diff --git a/src/OpenIDConnectClient.php b/src/OpenIDConnectClient.php
index ee81b02c..43f9d19b 100644
--- a/src/OpenIDConnectClient.php
+++ b/src/OpenIDConnectClient.php
@@ -437,16 +437,16 @@ public function authenticate() {
      *
      * @throws OpenIDConnectClientException
      */
-    public function signOut($accessToken, $redirect) {
+    public function signOut($idToken, $redirect) {
         $signout_endpoint = $this->getProviderConfigValue('end_session_endpoint');
 
         $signout_params = null;
         if($redirect === null){
-            $signout_params = array('id_token_hint' => $accessToken);
+            $signout_params = array('id_token_hint' => $idToken);
         }
         else {
             $signout_params = array(
-                'id_token_hint' => $accessToken,
+                'id_token_hint' => $idToken,
                 'post_logout_redirect_uri' => $redirect);
         }