Michael Jackson went for 60 days without sleep, making him the only person ever to have done so, a sleep expert has claimed.

Charles Czeisler, a Harvard Medical School sleep expert, said he has never heard of any person who has gone 60 days with Rapid Eye Movement (REM) sleep as he testified at the wrongful death trial of concert promoter AEG LIve.

As reported by CNN, the jury was told by Dr Czeisler that the 60 nights of propofol infusions which Dr Murray said he gave Jackson to treat insomnia has never before been undertaken.

Dr Czeisler, a sleep consultant to NASA and the CIA, told the jury that the drug does not offer REM sleep and disrupts the normal sleep cycle.

But it leaves those who take it refreshed and feeling as though they have had a proper night’s sleep.

The jury was told that rats tested by scientists died after five weeks of no REM sleep.

People who are deprived of REM sleep for long periods become depressed, paranoid and anxious. They also lose their balance and appetite, and can have slower physical and emotional reactions.

These are symptoms which Jackson was said to be suffering from in his final weeks. His show’s producers reported that he became thinner, paranoid and forgetful, and was heard talking to himself.