Or so it used to be until human innovation intervened.
When does Alzheimer's disease start? No one knows. The secret is locked inside the skull, and the disease cannot even be diagnosed until after a patient has died and an autopsy has been performed. And what cannot be diagnosed cannot be fully understood or treated.
But a private company has made a breakthrough that could allow doctors to catch Alzheimer's in it's early stages, by peering inside the living brain. This technology also has promise for improving diagnosis and treatment of other problems such as depression. You can learn more here.