She said there were more than 100 forms of dementia, divided into six main types, of which Alzheimer's is the most common.
Alzheimer's begins with the sufferer having difficulty remembering recent events. Other symptoms include confusion, irritability, aggression, mood swings, language problems, memory loss and, eventually, loss of bodily functions.
Ms Spence said there was still a lot of stigma associated with dementia.
"People often withdraw from society, they feel embarrassed by their limitations."
For that reason a major focus of Alzheimer's Wanganui is their organised social outings - twice a week in Wanganui and once a week in Marton - where they visit different parts of the district and socialise with each other.
Those social connections are vitally important, according to diversional therapist Maree Cairns.
"They say that laughter is the best medicine. And we've had some friendships formed within our social outings."
Ms Cairns said the focus was on what people can still do, rather than what they have lost.
Other activities for Alzheimer's Wanganui include workshops for carers, programmes on living with memory loss, holding public talks on dementia, and giving information to people who come in for help.
They help people in the entire Whanganui District Health Board area, and currently are working to support 113 people living with dementia, plus their families and carers.
"The support we give is quite intensive," Ms Cairns said.
"Our mission is help make life better for all people affected by dementia."
The Wanganui branch of Alzheimer's New Zealand has been operating since 1985. There are currently five staff members and about 10 volunteers.
"Our volunteers are amazing, and we would welcome more," she said.
Apart from two contracts with the Whanganui District Health Board, the organisation is dependent on grants and community support.
"That is why it is good for people to know that their donations stay in our region and are used here," Ms Cairns said.
Alzheimer's Wanganui will be holding its street appeal this Friday in Wanganui, Taihape and Marton. For more information, visit http://www.alzheimers.org.nz.