DR. BHARAT BHUSHAN(DM-NEUROLOGY)

ASSOCIATE PROFESSOR GOVERNMENT MEDICAL COLLEGE,KOTA

SUPRA NUCLEAR GAZE DISORDERS

Supra nuclear ocular motility disorders

Disorder of ocular motility- Cerebral/ vestibular descending pathways

Other pathways – MLF

NEURAL MECHANISMS

SUPRA NUCLEAR // INTERNUCLEAR

Ocular motility –OCULAR MOTOR SYSTEM

AIM : Place the image of regard on the FOVEA

Maintain foveation

FOVEA : Highly sensitive part of the retina

Resolving angle of < 20˚

Various combinations of eye movements

Muscle Primary Secondary TertiaryMedial rectus AdductionLateral rectus AbductionSuperior rectus Elevation Intorsion AdductionInferior rectus Depression Extorsion AdductionSuperior oblique Intorsion Depression AbductionInferior oblique Extorsion Elevation Abduction

CONJUGATE : VERSIONALDYSCONJUGATE : VERGENCE

MUSCLES PRIMARY SECONDARY TERTIARY

MEDIAL RECTUS ADDUCTION

LATERAL RECTUS ABDUCTION

SUPERIOR RECTUS

ELEVATION INTORSION ABDUCTION

INEFERIOR RECTUS

DEPRESSION EXTORSION ABDUCTION

SUPERIOR OBLIQUE

INTORSION DEPRESSION ADDUCTION

INFERIOR OBLIQUE

EXTOESION ELEVATION ADDUCTION

WHEN THE EYE IS ABDUCTED – SR ELEVATES THE EYE

WHEN THE EYE IS ADDUCTED- SR INTORTS THE EYE

THE ACTION OF SUP AND INF RECTI ARE SOLELY VERTICAL WHEN ABDUCTED 23 ˚

THE ACTION OF SUP AND INF OBLIQUE MUSCLES IS SOLELY VERTICAL WHEN

ADDUCTED 51˚

CORTEX

BG

THALMUS

MID BRAIN

PONS

NuclearSupra nuclear control

Where to start …Functional classes of eye movements

1. Holding gaze … on fovea FIXATION

2. Holding Gaze…….. during head movement

VESTIBULAR

3. Keeping image stable on retina , prolonged head rotation

OPTOKINETIC

4. Bring object of interest on fovea SACCADES

5. Holding image of moving target on fovea

SMOOTH PURSUIT

6. Moves eyes in opp direction to bring image on fovea

VERGENCE

7. Resets eye during prolonged head rotation

NYSTAGMUS

FINALLY……….HORIZONTAL ….. Conjugate

Vergence

VERTICAL …… Down gaze Up gaze

FINAL ORBITAL MECHANICS

1.MOVEMENTS : HORIZONTAL CONJUGATE

1.MOVEMENTS :

convergence

2.MOVEMENTS : VERTICAL UPGAZE

2.MOVEMENTS : VERTICAL DOWN GAZE

ORBITAL MECHANICS

Mechanical Restraint ---- Supporting structures We AIM -- Phasic increases … gaze holding ..

Tonic increase in neural activity

POSITION COMMAND : STEP VELOCITY COMMAND : PULSE

STEP – PULSE INNERVATION

NEURAL INTEGRATOR- Velocity coded signal into position coded signal

BURST CELLS : Control The pulse of innervationOMNIPAUSE NEURONS : Tonic inhibitory control

