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Neuro > Visual, Auditory, Vestibular systems > Flashcards

Visual, Auditory, Vestibular systems Flashcards

1
Q

presbyopia

A

age related impairment of near vision

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2
Q

if a pt has difficulty reading the Snellen chart what additional test can you do to see if glasses would correct the problem

A

have them try to read it when looking through a pin hole.

If that corrects the vision the it is an ocular problem and glasses are needed

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3
Q

what does a acuity problem that does not correct indicate

A

if it doesn’t correct there may be a lesion of the optic nerve or macula

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4
Q

what is a highly accurate way to record visual fields

A

using Perimetry, a computer flashes dots of light on the screen and the patient presses a button when seen

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5
Q

what causes the physiologic blind spot

A

where the optic disk is in the nasal retina since there are no rods or cones there

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6
Q

when may a patients blind spot be enlarged

A

papilledema

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7
Q

what is papilledema

A

when increased intracranial pressure causes the optic nerve to appear swollen

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8
Q

what is a scotoma

A

a pathological, abnormal bind spot (not at the optic disc) in the visual field of one eye where vision is lost or decreased

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9
Q

what causes a scotoma

A

lesions in the retina (infections, inflammation, macular degeneration, or retinal detachments) or optic nerve (demyelination or ischemia)

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10
Q

what would you call an abnormally narrowed or mall visual field

A

constricted or contracted visual fields

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11
Q

what could cause a constricted or contracted visual field

A

glaucoma or a retinal degenerative disease

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12
Q

when is a constricted visual field likely due to a psychiatric problem

A

if it doesn’t expand in a cone-shaped fashion = tunnel vision

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13
Q

what is a homonymous hemianopsia

A

a deficit of the nasal half of one eye and the temporal half of the other eye’s visual fields

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14
Q

where is a lesion located that presents with macular sparing

A

occipital lobe

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15
Q

how does congruence change with the location of a lesion affecting the visual tracts

A

congruence increased when the lesion is more posterior

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16
Q

what is a heteronymous hemianopsia

A

a visual deficit involving the nasal halves of bother eyes or the temporal halves of both eyes

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17
Q

where would a lesion causing a heteronymous hemianopsia be located

A

the optic chiasm

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18
Q

what would someone with a optic chiasm lesions visual fields look like

A

heteronymous hemianopsia - loss of both temporal visual fields

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19
Q

what is the most common causes of acute unilateral optic nerve lesions

A

demyelination (MS or ischemia)

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20
Q

how does MS frequently initially present

A

optic neuritis - may have sudden blindness of part or all of one eye which may feel achy or tender with eye movement, pupils constrict poorly when light is shone in the affected eye but both react normally when light is shone in the other eye

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21
Q

in optic neuritis what is seen on fundoscopic examination

A

the optic disc appears swollen with indistinct, blurry margins.

exception is retrobulbar neuritis where the inflammation is further back along the optic nerve therefore the disc looks normal

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22
Q

how does optic atrophy appear on fundoscopic exam

A

optic disc appears more white or pale with sharply defined edges

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23
Q

what is optic atrophy

A

loss of ganglion cell axons in the optic nerve or optic chiasm - occurs when vision is not restored after optic neuritis

24
Q

how is optic neuritis differentiated from papilledema

A

optic neuritis occurs in one eye but papilledema would present in both eyes simultaneously

25
Q

what other symptoms do patients with papilledema experience

A

headache, nausea, vomiting, impaired consciousness, vision will not be affected immediately but may become impaired if not treated

26
Q

how does a pituitary tumor affect vision

A

pressed on the center of the optic chiasm from below - affects the decussating, inferior, nasal retinal fibers first

27
Q

what visual field losses are seen with a pituitary tumor

A

superior temporal quadrants or if there is a total lesion of the optic chiasm a bitemporal heteronymous hemianopsia

28
Q

what other symptoms besides visual field defects are commonly seen with a pituitary tumor

A

endocrine symptoms- i.e. hirsutism, galactorrhea, infertility, amenorrhea, coarse feactures, enlarged jaw, nose, tongue, cushing syndrome, impotence, diabetes

29
Q

what is cortical blindness

A

severe visual loss from bilateral occipital lobe lesions

30
Q

what causes a bilateral occipital lobe lesion

A

thrombosis of the distal basilar artery or emobli down its posterior cerebral artery brances

