Speaking more than one language can slow down dementia

Growing up speaking more than one language can help delay the effects of dementia. 

It's good news for those living in Australia's many culturally diverse households, according to a study led by University of Sydney clinical researcher Amira Skeggs and published in the prestigious Journal of Neurology.

Around 29 per cent of the Australian population is born overseas and researchers found being multi-lingual can act as a neurological shield in dealing with dementia.

The study focused on one of three types of the disease known as behavioural variant frontotemporal dementia (bvFTD). 

Frontotemporal dementia refers to a set of younger-onset dementia syndromes, which are typically diagnosed before the age of 65.

Last month, US action star Bruce Willis announced he had been diagnosed with frontotemporal dementia.

The progressive neurodegenerative disease affects brain areas responsible for behaviour, personality, language and emotions.

"When it comes to neurodegenerative syndromes like bvFTD, culturally diverse people can have a later onset of the disease compared to monolingual Australians because they have other factors which could increase their resilience or cognitive reserve," Ms Skeggs said.

Cognitive reserve is a kind of a neural fort that helps the brain weather neurogenerative disease before symptoms of mental decline kick in. 

"There is a tendency for culturally diverse patients, particularly those who come to Australia, to have higher levels of cognitive reserve," Ms Skeggs said.

"Multilingualism, education, working in a complex profession for a long time, all of these factors add up and make you more resilient to cognitive decline – up to a point".

Researchers compared clinical symptoms of 107 people separated into three groups: Australians who speak only English, another group that spoke English as their first language and another that spoke a different mother tongue growing up.

"Comparisons revealed that the group who spoke a non-English first language performed worse than the other groups on verbal tests but better on non-verbal tests," Ms Skeggs said.

"The poor verbal performance in the non-English speaking group is probably influenced by cultural biases within current clinical tests, so the reason they are showing decline may not actually be because they are declining."

Ms Skeggs also found that bilingual patients can still communicate with loved ones in a language other than English, which can help them navigate the disease as they deteriorate.

"We had one Vietnamese patient who spoke English perfectly before disease onset, but by the time the disease had progressed, he had completely lost his English ability and could only communicate in Vietnamese, even though he had been speaking English perfectly for over 50 years," she said.

She recommended that clinics collect information about a patient's cultural background and ability to speak multiple languages in order to offer alternatives during diagnosis such as having a translator.