SUPRANUCLEAR CONTROL

1. THE SACCADIC SYSTEM2. THE SMOOTH PURSUIT SYSTEM

3. THE VESTIBULAR SYSTEM

EYE MOVEMENTS – REDIRECT GAZE TO DIFFERENT OBJECTS

STABLIZE THE IMAGE ON THE RETINA

PURSUIT : TRACK MOVING OBJECTS SLOWLY

70˚/SEC

SACCADE : quick refixations MOVES EYES RAPIDLY TO FIXATE NEW TARGETS

800˚/SEC

SACCADES – MECHANICAL PROPERTIES

1. PULSE (sudden increase in neuronal firing) OVERCOMES RESISTANCE OF ORBITAL TISSUES ----- VELOCITY COMMAND

2. STEP (return to a new baseline firing level) OVERCOMES ELASTICITY ,KEEPS IN POSITION –----- POSITION COMMAND

3. PULSE – SLIDE - STEP SLOW TRANSITION

AMPLITUDE : ANGLE SUBTENDEDVELOCITY :DEGREES /SECLATENCY : TARGET – GENERATION OF SACCADE– 200 ms

PLAN CORTEXMOVE (VELOCITY) PRODUCING MOVEMENT BURST OF NEURONS KEEP (POSITION) INTEGRATOR

INTEGRATOR : MATHEMATECAL INTEGRATION TO CONVERT THE VELOCITY CODED INFORMATION TO A POSTION CODED INFO

INSPECTING A SCENECAN BE VOLITIONAL (PRODUCE OR INHIBIT) / INSPECTION / ON COMMAND / DURING OKN/ VEST STIM

TYPES :1.REFLEXIVE (visual/auditory) 2.INTENTIONAL

3.ANTISACCADES 4.SPONTANEOUS(speech/rest)

HORIZONTAL GAZE

CORTICAL : Voluntary – FRONTALReflexive – POSTERIOR PORTIONS

CONTRALATERAL

C/L

1. DIRECT

2.PEFThro’ caudate/SNc/SC

3. PEF :

Thro’ SC

PPRFC/L

BALANCE b/w

reflexive and

purposeful

voluntary saccade

BASAL GANGLIAGates the selectively reflexive and voluntary

saccades generated by SC

SC

CORTEX

C

SN---

+V

--

-R

CEREBELLUM

LEICHNETZ – Victor and Adams textbook

BURST of excitation ---- PPRFSTEP of innervation after each saccade – NI / NPH /MVN

BURST of Inhibtion -(silencing the antagonists ) –Nu paragigantis cellularis-medulla

Inhibiting unnecessary saccades – omnipause neurons , mb and pons

BALANCING THE REFLEXIVE AND THE VOUNTARY SACCADES : BG

Excitatory Burst Neurons

Inhibitory Burst neuron

Neural Intergrator

Omnipause Neurons

Horizontal PPRF Ponto-mesenAbove 6th

Dm MedullaBelow 6th

Nu. Hypoglossi Propositus

Nu. Reticularis Pontine Caudalis INHERENTLY

LEAKY ---Vest /

cerebellum

CEREBELLUM

ASSESMENT

REFIXATE 2 TARGETS 30 ˚TO 40˚

Apart

NORMAL : ONE SACCADE , 1 / 2 Catch up saccade

ABNORMAL : Assymetric3 /4 catch up saccades

Over shoot

Undershoot ?/ non localizing

ANTI SACCADE : Suppress the natural tendency to refixate to a new target –

Frontal lobe – BG connections

SACCADIC DISORDERS

H EMISPHERIC :

U/L-REDUCED EFFICACY , INCREASED

LATENCY NORMAL SPEED

B/L OR LARGE ABOLISH SACCADES SPARING THE VOR

Pursuits

TRACK MOVING OBJECTS SLOWLY (70˚(30-40˚)/SEC)Match the velocity of moving target

Visual motion processing drives pursuits

CORTICAL : OCCIPITAL AND TEMPORAL (Medial temporal and medial superior temporal in monkeys )CONTRIBUTION FROM: POST PARIETAL

SEF/ FEF

INVOLUNTARY

IPSI LATERAL

VISUAL STIMULI STRiate CORTEX Rem. also FEFMST +MTDLPNCEREBELLUM (Fastigial+vermis> flocculus)VN(UPWARD INC>PC; DOWNWARD INC)6TH NEREV

SO;1. I/L2. NO PPRF3. VERTICAL > ROLE OF PC/INC4. INVOLUNTARY

li RetinaLGBStr corte

xMT/PCFEF/ SEF

Pontine nuclei(DLPN)

