DR. AYMAN AL-MALT

NYSTAGMUS and

ocular movementdisorders

Highest level of visual acuity

• 3 mechanisms are involved in maintaining foveal centration of an object of interest:

1- Fixation, 2- Vestibulo-ocular reflex, 3- Neural integrator.Aymanneuro: omar3SARAm

1- Fixation• Fixation in the primary position involves the

visual system's ability to detect drift of a foveating image and signal an appropriate corrective eye movement to refoveate the image of regard. The vestibular system is intimately and complexly involved with the oculomotor system

2-Vestibulo-ocular reflex • a complex system of neural interconnections

that maintains foveation of an object during changes in head position. The proprioceptors of the vestibular system are the semicircular canals of the inner ear. Three semicircular canals are present on each side, anterior, posterior, and horizontal. The semicircular canals respond to changes in angular acceleration due to head rotation

3- Neural integrator• A gaze-holding network called the neural

integrator generates the signal. The cerebellum, ascending vestibular pathways, and oculomotor nuclei are important components of the neural integrator

• maintain a constant innervation of extra-ocular eye muscles to avoid backward drift of the eyes.

• deficit in the neural integrator can result in gaze-evoked nystagmus and oscillopsia in the eccentric eye position.

Movement of eye ball

• The movement are tested uniocular (duction) as well as binocularly (versions) in all the 9 diagnostic positions of gaze.

• Uniocular – Adduction, abduction, depression, elevation, depression and elevation in adduction and abduction

Terminology• Duction: describes movement of one eye

– Abduction– Adduction– Supraduction or elevation– Infraduction or depression– Incycloduction or intorsion– Excycloduction or extorsion

Terminology

• Version: describes movement of two eyes in the same direction(conjugate).– Dextroversion– Levoversion– Supraversion– Infraversion

Eye Movement Terminology - YouTube2.flv

Terminology

• Vergence: describes movement of two eyes in opposite directions– Convergence– Divergence

Functions of Extra ocular Muscles

• Superior rectus – moves eye up • Inferior rectus – moves eye down • Medial rectus – moves eye in (a-d-duction)• Lateral rectus – moves eye out (a-b-duction)• IO– moves eye up when it is in an adducted position;

also extorts the eye.• SO– moves eye down when it is adducted; also intorts

the eye.

left

Broad H Test

Muscles and Their Fields of Action

Broad H Test• Look for lags or overshoots at various diagnostic

positions of gaze• Look for smooth and accurate pursuit movements• Look for any gaze restrictions or overactions of

muscle in the 9 positions• Look for comitancy ( deviation of the visual axes

remains constant in all fields of gaze, there is comitancy)

Saccade Test• Test set-up is the same as for the broad H test• Direct patient to look quickly from positions 8

to 2, and then back to 8• Repeat rapid shifts of gaze from positions 6 to

5, and then back to 6• Look for accuracy of movement (i.e.,

overshoots and undershoots), speed of initiation ,latency and velosity.

Pursuit system OKN systemSaccadic systemVergence systemVestibular Each of these systems are controlled by different anatomical pathways.

SYSTEMS THAT CONTROL EYE MOVEMENT

Control of Gaze

1) Gaze Stabilisation system.

2) Gaze alignment system.

Gaze Stabilisation System

Compensates for self-motion stabilising visual world on the retina to achieve highest vision

-Vestibulo-ocular system-Optokinetic System (fixation)- Neural integrator.

• Main mechanisms of maintaining steady gaze:1) fixation (Optokinetic System) (vol): >6months a) prevent retinal image drift b) suppress unwanted saccades2) Vestibulo-ocular reflex (VOR): is a reflex eye

movement (pursuit) that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field.

Moving object

Gaze Stabilisation System

Gaze Alignment SystemKeeps object of interest within the visual

world centred on fovea:-Saccades

-Smooth pursuit

Object Tracking Movements• Saccade : (voluntary) fast, step-like eye movement

(up to 1000 deg/sec) that places image of the target on the fovea– Reading -Looking from point A to B– alternate fixation bet different objects– How to elicit? 1-Voluntary (internally triggered)

 2 -Reflexive (externally trig by visual or auditory stimuli) 3- Spontaneous (searching, REM of sleep)  4-Fast phases of nystag (physiologl or patholog).

