Dial maintains previous variable adjustment across slides
I'm making a unit for nurses and doctors to interact with a fictional character. They will select a response to a patient and a dial will adjust to show changes in that patient's motivation to do something.
I want to carry the "level of motivation" across slides when I present new things the nurse/doctor can say. So, they say something unhelpful and the dial drops by -1, on the next slide they say something helpful and it increases by 2 so I want their dial to now show 1.
I will want to repeat this for many questions while maintaining the learner's previous motivation meter throughout to eventually show how motivated they are at the end of the scenario.
I can't figure out how to maintain the previous slide's dial level onto each new choice. How would I do that?