Cerebellar cortex

(DV/Floccular complex)

Fastigial nu / med vest nu

Ocular motor nuclei and

motor neurons(3/4/6)

Smooth pursuit eye movements

DOUBLE DECCUSATION

SMOOTH PURSUIT DISORDERS

ASSYMETRIC Later alized neuro deficit

Cortical

SYMMETRICALLY IMPAIRED PURSUITS

VERTICAL GAZE

Meso Diencephalic

B/L

Medulla and Pons

MLF

PC

Excitatory Burst Neurons

Inhibitory Bn

Neural Intergrator

Omnipause Neurons

VERTICAL ? CAUDAL PPRF

ri MLF – MB

?PC

ri MLF MB INC

? Vestiblo cerebellum

Nu.Raphe Interpositus

VESTIBULAR SYSTEM

THE VESTIBULAR SYSTEM AIM:drives the eye equal velocity in a direction opposite to the disruptive head motion

Coordinate stablization of gaze (SUM OF EYE MOVEMENTS AND HEAD POITION ) and posture Contributes to perception of verticality and self motion

VOR: Reflex by which the vestibular system perceives the head movement and makes the eyeball move in the opposite direction

CORTICAL PROCESSING :? Post insular cortex / pc/fc

VESTIBULO OCULAR REFLEX SENSORY ARC : SCC (INNER EAR )

Flourens law : SCC stimulated by the Movements in its plane and also moves eye in its plane

MVN

HOR SCC

POST SCC

HOR SCC

ANT SCC

HEAD TO LEFT

HEAD UP HEAD DOWN

HEAD TO RIGHT

CANCELLATION OF VOR : pursuing an objectIMPAIRED : Most often – cerebellar

Non specific – cerebral hem , brain stem NORMALLY FATIGUES IN 30 sec

CLINICAL EVALUATION

VOR GAIN : eye velocity / head velocity NORMAL : 1

ABNORMAL VOR GAIN –Images move across retina – oscillopsia

TESTS : 1. DYNAMIC VISUAL ACUITY TEST

2. HEAD IMPULSE TEST (more sensitive )3. OTHER FIXATION TESTS

HEAD IMPULSE TEST :

FIXATE RAPID horizontal head rotation – 20 to 30 ˚

NORMAL VOR GAIN : eye at the targetABNORMAL :catch up saccade back to target

CLINICS1. VOR SUPPRESION (Fixation suppresion of

vestibulo ocular reflex)2. OPTOKINETIC NYSTAGMUS

3. BITHERMAL CALORIC TESTING

OKN : both foveal and parafoveal stimulation FULL FIELD STIMULUS/Large rotating drum

Saccade generation

Vestibulo ocular reflex :extended arm fixtion at abducted thumbs

Rotation of chair

BITHERMAL CALORIC TESTING

Head 30 ˚ angle with hor plane > Each canal irrigated for fixed duration (30-40 sec)

Constant flow of water -7˚C below and above body temperature

Inspection of EAC

ENDOLYMPH MOVEMENT: COLD WATER – ampullo fugal HOT WATER - ampullo petal

COLD > AMPULLO FUGALGAZE

>>>>>>>>>>>>>>>>>

NYSTAGMUS FAST

<<<<<<<<<<<<<<<<COWS

COMATOSE PATIENTS: Eyes drift to the same side

for 10 to 25 sec ; no quick jerks noted

OKN Series of visual targets (trees /

drum)Pursuit and refixation

i/l post parietal

SUPRANUCLEAR GAZE DISORDERS

Interruption of saccadic / pursuit pathyways before they reach the eye movement generators in the

