The journalist and news anchor, who penned a bestselling book about her own experience dealing with her mother's battle with the disease, will chair the event in Edinburgh on Monday.
The discussion will probe the huge health, economic, legal and social care challenges posed by dementia and raised by Magnusson in her bestselling book Where Memories Go: Why Dementia Changes Everything.
Magnusson has spoken of how she was in tears one Christmas Eve when her mother did not recognise her. Quizzed by her GP in 2009, Mamie Magnusson believed it was 1946, and also periodically believed her son Siggy, who died in a road crash in 1973, was still alive.
Magnusson said: "She described it as feeling like being on 'a long road, getting further and further from myself', which is as perfect a description as I've heard."
The panel includes Henry Simmons, chief executive of Alzheimer Scotland; Geoff Huggins, head of mental health for the Scottish Government; and Dr Peter Connelly, co-chairman of the Scottish Dementia Research Network.
The event will be held at 6.30pm on Monday in Surgeons' Hall, Edinburgh.