From blood markers and brain scans to eye tests and voice cues, there are a myriad of ways that researchers are trying to detect dementia long before it sets in – and those studies are all just from the past six months.
One common indicator of cognitive decline is simply the experience of losing your memory. Yet knowing when it is the result of aging and when it is pathological is far from straightforward.
A new cognitive screening tool developed by Australian researchers to gauge six critical aspects of people's brain function could help. Like any and all of these potential diagnostic aids, the tool needs further validation in larger studies, yet a recent evaluation has concluded it is acceptably accurate.
So far, 526 people have tested the screening tool, a 46-item questionnaire from which their cognition is scored across six domains: memory, language, orientation, attention and concentration, executive function, and ability to copy and draw geometric figures, such as a clock.
This last domain, what's known as visuoconstruction abilities, requires fine motor skills, spatial awareness, as well as planning, one of many executive skills.
Called the 'McCusker Subjective Cognitive Impairment Inventory', the tool captures people's concerns about their current mental capacity. This subjective measure often serves as an early warning sign of declining cognitive abilities, foreshadowing dementia or at least placing individuals in a higher risk category so their health can be monitored more closely.
"Imagine if you could predict your risk for dementia well before it takes hold, and you could start treatment and stop the disease from progressing?" says clinical psychologist and lead author Hamid Sohrabi of Murdoch University in Western Australia.
In spite of its potential, there is little consensus among researchers and clinicians on the reliability of people self-reporting cognitive concerns. Being a self-assessment, people may be reluctant to admit changes they've noticed to their memory or speech, or not even be aware of them if the disease has progressed too far.
There's also the general mental decline of 'normal' aging a questionnaire would need to distinguish dementia from.
Nevertheless, a standardized framework tested on large numbers of people and assessing a broad range of cognitive abilities could help doctors recognize subtle changes that warrant further attention.
Alternatively, researchers have recently tasked artificial intelligence with scanning health records to spot patterns in conditions that may be connected to the onset of Alzheimer's disease. But this relies on doctors diagnosing those conditions – and those connections truly reflecting Alzheimer's risk.
The screening tool developed by Sohrabi and colleagues consists of 46 questions asking people about gradual changes they may have experienced or noticed in the past two years, compared to five years earlier, such as difficulty hearing, concentrating, or with language. Answering on a five-point scale of 'almost always true' to 'almost never true', higher scores represent more concerns.
The questions were pulled from previously published questionnaires on subjective cognitive decline and designed to reflect other aspects of mild cognitive impairment reported in studies of early Alzheimer's disease and dementia that those prior questionnaires didn't capture.
Using a series of statistical methods to assess the results, the researchers found the screening tool accurately identified individuals with moderate to severe levels of subjective cognitive decline – and more reliably so than previous, narrower questionnaires.
The team also determined what they say could be a fairly sound 'cut-off' score for grouping respondents with a higher risk of dementia.
But participants in the analysis were otherwise healthy people, aged between 39 and 97 years, and involved in ongoing, longitudinal studies of aging, so the researchers will have to track their progress in years to come.
Like them, we're all confronted with the inevitability of aging and perhaps eager to know how our lives pan out.
The research has been published in Age and Ageing.