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o and m yr 3 > Supranuclear Palsies > Flashcards

Supranuclear Palsies Flashcards

1
Q

what are the two principles of eye movement

A

keeping image steady on the retina

e.g. vestibular

optokinetic

pursuit

fixation

those that change the line of sight , acquire an image and hold it on the fovea - so that both eyes are looking at the target stimulating the fovea to get binocular single vision

e.g. saccades and vengeances

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2
Q

what pathways are involved in saccades

A

there are parallel pathways that converge on the brainstem from the frontal cortex and the posterior parietal cortex they descend and end with a signal at the pprf - the signal decussates and gets to the pprf - that is what generates horizontal saccades

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3
Q

what structures are inolved in horizontal saccades

A

pathways from frontal eye fields

parietal cortex, and superior colliculus

pathways decussate and terminate in the pprf

stimulation of the frontal eye fields results in

conjugate movement to the contralateral side

if you stimulate the left frontal eye field then you will get a saccade to the right

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4
Q

what structures are involved in vertical saccades

A

pathways from the frontal eye fields

pathway descends to rimlf in the mid brain

bilateral stimulation of the frontal eye fields results in vertical saccades- conjugate movement to the contralateral eye

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5
Q

what are the slow eye movement pathways

A

smooth pursuit , vestibular , optokinetic system , vergences

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6
Q

what structures are involved in smooth pursuits

A

Pareto occipital temporal junction is important - pathway is important because it changes two times (double decussation) - so clinically people say it is under ipsilateral control

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7
Q

vestibular ocular reflex ( What structures are involved)

A

vestibular - information comes from the semicircular canals (information comes from the inner ear)

ipsilateral horizontal vestibular nuclear complex (this is where the signals get to)-that relays information to the contralateral 6th nerve nucleus

vestibular eye movements to the contralateral side

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8
Q

optokinetic system

A

head rotation

system that initiates sustained head rotation and when we stop spinning - nucleus of the optic tract (in the brainstem) is important

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9
Q

what structures are important in vergence eye systems

A

pretectal nuclei = important

pathway= runs with 3rd cranial nerves

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10
Q

what are supranuclear pathways

A

how to the signals get to the cranial nerve nuclei

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11
Q

what are the different possible sites of lesions

A

supranuclear pathways ( supranauclear)

cranial nerve nuclei (nuclear) - internuclear- between cranial nerve nuclei

infra nuclear pathway (course of nerve) is infra nuclear

neuromuscular junction

extraocular muscle

globe

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12
Q

what happens when you get a lesion above the level of the nucleus

A

a lesion above the level of the nucleus

resulting in gaze palsies

horizontal

vertical

global paralysis

i..e you can’t make a horizontal gaze or a vertical gaze

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13
Q

what type of gaze tends to be affected in a supranuclear palsy

A

conjugate gaze tends to be affected
i.e. both eyes not looking into the positon

diplopia is often not a problem because both of the eyes are doing the same thing

lesions can be paralytic , destructive , irratative

complete/partial

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14
Q

what are the different types of lesions causing supranuclear palsies

A

parlaytic/ destructive/ irritative

complete/partial
paralytic lesion meaning there is a complete failure of function - and the eyes deviate towards the side of the lesion

irratative lesion = increase in stimulation of affected area

eyes deviate to the opposite side of the lesion

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15
Q

what are signs of frontal lesions

A

drowsiness/impaired concious rate

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16
Q

what are signs of unilateral frontal lobe lesions

A

unable to perform saccades

  • affeceting the frontal eye filed so saccadic signals are disrupted

paralytic lesion - visual hemineglect to the same side as the lesion

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17
Q

if you had a right frontal lobe lesion what would be affected

A

right frontal lobe lesion = failure of saccades to the left

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18
Q

in bilateral frontal lobe lesions what would you expect to see

A

you wouldn’t be able to make saccades to either side

vor (which is a reflex movement) will be intact

so you need to compare saccades to VOR to distinguish between bilateral and unilateral frontal lobe lesions

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19
Q

what will happen if you have a occipital lobe lesion

A

you will have a contralateral visual field defect

unilateral lesion results in contralateral hemianopia and saccadic Dysmetria in direction of the visual field defect

bilateral lesions result in cortical blindness

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20
Q

what is a right hemianopia caused by

A

right homonymous hemianopia can’t see anything on right visual deed and is caused by left occipital lobe lesion

