Alzheimer's 'caused by brain getting stuck in reverse'

Scientists believe they have found the key to understanding how Alzheimer's disease (AD) causes profound memory loss.

The normal forgetting process is constantly 'cleaning house' by culling inconsquential information from our brains.

Researchers at Buck Institute, who managed to block Alzheimer's disease in mice last year, believe that the brain becomes stuck in the process of breaking memories in sufferers.

"Young brains operate like Ferraris – shifting between forward and reverse, making and breaking memories with a facility that surpasses that of older brains, which are less plastic," said researcher leader Dale Bredesen, MD.

"We believe that in ageing brains, AD occurs when the 'molecular shifting switch' gets stuck in the reverse position, throwing the balance of making and breaking memories seriously off kilter."

They were first alerted to this phenomenon after studying the splitting of one molecule called amyloid precursor protein (APP) in human brain tissue. They found those suffering AD showed more of this splitting process than people of the same age who did not have the disease.

However, they discovered that younger people displayed as much as 10 times the amount of the splitting event as AD patients.

The American scientists concluded in their report published in the Journal of Alzheimer's Disease, that normal memory loss is hyper-activated in those with Alzheimer's.

Alzheimer's disease is the most common form of dementia, where healthy brain tissue degenerates, causing a decline in memory and mental abilities.

The incurable condition affects around 450,000 people in the UK and the average length of time from diagnosis to death is eight years.