Hearing and vision

Question 1

___% of over 50 yr olds and ___% of over 70 yr olds have some kind of hearing loss

Answer 1

40% of over 50 yr olds (mostly mild) and 70% of over 70 yr olds (mostly moderate) have some kind of hearing loss

Question 2

What is presbycusis?

Answer 2

Presbycusis = progressive, bilateral, age- related hearing loss

Typically symmetrical sensorineural high-frequency hearing loss

Question 3

What changes in conductive mechanisms occur with age?

Answer 3

increased pinna size, stiffening of ossicular chain and tympanic membrane, collapse of external cartilagnious wall of external auditory canal
IMPACTED EARWAX (very common)

Question 4

What changes are there to the cochlear in older age?

Answer 4

loss of hair cells (and no regeneration), particularly at base of cochlea = high frequency hearing loss
loss of cochlear neurones = loss of speech discrimination
degeneration of lateral cochlear wall = hair cell depolarisation = quieter sounds harder to hear

Question 5

What changes are there to the central auditory system in old age?

Answer 5

reduction in cell numebrs in auditory cortex and nuclei, decline in neurochemical function, loss of neural input from impaired peripheral system
central changes result in reduced compensation for high frequency loss

Question 6

What changes happen that affect vision?

Answer 6

astigmatism, hardening of the lens = reduced ability to focus on close objects = presbyopia
lens opacification = cataracts
changes to retina result in decreased visual acuity (sharpness) and decreased contrast sensitivity
age-related macular degeneration (AMD) is sig cause of visual impairment - difficult to see things when looking straight at them (impairs central vision)

Question 7

What are the functional changes in vision with ageing?

Answer 7

Reduced contrast sensitivity (interferes with depth perception) and colour vision

Decreased ability to distinguish blues and greens due to reduced blue light perception – warm colour tones may aid contrast sensitivity
Difficulty adapting in bright light and darkness, intolerance of glare
Red light may aid vision – e.g. at night

Reduced visual acuity and presbyopia
Objects in near vision may not be seen clearly – potential impact on reading

Reduced visual field size
Narrowed field of vision, may not notice objects in periphery of vision – potential impact on driving (along with changes in light sensitivity)