MRF/ PPRF

Loss of VOLUNTARY eye movements Preservation of REFLEX movements – VOR, OKN,

Bell phenomenon

HORIZONTAL

S

NUCLEAR I/L GAZE PALSY SUPRANUCLEAR

1. PPRF Loss of I/L horizontal saccades C/L GAZE DEVIAT ION

2. CEREBRAL

STRAITE CORTEX

I/L GAZE DEVIATION Selective saccades loss

SACCADES ??/

3.CONNECTIONS

MEDIAL LONG FASCICULUS

INTERNUCLEAR OPHTHALMOPLEGIA

C/L FEF

REM .SAME SIDE PPRF

RIGHT CORTEX

HORIZONTAL GAZE PALSY

FAMILIAL :

Familial horizontal gaze palsy with scoliosis Pontine hypoplasia

Impaired gaze, OKN,VORNUCLEAR

AQUIRED :20% ACUTE STROKE

WRONG WAY EYES

CONJUGATE DEVIATION TO THE OPPOSITE SIDE AWAY FROM THE LESION

CONTRA VERSIVE EYE DEVIATION

1. IRRITATIVE / SEIZURE FOCUS

2. I/L FRONTAL LOBE ??( CENTER FOR I/L GAZE)

3. IRRITATION OF INTRA LAMINAR THALMIC

INTER NUCLEAR OPHTHALMOPLEGIA

WEBINO : Wall eyed B/L INO Syndrome

Both eyes : ABDUCTED SLOW ABDUCTING SACCADES

LUT’Z POSTERIOR INO

IMPAIRED ABDUCTION WITH NYSTAGMUS IN ADDUCTED EYE

DAMAGE TO UNCROSSED FIBRES FROM PPRF

BRAIN STEM / PONTINE STROKE

MULTIPLE SCLEROSIS

ONE AND A HALF SYNDROME

I/L Gaze palsy with I/L INO Lesion : CAUDAL DORSAL PONTINE TEGMENTUM

OCULOMOTOR APRAXIA

Inability to perform voluntary saccades while spontaneous saccades and reflex eye movements are preseved

1. DIRECT

2.PEFThro’ caudate/SNc/SC

3. PEF :

Thro’ SC

PPRF

BALANCE

Aplasia or hypoplasia of the corpus callosum■ Aplasia or hypoplasia of the cerebellar■ Ataxia with “ocular motor” apraxia type I syndrome■ Aicardi syndrome■ Ataxia telangiectasia■ Autosomal recessive■ Bardet-Biedl syndrome■ Bilateral cortical lesions■ Birth injuries (see perinatal/postnatal disorders)■ Carbohydrate-deficient glycoprotein syndrome ■ Carotid fibromuscular hypoplasia■ COMA (occasionally may be familial)■ Congenital vertical ocular motor apraxia (rare)■ Cornelia de Lange syndrome■ Cockayne syndrome■ Dandy-Walker malformation

GM1 gangliosidosis■ Infantile Gaucher disease■ Infantile Refsum disease■ Hydrocephalus■ Joubert syndrome■ Krabbe leukodystrophy■ Leber congenital amaurosis■ Microcephaly■ Megalocephaly■ Microphthalmos■ Neurovisceral lipidosis■ Occipital porencephalic cysts■ Pelizaeus-Merzbacher disease■ Perinatal and postnatal disorders (hypoxia, meningitis, PV leukomalacia, athetoid cerebral palsy, perinatal septicemia and anemia, herpes encephalitis, epilepsy)■ Propionic acidemia■ Succinic semialdehyde dehydrogenase deficiency■ Wieacker syndrome

AT / AOAHUNGTINTONS

BIRTH INJURIES

SACCADE ABNORMALITIES

I/L Overshoot Hypermetric

SLOW SACCADES

PROLONGED LATENCY

Saccadic intrusionsSLOW SACCADES :

