A wife allegedly murdered by her husband suffered a lack of oxygen to her brain for up to an hour before her death, an expert told his trial.
Ian Stewart, 61, is accused of killing Diane Stewart, 47, at their home in Bassingbourn, Cambridgeshire in 2010.
Her cause of death was recorded at the time as Sudden Unexplained Death in Epilepsy (SUDEP).
Police investigated the case after a jury found Stewart guilty in 2017 of murdering children’s author Helen Bailey the year before.
Professor Safa Al-Sarraj, a consultant neuropathologist, was asked to examine preserved parts of Mrs Stewart’s brain.
The trial, at Huntingdon Crown Court, was earlier told that, while most of Mrs Stewart’s remains were cremated, she had donated her brain to medical science.
Prof Al-Sarraj said he observed “changes in the brain… consistent with early ischemia”.
He defined ischemia as “damage to the cells due to lack of oxygen and blood supply”.
He said he estimated the damage happened over 35 minutes to an hour but conceded he was a “bit reluctant” to give figures “as they are all estimates”.
Prosecutor Stuart Trimmer QC asked Prof Al-Sarraj: “(With a) healthy breathing human you don’t expect to find any evidence of ischemia, do you?”Prof Al-Sarraj said: “No.”
He said ischemia may be found in cases where a person dies after suffering from “restricted” breathing for “30 minutes plus”, but said: “You may have look carefully for it.”
Amjad Malik QC, defending, said: “SUDEP is possible as the cause of death for Diane Stewart, isn’t it?”
Prof Al-Sarraj replied: “I agree. Yes, it’s one of the things you have to consider – but it’s not the only cause of death you had to consider.”
A second expert witness, consultant neuropathologist Dr Kieren Allinson, said there was “no positive evidence of a recent seizure”, such as tongue biting.
He described epilepsy as “awful” and said “people die suddenly and unexpectedly of the disease”.
Dr Allinson agreed with Mr Malik that the absence of evidence of a recent seizure “doesn’t make it unlikely that SUDEP occurred”.
He said: “A history of recent seizure is a risk factor for SUDEP but often they haven’t had a seizure for many, many years.”
Consultant neurologist Christopher Derry said he estimated that the risk of Mrs Stewart having a fatal epileptic seizure was about one in 100,000.
He said he “cannot exclude it… but it seems she was at very low risk of it occurring”.
He noted that she was taking medication for her epilepsy.
Stewart denies the murder of his wife.
The trial continues.