The tall, blond-haired man, who is in his 20s or early 30s, has not said a word since he was found, distressed and dressed in a dripping wet suit, on the Isle of Sheppey in Kent county, southeast England, on April 7.
When staff at the Medway Maritime Hospital in Gillingham gave him writing materials, he drew detailed pictures of a grand piano and, when shown the piano in the hospital chapel, sat down and played for two hours, causing staff to nickname him "Piano Man."
Baffled staff said their problems have been compounded by the fact that all the labels were cut off the man's clothes.
"That is a real twist — and it's enough of a mystery without that," said Adrian Lowther, spokesman for the West Kent National Health Service Trust, which is caring for the man at a psychiatric unit in Dartford in north Kent.
"Apart from mentally, the man is healthy, and he is washing himself. But he does not communicate at all, so he cannot receive counseling."
Lowther said a tabloid newspaper has provided the man with a piano, and playing calms him down noticeably.
Lowther said the National Missing Persons Helpline has received 320 calls and 70 e-mails after releasing a picture of the man and one of his piano drawings Monday. The health trust also has received numerous telephone calls.
"We are wading through those with the police — we just hope that in among the calls may be someone who knows him," Lowther said. "But it will take some time."
The British press has likened his case to the Oscar-winning 1996 movie "Shine," about acclaimed pianist David Helfgott, who suffered a nervous breakdown while playing. It also is similar to the movie "Ladies in Lavender," which was recently released in the United States and is about a violinist who washes up ashore in Cornwall after a shipwreck, speaks only Polish and is nursed back to health by elderly sisters portrayed by Dames Maggie Smith and Judi Dench. He goes on to a triumphant concert.
But the piano man does not seem to be more than an accomplished amateur.
Michael Camp, the man's social worker, said that when he is not playing the piano, he remains very anxious.
"Someone, somewhere must be missing him," Camp said. "At the moment we only have six weeks' of history of this man to work on, which makes it very hard."
Hospital chaplain the Rev. Steve Spencer said the man "is not the virtuoso that he has been portrayed in the press. He knows a small number of tunes and plays them over and over — I recognized some John Lennon and a snippet from Tchaikovsky's 'Swan Lake.'
"When he plays, he is totally focused — he cuts out everything else and it makes him calmer."
Hospital staff have already ruled out reports that he recently attended a funeral locally. Interpreters from Poland, Latvia and Lithuania were brought in to see if the man was from Eastern Europe and possibly seeking asylum, but no one was able to get through to him.