The effect was greater in those who had greater ability in the languages than with those who had used both languages more during their life showing less severe symptoms than those who had used them less.
The finding lends support to the theory of cognitive reserve that while Alzheimer’s cannot be cured, people who have had higher levels of education build up a greater resistance to the wasting of the brain caused by the disease.
Daniela Perani, of Vita-Salute San Raffaele University in Milan, and colleagues published their findings in the Proceedings of the National Academy of Sciences. They compared 45 Alzheimer’s patients who spoke German and Italian with 40 sufferers who spoke only one of the languages.
It is believed that a lifetime of comfortably switching between languages develops stronger connections between certain areas of the brain, enabling it to cope better with damage before sufferers start to show outward signs of dementia. The researchers said: ‘These protective effects may be a direct consequence of how the human brain has adapted to the “extra effort” provided by handling two or more languages.’