Eye movement disorders - classifications

Question 1

what are the 4 general categories of eye movement disorders?

Answer 1

binocular diplopia, diplopia sub-type INO, gaze palsy, and nystagmus

Question 2

what is binocular diplopia?

Answer 2

patient see double with both eyes open - goes away when they close one eye (eyes are out of alignment)

Question 3

what is diplopia sub-type INO?

Answer 3

internuclear ophthalmoplegia = specific type of EOM anomaly that may or may not have diplopia in some positions

Question 4

what is a gaze palsy?

Answer 4

fusion is usually present but the eyes cannot move into certain positions of gaze

Question 5

what is nystagmus?

Answer 5

specific type of unsteady fixation characterized by slow movement in one direction and a fast movement in other direction

Question 6

what are the 3 main layers/levels that control eye movements?

Answer 6

supranuclear level, premotor level, and the final common pathway

Question 7

what is the supranuclear level for controlling eye movements?

Answer 7

structures in the cortex for saccades, pursuits, OKN, and VOR (cortical and subcortical) and control pre-motor nuclei

Question 8

what is the pre-motor level for controlling eye movements?

Answer 8

organize eye movements by coordinating the nuclei that control the muscles = riMLF, PPRF, vestibular nuclei

Question 9

what is the final common pathway for controlling eye movements?

Answer 9

the cranial nerves that control movements = CN3, CN4, CN6

Question 10

what are 3 locations that pathology can occur for EOM functions?

Answer 10

in a muscle, in the synapse between a nerve ending and the muscle, and in the orbit

Question 11

what are 3 locations that pathology can occur for a nerve that controls EOMs?

Answer 11

in the brainstem nucleus (midbrain or pons), interstitial compartment in the brainstem, and in the space where the axons exit the brain

Question 12

what are the 4 locations of pathology for the pre-motor structures that control EOM location?

Answer 12

PPRF (horizontal), riMLF (vertical), vestibular nuclei (CN8), MLF (internuclear)

Question 13

what are the 4 locations of pathology for the structures that control and maintain fixation?

Answer 13

semicircular canals, CN8, vestibular nuclei, and cerebellum (especially the flocculonodular lobes)

Question 14

what are the 3 locations of pathology for the higher order supranuclear structures?

Answer 14

superior colliculus, frontal eye fields (frontal lobe - saccades), occipital eye fields (pursuits)

Question 15

what is the general symptom/sign for pathology in the orbit, EOM, or synapse?

Answer 15

diplopia

Question 16

what is the general symptom/sign for pathology in the nucleus or nerve?

Answer 16

diplopia

Question 17

what is the general symptom/sign for pathology in the pre-motor structures?

Answer 17

INO

Question 18

what is the general symptom/sign for pathology in the supranuclear structures?

Answer 18

gaze palsy

Question 19

what is the general symptom/sign for pathology in the vestibular system and CN8?

Answer 19

nystagmus

Question 20

what structures are present in the orbit?

Answer 20

EOMs, nerves, fascia, connective tissue

Question 21

what structures are present in the orbital apex?

Answer 21

superior orbital fissure and optic canal

Question 22

what structures are present in the nerve?

Answer 22

subarachnoid space, circle of willis, cavernous sinus, superior orbital fissure and posterior orbit

Question 23

what structures are present in the nerve nucleus and interstitial axons (midbrain)?

Answer 23

descending pyramidal system rostral to the decussation and red nucleus (motor system)

Question 24

what structures are present in the nerve nucleus and interstitial axon (pons)?

Answer 24

descending pyramidal system rostral to the decussation, vestibular nuclei, and cerebellum is nearby

Question 25

what structures are present in the pre-motor (brainstem)?

Answer 25

MLF, SC, vestibular system, and cerebellum

Question 26

what structures are present in the pre-motor (supranuclear)?

Answer 26

frontal and occipital lobes

Question 27

what structures are present in the vestibular system and CN8?

Answer 27

facial nerve, auditory system, descending pyramidal system rostral to decussation

Question 28

what are the associated signs and symptoms for the orbit?

Answer 28

space-occupying lesion and CN5

Question 29

what are the associated signs and symptoms for the orbital apex?

Answer 29

space-occupying lesion and CN2

Question 30

what are the associated signs and symptoms for the nerve?

Answer 30

aneurysm, space-occupying lesion and inflammation

Question 31

what are the associated signs and symptoms for the nerve nucleus and interstitial axons (midbrain)?

Answer 31

contralateral voluntary somatic movement and incoordination

Question 32

what are the associated signs and symptoms for the interstitial axons (pons)?

Answer 32

contralateral voluntary somatic movement, incoordination, dysmetria, imbalance, and dizziness

Question 33

what are the associated signs and symptoms for the pre-motor (brainstem)?

Answer 33

incoordination, dysmetria, imbalance and dizziness

Question 34

what are the associated signs and symptoms for the pre-motor (supranuclear)?

Answer 34

aphasia, psychological, and VF defects

Question 35

what are the associated signs and symptoms for the vestibular system and CN8?

Answer 35

contralateral voluntary somatic movement, facial asymmetry, reduced auditory sensitivity