Where do I call to get mum with dementia assessed by a social worker?

You may consider starting with her own doctor to ask what resources he knows of that might help you now with whatever you are dealing with. Can you give us more information about what you currently would like to take up with a Social worker?

Assessed in like what resources you can take advantage of? That would be your County Office of Aging. Sounds like your maybe from England so it would be what ever agency handles Seniors. If you wait, Country Mouse is from the UK she will chime in. She is very familiar what is available.

Or assessment concerning her Dementia? A SW is not qualified to do that. You would need a neurologist to exam her and run the appropriate tests. I do feel that finding which Dementia a person has is important. I have read that Lewy Body and Parkinsons mimic each other. But you don't give someone who is actually suffering from Lewy Body Dementia meds for Parkinsons. It can have serious results.

Helen, if you are in the US, each county has a local Area Agency on Aging that you can call for help.

Answer depends on what country, state/province, county you live in. Please provide this info.