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21
Q

what does a unilateral lesion of the partial occipital lobe cause

A

failure of smooth outset and to affected side - pt wont be following the target properly - but will be aware that the image slips off the fovea

leads to retinal slip and catch up saccades

repeated catch up saccades

cogwheel pursuits

look for cog wheeling

saccadic dymetrica- hyp oand hypermetric

vor intact more of a reflex movement

vr defect is likely- because the occipital Lobe is intact

22
Q

what are subcortical lesions

A

lesions affecting pathways between the cortex and the pprf

23
Q

what are the types if subcortical lesions

A

global paralysis

horizontal gaze palsy

vertical gaze palsy

24
Q

what is global paralysis

A

roth bielshowsky syndrome

loss of all movements

saccades/smooth pursuits

dolls head test and vestibular nystagmus = normal

pons = intact

lesion = small lesion In the upper midbrain

where saccade and pursuit pathways come together

lesion = diffuse bilateral hemispheric lesions = including the brainstem

25
Q

what are the different types of lesion causing horzizontal gaze palsy and what to they csue

A

lesion before deccusation

loss of conjugate gaze to the contralateral side

lesion in the basal ganglia

  • parlaytic lesion = parksinsons disease / Huntingtons disease

irratative lesion = oculogyric lesion (eyes roll back into head)

lesion at decussation
loss of movement to both sides

lesion below decussation (in pons)

loss of conjugate movement to the ipsilateral side

cranial nerve , 3 , 6, 7, 8 can also be involved

26
Q

describe the horizontal gaze pathway

A

fibres descend from the frontal eye fields through the basal ganglia decussating just above/ at the top of the pons - descend though the pons to the PPRF

27
Q

what lesions cause a horizontal gaze palsy

A

lesion in the ipsilateral pprf /6th nerve nucleus

acquired pprf lesion

partial pprf lesion

bilateral pprf lesion

acquired nuclear 6th nerve plays

congenital horizontal gaze palsy

oculomotor aphaxia

28
Q

what happens in in a nuclear 6th palsy

A

you get a 6th nerve palsy and a gaze palsy so gaze needs to be looked at to determine weather it is a nuclear or infarnuclear palsy

29
Q

what is affected in a horizontal gaze palsy

A

right gaze palsy

and a left gaze palsy - they cannot look right or left but they can converge - if the eyes look very limited but then you test convergence and the eye movements suddenly look a lot better - that suggests that the lesion is supranuclear and it is not a mechanical problem that the eyes dont move that way

30
Q

why is it important to test convergence

A

if convergence is intact suggests that there is a high likelihood that it is a suprnucelar p palsy

could be at the level of ducessation i.e. the pons (pontine lesion)

31
Q

what are the features of an acquired pprf lesion

A

an acquired pprf lesion

chronic =- total horizontal gaze plasy to the ipsilateral side so a right pprf lesion will give you a right horizontal gaze palsy

can be acute = partial restriction of horizontal gaze

32
Q

what are features of a partial pprf lesion

A

gaze preference to the contralateral side

saccades to the ipsilateral side

= infrequent and small amplitude/slow

nystagmus when attempt to look towards the affected side

gaze paretic nystagmus - eyes fail to maintain eccentric gaze

33
Q

what are features of bilateral pprf lesions

A

if you have a lesion that takes out both pprf you will not be making any fast eye movements right to left

ateiology can be

vascular = incomplete, tend to recover

tumour?primary/metatstic

degenerative = including PSP

34
Q

what are features of an acquired 6th nerve nucleus lesion

A

you will have a gaze palsy to the ipsilateral side

convergence will be intact but because the 6th cranial nerve is quite close to the 7th cranial nerve careful attention to ensure facial palsy is not occurring aswell

usually a metastatic cause and it is quite rare that it is vascular

35
Q

what is a congenital horizontal gaze palsy

A

usually they have a total absence of horizontal gaze

associated with spinal abnormalities

ateioology is usually unknown

? aplasia (underdevelopment) of 6th nerve nucleus and MLF

CCDD

36
Q

what is oculomotor apraxia

A

selective horizontal gaze palsy

absent voluntary horizontal saccades

reflex induced horizontal saccades = normale

vertical saccades and pursuit movements= normal

blink and head jerks/thrusts used to change fixation

manoeuvre pts adopts/learns to innate saccades

tend to become more accurate

to view target - blink - use head thrust

intact vor- eyes moved and positioned on target

ateiology- being, bilateral FEF lesions , corpus callous lesion , acquired (balints syndrome) bilateral frontal/ front partial lesions

