Lecture 14- Special Senses (Vision, Hearing, Vestibular) Flashcards
There is a greater proportion of our brain devoted to ______ than any other sense.
sight
What are the 7 types of visual field losses?
- ipsilateral blindness
- binasal hemianopsia
- bitemporal hemianopsia
- homonymous hemianopsia
- upper quadrantanopia
- lower quadrantanopia
- homonymous hemianopsia with macular sparing
- Where would a lesion occur in Ipsilateral Blindness?
- How does Ipsilateral Blindness impair the visual field?
- lesion before chiasm
- blindness in ipsilateral eye
What are the functional implications of Ipsilateral Blindness?
Difficulties with visualizing objects in far periphery
- Where would a lesion occur in Binasal Hemianopsia?
- How does Binasal Hemianopsia impair the visual field?
- compression to optic chiasm
- loss of nasal fields bilaterally
What are the functional implications of Binasal Hemianopsia?
Not huge… patients able to compensate more easily here than other lesion locations
- Where would a lesion occur in Bitemporal Hemianopsia?
- How does Bitemporal Hemianopsia impair the visual field?
- What is this seen commonly with?
- lesion to optic chiasm
- loss of bilateral temporal fields
- pituitary tumors
What are the functional implications of Bitemporal Hemianopsia?
- “Tunnel Vision”
- Peripheral objects go missed on both directions
- HIGH fall risk!
- Where would a lesion occur in Homonymous Hemianopsia?
- How does Homonymous Hemianopsia impair the visual field?
- What is this seen commonly with?
- damage at the optic tract (after optic chiasm)
- temporal half of R/L visual field + nasal half of R/L visual field
- CVA (stroke)
What are the functional implications of Homonymous Hemianopsia?
- bump into objects on affected side
- will need to compensate by turning head towards side of impairment to ensure complete visual awareness
How does Homonymous Hemianopsia differ in presentation from visual neglect?
With neglect, difficulty in turning head to involved side to compensate
- Where would a lesion occur in Upper Quadrantanopia?
- How does Upper Quadrantanopia impair the visual field?
- lesion to lower division of optic radiations (temporal lobe)
- upper L/R quadrant vision loss
What are the functional implications of Upper Quadrantanopia?
None, just an annoyance
- Where would a lesion occur in Lower Quadrantanopia?
- How does Lower Quadrantanopia impair the visual field?
- lesion to upper division of optic radiations (parietal lobe)
- lower L/R quadrant vision loss
What are the functional implications of Lower Quadrantanopia?
Mild difficulties avoiding objects on floor on side of visual loss
- Where would a lesion occur in Homonymous Hemianopsia with Macular Sparing?
- How does Homonymous Hemianopsia with Macular Sparing impair the visual field?
- lesion to both divisions of optic radiations or lesion to visual cortex
- same as Homonymous Hemianopsia but with middle circle/focal point sparing.
What are the functional implications of Homonymous Hemianopsia with Macular Sparing?
Same as homonymous hemianopsia
How is Homonymous Hemianopsia with Macular Sparing functionally different from Homonymous Hemianopsia with optic tract lesions?
It isn’t
HEARING
HEARING
Does each ear send information to only the ipsilateral temporal lobe?
No, each ear sends bilaterally to temporal lobes
Monaural hearing loss is due to a _______ lesion or damage to ________.
- cochlear
- CN8
Why do we have 2 ears?
inter-aural time difference and inter-aural intensity helps to localize source of sound
Cells in the ___________ are “tuned” to detect certain amount of time delay between 2 ears.
superior olive
The _________ is activated by combinations of frequencies and time intervals between frequencies.
thalamus
