A QUICK and cheap test that鈥檚 already used to check sports players for concussion could double as a means of spotting whether someone will get Alzheimer鈥檚 disease, years before the first symptoms of dementia appear. It may help companies develop drugs to prevent the disease.
At the moment there is no straightforward way to detect the very earliest stages of Alzheimer鈥檚. And without such a test, it鈥檚 hard to discover whether a drug can delay the onset of the disease, rather than just relieve the symptoms. 鈥淏y the time we give drugs nowadays, people need carers,鈥� says neurologist David Darby of CogState, the Melbourne company that developed the test.
The 18-minute test evaluates three aspects of brain function: attention, memory and executive function (the ability to plan and integrate information), all based on how fast people pick out playing cards on a computer screen. CogState already sells the test as a tool for managing sports concussion. Players do a baseline test, and repeat it if they get hit on the head. The test has been adopted by sporting organisations such as South Africa鈥檚 Springbok rugby team, the British Jockey Club and Millwall Football Club in London.
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But CogState鈥檚 main interest is Alzheimer鈥檚. The company has assessed the test鈥檚 ability to pick up the early signs of the disease in apparently healthy volunteers aged around 70 who had gone through a battery of cognitive tests over five years. The tests revealed that 15 had mild cognitive impairment, which often heralds Alzheimer鈥檚 disease, while the other 35 did not.
The volunteers then did the card test four times, spread over a year. All the volunteers with mild cognitive impairment showed a progressive decline in test performance, unlike the normal volunteers. The results were reported at an Alzheimer鈥檚 conference in Stockholm this week.
鈥淗ere鈥檚 a group of people who are probably within five to ten years of getting Alzheimer鈥檚 disease. The beauty is that once you鈥檝e excluded other causes like depression, you can now consider treating them with drugs that would delay the onset of the disease,鈥� says Darby.
The current gold standard for diagnosing Alzheimer鈥檚 is a full-blown cognitive examination by a specialist. It takes over an hour, and even then it can鈥檛 pick up a mild impairment unless the exam is repeated over several years. A number of groups are developing ways of imaging living brains to look for the plaques characteristic of the disease (快猫短视频, 19 January, p 22). But these tests are expensive and time-consuming.
Other alternatives being developed include phone consultations and monitoring urine for levels of a protein that the brain releases when nerves degenerate.
