GETTY STOCK IMAGE Scientists say a mental skills test could show Alzheimer's disease years before symptoms develop

The simple brain MOT measuring memory, language and other thought processes such as awareness can detect the earliest signs of the devastating neurological disorder. It could be as effective as PET (positron emission tomography) scans or lumbar punctures that analyse brain fluid to look for the rogue amyloid and tau proteins behind dementia. These are both expensive and invasive, say the researchers.

Catching Alzheimer's early will give doctors more time to intervene and slow the progression of the disease, by advising lifestyle changes such as a healthy diet and more exercise. Eating plenty of oily fish, for example, has been shown to protect against neurodegeneration, while physical activity also boosts blood flow to the brain. Neuropsychologist Professor Duke Han, of the Keck School of Medicine at the University of Southern California, Los Angeles, said: "In the last decade or so, there has been a lot of work on biomarkers for early Alzheimer's disease. "There are new imaging methods that can identify neuropathological brain changes that happen early on in the course of the disease.

GETTY STOCK IMAGE These are both expensive and invasive, say the researchers

I wanted to see whether the cognitive tests I regularly use as a neuropsychologist relate to these biomarkers Neuropsychologist Professor Duke Han

The problem is that they are not widely available, can be invasive and are incredibly expensive. "I wanted to see whether the cognitive tests I regularly use as a neuropsychologist relate to these biomarkers." His researchers pooled results from 61 previous studies and found people over 50 who had amyloid plaques performed worse on neuropsychological tests than those who didn't. These measured global cognitive function, memory, language, visuospatial ability, processing speed, and executive function which is the brain's control centre.

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Professor Han said the findings published in Neuropsychology Review may lead to identifying early Alzheimer's disease in adults over 50 with normal cognition. They also showed people with tangles of tau performed worse on memory tests than those with amyloid plaques. The disease triggering proteins were confirmed by PET scan or brain fluid analysis. Professor Han said: "The presumption has been there would be no perceivable difference in how people with preclinical Alzheimer's disease perform on cognitive tests. This study contradicts that presumption." He believes the results provide a strong argument for incorporating cognitive testing into routine, annual checkups for older people.

GETTY STOCK IMAGE Catching Alzheimer's early will give doctors more time to slow the progression of the disease

Professor Han said: "Having a baseline measure of cognition before noticing any kind of cognitive change or decline could be incredibly helpful because it is hard to diagnose early Alzheimer's disease if you don't have a frame of reference to compare to. "If people would consider getting a baseline evaluation by a qualified neuropsychologist at age 50 or 60, then it could be used as a way to track whether someone is experiencing a true decline in cognition in the future." He said early detection could be a powerful tool to manage Alzheimer's, giving people precious time to try different medications or interventions that may slow the progression of the disease early on. Professor Han added: "While there is no cure for Alzheimer's disease, the earlier you know you are at risk for developing it, the more you can potentially do to help stave off that diagnosis in the future.