Lecture 14- Special Senses (Vision, Hearing, Vestibular) Flashcards

1
Q

There is a greater proportion of our brain devoted to ______ than any other sense.

A

sight

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2
Q

What are the 7 types of visual field losses?

A
  • ipsilateral blindness
  • binasal hemianopsia
  • bitemporal hemianopsia
  • homonymous hemianopsia
  • upper quadrantanopia
  • lower quadrantanopia
  • homonymous hemianopsia with macular sparing
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3
Q
  • Where would a lesion occur in Ipsilateral Blindness?

- How does Ipsilateral Blindness impair the visual field?

A
  • lesion before chiasm

- blindness in ipsilateral eye

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4
Q

What are the functional implications of Ipsilateral Blindness?

A

Difficulties with visualizing objects in far periphery

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5
Q
  • Where would a lesion occur in Binasal Hemianopsia?

- How does Binasal Hemianopsia impair the visual field?

A
  • compression to optic chiasm

- loss of nasal fields bilaterally

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6
Q

What are the functional implications of Binasal Hemianopsia?

A

Not huge… patients able to compensate more easily here than other lesion locations

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7
Q
  • Where would a lesion occur in Bitemporal Hemianopsia?
  • How does Bitemporal Hemianopsia impair the visual field?
  • What is this seen commonly with?
A
  • lesion to optic chiasm
  • loss of bilateral temporal fields
  • pituitary tumors
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8
Q

What are the functional implications of Bitemporal Hemianopsia?

A
  • “Tunnel Vision”
  • Peripheral objects go missed on both directions
  • HIGH fall risk!
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9
Q
  • Where would a lesion occur in Homonymous Hemianopsia?
  • How does Homonymous Hemianopsia impair the visual field?
  • What is this seen commonly with?
A
  • damage at the optic tract (after optic chiasm)
  • temporal half of R/L visual field + nasal half of R/L visual field
  • CVA (stroke)
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10
Q

What are the functional implications of Homonymous Hemianopsia?

A
  • bump into objects on affected side

- will need to compensate by turning head towards side of impairment to ensure complete visual awareness

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11
Q

How does Homonymous Hemianopsia differ in presentation from visual neglect?

A

With neglect, difficulty in turning head to involved side to compensate

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12
Q
  • Where would a lesion occur in Upper Quadrantanopia?

- How does Upper Quadrantanopia impair the visual field?

A
  • lesion to lower division of optic radiations (temporal lobe)
  • upper L/R quadrant vision loss
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13
Q

What are the functional implications of Upper Quadrantanopia?

A

None, just an annoyance

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14
Q
  • Where would a lesion occur in Lower Quadrantanopia?

- How does Lower Quadrantanopia impair the visual field?

A
  • lesion to upper division of optic radiations (parietal lobe)
  • lower L/R quadrant vision loss
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15
Q

What are the functional implications of Lower Quadrantanopia?

A

Mild difficulties avoiding objects on floor on side of visual loss

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16
Q
  • Where would a lesion occur in Homonymous Hemianopsia with Macular Sparing?
  • How does Homonymous Hemianopsia with Macular Sparing impair the visual field?
A
  • lesion to both divisions of optic radiations or lesion to visual cortex
  • same as Homonymous Hemianopsia but with middle circle/focal point sparing.
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17
Q

What are the functional implications of Homonymous Hemianopsia with Macular Sparing?

A

Same as homonymous hemianopsia

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18
Q

How is Homonymous Hemianopsia with Macular Sparing functionally different from Homonymous Hemianopsia with optic tract lesions?

A

It isn’t

19
Q

HEARING

A

HEARING

20
Q

Does each ear send information to only the ipsilateral temporal lobe?

A

No, each ear sends bilaterally to temporal lobes

21
Q

Monaural hearing loss is due to a _______ lesion or damage to ________.

A
  • cochlear

- CN8

22
Q

Why do we have 2 ears?

A

inter-aural time difference and inter-aural intensity helps to localize source of sound

23
Q

Cells in the ___________ are “tuned” to detect certain amount of time delay between 2 ears.

A

superior olive

24
Q

The _________ is activated by combinations of frequencies and time intervals between frequencies.

A

thalamus

25
Q

What are 5 common causes of acquired hearing loss?

A
  • Acoustic Neuroma
  • Meniere’s Disease
  • Traumatic Brain Injury
  • Ototoxicity
  • Presbycusis
26
Q

What is acoustic neuroma?

A

1

27
Q

What is Meniere’s Disease?

A

1

28
Q

What is TBI?

A

1

29
Q

What is Ototoxicity?

A

2

30
Q

What is Presbycusis?

A

1

31
Q

What are the functional implications of hearing loss?

A
  • None, no dysfunctions in tasks

- More so involved in participation levels

32
Q

VESTIBULAR

A

VESTIBULAR

33
Q

What are the 3 key reflexes in the vestibular system?

A
  • VOR (vestibuloocular reflex)
  • VSR (vestibulospinal reflex)
  • VCR (vestibulocollic reflex)
34
Q

The VOR involves gaze ________ and results in ___________ that equally counter head movements.

A
  • stabilization

- eye movements

35
Q
  • With L head rotation we are using our __ abducens and __ oculomotor nerve.
  • With L head rotation we are inhibiting our __ abducens and __ oculomotor nerve.
A
  • R, L

- L, R

36
Q
  • Vestibular damage involving VOR centrally comes from damage to the _________, _____.
  • Vestibular damage involving VOR peripherally comes from damage to ______, _________.
A
  • midbrain, pons

- CN8, labyrinth structures

37
Q

Bilateral vestibular dysfunction results in ________ which is what?

A
  • oscillopsia

- bouncing vision

38
Q

Unilateral vestibular dysfunction can result in _______ and _______, what are they?

A
  • nystagmus- repetitive uncontrolled movements

- saccades- quick movement towards fixation point

39
Q

Both the VSR and VCR are responsible for ________ adjustments

A

postural

40
Q

The VSR otoliths (saccule and utricle) project to the ____; axons then descent to antigravity muscles at all levels of the ____________

A
  • LVN (lateral vestibular nucleus)

- spinal cord

41
Q

The VCR _____ axons descend in the _______ to upper cervical levels of the spinal cord. This dictates _____ position in response to head rotation.

A
  • MVN (medial vestibular nucleus)
  • MLF (medial longitudinal fasciculus)
  • head
42
Q
  • If the head is tilted to one side the canals and otoliths are stimulated __________ (and inhibited _____________)
  • Increased input through the vestibular nerve to the vestibular nuclei __________
  • Impulses transmitted through the lateral and medial vestibulospinal tracts to the spinal cord
A
  • ipsilaterally
  • contralaterally

-ipsilaterally

43
Q

With no damage to the VSR/VCR, if a person sways to the left, ___ VSR activated to bring body/trunk back to midline

A

left

44
Q

Damage to the VSR/VCR results in __________ instability, difficults sensing falling/tipping. It can also result in truncal ataxia, which is what?

A
  • postural

- incoordination, unstable trunk movement during movement