Pursuit system• Pursuit : (reflex) slow, smooth-following movement

(up to 30 deg/sec) that maintains image of the moving target on the fovea.

The generation of PE movement consists of 3 essential elements: •   A sensory component driven by an image moving across the fovea.  •   A motor component generated near the parieto–occipito–temporal junction that projects to the ipsilateral PPRF.  •   An attentional–spatial comp for concentration on selected targets, orientation in space.

• Saccades =contralateral frontal pre-motor area• Pursuit= ipsilateral occipito-parietal area• Vestibular reflexes= vestibular nuclei in the Pons:

pathways contain relatively few synapses (2-3) → very fast response (<6 ms)

• 3 primary reflexes:– vestibulo-ocular (VOR) -vestibulocerebellar– Vestibulospinal

Centers of Conjugate eye movement

SUPRANUCLEAR GAZE CONTROL

• Signals which control ocular movement are initiated in the cerebral hemispheres.

• They are then transmitted to the gaze centres and oculomotor nuclei in the midbrain and pons and leave the brain in the 3rd, 4th and 6th cranial nerves

• Supranuclear neuronal pathways: conduct impulses from cerebral hemispheres to gaze centres

• Internuclear pathways: conduct impulses from gaze centres to ocular motor nucleii

• Infranuclear pathways: 3rd, 4th and 6th cranial nerves• There are three forms of conjugate eye movement

• These impulses are transmitted to the gaze centres, which mediate the conjugate eye movement.

• Horizontal and vertical gaze control are quite separate.

• The horizontal gaze centre is in the pons at the level of the 6th nerve nucleus.

• Horizontal movement to the left is controlled by the left horizontal gaze centre and vice-versa for the right.

• The vertical gaze centre is in the midbrain but not much is known about vertical gaze control.

Lesions• Unilateral lesions of the PPRF produce characteri-

stic findings Loss of horizontal saccades directed towards the side of the lesion.

• Contralateral gaze deviation (acute lesions, such as early stroke)

• Gaze-evoked lateral nystagmus on looking to the direction of previous gaze palsy (recovery).

• Bilateral lesions produce horizontal gaze palsy and slowing of vertical saccades.

Vergence SystemEnables eyes to move disconjugately in the H plane

and allows binocular fixation of an object that moves toward (converg) or away (diverg) from the subject.

The main stimuli for Verg are retinal blur (unfocused object) and diplopia (fusional disparity); converg is associated with accommod and miosis (the near triad).

The pathways that generate Verg are not known precisely, but the occipital lobe, MB, and cerebellum play significant roles.

Gaze Palsies• An inability to make a conjugate ocular movement

in one direction. • This does not cause diplopia since the visual axes

remain parallel.• By investigating each reflex and conjugate

movement in turn, it is possible to establish where a lesion exist.

9.flv

Horizontal Gaze Palsies

• Unilateral horizontal GP.• Bilateral HGP.• INO.• One and half syndrome.

INO

Think: Elderly-small vessel diseaseYoung Adult-MSChild-Pontine Glioma

Eye Movements Disorders ( Internuclear Ophthalmoplegia ) 8_34 - YouTube2.flv

• Complete HGP in one direction and an INO in the other".

• limitation of horizontal eye movement to abduction of one eye (e.g. right eye ) with no horizontal movement of the other eye (e.g. left eye).

• Nystagmus is also present when the eye on the opposite side of the lesion is abducted.

• Convergence is classically spared as Cranial Nerve III (oculomotor nerve) and its nucleus is spared bilaterally.

One and a half syndrome

The syndrome usually results from single unilateral lesion of the PPRF and the ipsilat MLF. An alternative anatomical cause is a lesion of the abducens nucleus (VI) on one side, with interruption of the ipsilateral MLF after it has crossed the midline from its site of in the contralateral oculomotorius (III) nucleus (resulting in a failure of adduction of the ipsilat eye).

One and a half syndrome

LtRtFast

Vertical Gaze Palsies• Dorsal midbrain (parinaud‘s) syndrome

(Convergence-retraction Nystagmus).• Skew deviation.• Vertical one and half syndrome• Ocular tilt reaction (OTR).

Parinaud’s Convergence-retraction Nystagmus

• Loss of upword gaze involving all types of ocular movement.

