Tests have shown activity on both sides of Prime Minister Ariel Sharon's brain but he shows no sign of emerging from a coma, Israeli hospital officials say.
Sharon's cabinet will meet without him on Sunday
Doctors are trying to wake Mr Sharon from a medically induced coma, 10 days after he suffered a massive stroke.
His condition is said to be serious but stable with normal vital signs.
His replacement, Ehud Olmert, is meanwhile set to stay on as acting prime minister until Israel goes to the polls on 28 March, reports say.
According to Israeli media, Attorney General Meni Mazuz will tell Mr Olmert on Sunday that he can continue in his current capacity because Mr Sharon remains unable to run the country.
Mr Olmert's cabinet colleagues are expected on Sunday to approve voting by Palestinian residents of occupied East Jerusalem in the 25 January elections.
The government had threatened to stop voting there, in protest at the participation of militant group Hamas in the Palestinian elections.
ARIEL SHARON'S HEALTH
Sharon suffers minor stroke on 18 December 2005
Doctors discover small hole in heart, schedule operation for 5 January
Sharon rushed to hospital one day before scheduled surgery with major stroke
Undergoes two operations overnight on 4/5 January, followed by third on 6 January
Issuing their first bulletin in 24 hours, officials at the Jerusalem hospital treating Mr Sharon said his pulse, breathing rate and blood pressure were normal and stable.
The tests had shown "activity in both brain hemispheres in keeping with the prime minister's state of consciousness".
There has been no swelling of Mr Sharon's brain following the removal of a fluid-draining catheter inserted, the report added.
Doctors have been attempting to rouse him from his coma in order to determine the damage caused by the stroke.
Medical observers say Mr Sharon's failure to wake may mean his comatose condition is due to the stroke itself and not the sedatives, the Associated Press news agency says.
As Mr Sharon's coma drags on, Israelis are resigning themselves to the idea of a political future without him.
His cabinet will meet on Sunday to give final approval to a decision to allow the Palestinian vote in East Jerusalem.
Israel has occupied East Jerusalem since 1967. It has annexed the area and sees it as its exclusive domain.
Under international law the area is considered to be occupied territory.
The area is often called Arab East Jerusalem because the majority of its residents are Palestinian, and Palestinians hope to make it their future capital.