"I believe that that constellation of symptoms was more probably than not induced by total sleep deprivation over a chronic period," he testified.
Propofol disrupts the normal sleep cycle and offers no REM sleep, yet it leaves a patient feeling refreshed as if they had experienced genuine sleep, according to Czeisler.
If the singer had not died on June 25, 2009, of an overdose of the surgical anesthetic, the lack of REM sleep may have taken his life within days anyway, according Czeisler's testimony Friday.
Lab rats die after five weeks of getting no REM sleep, he said. It was never tried on a human until Murray gave Jackson nightly propofol infusions for two months.
Translating that to a human, Czeisler estimated, Jackson would have died before his 80th day of propofol infusions. Murray told police he had given it to him for 60 nights before trying to wean him off it on June 22, 2009 -- three days before his death.