Pathology of special senses

Question 1

5 special senses

Answer 1

1. vision
2. smell
3. taste
4. hearing
5. equilibrium (balance)

Question 2

visual impairment

Answer 2

result of damage to any part of vision pathway

Question 3

cataracts

Answer 3

• lenses slowly become hardened and cloudy as time passes

- causes blurry vision (light can’t enter lens clearly to be refracted onto retina)

Question 4

diplopia

Answer 4

• double vision
• caused by damage to abducens (CN VI)
• to test for this:
  if eye cant rotate laterally when looking to same side –> nerve damaged
  affected eye will deviate medially when person looks straight (due to imbalanced muscle tone)

Question 5

deafness

Answer 5

• hearing loss

- can be partial or total

Question 6

conduction deafness

Answer 6

• deafness caused by damage to outer or middle ear structures
• incomplete (sound waves can still be conducted via cranial bones to move organ of corti)
• potential causes: build up of cerumen partially blocking sound waves; fusion of ossicle bones decreasing amt of vibrations transmitted to inner ear

Question 7

nerve deafness

Answer 7

• deafness caused by damage to the nerve pathway (receptor cells or cochlear nerve)
• can be partial or complete, in one or both ears (depends on amount of damage to nerve pathway)

Question 8

anosmia

Answer 8

• lack of smell
• common after brain injury (can be temporary or permanent)
• if happens gradually, can signal a brain tumor is growing and blocking olfactory path)

Question 9

aguesia

Answer 9

• lack of taste
• potential causes: obstruction of olfactory receptors (e.g. by nasal congestion); damage to taste pathway (from TBI or tumor)