• Upon attempt to upword saccade there is converg with retraction of the globe followed by diverg. movement

• Not a true nystagmus: co-contraction of horizontal recti on attempted upgaze

• Loss light reflex• Commonly associated with dorsal midbrain syndrome• Localizes to pretectal area, posterior commissure.• Pineal cyst or tumor, demyelination, stroke.

4.flv

Skew deviationSkew deviation, is a relatively common supranuclear vertical

divergence of the eyes that is associated with lesions in the posterior fossa, particularly those involving the brainstem tegmentum from the diencephalon to the medulla oblongata

With INO higher in the side of lesion.

Eye Movements Disorders ( Skew Deviation ) 21_34 - YouTube.FLV

Definitions• Nystagmus: involuntary rhythmic oscillation

of the eyes that is initiated by a slow phase. The oscillations may be sinusoidal and of approximately equal amplitude and velocity (pendular N) or, more commonly, with a slow initiating phase and a fast corrective phase (jerk N) or mixed.

• N is common with a prevalence of around 0.1%.

Examined by fixation of the to 30 degree from gaze center.

Definitions• Saccadic oscillation: burst of saccades

which may be intermittent or continuous disrupting fixation ( intersaccadic interval and back to back saccades).

• Oscillopsia: visual disturbance in which objects in the visual field appear to oscillate.

• Previously Nystagmus considered untreatable, in recent years several pharmaceutical drugs have been identified for treatment of Nystagmus.

Clinical features

• Signs: Repetitive movement of the eye Binocular or monocular Direction Wave form Effect of gaze Associated movement, Any change with change posture, Periodicty.

•Symptoms : TO and Fro movement of the eye , reduced visual acuity, blurred vision , oscillopsia ( > 8 years).

Common Effects• Nystagmus affects people in different ways. The

most significant effect is the reduced visual acuity -Factors such as stress, tiredness, and nervousness

can cause changes in ability to focus. -Distance visual acuity is poorer than near vision. -Balance may be affected due to poor depth perception or due to vestibular problems.

-Head nodding is common (corrective). Also, child will often tilt his/her head to temporarily

improve vision.

Clinical Assessment• Ask patient to fix and follow on your finger (about

30 cm away)• Move slowly to Broad H Test waiting 5 seconds at

each position• Do not move more than 30 degrees from midline• Nystagmus must be sustained for more than a few

beats to be significant.

Broad H Test

Grading System (e.g. for right beating nystagmus)

• Grade 1 = present in right gaze only• Grade 2 = present in right gaze and primary

position• Grade 3 = present even in left gaze

Classification of Nystagmus

1) Pendular Vs Jerky

2) Physiological Vs Pathological

3) Congenital Vs Acquired

4) Peripheral Vs Central

5) Spontaneous Vs Gaze-evoked

NYSTAGMUS • (cong or acq.

central)-thought to be a result of a delay in messages to the brainstem-characterized by eye movements that are equally paced in each direction

• (phys or path)

-characterized by an FEM in one direction and a slower movement in the opposite direction-thought to result from extra input to the oculomotor system from the brainstem.

Jerky Pendular

Rapid oscillatory movement of the eye balls

General Types• Physiological:- A normal response that is induced

because of excessive demand or imbalance in the vestibular or ocular motor system.

• Pathological:- An abnormal response that occurs spontaneously or appears in an individual looking at a stationary object.

-Congenital (early infancy-6 months) -Acquired (after 6 months).

Physiological Nystagmus

• Not due to a disease process.• Has no benefit, except as a diagnostic tool.• Types1-Postrotational nystagmus.2-End point nystagmus (extreme gaze).3- Induced caloric testing (vestibulo-ocular reflex).4-Optokinetic nystagmus.5- Voluntary nystagmus.

1- Postrotatory nystagmus

• If one spins in a chair continuously and stops suddenly, the fast phase of nystagmus is in the opposite direction of rotation, known as the "post-rotatory nystagmus," while slow phase is in the direction of rotation.

2- Gaze-evoked nystagmus

• GEN: healthy subject ; called end-point N (lower intensity and, more importantly, no other ocular motor abnormalities).

• Gaze paretic nystagmus (pathological).

3-Caloric response= vestibular function

• Caloric testing is dependent on endolymph convection currents.

• Supine position head elevated 30 d 1st 30 Celsius water 5ml later 44 C in EM.

