Multilingualism and Neuroprotection
With the population aging and a dramatic increase in the number of senior citizens, public health systems will be increasingly burdened with the need to deal with the care and treatment of individuals with dementia. Enabling people to function independently for longer has immediate social and economic benefits by adding quality of life to the patient and time during which health care resources are not required. Importantly, some environmental factors have been shown to maintain cognitive functioning with aging and postpone the onset of symptoms of dementia. These factors contribute to a concept called 'cognitive reserve', and include education, occupational status, socio-economic class, and involvement in physical, intellectual and social activities. During my lessons, I provide evidence demonstrating how a particular experience, multilingualism, has been shown to protect cognitive function in older age and delay onset of symptoms of dementia. Indeed, as I will review, lifelong multilingualism may represent a powerful cognitive reserve delaying the onset of dementia by approximately 4 to 5 years. As to the causal mechanism, because speaking more than one language heavily relies upon executive control and attention, brain systems handling these functions are more developed in bilinguals resulting in increases of grey and white matter densities that may eventually help protect from dementia onset. These neuro-cognitive benefits are even more prominent when second language proficiency and exposure are kept high throughout life.