Ageing and Cognition Flashcards
What are the two methods for studying ageing
Longitudinal and cross-sectional
What is a longitudinal study
Recruitment of a representative sample tested repeatedly over time
What are the advantages of longitudinal studies
Effect of age can be determined on an individual basis, useful in pinpointing precursors of disease
What are the disadvantages of longitudinal studies
Expensive, time consuming, high dropout rate (becoming less representative), practice effects (i.e. participants get better at the same test with repeated exposure)
What is a cross-sectional study
Recruitment of different groups of people are sampled across the age range, with each being tested once
What are the advantages of cross-sectional studies
No re-testing, quicker and less expensive, lower dropout rates
What are the disadvantages of cross-sectional studies
Performance can’t be related to individual earlier/ future performance, cohort effects (i.e. people born at different times differ due to changes in diet, education, social factors, family size etc.)
Describe cohort effects on memory
Flynn effect- substantial and sustained rise in IQ scores (fluid and crystallised intelligence) since 1932. Improvements in education (more people in secondary and tertiary education), nutrition and decrease in family size (parents focus resources on less children) over recent decades contribute to improved performance on memory tasks and IQ tests
What is one standard deviation in IQ
15
Account for the slightly different results in longitudinal and cross-sectional studies
Longitudinal studies might underestimate age-related changes (e.g. practice effects); cross sectional studies might overestimate them (e.g. cohort effects
What happens to short term memory
It progressively declines with age
What are there more pronounced ageing effects on
Tasks that require manipulation of information to be remembered
What happens to episodic memory through the adult years
It declines across the board: recall and recollection tests, verbal and visual materials, door and people test (people’s names and locations), memory for card hands, memorising passages, memory for conversations
What happens to semantic memory as you age
It does not decline, it actually expands in some areas
What happens to motor and perceptual performance with age
Declines, but older adults retain ability to learn implicit skills. Older adults take longer to acquire new skills but then their maintenance is the same as young adults
Describe the general mental slowing hypothesis
Many of the cognitive effects of ageing are caused by reduced processing speed-the rate at which tasks can be performed, due to ageing nervous systems. Age-related sensory limitation (visual defects) and slowing of neural transmission thought to be responsible
Describe the common cause hypothesis
Sensory and cognitive functions correlated in older people, hand grip strength and cognition correlated in older people, slowed processing speed reflects a brain that it deteriorating in parallel with other bodily systems
Describe the inhibition deficit hypothesis
A major cognitive effect of ageing is the reduced capacity to inhibit relevant stimuli, linked with central executive component of working memory, reduced performance on Stroop task dual-tasking with increasing age in adulthood, ageing leads to mild “dysexecutive syndrome” like that seen after damage to frontal lobes. Mental slowing is die to degeneration of the nervous system
What happens to the overall brain as we age
Shrinks
What happens to the ventricles as we age
Expands
What happens to the frontal lobes as we age
Shrinks most rapidly
What happens to the temporal lobes as we age
Shrinks slowly
What happens to the hippocampus as we age
Shrinks slowly, then accelerates (possibly due to disease). Loses 20-30% of its neurons by age 80
What happens to the occipital lobes as we age
Shrinks slowly
What is dementia characterised by
A progressive deterioration of previously acquired intellectual abilities that interferes with social or occupational functioning
What are the risk factors for Alzheimer’s disease
Age is the strongest risk factor for AD (but AD is not an inevitable component of ageing); Genetics-family history of AD, specific risk genes (APOE-ε4); Medical history- vascular disease, depression; Life events- lifestyle factors (poor health habits, e.g. smoking, overweight, etc.), head injury (dementia pugilistica in boxers). A decrease in the concentration of glutamate plays a key role in Alzheimer’s