuit, and vergence.
  14. 14. ROLE OF CEREBELLUM  Two distinct parts of the cerebellum contribute to ocular motor control:  (1) the vestibulocerebellum (flocculus, paraflocculus, nodulus, and ventral uvula) and  (2) the dorsal vermis of the posterior lobe and fastigial nuclei. The vestibulocerebellum deals with stabilization of sight during motion, whereas the dorsal vermis and fastigial nuclei influence voluntary gaze-shifting (i.e., saccades, pursuit and vergence).
  15. 15. BASIC BINOCULAR EYE MOVEMENTS AND THEIR PATHWAYS
  16. 16. EYE MOVEMENTS
  17. 17. EYE MOVEMENTS CLASS MAIN FUNCTION Vestibular Holds retinal image steady during brief head rotation or translation Optokinetic Holds images steady on the retina during sustained head rotation Smooth pursuit Holds target image steady during linear movement of object or self Saccades Rapidly bring object of interest to focus on fovea Vergences Moves the eye in opposite directions so a single image is simultaneously held on each fovea
  18. 18. 1. SACCADES  Rapid movement to bring object of interest on fovea  Clinical exam to Check saccades
  19. 19. SACCADIC SYSTEM  STIMULUS  Visually reflexive – Parietal lobe Contralateral  Memory guided or volitional – Frontal lobe Contralateral  CENTRE  Horizontal Saccades -> PPRF -> Pons  Vertical Saccades -> riMLF & PC -> Midbrain
  20. 20. SACCADIC PATHWAY- HORIZONTAL C/l Frontal cortex I/l PPRF & VI n Nu Via MLF to C/l IIIn Nu Created by: Dr. Shruti Chandra
  21. 21. VERTICAL SACCADE PATHWAY riMLF : upward and downward eye movements and for ipsilateral torsional saccades. Projects to motoneurons of elevator muscles bilaterally but projects to motoneurons of depressor muscles only ipsilaterally The INC projects by way of the posterior commissure to motoneurons of the contralateral nuclei of the third and fourth cranial nerves and the contralateral INC
  22. 22. VERTICAL SACCADE PATHWAY
  23. 23. SACCADIC SYSTEM – Features of a saccade  Latency : duration of stimulus to movement  Accuracy : arrival of eyes on target  Velocity and conjugacy : degree to which 2 eyes move together  Hypometric saccades : saccade that falls short of intended target  Hypermetric saccades : overshoots the target
  24. 24. SACCADIC DYSFUNCTION CLINICAL FEATURE SITE OF LESION Prolonged Latency Degenerative disorders Hypometric saccades PPRF lesion Slow saccades in horizontal plane Pons Slow saccades in vertical plane Midbrain Hypermetric saccades Cerebellar lesions
  25. 25. 2. SMOOTH PURSUIT  Saccade and pursuit have common neural pathway  Cortical centres Middle Temporal & Medial Superior Temporal  Ipsilateral cortical control
  26. 26. PURSUIT PATHWAY I/l Posterior parietal cortex (PPC) I/l PPRF C/l MLF and VI Nu Created by: Dr. Shruti Chandra
  27. 27. PURSUIT SYSTEM  Relatively slow moving target <30 degress per second  Initiation of pursuit - latency  Gain of eye movements = output/input
  28. 28. PURSUIT DYSFUNCTION  Low gain -> saccadic pursuit  Poor initiation -> Frontal / parietal lobe lesions  Deficits found usually in both vertical and horizontal planes
  29. 29. 3. OPTOKINETIC NYSTAGMUS
  30. 30. OKN DYSFUNCTION  Parietal or temporal lobe lesions -> abnormal OKN towards the side of lesion  Locate and define extent of cerebral lesions
  31. 31. 4. VESTIBULAR OCULAR REFLEX  Brief, high frequency rotation of the head  SCC – angular movements  Otoliths of utricle & saccule – linear acceleration  Centre: Vestibular nuclei  Efferent: fibres carried via MLF to cranial nerve nuclei  Velocity Storage mechanism
  32. 32. SCC PROJECTIONS - EXCITATORY
  33. 33. VESTIBULAR OCULAR REFLEX  Examination for VOR dysfunction - Spontaneous nystagmus - Horizontal head shaking  VOR gain = Amplitude of eye rotation/ Amplitude of head rotation  Bilateral VOR dysfunction - dynamic visual acuity
  34. 34. 5. VERGENCES  Vergence eye movements drive the eyes in opposite directions to maintain the image of an object on the fovea of both eyes as the object moves toward or away from the observer.  Vergence eye movements are driven primarily by a disparity in the relative location of im· ages on the retinas.
