Doctors treating Ariel Sharon are said to be worried that he still has not emerged from an induced coma after suffering a massive stroke. Medics at the Hadassah Hospital in Jerusalem have been reducing the Israeli prime minister’s sedation and gradually trying to wake him since Monday.But so far the 77-year-old has shown no sign of regaining consciousness. The situation is “very worrying” according to reports on Israeli public radio. A national newspaper has cited unnamed medical sources as saying that early optimism about the premier’s chances for recovery has turned to increasing concern. Doctors are carrying out neurological tests to assess brain damage following his stroke last week.