While the responses did not mean Mr Sharon was likely to fully regain consciousness, doctors said they were "encouraging".

BBC: Ariel Sharon: Israeli ex-PM in coma 'has brain activity'

Dr Petelenz told the European Society of Cardiology conference in Vienna that properly timed and performed coughs could allow the patient to maintain consciousness and even regain an effective heart beat.

BBC: Coughing 'could stop heart deaths'