Brain drainage hope for Alzheimer's

There is a theory that Alzheimer's may be in part caused by a build up of cerebrospinal fluid (CSF) in the chambers of the brain called ventricles.

Some scientists believe this build up of pressure squeezes the tissues of the brain, and reduces blood supply, leading to the death of cells that is associated with Alzheimer's.

They believe that the problem can be addressed by draining away fluid from the brain to other parts of the body using a tube known as a CSF shunt.

The use of CSF shunts was first tested in the late 1960s. However, it was abandoned after producing mixed results, and an unacceptably high level of side effects.

Now scientists from three research centres in the US have re-examined the technique, and found it to produce promising results.

Similar condition

The study followed separate work on patients with the condition called hydrocephalus - an abnormal build-up of CSF in the ventricles of the brain.

It was found that shunting CSF to other parts of the body appeared to slow down mental decline in patients who also had symptoms of Alzheimer's dementia.

Lead researcher Dr Gerald Silverberg, of Stanford University, said his team had speculated that although hydrocephalus and Alzheimer's were separate diseases, they might both be linked to a failure to circulate CSF properly.

A total of 23 patients took part in the trial, with 12 being surgically implanted with a shunt to drain away CSF.

Tests carried out every three months for the following year showed that mental decline was less marked in those patients who had undergone surgery.

The researchers say the results are encouraging, but that the study was too small to draw firm conclusions.

They are now working on a larger scale study.

Post mortems

Dr Richard Harvey, director of research at the UK Alzheimer's Society, said post mortems had not found large amounts of CSF in the brains of Alzheimer's patients.

He said it was possible that the placebo effect may be responsible for the positive results.

Dr Harvey said: "This work has to be treated with extreme caution because of the very small numbers of people involved and the major severity of the procedure performed on them.

"People should certainly not be asking for shunts on the basis of this one study."

Harriet Millward, deputy chief executive of the Alzheimer's Research Trust, was also cautious.

"When shunting was previously tried as a treatment for dementia, there were many side-effects.

"Now, it may be that these adverse effects can be avoided by the more cautious procedure proposed.

"However, this was a very small trial and while the results were encouraging, it is too early to say if this procedure can be safely and effectively used as a treatment for Alzheimer¿s.

"It is vital that further research is done to find an answer to this awful disease."

The research is published in Neurology, the scientific journal of the American Academy of Neurology.