Alzheimer’s disease

The major cause of dementia is Alzheimer’s Disease, and this probably accounts for around 50% to 60% of cases of dementia worldwide. We know that Alzheimer’s Disease is characterised by specific pathological changes that occur inside the brain which were originally described by Dr Alois Alzheimer as we discussed in a previous topic. Scientists now believe that these pathological changes begin in middle age and accumulate slowly.

Changes include those that happen at the macroscopic level, which involves shrinkage or atrophy of the brain, and this can affect certain structures of the cerebral cortex, including the frontal lobe, temporal lobe and parietal lobe.

Pathological changes occur at the microscopic level, and these are neurofibrillary tangles and amyloid plaques.

A-beta  or amyloid beta is a normal protein that you would find in all our brains, but in Alzheimer’s disease it mutates or changes.  When plaques form in the brain, they damage nerve cells and these damaged nerve cells cannot regenerate and they die.

The other major microscopic change that occurs inside the brains of people with Alzheimer’s disease is the neurofibrillary tangle. The main protein composition of the tangle is again a changed form of a normal brain protein called tau.  These tau tangles are impenetrable, so when the nerve cell dies, all that is left behind is this tau tangle which is sometimes referred to as a ‘ghost tangle’.

Symptoms a person might experience include


Memory loss

Difficulty carrying out activities of daily living

Poor concentration


Spatial awareness difficulties

Misplacing items

Problems with communication and language

Obsessive or repetitive behaviours

Changes in mood