37
Q

what structures are important in making vertical gaze

A

vertical gaze plays usually related to lesions of the posterior composure

rostral interstitial nucleus of the MLF (riMLF)

bells phenomenon and vertical dolls head test should be intact (more of a reflex movement)

upgaze reduces with age - so need to consider what his a significant reduction of elevation

38
Q

how to test bells phenomena

A

when the eyelids are being forced closed the eye should roll upwards underneath the eyelid - you are asking them to screw there eyelids up tight and forcing the lids open to see if you can see weather the eyelids go up

If the eyelids go up then bells phenomena is intact if the eyes do not then bells phenomena is not intact -

39
Q

how to do a vertical dolls head test

A

you grab the head and make it go up and down - the movement of the head is being detected by the inner ear and the eyes are moving in response to the vestibular system

40
Q

what conditions cause vertical gaze palsy

A

progressive supranuclear palsy (psi)

defective vertical scales and progressive loss of vertical movements - can’t moves eyes up and down

oculogyric crisis

loss of balance

ateiology

extreme brain degeneration

progressive until death

41
Q

what does progressive supranuclear palsy need to be differentially diagnosed from

A

Parkinson’s disease

defective upgaze and slow vertical saccades

absent impairment of downsize

hutingtons chorea

defective saccades on upgaze (in early part of saccade)

42
Q

what is parniauds syndrome

A

can cause a vertical gaze plays

also known as dorsal midbrain syndrome

loss of upgaze

saccades/ smooth pursuits / vor and dolls head / bells phenomena

on attempted upgaze = lid retraction and convergence retraction nystagmus

lid retraction on downgaze (colliers sign)

convert weakness

if progressive = downsize weakness (saccades/sm pursuit/vor)

light / near dissociation of the pupils

?skew deviation

paipillodema

acute stage= ‘‘setting sun sign’’ (associated with hydrocephalus)

42
Q

what is the light near dissociation response

A

they typically have mid dilated pupils with no reaction to light but when you show them near target and you get them to accommodate the pupils do constrict - differential needs to be made between a light stimulus for the pupils and an accomodative target for the stimulus which can be tested during convergence - so you are watching to see if the pupils constrict

43
Q

what its papillodema

A

swollen optic discs

44
Q

what is the ateiology of parinauds

A

lesion in the region if the sylvan aqueductt in the upper dorsal midbrain

pineal gland tumour

pinealoma can compress superior colliculus

?obstructive hydrocephalus - flow of css gets blocked and they have high icp

45
Q

what are features of a vertical gaze palsy caused by hydrocephallus

A

these are infants with raised icp, the eyes do not look up and are fixed in downgaze - sometimes referred to are setting sun sign and the aetiology is something that is blocking the flow of csf- they have an obstructive hydrocephalus and get an increased amount of pressure in the third ventricle - the outflow area gets blocked or they have a space occupying lesion causing a hydrocephalus- they dont have fixed cranial sutures so they will usually have quite large heads

46
Q

describe the features of a double elevator palsy

A

usually associated with a supranuclear ateiology and is a type of vertical gaze palsy

may have a secondary mechanical restrictions / inferior rectus contracture

this is where they have a limitation of one eye - usually unilateral (bilateral is very rare)

usually congenital - acquired is rare

in primary position NAD/ hypotonia

have chin elevation

ptosis or psudopotsis

suprancular palsy- intact bells and vert VOR

46
Q

what is the ateiology of a supranuclar palsy

A

suprnauclear lesion in dorsal midbrain

nuclear lesion is unlikely = ipsilateral inferior oblique and contralateral superior rectus

total paralysis of the Superior Rectus

usually genetic

47
Q

what are the aims of the investigation

A

examine each ocular movement system

diagnose any failures of the systems

propose the possible sites of the lesions

document findings

repeat assessment regularly to monitor progress

48
Q

what extra tests needed to be included when testing supranuclear testing

A

observation - ptosis

general history

ocular history

symptoms

gh

previous ocular history

va

ct

om - all systems

pupils

spinning

caloric irrigation

bells phenomena

vf

innattention tests

colour vision

contrast sensitivity

eye movement recordings

49
Q

what further investgations need to be done

A

ophthalmological , medical and neurological investigations available

car plan and prognosis developed after considering

ateiology of condition

gh

presence/ absence of symptoms

ability to regain fusion (investigating bsv and potential bsv)

previous treatment

presence of ahp

50
Q

what is the role of the orthoptist

A

investigation

diagnosis

monitoring coniiditon

conservative managment options

prism therapy

ahp - advice/information

head movements

occlusion to eliminate diplopia

excerices

adaptation

ptosis props

o and m yr 3 (17 decks)

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