set_userdata() not work

[eluser]phparif[/eluser]
I am facing a problem with CI session.
I use this code :
$sessionData = array(
'userName' => $name,
'email' => $email,
'password' => $password,
'isLogedIn'=> TRUE
);
$this->session->set_userdata($sessionData);
But when i try to retrieve data it show only this data, My original data not show :

var_dump($this->session->all_userdata());

array(4) {
["session_id"]=> string(32) "e61ca2c94c6832577aa9296424718caf" ["ip_address"]=> string(9) "127.0.0.1"
["user_agent"]=> string(90) "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.28) Gecko/20120306 Firefox/3.6.28" ["last_activity"]=> int(1334332439)
}