PONS/ MBMSA, HD, SND,BSE

PROLONGED LATENCYFTD,AD,HD,PD

SLOW SACCADES   AIDS dementia complex■  ALS■  Anticonvulsant toxicity ■  Ataxia-telangiectasia■  Brainstem encephalitis■  Hexosaminidase A deficiency■  HD■  INO (slow abduction)■  Joseph disease■  Kennedy disease)■  Lesions of the paramedian pontine reticular formation■  Lipid storage diseases■  Long-standing cholestasis ■  Lytico-Bodig disease ■  Myasthenia■  Myotonic dystrophy■  Nephropathic cystinosis■  Ocular motor apraxia■  Ocular motor nerve or muscle weakness■  Olivopontocerebellar degeneration (ADCA type I)■  PSP■  Pseudo-PSP■  Striatonigral degeneration■  Wernicke encephalopathy■  Whipple disease■  WD

SPONTANEOUS , SMALL AMPLITUDE PAIRED SACCADES WITH AN INTERLATENCY INTERVAL OF 150- 200 msec THAT BRIEFLY INTERRUPET FIXATION

MACRO – LARGE AMPLITUDE 10 – 40 ˚ AND SHORTER LATENCY(80 msec)

SQUARE WAVE JERKS

INTER SACCADIC LATENCY : ? SUPRATENTORIAL

OTHER SACCADIC INTRUSIONS : DYSFUNCTION OF OMNI PAUSE NEURONS

■  Normal subjects (<2 degrees)■  Excitement in normals■  Catecholamine depletion in normals■  Aging■  Strabismus■  Congenital nystagmus■  Latent nystagmus■  Dyslexia (suppressed by methylphenidate)■  PSP■  Schizophrenia■  Cerebral hemisphere tumors and stroke■  PD; ■  Wernicke encephalopathy■  Friedreich ataxia■  Joseph disease■  Gerstmann-Sträussler-Scheinker disease■  Lithium, Tobacco■  AIDS-dementia complex (HIV encephalitis)■  OPCA■  MS (cerebellar dysfunction

MULTIPLE SCLEROSISFRIEDRICHS ATAXIA AIDS DEMENTIAADHDPD

FASTGIAL NU >> SC FIXATION

MSW : MS , CEREBELLAR HGE , MSA , ACM

SACCDIC OSCILLATIONS

SACCADIC INTRUSIONS

OCULAR FLUTTER

Back to back saccades In intermittent bursts > On fixation, > change of postureLoss of pause cell inhibition of EBN in PPRF

a/w OCULAR DYSMETRIA opsoclonus

O FL

HY METRIA

HYPO

FL DYSMET

RIA

SPONTANEOUS , CHAOTIC ,MULTIVECTOR saccadic eye movement disorder> On fixation Dancing Eyes Dancing Feet syndrome

Dysfunction of pause cells in PONS Disinhibition of fastigial nuclei inhibiting

omnipause neurons

OPSOCLONUS

OCULAR MICROFLUTTER- ? OpsoclonusMS , Cerebellar degeneration,

NeoplasmOCULAR DYSMETRIA- INTERSACCADIC

LATENCY OF 200 msFLUTTER DYSMETRIAOCULAR BOBBING

DISORDERS OF VERTICAL GAZE UPGAZE

UPGAZE AND DOWN GAZEU/LBURST NEURONS D > U

B/L DOWN GAZE PALSY

REM. PSP, Whipples ,AIDS

REM. PUPILLARY LIGHT REFLEXES ARE MORE SUPERFICIAL ACCOMODATION ARE DEEPER

EXTRINSIC LESION – Light reflex goes

INTRINSIC LESION – Acc reflex goes

PRETECTAL SYNDROME

1.Upgaze palsy2.Convergence Impaired3.Light Near dissociation4.Convergence Retraction Nystagmus

PERINAUDS SYNDROME DORSAL MID BRAIN SYNDROMESYLVIAN AQUEDUCT SYNDROMEKOERBER SALUS ELSCHING SYNDROMEPRETECTAL SYNDROME

OCULO GYRIC CRISES

VERTICAL NEURAL INTEGRATOR Episodic Conjugate , Spasmodic ocular deviation

Upward and lateral direction

Post encephlitic Encephalitis lethargicNeuroloeptic drugsDegenerative d/o ? Ca / wilsons

QUESTIONS VIDEOS