Forms :: Duplicating Values From Previous Record Of Patient In New Form

In my database scenario, a patient would see a doctor and the doctor would check off fields in a form representing different disease symptoms that the patient has to calculate a final score (for ex. if the patient has 2 symptoms, the final score would be 2).

After a few months, the patient would visit the doctor again, and the doctor will have to fill out the same form, adding any new symptoms the patient might now have. I would like to have the disease symptom fields checked off in the previous visit automatically show up in the new form, so that the doctor only has to add the new symptoms, and then recalculate the score using both the old and new data (for ex., if the patient had 2 symptoms before and 3 more symptoms now, the score would be 5).