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More than 41m dementia cases globally are undiagnosed – study

<span>Photograph: MBI/Alamy</span>
Photograph: MBI/Alamy

More than 41 million people living with dementia worldwide have not yet been diagnosed, according to a report by Alzheimer’s Disease International (ADI).

Experts say getting diagnosed with the disease is vital, enabling those affected to receive support and treatment, which is more effective the earlier it begins, and to take part in clinical trials.

However, research by McGill University in Montreal, Canada, shows that in some countries as many as 90% of people with dementia have not been diagnosed. The stark findings, revealed in a report published by ADI, suggest that more than 41 million cases globally remain undiagnosed.

Dementia is one of the world’s biggest health challenges. Globally, the number of people living with it is expected to exceed 130 million by 2050.

Paola Barbarino, the chief executive of ADI, said a lack of awareness and stigma within healthcare systems was severely hampering efforts to support people living with dementia.

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“This misinformation in our healthcare systems, along with a lack of trained specialists and readily available diagnosis tools, have contributed to alarmingly low diagnosis rates,” said Barbarino, who also serves as a board member of the World Dementia Council.

She said her chief concern was that governments are still unprepared for the predicted future increase in cases. “Frankly, progress has been too slow,” she said.

Prof Serge Gauthier, of the neurology and neurosurgery department at McGill University, said he was expecting a “tsunami of demand for diagnosis”, a trend that would put “extreme pressure” on healthcare systems.

Responding to the report, Richard Oakley, the head of research at the Alzheimer’s Society, said a failure to diagnose all those with dementia had left many people “unable to get the support they so crucially need”.

He said: “Low dementia diagnosis rates were already a global problem, but these new figures show the scale of the crisis. For those who don’t get a diagnosis, this can cause stress, confusion, and leave them vulnerable to the effects of their condition.

“However, current diagnostic tests are expensive, often inaccessible and to make matters worse there’s still stigma around getting dementia, creating additional barriers particularly in some cultures. This has been exacerbated by the pandemic.”

Researchers have developed a two-minute computer test that could enable Alzheimer’s disease to be diagnosed up to five years earlier than by current methods. This would enable patients to begin taking disease-modifying drugs sooner, researchers said.

“The tests we currently use to diagnose Alzheimer’s miss the first 20 years of the disease, which means we are missing huge opportunities to help people,” said Dr George Stothart, of the University of Bath, who led the research.

The new technique involves participants looking at a series of flashing images on a computer screen while wearing an electrode cap. The cap detects subtle changes in brainwaves that occur when remembering an image, which are different in people with Alzheimer’s disease.

Research published in the journal BRAIN suggests the test is able to discriminate between healthy older adults and those with mild to moderate Alzheimer’s with a high degree of accuracy.

“The holy grail of a tool like this would be a dementia screening tool used in middle age for everyone, regardless of symptoms, in the same way we test for high blood pressure,” said Stothart. “We are a long way from that, but this is a step towards that goal.”