Thanks for asking this question. As a former phsysiotherapist and with years of modelling experience I find this a relevant and useful modelling challenge.
As @ian.mcnicoll , @heather.leslie and @siljelb have mentioned the EVENT structure is great to model this.
What I also found interesting for this use-case is the, not so widely used, summary attribute on HISTORY. See: Data Structures Information Model
It’s defined as : *Optional summary data that aggregates, organizes, reduces and transforms the event series. This may be a text or image that presents a graphical presentation, or some data that assists with the interpretation of the data.
*
This could be a useful attribute to store an aggregated outcome for series of events. I am not sure if it is relevant here; but we could calculate and store a summary of all the events here.
I tried to add summary to an OBSERVATION archetype using AD. It is not supported as far as I can see.
This is the best I could do with some handcoding of the ADL.
NOTE: it is not correct - just for an illustration
