Former Liverpool forward Cisse joins the Stadium of Light
outfit on loan while Northern Ireland international Healy has left
Barclays Premier League rivals Fulham for an undisclosed fee.
Cisse has joined the north-east club with a view to a permanent
deal and manager Roy Keane believes his arrival is a statement of
the club's intent.
Keane told the club's official website: "This signing shows our
ambitions and intentions.
"We're delighted with the new faces we've brought in, we've been
working hard all summer to significantly improve the squad."
Healy has joined the Black Cats on a three-year deal. He arrived
at Craven Cottage from Leeds United a year ago for a fee of
£1.5million, and scored four Barclays Premier League goals last
season.
Keane revealed it was the striker's international goalscoring
record that impressed him. He said: "David will be a good signing
for us.
"He has lots of experience at the top level and his
international record is phenomenal."