LOS ANGELES (CBSLA.com) — Renowned sleep expert Dr. Charles Czeisler spent a second day on the witness stand testifying at the Michael Jackson wrongful death lawsuit against AEG.

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He testified that Jackson clearly suffered from insomnia while on tour and while preparing for tours.

Dr. Czeisler also said Jackson was suffering from sleep deprivation in the weeks leading up to his death, according to KCAL9’s Randy Paige.

The sleep expert from Harvard said he spent more than 100 hours reviewing documents, including e-mails from people who worked with Jackson, to confirm his diagnosis.

In the e-mails, people described Jackson’s condition as deteriorating including losing weight, paranoia, unable to remember what he just said, wearing layers of clothing and appearing cold while others around him were warm, all called classic symptoms of sleep deprivation.

Dr. Czeisler said he was also astounded that Jackson couldn’t sing his own songs without the help of a Teleprompter.

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“The most successful performer of all time had to read the words to his own songs, shocking, and indicates to me the profound impact that this sleep deprivation was having on his memory,” testified the doctor.

Czeisler said he believed the evidence showed Dr. Conrad Murray was administering the anesthetic Propofol into Jackson’s veins and that the drug was keeping Jackson’s brain from getting the sleep and nourishment it desperately needed.

“The chronic exposure to Propofol as a drug induced coma led to a dissipation of his sleep drive without satisfying any of his sleep need thereby leading to a massive sleep deficiency with all of its attendant adverse consequences,” the doctor testified.

KNX 1070’s Ron Kilgore also reported the doctor had to concede he didn’t know how long Jackson was taking the drug.

On cross examination, Dr. Czeisler acknowledged that the evidence showed two doctors tried to convince Jackson to seek a medical specialist for his sleep disorder and he refused.

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AEG maintains this case is about personal responsibility.  The Jackson family sees it as corporate negligence.