Aging and perception Flashcards
What is presbycusis?
Age related hearing loss which is greater for high frequencies and greater in older men than women
What did Dubno et al (1984) find?
Compared participants under 44 to ppts over 65 in understanding speech with background babble. Found older adults needed speech to be louder than background noise than younger
What are the causes of age-related hearing loss?
Deterioration in the cochlea and decreased efficiency of sound transmission through ossicles. Decreased flexibility through basilar membrane. Lifetime exposure to loud sounds and changes in cortical auditory processing. Genetic factors
What is high contrast acuity?
Ability to see fine detail under high contrast e.g reading. Found high contrast acuity declines with age (Haegerstron-Portnoy, Schmeck and Brabyn, 1999)
What is low contrast acuity?
Ability to see fine detail under low contrast. Low contrast acuity declines with age (Haegerstron-Portnoy, Schmeck and Brabyn, 1999)
What is contrast sensitivity?
Ability to detect finer and finer increments of light and dark
What is contrast sensitivity function?
Ability to detect different spatial frequencies at different contrasts
What is the relationship between high and low contrast acuity and contrast sensitivity?
High contrast acuity - ability to distinguish increments of light and dark at high contrast
Low contrast acuity - ability to distinguish between increments of light and dark at low contrast
What is stereopsis?
Ability to perceive depth decreases with age
What is pupillary miosis?
Size of pupil normally changes in response to amount of light. Pupil size of older adults is smaller in both light and dark conditions - reduced amount of light enters the eye
What is presbyopia?
Reduced flexibility in the lens so loss of near focusing ability. In the absence of vision care, can lead to significant visual impairment
What is clouding of the lens?
In young adults the lens is clear. Proteins in the lens change shape and clump together as we get older - cataracts
What did Laitinen at al find (2005)?
Ppts aged 30+ tested their visual abilities. Proportion of young adults with good visual acuity ranges from 99.5% in 30-44yrs to only 54.9% in 85+yrs
What did Holden et al (2008) find?
Estimated that globally half of older adults with presbyopia have no or inadequate spectacles, and most of these experience difficulty with everyday tasks
What are cataracts?
Proteins in the lens change shape and clump together as we get older - disease
What are risk factors for cataracts?
Age, diabetes, eye trauma, being very short sighted, some prescription drugs
How do cataracts affect vision?
Sight is misty, colours look washed out - estimated 2.5 million people in England and Wales have some degree of visual impairment caused by cataracts
What is glaucoma?
Aqueous fluid normally drains away at the same rate it’s produced., keeping the eye at the correct pressure. If more fluid is produced than drains, pressure will build, damaging the optic nerve - disease
What are risk factors for glaucoma and how does it affect vision?
Age, family history, African-Caribbean ethnic background
Affects peripheral vision first - tunnel vision and affects about 1 in 50 people over 40, 1 in 10 over 75
What is age-related macular degeneration disease?
Most common cause of visual impairment in the UK. Central vision loss due to deterioration of macula. Can appear as a smudge at centre of vision that can gradually become bigger with peripheral vision usually unaffected. Dry AMD - yellow deposits in macula leading to dimming/ distortion of vision. Wet AMD - growth of abnormal blood vessels leaking blood and fluid into retina, causing distortion, blind spots and loss of central vision
What happens in advanced stages of age-related macular degeneration?
May not be possible to use central vision so adopt “preferred retinal locus”, shifting focus of vision slightly so that peripheral vision is used instead. Much less suited to fine detail
What are risk factors for age-related macular degeneration?
Age, women more than men, family history, high blood pressure and lack of exercise, smoking and exposure to sunlight
What is the common cause hypothesis?
A third, general factor underlies the decline in both perception and cognition. Molecular and cellular changes as a result of aging will affect sensory systems, as well as others
What is cognitive load on perception?
Poor cognition affects performance on perceptual tasks, even measures that may be considered entirely sensory are influenced by cognition
What is information degradation?
Impoverished perceptual input impacts on cognitive resources. When perceptual input is poor, additional cognitive resources are needed to decipher the signal. This leaves fewer cognitive resources available for performing the cognitive task
What is sensory deprivation?
Sensory impairment leads to cognitive decline
