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Superagers
Ageing can be a major risk factor in deterioration of the brain and cognitive decline. Yet some older adults manage to maintain the cognitive abilities from their youth. Superagers are older individuals that significantly resist the effects of aging on the brain, and maintain the cognitive abilities similar to younger age groups. Memory and attention performance are normally negatively affected by age, but superagers retain these abilities. There is a lack of consensus on a specific age range for superagers. Some researchers set the minimum age of superagers at 60-80 years old, whereas other research categorises them as 80 years old and over. However, superagers are always categorised as older individuals who show significantly less cognitive impairment compared to the average of their age group.

Cognitive differences
Cognitive abilities such as memory are reduced in the normal ageing process, even in individuals without a neurodegenerative disease. Superagers have “youthful memory”, meaning their memory ability was maintained from their youth, particularly their episodic memory abilities. Research has shown superagers categorised as aged 60-80 years old performing similarly to 18-32 year olds in memory recall tasks. Research that categorised superagers aged 80 and older showed they could perform similarly or greater on episodic memory tasks than 50-65 year old control group. Superagers perform better on a wide range of memory tasks, this includes face-name association, word recall, and vocal learning tasks. Furthermore, superagers show better performance with their attention abilities such as selective attention, which can aid the memory process, compared to an age matched control

Structural differences
Neuroimaging research has found abnormalities in the neuroanatomy of superagers. MRI scans were used in a study comparing superagers with an age-matched and middle-aged control while they completed tests engaging their episodic memory. Superagers were found to have less thinning in multiple regions of the cortex compared to the age-matched control. Furthermore, superagers were found to have a region of the left anterior cingulate cortex that was significantly thicker than the elderly and middle age control groups. The anterior cingulate cortex is involved in higher level functions such as attention regulation (Harrison et al., 2012). Other research using MRI scans found superagers brain’s anatomically indistinguishable from young adults. Further research using fMRI scans found a more powerful functional connectivity between the anterior cingulate cortex and the hippocampus. The connectivity between these regions is significantly linked to recognition and recall memory. Research has also tested differences between superagers, those maintain their cognitive performance for over 3 years, and those who do not. Superagers who maintain their cognitive abilities for 3 years were found to have lower amyloid burdens at the baseline of the study. Amyloid burdens are linked with the development of memory loss and risk of Alzheimer’s disease.

Histological research was used to conduct post-mortem tests on brains of previously labelled superagers against age-matched controls. It was found that superagers had lower rates of neurofibrillary tangles and amyloid plaques in the anterior cingulate cortex, both which can lead to decline in cognitive performance. There was no significant difference in the neuron count of the brain.

Cognitive reserve
The majority of research into superagers looks at how they are able to resist the typical anatomical changes of ageing, and how this allows for greater cognitive performance. However, some superager individual have a typical brain anatomy for their age, or even the development of pathologies within their brain. These individuals have resisted the cognitive signs of aging, despite the ageing of the brain. This is known as cognitive reserve. It is theorised that certain environmental factors in early and later life provide a buffer against the impact ageing has on cognition, but doesn’t protect against neuropathological changes. Evidence for cognitive reserve can be found in certain life experiences such as education level, cognitively challenging activities, and social engagement, are found in a higher rate in superagers. It has also been suggested that a difference in cognitive perspective in superagers when facing intense stressors may help build cognitive reserve. Superagers show a typical rate of experiencing past trauma and daily stressors, but have a higher rate of reacting positively or proactively to these difficulties. It is unclear whether these factors increase the chance of being a superager, or if internal factors cause superagers to more likely to carry out these experiences. For present lifestyle differences in superagers, that a greater cognitive ability may make engaging in cognitively challenging activities more satisfying (Goldberg, 2019). As for past experiences, higher education level has been shown to correlated with greater cognitive function in the elderly population. However, even after education levels are accounted for, superagers still demonstrate superior memory and attention abilities (Godoy et al., 2021).

Genetic differences
Genetic differences have been found in a minority of superagers compared to the general age-matched population. A study found a decline in the activity of the MAP2K3 gene for 20% of superager participants compared to the control group of younger and older adults. The MAP2K3 gene has been correlated with Alzheimer’s disease biomarkers, and therefore a decrease in MAP2K3 activity may lessen the chances of Alzheimer’s disease developing.

Longitudinal research
Research has found the resilience to cognitive decline in superagers to be maintained. In Cook et al.’s (2017) study, it was found over a testing period of 18 months, only 11% of superager participants started to cognitively decline to the normal aging rate. Over longer periods of time the chances of superagers ageing typically, increases. tested superagers over 3 years, identifying a superager phenotype of a cerebral cortex similar to younger adults. They found that 45% of superagers fell out of this phenotype over time. Due to the superagers being a relatively new area of research, there is a dearth of studies testing the differences in superagers over their lifetime. This leaves researchers uncertain when the differences in cognitive performance and neuroanatomy begins for superagers.

Implications
Identifying the factors that cause individuals to become superagers may be beneficial to both the clinical and sub-clinical population. The negative effects of ageing on the memory and attention can be linked to a lower sense of wellbeing. If the effects of ageing on cognition could be negated for an extended time period, then the older populations general wellbeing may be increased. Furthermore, factors linked to superagers may also provide novel methods of treatment for pathologies. For example, that inhibits the activity of the MAP2K3 gene may help decrease the chances of development of Alzheimer’s disease.