Learning many languages can delay onset of dementia by a few years, NTU scientists say

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An American linguist Benjamin Lee Whorf proposed almost a century ago that language affects perception and thought. Now, Associate Professor Chan Hiu of Dan Alice School of Humanities and Principal Investigator in the Neurolinguistics and Cognitive Science Lab at NTU's School of Humanities said speaking more than one language can delay the onset of dementia by a few years.

Even though the American chemical engineer Whorfian's effects have been found in behavioural studies, no research on the brain has been carried out so far to investigate whether language influences brain activity associated with perception.

In a study, the Assoc Prof Chan said, "One of the research interests of our lab is to locate the language function in the brain and understand how these language-related locations interact with brain regions related to other functions such as perception and cognition."

She mentioned that by using the state-of-the-art functional magnetic resonance imaging (fMRI), the team of researchers showcased that brain regions mediating language processes participate in neural networks which activate by the perception of colour.

In terms of brain imaging experiments, the research team asked the participants to perform a discrimination task on colour patches without requiring them to label the colour name of the patches.

The results showed the brain regions associated with word-finding processes were strongly engaged while performing the task. The outcome of the experiment suggests the language-processing areas of the human brain are automatically involved during colour perception while providing the first neuroimaging support for the hypothesis given by Whorf.

The follow-up study conducted by the researchers showed that the participants had to "find a patch with a slightly deviating colour tone among 12 otherwise identical patches and name the number of the respective deviating patch."

The results also gave further evidence that the brain region is responsible for naming colours was activated during a colour-searching task.

In addition, the scientists also unveiled that enhanced activity in the visual cortex are responsible for colour perception coexists with enhanced activity in language-related regions.

Previously researchers mentioned that speaking more than one language can delay the onset of dementia by a few years. Now Prof Chan and the team aim to apply their understanding of the language's influence on perception and cognition to evaluate language learning as a means to counter the negative effects of ageing, for instance, in memory capacity and cognitive control.

Early fMRI studies were done by the team of researchers, suggested that language learning is highly correlated to activity in the left fusiform gyrus and caudate nucleus.

In this on-going project, the scientists are using electroencephalography, another brain imaging technique and they asked participants to learn a new writing system. Soon after one week of training, they found that the brain waves related to writing-to-speech-sound mapping in our young adult participants had changed and it suggests that for adults new learning changes the brain in language-related areas but also in other cognitive control areas.

The new study researchers now hope that "these interventions will ultimately aid them in maintaining healthy and active lifestyles, thereby impacting society at large."