So you can imagine my relief when I discovered that a scientific explanation for this phenomenon has finally been found! Apparently Berlusconi affects a different part of our brain from all the other people we interact with on a regular basis. The findings appear in an article that is to be published in the scientific journal Cortex (via Corriere della Sera):
A patient (V.Z.) is described as being affected by progressive bilateral atrophy of the mesial temporal lobes resulting in semantic dementia. Vis-à-vis virtually nil recognition of even the most familiar faces (including those of her closest relatives) as well as of objects and animals, V.Z. could nevertheless consistently recognize and name the face of Silvio Berlusconi.(There are no permalinks, so to find the abstract - at this time - click on "Papers in Press" in the left-hand column and scroll down to "How Berlusconi Keeps his Face: A Neuropsychological Study in a Case of Semantic Dementia" by Sara Mondini and Carlo Semenza.)
So I was right after all - Berlusconi has figured out how to etch himself into our brains even more permanently than our closest relatives and loved ones. If that is not a stroke of genius for a politician, I don't know what is.