The most common form of dementia is Alzheimers Disease in which tau and amyloid protein accumulates in the brain which damages and ultimately kills the neurones (brain cells). These pathological processes are present in 20% of us as we reach 80 years old and 40% at 90 years old.
However although these processes are gradually impairing the brain the rest of the brain can compensate to some extent so that obvious dementia only occurs in 10% of 80 year olds and 25% of 90 year olds.
There are known ways to alter lifestyle to minimise the risk of dementia-probably almost everyone would benefit from one appointment as early in their life as possible to discuss these.
MR Scan (on left) of 58 year old man who had difficulty remembering names and numbers. Two years later (scan on right) he was frequently getting lost when driving and would forget to turn off the shower or oven after using them-he had Alzheimer’s disease. The brain is not normal on the scan on the left but is much more shrunken in the scan on the right.