Garion, you clearly need to add another association from the Siezure object to the TypesOfSiezure object so that you can categorize the siezure to a particular type. To restrict the choices of Types to the relevant list for that Person, look at the ConstrainedBy property of the association when you add it to your Siezure form/page.
You’ll most likely want to have Person linked to Seizure ( 1-* ) and then Seizure linked to Type (*-1).
That way a seizure will always have a type and you can retrieve all types a person has had via association.
Hope this helps