Berlusconi has been advised to cancel all public activities until after Chritsmas as he recovers from the attack.
'Signs of recovery'
Alberto Zangrillo, Berlusconi's doctor he must "abstain from all activities that would expose him to public situations, to stress."
"Physically, he is eating normally, but with a bit of difficulty," Zangrillo said.
"In terms of morale, it's still a matter of concern ... but he is showing signs of recovery."
The 73-year-old will spend a third night in hospital on Tuesday.
The attack had already forced the cancellation of some of Berlusconi's plans, including a meeting with Recep Tayyip Erdogan, the Turkish prime minister, on Wednesday.
Berlusconi's participation at the UN climate summit in Copenhagen is also unlikely.
The attack comes at the end of a difficult year for Berlusconi.
His popularity recently plummeted after accusations of sexual encounters with escorts, a separation from his wife, the loss of immunity prosecution and the restart of two corruption trials.
The prime minister faces allegations that he paid his British former tax lawyer, David Mills, $600,000 to give false evidence in two trials in the 1990s.
Earlier this month, about 350,000 Italians called for his resignation in what they dubbed the "No Berlusconi Day".
But messages of support have poured in from Italians and foreign officials, including Hillary Clinton, the US secretary of state, and Nicolas Sarkozy, the French president, since the assault.
Vladimir Putin, Berlusconi's Russian counterpart, called the Italian prime minister to praise his response to the attack.
Putin expressed "words of solidarity, support and strongly condemned what happened," Dmitry Peskov, his spokesman, told reporters.
"He remarked that Berlusconi had behaved in a manly way in an extreme situation."
In 2004, an Italian bricklayer hurled a camera tripod at Berlusconi, injuring him slightly on the head.