An extensive vocabulary can protect against mental deterioration, according to a recent study.

Some people suffer incipient dementia as they get older. To make up for this loss, the brain's cognitive reserve is put to the test. Researchers from the University of Santiago de Compostela found that having a higher level of vocabulary can help to improve this ability.

Cognitive reserve is the name given to the brain's capacity to compensate for the loss of its functions. This reserve cannot be measured directly; rather, it is calculated through indicators believed to increase this capacity.

"We focused on level of vocabulary as it is considered an indicator of crystallized intelligence (the use of previously acquired intellectual skills). We aimed to deepen our understanding of its relation to cognitive reserve," Cristina Lojo Seoane, co-author of the study, said in a statement.

For the study, researchers chose a sample of more than 326 subjects older than 50 years old - 22 healthy individuals and 104 with mild cognitive impairment. They then measured their levels of vocabulary, along with other measures such as their years of schooling, the complexity of their jobs and their reading habits.

Researchers also analyzed the scores they obtained in various tests, such as the vocabulary subtest of the "Wechsler Adult Intelligence Scale" (WAIS) and the Peabody Picture Vocabulary Test.

"With a regression analysis we calculated the probability of impairment to the vocabulary levels of the participants," Lojo Seoane said in a statement.

The results revealed a greater prevalence of mild cognitive impairment in participants who achieved a lower vocabulary level score.

"This led us to the conclusion that a higher level of vocabulary, as a measure of cognitive reserve, can protect against cognitive impairment," the researchers conclude.

The findings were published in the journal Annals of Psychology.