Keith Wiles vividly remembers an incident some 70 years ago when a boy delivering bread rode his bicycle along a bridge parapet - but he often forgets what he started talking about less than a minute beforehand.

Mr Wiles, 79, has been diagnosed with the start of dementia and wants to warn other families about telltale symptoms so that they can seek help for loved ones as soon as possible.

He is also appealing for greater public understanding towards sufferers who, like him, are left feeling scared, emotional and confused because of the condition.

Mr Wiles, of Harvey Drive, North Walsham, is a retired chartered engineer who once designed a factory for Coca Cola in Nigeria.

He and his wife Elizabeth moved to north Norfolk, living first in Cromer, 40 years ago, and he is a former president of Cromer Chamber of Trade.

Until recently he enjoyed compiling books of sudoku puzzles but his memory problems mean that he has now had to give up a hobby he found stimulating and enjoyable.

Mr Wiles said it was his daughter Sharon who first became alarmed about six months ago when she noticed her father becoming short-tempered, frustrated, forgetful and he would frequently phone her at work with queries which could easily have waited until she was home.

'My memory of years ago is fine, but I just can't remember where I've put things and it makes me very frustrated so that I burst out crying,' said Mr Wiles, who suffered a stroke in February but believed he had made a complete recovery.

His daughter persuaded him to see his GP and he was referred for assessment at Kelling Hospital where his condition was finally diagnosed.

Mr Wiles said he had to keep a diary of all his appointments because he could no longer trust his memory.

He is also aware of his fragile emotional state, especially since the death in March of his beloved Boxer dog, Floyd, for whom he is still grieving.

'I was very relieved that I haven't got Alzheimer's but I've got no idea what to do. I just want to record what it's like to be in this situation so that if other families spot symptoms in a parent or grandparent, they can do something about it,' said Mr Wiles, who increasingly finds he is talking to himself in his native Welsh.

'I don't want sympathy and I'm not ashamed. I just want understanding and tolerance.

'If other people learned to speak Welsh, that would help - thank God I haven't lost my sense of humour,' he added.

Paul Dunnery, area manager for the Alzheimer's Society in East Anglia, said as the number of people with dementia increased, it was vital everyone understood and talked about the condition.

'People with dementia and their families have told us that a diagnosis opened the door to support, treatment and information they wouldn't otherwise have had access to,' said Mr Dunnery.

'This includes Alzheimer's Society's activities in Norfolk such as singing groups, 'fish and chip' groups, carers' support, and drop-in services.

Anyone worried about their own or a loved one's memory should talk to their GP, he added.

Contact the Alzheimer's Society in Norfolk: 01603 763517, the national dementia helpline: 0845 300 0336, or online: www.alzheimers.org.uk