• Normal response (after 20 sec)Warm water in the right ear produces a right-

beating nystagmusCold water in the right ear produces a left-beating

nystagmus

Significance of caloric test• 1) Absent reactive eye movement suggests vestibular

weakness of the HSC of the side being stimulated (canal paresis) (peripheral lesion) .

2) In comatose patients with cerebral damage, the fast phase of nystagmus will be absent as this is controlled by the cerebrum. As a result, using cold water irrigation will result in deviation of the eyes toward the ear being irrigated. If both phases are absent, this suggests the patient's brainstem reflexes are also damaged and carries a very poor prognosis.

4-Optokinetic nystagmus

• OKN occurs normally in response to a rotation movement. The OKR allows the eye to follow objects in motion when the head remains stationary (e.g., observing telephone poles on the side of the road as one travels them in a car). The reflex develops at about 6 months of age.

• How to elicit? OK drum.• Crude assessment of the visual system, particularly

in infants. When factitious blindness or malingering is suspected, check for OKN to determine whether there is an intact visual pathway.

Optokinetic Nystagmus 12_26 - YouTube.FLV

5-Voluntary nystagmus

Horizontal

Not true nystagmus but saccadic osscillation.

Pt converge to initiates nystagmus,

maintained up to 30 sec,

?? familial

Voluntary Horizontal Nystagmus Example - YouTube.flv

Biphasic FAST ONLYBack to back saccades No interval.

Congenital vs Acquired

• ‘Early onset N’-can be inherited (AD).

• pendular, all positions• Defect in the eye or the visual

pathway from the eye to the brain (sensory nyst). It can be a side effect of vision loss from eye diseases such as albinism, cataract, and glaucoma.

• People are not likely to suffer from ‘oscillopsia’- constant moving image b/c the brain can adapt. (unaware of it)

• ‘Late onset nystagmus’• Can be acquired due to

neurological dysfunction such a stroke, MS, or a head injury.

• People are likely to suffer from ‘oscillopsia,’ which can cause a vertigo effect.

• Medications such as Dilantin and Phenobarbital given to prevent seizures may cause nystagmus.

CHILDHOOD NYSTAGMUSCongenital nystagmus• usually recognized in first few months of life – life long• May have good vision idiopathic ( motor, efferent,

oculomotor abnormality) or poor vision (sensory, afferent)• Failure of early sensorimotor integration• Most often occurs in isolation (motor), but may be

associated with albinism or optic atrophy• Uniplanar, horizontal irrespective of gaze position,

esotropia• Dampened by convergence and darkness, in sleep• increase by fixation , anxiety.

• Gabapantin 300mg qid, Memantine 10 mg qid

Congenital Nystagmus - YouTube.flv

• Usually monocular, vertical, low amplitude oscillation• Eye with nystagmus may have afferent visual

(sensory) dysfunction• Requires neuroimaging (chiasmal glioma).

Monocular nystagmus of childhood

idiopathic I NNull zone, in which nystag is minimal & VA maximaum. Uncertain; ?? afferent visual system anomalies; hereditary X linked (e.g., FRMD7 mutations).Gabapentin (300 mg qid) memantine (10 mg qid).

• Usually appears within first few months of life.• Horizontal jerk nystagmus appearing only under

monocular viewing conditions.• Absent in binocular viewing.• Fast phase beats away from occluded eye• Strong association with esotropia• If there is ambylopia it present on binocular

viewing Manifest latent nystagmus.

Latent nystagmus

Spasmus Nutans• Triad of nystagmus, head nodding and Torticollis

(abnormal head posture, not corrective).• Onset 3-15 months with disappear by 3 or 4 years. • it may be present to age 5-6 years. • The nystagmus typically consists of small-amplitude,

high frequency oscillations and usually is bilateral, but it can be mono-cular, asymmetric, and variable in different positions of gaze.

• 2% Glioma of the anterior visual pathway. (Requires neuroimaging).

Spasmus Nutans - YouTube_2.flv Spasmus Nutans - YouTube2.flv

ACQUIRED NYSTAGMUS

ACQUIRED NYSTAGMUS

• Occurs in many CNS disorders, especially those involving the cerebellum, brainstem and vestibular mechanism.

