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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