Pat Hume, the wife of Nobel Peace Prize winner John Hume, has spoken for the first time about her husband's ongoing struggle with dementia.

Speaking on RTÉ's Sunday with Miriam, Mrs Hume said her husband "is having severe memory difficulties at the moment."

She said her husband first became ill in the late 1990s when he was speaking at a conference in Austria. It is believed Mr Hume suffered some brain damage as a consequence of the illness.

This brain damage has gradually got worse in the intervening years.

However, she said "it hasn’t actually taken away all his quality of life in that Derry is a very dementia-friendly city. People love John."

Mrs Hume said the 78-year-old former SDLP leader struggles to remember day-to-day occurrences.

"If John was speaking to you now and I said to him in half an hour, 'it was lovely to see Miriam', he would say 'where did we see Miriam?' He just wouldn’t know that he’d seen you ... So it really is very sad."

Mrs Hume was speaking as part of a wide-ranging interview about her marriage, which she wrote about in a new book entitled 'John Hume - Irish Peacemaker'.

She said her husband will not be attending the launch of the book in Dublin next week, as he "doesn't like being away from home now. He loves Derry."

Mrs Hume also said that caring for someone with dementia "can be very tough".

She added that she would love if her story created "a greater knowledge of being dementia friendly."