Posterior cortical atrophy (PCA), also called Benson's syndrome, is a form of dementia which is usually considered an atypical variant of Alzheimer's disease. The disease causes atrophy of the back (posterior) part of the cerebral cortex, resulting in the progressive disruption of complex visual processing. The disease causes atrophy of the back (posterior) part of the cerebral cortex, resulting in the progressive disruption of complex visual processing.
Although no cure for posterior cortical atrophy exists, several medications as well as many non-pharmaceutical approaches can potentially improve daily functioning and quality of life. Patients with posterior cortical atrophy can often benefit from physical and occupational therapy. Cholinesterase inhibitors approved for Alzheimer's disease, like donepezil (Aricept®), rivastigmine (Exelon®) and galantamine (Razadyne®/Reminyl®), can help the symptoms of PCA by boosting the function of brain cells to compensate for damage caused by Alzheimer's disease. Patients experiencing depression, irritability, frustration and a loss of self-confidence may benefit from antidepressant medication.
In the absence of hard facts we are left with speculation as to the causes of certain diseases. Pratchett lays the blame on the old mercury amalgam fillings in his teeth, which he has now had removed. Although there is no scientific proof to support this view, Pratchett says some of his fans are pretty high up in the medical profession. He says he's been told that anything that reacts with mercury in your teeth is bound to have some effect. By his own admission he's trying things because he has the money. Pratchett is too young to be prescribed Aricept, so he's paying for his own.