• More common in adults– labyrithitis, – central vestibular disease/tumour, – cerebellar damage– BS diseases

1-VESTIBULAR NYSTAGMUSPERIPHERAL

• Severe vertigo (closing eye)• Days to weeks duration• Hearing loss, tinnitus • Dampened with visual

fixation• horizontal with torsion• unidirectional with the fast

phase opposite the lesion

• Very rarely purely vert or tor• Commonly peripheral

vestibular organ dysfunction: labyrynthitis, meniere’s

CENTRAL• None or mild vertigo.• Often chronic

• visual fixation has no effect• May be purely vertical or torsion• the direction of the fast phase is

directed toward the side of gaze (eg, left-beating in left gaze, right-beating in right gaze, up-beating in upgaze).

• Downbeat, upbeat, torsional• Etiologies commonly vasc,

demyelination, pharmacologic, toxic

2- Gaze-paretic nystagmus

• Gaze-paretic N: is most common form of N., recovering from a gaze palsy.

• Fast phase to direction of gaze.• Usually symmetrical.• Defect in NI• Drug (anticonvulsant and tranquilizers)• Alcohol.• Asymmetrical dt structural BS or cerebellar.

8.flv

3-Acquired pendular nystagmus

– Mainly horizontal, vertical, torsional, or any combination (usually one predominates).

– Oscillopsia ++– asymmetric or even monocular.– asymmetric brainstem disease (MS, oculopalatal

myoclonus).– Gabapantin 300mg qid, Memantine 10 mg qid– Congental due diminution vision ( searching).

Pendular Nystagmuhhhhhhhhhs and Palatomyoclonus - YouTube22w.flv

• APN (Vertical) (1-4 Hz) associated with rhythmic upward movement of palate even during Sleep, possibly including face, neck, upper arm and diaphragm.

• Caudal brainstem pathology: red nucleus, inferior olive, and dentate nuc Occurs 2-49 months after specific brainstem injury from stroke, trauma, neoplasm, brainstem angioma, MS, syringobulbia , encephalitis, degenerating conditions.

• Oculomasticatory myorhythmia: convergence induced slow 1 HZ V pendular nyst. synchronous jaw contraction.(somnolence, altered mentation, mild uveitis, retinopathy) whipple‘s disease, MS, IS BS.

4- Oculopalatal myoclonus

Pendular Nystagmus and Palatomyoclonus - YouTube.flv

5- Periodic alternating nystagmus

• Horizontal jerky N• Present in primary position• Cresendodecresendo fashion• Duration of cycles from 30 seconds to 3 minutes• Craniocervical j,BS, cerebellar tumour.• MS, drugs, ethanol, paraneoplastic syndromes• Baclofen (5-10 mg) (GABAergic) effective• ?? Memantine (antiglutamate).

7.flv

• Present in PP or upword gaze.• Large amplitude N that increases in intensity with

upward gaze. • Classically localizes to a lesion of ant cerebellar

vermis and pontomedullary junction. • More generally implicates posterior fossa disease

stroke, cerebellar deg, demyelination,tumours and Wernicke’s encephalopathy

Baclofen (5–10 mg tid) 4-aminopyridine (5–10 mg tid)

6- Upbeat nystagmus

Upbeat Nystagmus - YouTube2.flv

• Vertical, upward slow drift of eyes.• Secondary downward corrective fast phase.• Present in PP or maximal intensity when the eyes are

deviated laterally and slightly inferiorly, supine posture change to upbeats n.

• Localizes to cervico-medullary junction.• Arnold-Chiari malformation 1. Ttt with 4-Aminopyridine (Neurelan in USA) (5–10

mg tid), 3,4-diaminopyridine (10–20 mg tid), baclofen (5 mg tid) clonazepam (0.5 mg tid).

7-Downbeat nystagmus

Downbeat Nystagmus - YouTube2.flv

8- Torsional nystagmus• Rotary movement of the globe about its AP axis

accentuated on lateral gaze.• associated with other types of nystagmus APN .• lesions of the anterior and posterior SC on the same

side (eg, lateral medullary syndrome). TN with the fast phase directed away from the side of the lesion.

• accentuated by otolithic stimulation by placing the patient on their side with the intact side down (eg, if the lesion is on the left, the nystagmus is accentuated when the patient is placed on his right side).

