What is a compulsive punster called?

In his book, The Act of Creation (1964), Arthur Koestler reported on the phenomenon of compulsive punning, known as Forster’s syndrome, after the German surgeon who first observed it. In 1929, Forster was operating on a patient suffering from a tumour in the third ventricle – a small cavity deep down in the phylogenetically ancient regions of the mid-brain, adjacent to structures intimately concerned with the arousal of emotions. When the surgeon began to manipulate the tumor, affecting those sensitive structures, the (conscious) patient burst into a manic flight of puns. He exhibited typical sound associations, and with every word of the operator broke into a flight of ideas. The sound of one word swiftly echoed in the sound of the next, and all of the words had something to do with knives and butchery. This gruesome humour, Koestler noted, all came "from a man tied facedown to the operating table with his skull open."