  35. 35. 5. VERGENCES  Convergence centre : Pretectal area (mesencephalic reticular formation, just dorsal to the third nerve nuclei )  Inputs from bilateral cerebral hemispheres give inputs to the centre and from there to both 3rd nerve nuclei.
  36. 36. STEP WISE EVALUATION OF EOMS
  37. 37. EVALUATION OF EOMs  Q1. Is there a manifest strabismus?  How to check – Hirschberg, PBCT  What to look for – Comitant or incomitant strabismus  Generally a feature of infra-nuclear lesions  Q2. Is there limitation of range of movement? If yes, is it horizontal, vertical or both?  How to check – Ductions and versions  What to look for – uniocular/binocular limitation, conjugate limitation  Conjugate limitation: supra-nuclear lesion  Diplopia and limitation of ductions: infra-nuclear lesions
  38. 38. EVALUATION OF EOMs  Q3. Is there impairment of latency, accuracy or velocity of voluntary saccade?  How to check - saccades 20 - 30° on either side of primary position  What to look for –  Full range of movement with slow saccades: supra-nuclear lesion  Limited range of movement with slow saccades: infra-nuclear lesions  Limited range of movement with normal saccades in the movement range allowed: myasthenia gravis  Difference in saccadic velocity of both eyes
  39. 39. EVALUATION OF EOMs  Q4. Is their impairment of latency or velocity of smooth pursuit?  How to check – Follow a small target smoothly 20° on either side of primary position  What to look for – Catch up saccades  Cortical lesions causing latency in pursuits: patient has catch up saccades for foveation  Q5. Is their impairment of OKN?  How to check – OKN drum or scanning a newspaper in front of the patient’s eye  What to look for – impaired or absent OKN  Localises lesion to the cortex. OKN is also a good method for checking visual acuity in children
  40. 40. EVALUATION OF EOMs  Q6. Is there impairment of VOR?  How to check – doll’s head or oculocephalic maneuvers  What to look for – Corrective saccades, jerk nystagmus on rapid head movement  Spontaneous jerk nystagmus on head shaking: VOR dysfunction  Corrective saccades after head rotation: due loss of velocity storage mechanism of VOR  Q7. Is there impairment of VOR suppression?  How to check - watching if the patient can keep their gaze fixed on the thumb of their outstretched hand while oscillating or being oscillated en bloc.  What to look for – quick phases in direction of head
  41. 41. EVALUATION OF EOMs  Q7. Is there impairment of VOR suppression?  How to check - watching if the patient can keep their gaze fixed on the thumb of their outstretched hand while oscillating or being oscillated en bloc.  What to look for – quick phases in direction of head movement  Normally the patient should be able to maintain gaze on the thumb of outstretched hand when swilled in a chair  Spontaneous nystagmus indicates a VOR dysfunction
  42. 42. EVALUATION OF EOMs  Q8. Is there impairment of vergence?  How to check – Moving object towards bridge of the nose  What to look for – pupillary constriction present or not, adduction present or not  Light near dissociation is a feature of dorsal midbrain syndrome: Here the pretectal area is affected leading to damage of pupillary light reflex centres. But since the convergence centre lies ventral to it, accomodation reflex is spared leading to miosis on convergence.  In cases of horizontal gaze palsy, there is limitation of adduction due to MLF lesion. But the convergence centre remains intact in midbrain, hence the patient can have adduction on convergence.
