visual, auditory, and vestibular systems

Question 1

Is impaired visual acuity from a lesion of the optic nerve or macula improved by looking through a pinhole or by corrective lenses?

Answer 1

no

Question 2

Perimetry

Answer 2

computer flashes dots

Question 3

blind spot, when does it enlarge

Answer 3

optic disc in the nasal retina is devoid of rods and cones

-papilledema: increased intracranial pressure causes the optic nerve to appear swollen on ophthalmoscopic exam

Question 4

Scotomas

Answer 4

abnormal blind spots
due to:
1.lesions in the retina (infections or inflammation, macular degeneration, or retinal detachments)
2. lesions of the optic nerve (demyelination or ischemia)

Question 5

constricted fields can be caused by glaucoma or retinal degenerative disease, but as the examiner moves back the visual field should enlarge, what is it called if it doesn’t?

Answer 5

tunnel vision

-psych problem

Question 6

Deficit: blindness in left eye
Lesion:

Answer 6

left optic nerve

11 00

Question 7

Deficit: bitemporal heteronymous hemianopsia

Answer 7

inner optic chiasm

10 01

Question 8

Deficit: binasal heteronymous hemianopsia

Answer 8

outer optic chiasm

01 10

Question 9

Right homonymous hemianopsia

Answer 9

left optic tract

Question 10

Right superior homonymous quadrantanopia

Answer 10

left inferior optic radiation (temporal lobe, meyer’s loop)

Question 11

Right inferior homonymous quadrantanopsia

Answer 11

left superior optic radiation (parietal lobe)

Question 12

Right homonymous hemianopsia (with macular sparing)

Answer 12

left occipital lobe

Question 13

Does congruence increase when the lesion is more anterior or posterior

Answer 13

posterior

Question 14

Optic nerve lesions produce what 2 deficits?

Answer 14

scotomas or monocular blindness

Question 15

Optic chiasm lesions produce what

Answer 15

heteronymous visual field defects

Question 16

Lesions of the optic tract or optic radiation or occipital visual cortex

Answer 16

homonymous visual field defects

Question 17

optic neuritis
What is it?
How does it look on ophthalmoscopic exam?
Who gets it?

Answer 17

sudden blindness of part or all of one eye, which may feel achy or tender with eye movements
-pupils constrict poorly when shined in the bad eye or not at all but constrict normal when light is shined in the good eye
-weeks to months later the vision returns completely or partially (RAPD)
Ophthalmoscopic exam: optic disc appears swollen with indistinct blurry margins
-get it in MS

Question 18

Optic atrophy

Answer 18

optic disc appears more white or pale with sharply defined edges
-some loss of ganglion cell axons has occurred

Question 19

Are most one eye visual deficits with abnormal pupillary light reflex and swelling of the optic disc due to lesions before or posterior to the lateral geniculate body?

Answer 19

before usually of lesions of the optic nerve or optic chiasm

Question 20

What is a common lesion affecting the optic chiasm?

Answer 20

pituitary tumor

• arises from sella turcica
• pressure from below
• ->superior temporal quadrants of the patient
• ->endocrine symptoms as well

Question 21

What most often causes lesions in the optic radiations?

Answer 21

tumors or ischemic infarctions

Question 22

Cortical blindness

Answer 22

severe visual loss from bilateral occipital lobe lesions
-usually a stroke syndrome from thrombosis of the distal basilar artery or emboli down its posterior cerebral branches

-pupillary light reflex is intact and the optic disc appears normal since the retinal ganglion cells are not involved

Question 23

Conductive deafness

Answer 23

impaired air conduction of sound stimuli-water or wax plugging up the external ear canal or fusion or disruption of the bony ossicles

Question 24

Nerve(sensorineural) deafness

Answer 24

damage or impairment of the hair cell receptors or auditory nerve
as from drug toxicity or persistent exposure to loud nois

Question 25

low tone loss

Answer 25

conduction

Question 26

high tone loss

Answer 26

sensorineural

Question 27

complete unilateral nerve deafness

Answer 27

8th cranial nerve lesion

-since the more proximal auditory pathways are bilaterally represented

Question 28

Which is normally more efficient air or bone conduction

Answer 28

air

Question 29

Weber test

Answer 29

top of skull
-nerve deafness-both air and conduction impaired in bad ear so better heard in normal ear

-conduction deafness-better in bad ear because in that ear the environment noise is suppressed so bone conduction is enhanced

Question 30

Rinne test

Answer 30

mastoid process–>outside the ipsilateral ear

• should be heard by air conduction when it stops being heard through bone conduction
• if partial nerve deafness than air conduction is better than bone but if conduction deafness the air no longer more efficient so it is not heard

Question 31

ENG

electronystagmogram

Answer 31

used to record eye movements and nystagmus induced by currents of warm or cool air entering the external ear
-determines whether right or left vestibular system is impaired

Question 32

Dix-Hallpike maneuver

Answer 32

head is tilted and lowered
-if this position creates rotatory nystagmus, that posterior semicircular canal is over sensitive and is likely to cause positional vertigo

Question 33

What can cause sudden severe unilateral deafness?

Answer 33

trauma

• petrous bone fracture
• ischemia in the territory of the AICA

Question 34

acute labyrinthitis

Answer 34

viral infection or inflammation cuasing severe vertigo with nausea and vomiting and hearing impairment and unsteadiness of gait

1. nystagmus
2. unilateral decreased hearing
3. gait ataxia

-resolves within days to weeks

Question 35

Meniere’s disease

Answer 35

recurrent episodes of vertigo, deafness and tinnitius
-membranous labyrinth swells and reptures allowing potassium rich endolymph to leak into surrounding perilymph, disrupting the ionic gradient required for normal hair cell function

same symptoms as acute labyrinthitis
1. nystagmus
2. unilateral decreased hearing
3. gait ataxia
but can progress to
permanent deafness 

-dietary restriction of salt and diuretics can reduce production of endolymph and lessen risk of chronic deafness

Question 36

benign positional vertigo

Answer 36

degeneration of otoliths and displaced calcium crystals and other debris can lodge around the cilia of the semicircular canal hair cells making them over sensitive to minute movements of the head