neuro 4b

Question 1

where do voluntary saccades originate

Answer 1

frontal eye field and superior colliculus contralateral to the direction fo gaze

Question 2

other areas that contribute to saccadic control

Answer 2

PPRF, dorsolateral prefrontal cortex, supplementary eye field, and parietal lobe

Question 3

vertical saccades

Answer 3

may also originate in frontal eye fields or superior colliculi and connect to the contralat riMLF

Question 4

inability to produce saccades is called

Answer 4

oculomotor apraxia

Question 5

hypermetric saccades

Answer 5

overshoot

Question 6

hypometric saccades

Answer 6

undershoot

Question 7

VOR (vestibulo-ochlear reflex)

Answer 7

coordinates eye movements with head movement; elicited by slow passive head movements

Question 8

pathway for VOR

Answer 8

semicircular canals (rotation) and otoliths (linear acceleration) and travels to the vestibular nuc and from there to the abducens nuc and then to CNs 3 and 4 through the MLF

Question 9

abnormalities of the VOR (vestibulo-ochlear reflex)

Answer 9

nystagmus

Question 10

nystagmus

Answer 10

rhythmic to and fro movement of the eyes

Question 11

jerk nystagmus

Answer 11

eye drifts away from fixation in a pursuit-like movmenet and returns with a fast saccadic movement

Question 12

direction of nystagmus named how

Answer 12

by the direction of the fast component

Question 13

comitant strabismus

Answer 13

misalignment is constant in all directions of gaze and each eye has full range of movement (usually an eye problem)

Question 14

incomitant strabismus

Answer 14

the degree of misalignment varies with the direction of gaze (usually a neuro problem)

Question 15

phoria (eso or exo)

Answer 15

misalignment of the eyes when binocular vision is absent

Question 16

tropia (eso or exo)

Answer 16

misalignemnt fo the eyes when both eyes are open and binocular vision is possible

Question 17

optokinetic nystagmus

Answer 17

normal response to a continuously moving object

Question 18

vestibulo-ocular nystagmus

Answer 18

by rotations of the subject’s head. Also irrigation fo the ear (caloric tes)

Question 19

endpoint nystagmus

Answer 19

few beats of nystagmus in eccentric gaze

Question 20

congenital nystagmus

Answer 20

jerk or pendular, present after birth and remains throughout life

Question 21

periodic alternating nystagmus

Answer 21

horizontal jerk nystagmus that changes direction every 2 or 3 mins

Question 22

downbeat nystagmus

Answer 22

present in primary position

Question 23

upbeating nysagmus

Answer 23

in primary position is associated with lesions of the

Question 24

differentiating between peripheral (vestibular) and central (brainstem) nystagmus

Answer 24

peripheral is unidirectional w fast phase away from lesion, visual fixation inhibits nystagmus and vertigo, tinnitus or deafness often present, romberg toward the slow phase, severe vertigo, short duration

Question 25

causes of peripheral (vestibular) nystagmus

Answer 25

vascular disorders, trauma, toxicity, Meniere disease, vestibular neuronitis

Question 26

causes of central (brainstem) nystagmus

Answer 26

vascular, demyelination, and neoplastic/paraneoplastic disorders

Question 27

central nystagmus

Answer 27

normally bidirectional, often pureley horixontal, vertical or torsional; not inhibited by fixation

Question 28

peripheral nystagmus

Answer 28

unidirectional, with the fast phase away from the lesion; it combines horizontal and torsional movements and is inhibited by fixation

Question 29

horizontal saccades initiated where

Answer 29

in the contralateral frontal eye field or superior colliculus

Question 30

where do vertical saccades originate?

Answer 30

bilateral frontal eye fields or the superior colliculus

Question 31

conjugate gaze deviation

Answer 31

lesions of the frontal lobe with destruction fo the frontal eye field; eyes deviate toward the side of the lesion