Torsional Nystagmus - YouTube.flv

9- Horizontal nystagmus• HN is a well-recognized finding in patients with a

unilateral disease of the cerebellar hemispheres, especially with large, posterior lesions. It often is of low amplitude. Such patients show a constant velocity drift of the eyes toward the intact hemisphere with fast saccade directed toward the side of the lesion.

Horizontal Nystagmus - YouTube2.flv

•Jerky , bilateral N•Slow, large amplitude nystagmus (gaze paretic N) when looking towards the side of the lesion (Lt). •Rapid, small amplitude nystagmus (vestibular N) when looking away from the side of the lesion.

• Small vestibular schwannoma (11% <3.5 cm)• Large cerebello-pontine tumour >3.5 cm (CPA)

67%.• ??AICA stroke

10- Bruns Nystagmus

Nystagmus Bruns- Acustic neuroma left - YouTube.flv

11- Ataxic Nystagmus

• Abducting nystagmus of INO• Abducting nystagmus of INO is, as the name

implies, nystagmus in the abducting eye contralateral to a medial longitudinal fasciculus (MLF) lesion

• Fast away from side of lesion.

Eye Movements Disorders ( Internuclear Ophthalmoplegia ) 8_34 - YouTube2.flv

One and a half syndrome

LtRtFast

12- Rebound Nystagmus

• Horizontal • Gaze evoked • Beats transiently in opposite direction after return

to primary position• 3-25 sec• cerebellar

Rebound Nystagmus - YouTube.flv

13-See-saw nystagmus• Vertical (MB) N (pendular)• Upward moving eye intorts followed by downward

and extorts other eye that alternates.• Chiasmal lesions , suggesting loss of the crossed

visual inputs from the decussating fibers of the optic nerve or lesions in the midbrain-thalamic.

• Bitemporal hemianopia.• Acquired SSN: suprasellar lesion or leigh disease. • Congential SSN (REVERSE): achiasma.

5.flv

14-Searching Nystagmus

Pendularcommon with congenital severe visual impairment,

MS.

15- Episodic Nystagmus

• Paroxysmal attacks of Ataxia, Vertigo, N.

• Lasting 24 h.

• Inborn error of metabolism.

• Basilar migraine.

• MS.

16- Ictal Nystagmus

• Occurs during refractory seizures.• Horizontal. • ?? Vertical (comatosed). ?? monocular.• Fast phase opposite to epileptic focus.• Adversive fits• Pupillary dilation even oscillation may occur

synchronous.• Periodic gaze deviation associated with periodic

head rotation may be clue for seizure.

17- Lid Nystagmus• Rhythmic jerky movement of the upper eyelid.• 1st Synchronous with V N (Midbrain tumour)

most common.• 2nd Synchronous with fast phase of HGEN

( lateral medullary syndrome).• 3rd type with voluntary convergence evoked nyst.

Eye Movements Disorders ( Eye lid Nystagmus ) 32 34 - YouTube22.flv

Saccadic oscillation

• Saccadic oscillation: burst of saccades which may be intermittent or continuous disrupting fixation ( intersaccadic interval and back to back saccades).

• Nystagmus: involuntary rhythmic oscillation of the eyes that is initiated by a slow phase. The oscillations may pendular N or, more commonly, with a slow initiating phase and a fast corrective phase (jerk N) or mixed.

• (SWJ), the most common saccadic oscillation, consist of small saccades that take the eyes away from a fixation target, followed by a saccade in the opposite direction to bring the eyes back to the target, with an intersaccadic interval of 200 ms .

• micro healthy individuals, • Macro in MS&OPCA and PD, PSP. . ?? cerebellar. NOT in dark• SWJ rarely degrade vision.

Saccadic disorders1-Square-wave saccadic jerks

2- Oculomotor apraxia• failure to initiate saccades on command (congental

or acquired (BS).•  more correctly, congenital saccadic palsy, is more

common in boys than in girls. Children > 4 m often 'thrust' their head from side to side to change the direction they are looking. 'Head Thrusts' are a typical movement that helps a child overcome their difficulty in moving their eyes quickly. Children may also blink to start a fast eye movement. 

OMA• MRI normal or may reveal poor development of

regions of the brain, in particular the corpus callosum, cerebellum, and/or fourth ventricle.