  43. 43. EVALUATION OF EOMs  Q9. Is there involvement of other cranial nerves?  How to check – Cranial nerve examination  What to look for – 2nd nerve important, other CN involvement helps in localisation  Other cranial nerve involvement can help localise the site of lesion  Eg: PPRF lesion and VI n Nu. Lesion present with similar gaze palsy. If there is associated VII n palsy, that helps localising the lesion to VI n as the VII nerve fibres loop around the VI n nucleas forming the facial colliculus.
  44. 44. EVALUATION OF EOMs  Q10. Is the limitation mechanical?  How to check – FDT, FGT  What to look for – Restriction vs Paralytic  Q11. Is there any spontaneous or inducible involuntary eye movement, ocular oscillation, or nystagmus?
  45. 45. SUMMARY  Supranuclear lesions- BE involvement  Saccade – Contralateral frontal lobe control  Pursuit – Ipsilateral parietal control  Horizontal movements – PPRF, MLF – Pons  Vertical movements – riMLF & PC – midbrain  VOR – Brief, high frequency rotations  Ocular stability dysfunction – Saccadic intrusions
  46. 46. LESIONS OF SUPRANUCLEAR PATHWAYS
  47. 47. GAZE PALSY  Symmetric limitation of movement of both eyes in the same direction.  Conjugate ophthalmoplegia
  48. 48. HORIZONTAL GAZE PALSY  Congenital – Mobius Syndrome  Acquired – Pontine lesions - Disrupt eye movements towards the side of the lesion.  Acquired – FEF lesions - Disrupt eye movements towards side of lesion
  49. 49. HORIZONTAL GAZE PALSY
  50. 50. VERTICAL GAZE PALSY  Lesions of riMLF or Posterior commissure
  51. 51. INTERNUCLEAR OPHTHALMOPLEGIA
  52. 52. RIGHT INO RL
  53. 53. ONE – AND – A HALF SYNDROME
  54. 54. BILATERAL INO
  55. 55. BILATERAL INO
  56. 56. ETIOLOGY OF INO  - Multiple sclerosis (commonly bilateral): Young patients - Brain stem infarction (commonly unilateral): Elderly patients
  57. 57. PARINAUD SYNDROME  EPIDEMIOLOGY  Sporadic  Causes: obstructive hydrocephalus, mesencephalic hemorrhage, multiple sclerosis, A/V malformation, trauma, compression from tumor (pineal tumors)
  58. 58. PARINAUD SYNDROME  SIGNS : MAJOR COMPONENTS  Vertical gaze disturbance  Convergence retraction nystagmus  Light near dissociation of the pupils  Lid retraction (Collier’s sign)
  59. 59. PARINAUD SYNDROME
  60. 60. PARINAUD SYNDROME  Differential Diagnoses for Dorsal Midbrain Syndrome  Light-near dissociation  Vertical Gaze Palsy
  61. 61. References  Neuro- Ophthalmology, American Academy of Ophthalmology, 2010-2011. 5th edition.  Walsh & Hoyt’s. Clinical Neuro- ophthalmology. 6th edition  Khurana AK. Anatomy and Physiology of eye. 2nd edition  Kanski. Clinical Ophthalmology, 7th edition  Yanoff and Duker. 6th edition  Peter Their, Uwe J. The neural basis of smooth pursuit eye movements. Current opinion in neurology 2005,15:645-652  David L sparks, Ellen J Barton. Neural control of saccadic eye movements. Current opinion in neurobiology 1993,3:966-972  Chen,Chien Ming, Lin, Sung Hsuing. Wall eyed bilateral internuclear ophthalmoplegia. Journal of Neuroophthalmology 2007,1:9-15
  62. 62. THANK YOU

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