'Superagers', Or Older Adults With Razor-Sharp Memory, Have Lower Depression Rates: Study In Lancet

Superagers, who recall everyday events and life experiences with the same accuracy as someone aged 20 to 30 years younger to them, show faster movement speed than other older adults.

Superagers, or adults in their eighties with razor-sharp memory, have lower rates of depression and anxiety. These adults, who recall everyday events and life experiences with the same accuracy as someone aged 20 to 30 years younger to them, show faster movement speed than other older adults, according to a study published July 14 (in India) in The Lancet Healthy Longevity journal. Superagers, unlike other older adults, have been observed to be able to avoid the age-related deterioration of memory function. 

Past studies comparing superagers with other older adults found differences in brain structure and lifestyle factors such as stronger social connections. However, most of these studies had small sample sizes and did not track changes over time because of which an in-depth understanding of lifestyle, clinical and demographic factors that help to preserve memory function into old age was lacking. 

How the study was conducted, and who the participants were

An international team of authors has helped address this problem by conducting one of the largest analyses of superagers to date. A project designed to help identify early indicators of Alzheimer's disease helped discover superagers and other older adults. The project is called the Vallecas Project, and its cohort in Madrid included people aged 69 to 86 years with no neurological or severe psychiatric disorders. There were 1,213 participants, who were recruited between 2011 and 2014. The participants included 64 superagers and 55 typical older adults. The superagers and normal older adults were aged 79.5 years or older. About 59 per cent of the superagers were women, while among the typical older adults, 64 per cent were women. 

The typical older adults performed well on several cognitive tasks but did not display superager memory ability. 

These superagers and typical older adults were included in the new study published in The Lancet Healthy Longevity journal. 

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How the performance of participants on cognitive tasks was assessed

The performance of participants in the Free and Cued Selective Reminding Test was assessed to identify superagers and typical older adults who performed well on cognitive tasks. The test helps assess one's memory function. 

It was found that superagers performed as well as people aged 30 years younger to them and with the same education level. 

How grey matter volume was analysed

The authors analysed demographic and lifestyle factors during six annual follow-up visits, a statement released by The Lancet said. The grey matter volume of the participants was analysed using magnetic resonance imaging (MRI) scans. During each follow-up, the participants were asked to complete clinical tests. 

How biomarkers and genetic risk factors for neurodegenerative diseases were tested

The researchers tested biomarkers for neurodegenerative diseases and a genetic risk factor for Alzheimer's disease using blood samples. 

How factors associated with superagers were identified

They identified factors associated with superagers with the help of a machine learning computer model including 89 demographic, lifestyle and clinical predictors.

Superagers had more grey matter than typical older adults

The superagers were found to have more grey matter than typical older adults. Grey matter consists of tissues important for normal brain function, including memory and movement signals. The degeneration of grey matter in superagers over a period of five years was slower than that in typical older adults. 

Factors associated with superagers

The machine learning model showed that better mental health and faster movement speed were the factors associated with superagers. 

Superagers performed better in motor function tests than other older adults

Other tests conducted were the Timed Up and Go Test, which analyse one's mobility, and a finger tapping test, which measures fine motor function. Superagers were found to perform better than typical older adults in these tests. This indicated that they had better mobility, agility and balance than other older adults. 

Superagers scored lower in tests for depression and anxiety than other older adults

Superagers scored lower than typical older adults in clinical tests to measure levels of anxiety and depression. These mental health disorders can impair one's memory, increasing the chances of developing dementia.

Superagers’ self-reported lifestyle habits

Some of the self-reported differences observed between superagers and typical older adults were that superagers were more active in midlife, were satisfied with their sleep duration, and were more likely to have a musical background than typical older adults, and also showed greater independence in their day-to-day living. 

Superagers had lower levels of biomarkers for neurodegeneration

The blood samples revealed that superagers had lower levels of biomarkers for neurodegeneration compared to older adults. However, no difference in the presence of a major genetic risk factor for Alzheimer's disease, called APOE e4, was observed between superagers and other older adults. 

In the statement, Marta Garo-Pascual, the first author on the paper, said the researchers are now closer to solving one of the biggest unanswered questions about superagers, which is whether they are truly resistant to age-related memory decline, or have coping mechanisms that help them overcome this decline better than their peers. 

Garo-Pascual explained that the study suggests that superagers are resistant to these processes, but the precise reasons are still unclear. 

Dr Bryan Strange, a senior author on the paper, said though superagers report similar activity levels to typical older people, it is possible they do more physically demanding activities like gardening or stair climbing, and lower blood pressure, decreased obesity level, and increased blood flow to the brain are some of the direct and indirect benefits of being physically active that may contribute to improved cognitive abilities in old age. 

Dr Strange explained that when young adults make movements at the same time as seeing pictures, they are more likely to later remember the picture than if they do not move, and it is also possible that having better brain health in the first place may be what is responsible for superagers having faster movement speed. 

The study found an overlap between risk or protective factors for dementia, and those associated with superaging, such as blood pressure, glucose control and mental health, indicating that some risk factors for dementia could be contributing to age-related decline in memory-related brain activity. 

Limitations to the study

Some of the limitations to the study included the fact that it was not possible to say whether the facts reported had any direct effect on superageing, because it is a self-reported analysis. Also, the machine learning model was able to distinguish superagers from typical older adults around 66 per cent of the time, despite using 89 variables. This means that additional factors, including genetic variables, could be associated with superageing.