Spinal tap test offers new hope to patients with early dementia

A spinal tap test to spot early-stage Alzheimer’s disease could soon be brought in by the NHS so a radical new treatment can be started in time.

Almost one million Britons have dementia – with Alzheimer’s being the most common form – which damages the brain, causing memory loss, confusion and behaviour changes.

A spinal tap, currently undergoing a pilot study, uses a long needle to remove fluid from the spinal cord and has been proved to correctly identify 90 per cent of dementia cases and experts believe it is quicker than the NHS’s traditional screening tools of memory tests and brain scans.

Although the procedure, also known as a lumbar puncture, is potentially painful, experts say the results could be worth it as it will allow doctors to offer anti-dementia drugs at the earliest stages of the disease, when they are most effective.

Early diagnosis of Alzheimer’s is also essential for a groundbreaking new drug, lecanemab, which has been found to slow the progression of the disease by almost a third and may be available on the NHS next year.

Alzheimer’s is believed to be triggered by a build up of amyloid, a toxic protein in the brain. Lecanemab, which is administered by injection every two weeks, is proven to bind to and destroy amyloid, slowing the disease’s progression. But currently just one in 20 Alzheimer’s patients are said to be able to benefit from the drug because many are diagnosed too late for it to be effective.

While most Alzheimer’s diagnoses in the UK are picked up using memory tests, many countries already use the spinal tap. This looks for build ups of amyloid in the spinal fluid as well as another protein, tau, which is suspected to be linked to Alzheimer’s. But many patients are opposed to undergoing the test due to side effects which can include headaches, swelling and prolonged back pain.

‘This test is cheap, effective and used around the world, so it is peculiar it’s not used on the NHS,’ says Professor Dag Aarsland, head of old age psychiatry at King’s College London. ‘Catching the disease early is always crucial, but it will be particularly so with this new drug.

While most Alzheimer’s diagnoses in the UK are picked up using memory tests, many countries already use the spinal tap

‘The earlier you find Alzheimer’s, the more brain there will be to save.’

Researchers at King’s College London are now running a pilot study which will analyse how feasible rolling out the lumbar puncture test – created by the medical firm Roche –would be on the NHS.

‘We want to know if patients are happy to undergo it and doctors are comfortable using it,’ says Prof Aarsland. ‘If lecanemab is approved then this will absolutely be adopted more across the NHS.’