Researchers have identified that cerebrospinal fluid levels of A beta 42 appear to decrease at least five to ten years before some patients with mild cognitive impairment develop Alzheimer's disease.
A study in Sweden has found that spinal fluid levels previously identified appear to be later markers of Alzheimer's, while A beta 42 is an early indication of the condition.
The discovery could improve Alzheimer's diagnosis and allow patients to receive treatment at an earlier date.
Therapies, such as immunotherapy, are more likely to be successful if started in the early stages of the disease, so there is a need to identify the condition before neurodegeneration becomes too severe.
Immunotherapy is also thought to protect against the condition among those with immune deficiencies.
Dr Peder Buchhave, lead author of the study, stated: "New therapies that can retard or even halt progression of the disease will soon be available.
"Together with an early and accurate diagnosis, such therapies could be initiated before neuronal degeneration is too widespread."
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