Supranuclear Palsies Flashcards
what are the two principles of eye movement
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
what pathways are involved in saccades
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
what structures are inolved in horizontal saccades
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
what structures are involved in vertical saccades
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
what are the slow eye movement pathways
smooth pursuit , vestibular , optokinetic system , vergences
what structures are involved in smooth pursuits
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
vestibular ocular reflex ( What structures are involved)
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
optokinetic system
head rotation
system that initiates sustained head rotation and when we stop spinning - nucleus of the optic tract (in the brainstem) is important
what structures are important in vergence eye systems
pretectal nuclei = important
pathway= runs with 3rd cranial nerves
what are supranuclear pathways
how to the signals get to the cranial nerve nuclei
what are the different possible sites of lesions
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
what happens when you get a lesion above the level of the nucleus
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
what type of gaze tends to be affected in a supranuclear palsy
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
what are the different types of lesions causing supranuclear palsies
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
what are signs of frontal lesions
drowsiness/impaired concious rate
what are signs of unilateral frontal lobe lesions
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
if you had a right frontal lobe lesion what would be affected
right frontal lobe lesion = failure of saccades to the left
in bilateral frontal lobe lesions what would you expect to see
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
what will happen if you have a occipital lobe lesion
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
what is a right hemianopia caused by
right homonymous hemianopia can’t see anything on right visual deed and is caused by left occipital lobe lesion
what does a unilateral lesion of the partial occipital lobe cause
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
what are subcortical lesions
lesions affecting pathways between the cortex and the pprf
what are the types if subcortical lesions
global paralysis
horizontal gaze palsy
vertical gaze palsy
what is global paralysis
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
what are the different types of lesion causing horzizontal gaze palsy and what to they csue
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
describe the horizontal gaze pathway
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
what lesions cause a horizontal gaze palsy
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
what happens in in a nuclear 6th palsy
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
what is affected in a horizontal gaze palsy
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
why is it important to test convergence
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)
what are the features of an acquired pprf lesion
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
what are features of a partial pprf lesion
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
what are features of bilateral pprf lesions
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
what are features of an acquired 6th nerve nucleus lesion
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
what is a congenital horizontal gaze palsy
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
what is oculomotor apraxia
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
what structures are important in making vertical gaze
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
how to test bells phenomena
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 -
how to do a vertical dolls head test
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
what conditions cause vertical gaze palsy
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
what does progressive supranuclear palsy need to be differentially diagnosed from
Parkinson’s disease
defective upgaze and slow vertical saccades
absent impairment of downsize
hutingtons chorea
defective saccades on upgaze (in early part of saccade)
what is parniauds syndrome
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)
what is the light near dissociation response
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
what its papillodema
swollen optic discs
what is the ateiology of parinauds
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
what are features of a vertical gaze palsy caused by hydrocephallus
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
describe the features of a double elevator palsy
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
what is the ateiology of a supranuclar palsy
suprnauclear lesion in dorsal midbrain
nuclear lesion is unlikely = ipsilateral inferior oblique and contralateral superior rectus
total paralysis of the Superior Rectus
usually genetic
what are the aims of the investigation
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
what extra tests needed to be included when testing supranuclear testing
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
what further investgations need to be done
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
what is the role of the orthoptist
investigation
diagnosis
monitoring coniiditon
conservative managment options
prism therapy
ahp - advice/information
head movements
occlusion to eliminate diplopia
excerices
adaptation
ptosis props
