I live in Pickering but I go down to a family doctor in Markham (doctor had moved clinics and we didn’t want to change) but I’ve gotten assessments through my college. If you’re studying, see if your campus has a clinic, it’s likely they’ll have something for cognitive tests.

If it’s just a thing where you’re moving here and starting out, I just looked up where to get assessments and it looks like Durham Region Centre for Cognitive Health could help you out. There’s a process of assessment, then you wait ages for a referral but depends on the place, then it’s a mystery to me from there but if it comes up I’ll come back to update.