Does the KA1 still have the Sketchpad, you could test touchscreen functionality/accuracy there.
If it does not have the Sketchpad, but the Webbrowser, you could go to this site:
http://metamorpher.de/sketchpad - it's a JavaScript Sketchpad, JavaScript is slow so it won't handle quick finger movements on the Kobo, but just for testing whether the touchscreen is responsive/accurate at all, it should suffice...
Not sure if there is a native sketchpad mod or something similar that could be used for touchscreen testing for the kobo