• Association Ataxia T, cerebral whipple‘s disease.• AE of OMA is usually not determined (idiopathic).• long-term prognosis of children born with OMA The

head thrusts associated with OMA typically diminish over time, but tend not to completely disappear.

• ?? true improvement versus an adaptive compensatory mechanism to mask the head thrust.

• Intermittent burst-like, back to back saccadic in Purely horizontal plane with high frequency, low amplitude.

• No intersaccadic latency• aggravated by change posture , attempt to fixation.• Recovering from opsoclonus.• Isolated OF in MS, Cerebellar signs.• Voluntary OF in 8% of population in attempt to converge• Dorsal midbrain lesion so associated with vertical gaze

palsy (parinaud‘s syndrome).

3-Ocular flutter

Eye Movements Disorders ( Ocular Flutter Dysmetria Opsoclonus ) 13 34 - YouTube2.flv

4- Opsoclonus Myoclonus (OMS)

• Eye : Opsoclonus (rapid, involuntary, chaotic, multidirection (horizontal ,vertical and torsional), unpredictable, conjugate fast eye movements without intersaccadic intervals).

• Myoclonus (jerky limbs) , fascial twitches , eye blinking, ataxia , (truncal , appendicular) .

• Called Dancing limb Dancing eye syndrome.• MS, Hyperosmolar ketoacidosis, viral encephalitis.• Drugs lithium,phyention, amitriptyline,cocaine.

Eye Movements Disorders ( Ocular Flutter Dysmetria Opsoclonus ) 13 34 - YouTube3.flv

PPRF

OMS• Paraneoplastic etiology: SCC of lung, ovarian,

breast CA, 50% of children with OMS have neuroblastoma , in 2% of children with neuroblastoma .

• Antineuronal abs anti Hu, Ri, Yo, Ma1 and antiamphyphyisin abs.

• ttt: propranolol, verapamil, clonazepam.• Tumour removal.• IVIG in idiopathic and postinfectious.• Brain stem lesion (MB, Pons)

5- Ocular bobbing• Spontaneous, vertical, Sudden conjugate rhythmic

downward jerk of the eyes followed by a slow return to the mid position.

• paralysis of horizontal conjugate gaze. • pontine hemorrhage (comatosed).• Atypical OB: intact horiz conj g (acute cerebellar

hge, metabolic enceph, obst hydrocephalus).• Reverse OB: fast movement is upward followed by

delayed slow return (TS, EBV encephalitis).

Social Impact• One major difficulty individuals suffering from nystagmus

face is the lack of knowledge about the disorder, from the outside community.

• In conversation, sufferers with involuntary head movement may cause people to think they are disagreeing with what they are saying.

• Reading speed is likely to be affected because of the extra time and effort it takes to scan words.

• Some people are unable to get their driver’s license. • People with the disorder find it difficult to play sports,

especially those involving good hand to eye coordination.

Nystagmus and alcohol• In police work, testing for horizontal gaze nystagmus is

one of a battery of field sobriety tests used by officers to determine whether a suspect is driving under the influence of alcohol.

• The test involves observation of the suspect's pupil as it follows a moving object, noting lack of smooth pursuit, distinct and sustained nystagmus at maximum deviation, and the onset of nystagmus prior to 45 degrees.

• published by the National Highway Traffic Safety Administration.

Tullio’s phenomenon• sound-induced subjective and objective responses. The

subject may feel sensations of unsteadiness, imbalance or vertigo, associated with disturbances of oculomotor and postural control.

• TP is provoked by very loud sound if physiological. It is pathological if it is provoked by normal sounds. Changes to the functioning and/or the morphology of the labyrinth should be looked for in patients with the pathological form: decreased thresholds for the acoustically evoked vestibular potentials, SC dehiscence, traumatic lesions of the labyrinth, ligament hyperlaxity.

Tullio’s phenomenon• Tullio’s phenomenon (TP) is a pattern of sound-induced

imbalance symptoms, motor responses of the eyes (nystagmus), head (myogenic responses) and other spinal neuron synkinesis (postural sway).It may be physiological or pathological.

• Pathological Tullio’s phenomenon is characterised by subjective and objective sonovestibular symptoms resulting from abnormal hypersensitivity to normal sounds of the vestibular end organs secondary to morphological changes in vibration and pressure transmission between the external and the inner ear.

Thank You