Vocabulary and Cognitive Impairment

A rich vocabulary can protect against cognitive impairment

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 have studied what factors can help to improve this ability and they conclude that having a higher level of vocabulary is one such factor. '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.

The study is in Spanish here:

Perhaps people with a wider range of vocabulary have one as a result of having a brain less susceptible to dementia, ie: larger in some parts. Correlation, causation, etc…