Linguistic Skills and Alzheimer’s Disease

The Nun Study provides long-term data from more than 600 nuns from Minnesota, allowing correlations to be drawn between early life experience and development of mild cognitive impairment and Alzheimer’s disease. On entering the convent in their 20s the novices wrote essays on their early life which provided evidence of their mental skills and education, using complexity of grammar and number of ideas expressed. As participants in the Nun Study, they gave permission for brain autopsy after their death. A report in the journal Neurology describes correlations between linguistic abilities as young adults and brain pathology typical of dementia.

The microscopic plaques and tangles that are characteristic of Alzheimer’ disease are often found in autopsied brains of elderly persons who have no symptoms of dementia. Neurologists call this ‘asymptomatic Alzheimer’s disease’, or ASYMAD. Using cognitive tests and brain pathology, the researchers formed 4 groups of nuns who had died: ASYMAD (10 subjects), mild cognitive impairment (5 subjects), Alzheimer’s (10 subjects), and age-matched controls (13 subjects). The subjects were scored on the basis of the linguistic ability shown in their novice essays, decades earlier.

An earlier study had shown that poor linguistic skills in the 20s was correlated with a higher likelihood of developing Alzheimer’s in later life. The new study carries this further. The nuns who avoided dementia later in life had 20% higher linguistic scores as young women. But what as remarkable was that this correlation held even when the brains of the nuns showed the typical plaques and tangles of Alzheimer’s, i.e. the ASYMAD subjects.

The researchers suggest that higher ‘smarts’ in early life can protect mental functioning, even in the face of pathological changes in the brain that are characteristic of Alzheimer’s. In some ways, it’s similar to the ability of someone likely to develop atherosclerosis to resist it through cardiovascular fitness.

There’s little doubt that mental alertness can be sharpened by various activities, even when youth is long past. There are plenty of ways to do this, with the intent of staving off Alzheimer’s; one of the best is to foster social interaction. It may not make up for linguistic ability, but it seems to be effective. . .