I Have Been Assesed With With Early Stage Dementia But

I have been assesed with with early stage dementia but I do not see what has been listed as the 10 stages of early dementia I have been refused a drivers test . I am 83 years young .Have never had an accident or even had a speeding ticket. My friends see no difference in me. they say I am a good careful driver.But my Doctor refused. to allow me the test that I was promised.My rights have been taken from me. What can I do?