31
Q

what other signs are present with cortical blindness

A

pupillary light reflex is intact and the optic discs appear normal in the retinal ganglion cells are not involved

32
Q

what is conductive deafness

A

deafness due to impaired air conduction of sound stimuli

33
Q

what causes conductive deafness

A

water or wax in the ear cannel, or fusion or disruption of the bony ossicles (anything before the hair cell receptors)

34
Q

what is another name for nerve deafness

A

sensorineural deafness

35
Q

what causes nerve/sensorineural deafness

A

damage or impairment of the hair cell receptors or auditory nerve

could be from drug toxicity or persistant exposure to loud noise

36
Q

what kind of deafness is associated with low tone hearing loss

A

conductive deafness

37
Q

what kind of deafness is assocaited with high tone hearing loss

A

nerve (sensorineural) deafness

38
Q

what causes severe unilateral deafness

A

CN VII lesion (more proximal ascending auditory pathways are bilaterally represented)

39
Q

what type of conduction is typically more efficient

A

air conduction is normally more efficient than bone conduction

40
Q

describe the Weber test

A

hold the tuning fork at the top of the skull or forehead

41
Q

what would result from a Weber test if nerve deafness had occured in one ear

A

since both air and bone conduction would be impaired the affected ear the tuning fork is better heard in the normal ear

42
Q

what would occur if a Weber test was done on someone with conductive deafness in one ear

A

the vibrating tuning fork is heard better in the deaf ear, since bone conduction is enhanced

43
Q

describe the Rinne test

A

begin by holding the vibrating tuning fork on the mastoid bone allowing the vibration to be heard by bone conduction. When it is no longer heard move it to next to the ear where it should still be normally heard (since air conduction is better than bone conduction)

44
Q

what is the result of the Rinne test in someone with conduction deafness

A

air conduction is no longer more efficient than bone conduction therefore the tuning fork would not be heard when moved off the mastoid bone

45
Q

what is the result of the Rinne test in partial nerve deafness

A

since air conduction is still better than bone conduction the tuning fork would be heard when moved off of the mastoid

46
Q

if a Weber test is louder in the right ear what are the possible defects

A

either Right conductive deafness or LEFT nerve defect

47
Q

what is an electronystagmorgram (ENG)

A

uses special equiptment to record eye movements and nystagmus induced by currents of warm or cold air entering the external ear canal and determines whether the right or left vestibular system is impaired

48
Q

How is a Dix-Hallpike maneuver preformed

A

patient lies supine on the examination table with his or her head tilted about 45 degrees below the edge of the table turned to the side.

49
Q

what is being tested by the Dix-Hallpike maneuver

A

the posterior semicircular canal of the tilted lower ear.
if this position creates rotatory nystagmus then that posterior semicircular canal is overly sensitive to head movement and is the cause of the vertigo

50
Q

what are 2 possible causes of acute severe unilateral deafness

A
  • trauma - particularly petrous bone fractures

* ischemia - in the territory of the anterior inferior cerebellar artery (AICA)

51
Q

what is acute labyrinthitis

A

when the labyrinth of the inner ear is affected by a viral infection or inflammation causing severe vertigo with nausear and vomiting, hearing impairment and unsteadiness of gait

52
Q

what 3 things are commonly found on examination of a patient with acute labyrinthitis

A

nystagmus, unilaterally decreased hearing, and gait ataxia

53
Q

what is Meniere’s disease

A

recurrent episodes of vertigo deafness and tinnitis

54
Q

what causes Meniere’s disease

A

the membranous labyrinth swells and ruptures allowing potassium-rich endolymph to leak into the surrounding perilymph, disrupting the ionic gradient required for normal hair cell function

55
Q

what is the prognosis of Meniere’s disease

A

the repetitive episodes may lead to complete, permanent deafness - the risk may be decreased by dietary salt reduction and diuretics (decrease the production of endolymph)

56
Q

who is most likely to experience benign positional vertigo

A

elderly patients

57
Q

what causes benign positional vertigo

A

degeneration of otoliths and displaced calcium crystals and other debris that lodges around the cilia of semicircular canal hair cells making them oversensitive to minor movements of the head

Neuro (11 decks)

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