diff --git a/lib/accesslib.php b/lib/accesslib.php
index e36c126..9b749d0 100755
--- a/lib/accesslib.php
+++ b/lib/accesslib.php
@@ -2779,6 +2779,11 @@ function role_unassign_all(array $params, $subcontexts = false, $includemanual =
 function isloggedin() {
     global $USER;
 
+// Validate user logged in status for SSO
+    if (isset($USER->auth)) {
+        $userauth = get_auth_plugin($USER->auth);
+        $userauth->auth_validate_loggedin_hook();
+
     return (!empty($USER->id));
 }
 
diff --git a/lib/authlib.php b/lib/authlib.php
index 334bd44..3a56287 100644
--- a/lib/authlib.php
+++ b/lib/authlib.php
@@ -380,6 +380,17 @@ class auth_plugin_base {
         return true;
     }
 
+// ou-specific begins #54
+    /**
+     * Hook for validating logged in user for this authentication plugin.
+     * This method is called from accesslib isloggedin() function for current $USER auth plugin.
+     * Allows user logged out from SSO sytem to be logged out from Moodle for example.
+     */
+    function auth_validate_loggedin_hook() {
+        //override if needed
+    }
+// ou-specific ends
+
     /**
      * Hook for overriding behaviour of login page.
      * This method is called from login/index.php page for all enabled auth plugins.