Inherited forms of Alzheimer's disease may be treatable 25 years before symptoms occur, increasing the chances of preventing brain damage, scientists have found.
In a study, a team of researchers at the Washington University School of Medicine analysed data from 128 participants with a genetic risk of inheriting the disease who underwent baseline clinical and cognitive assessments, brain imaging, and cerebrospinal fluid and blood tests.
Results showed that concentrations of amyloid-beta - a key ingredient of Alzheimer's brain plaques - appeared to decline in the spinal fluid 25 years before expected symptom onset.
The study, published in the New England Journal of Medicine, also showed that increased concentrations of tau protein in the cerebrospinal fluid and an increase in brain atrophy were detected 15 years before symptoms occurred.
At ten years, changes in the brain's use of sugar glucose and impaired memory became apparent and cognitive impairment was detected five years before expected symptom onset.
Dr Eric Karran, director of research at Alzheimer's Research UK, commented on the findings, "These results from people with the inherited form of Alzheimer's seem to be very similar to the changes in the non-genetic, common form of the disease."
"It's likely that any new treatment for Alzheimer's would need to be given early to have the best chance of success," Karran told the BBC.
"The ability to detect the very earliest stages of Alzheimer's would not only allow people to plan and access care and existing treatments far sooner, but would also enable new drugs to be trialled in the right people, at the right time."