Lydia H. Greiner

Linguistic Ability in Early Life and the Neuropathology of Alzheimer's Disease and Cerebrovascular Disease: Findings from the Nun Study

Abstract: Findings from the Nun Study indicate that low linguistic ability in early life has a strong association with dementia and premature death in late life. In the present study, we investigated the relationship of linguistic ability in early life to the neuropathology of Alzheimers disease and cerebrovascular disease. The analyses were done on a subset of 74 participants in the Nun Study for whom we had handwritten autobiographies completed some time between the ages of 19 and 37 (mean = 23 years). An average of 62 years after writing the autobiographies, when the participants were 78 to 97 years old, they died and their brains were removed for our neuropathologic studies. Linguistic ability in early life was measured by the idea (proposition) density of the autobiographies, i.e., a standard measure of the content of ideas in text samples. Idea density scores from early life had strong inverse correlations with the severity of Alzheimers disease pathology in the neocortex: Correlations between idea density scores and neurofibrillary tangle counts were −0.59 for the frontal lobe, −0.48 for the temporal lobe, and −0.49 for the parietal lobe (all p values < 0.0001). Idea density scores were unrelated to the severity of atherosclerosis of the major arteries at the base of the brain and to the presence of lacunar and large brain infarcts. Low linguistic ability in early life may reflect suboptimal neurological and cognitive development, which might increase susceptibility to the development of Alzheimers disease pathology in late life.

Language decline across the life span: findings from the Nun study

The present study examines language samples from the Nun Study. Measures of grammatical complexity and idea density were obtained from autobiographies written over a 60-year span. Participants who had met criteria for dementia were contrasted with those who did not. Grammatical complexity initially averaged 4.78 (on a 0-to-7-point scale) for participants who did not meet criteria for dementia and declined .04 units per year; grammatical complexity for participants who met criteria for dementia initially averaged 3.86 and declined .03 units per year. Idea density averaged 5.35 propositions per 10 words initially for participants who did not meet criteria for dementia and declined an average of .03 units per year, whereas idea density averaged 4.34 propositions per 10 words initially for participants who met criteria for dementia and declined .02 units per year. Adult experiences, in general, did not moderate these declines.

Linguistic Ability in Early Life and Longevity: Findings from the Nun Study

Findings from the Nun Study indicate that low linguistic ability in early life has a strong relationship to poor cognitive function and dementia in late life and to the number of Alzheimer’s disease lesions in the brain. In the present analyses, we investigated the relationship between linguistic ability in early life and all cause mortality in late life in a subset of 180 participants in the Nun Study. Two measures of linguistic ability in early life - idea (proposition) density and grammatical complexity - were derived from autobiographies written by the participants when they were 18 to 32 years old. An average of 58 years later, when these participants were 75 to 93 years old, all cause mortality rates were determined. Of the two linguistic measures, idea density in early life had the strongest and most consistent relationship to the rate of all cause mortality in late life. A one-unit decrease in idea density in early life (ie , one fewer idea expressed per 10 words in a sentence) was associated with a 49 % increase in the mortality rate (95 % CI = 17-89; p-value = 0.001). This finding did not appear to be due to confounding by birth year, education attained at the time when the autobiography was written, or age during the mortality suveillance period. Standard life table analyses indicated that the median age at death for 75-year-olds was 81.7 years for those with low idea density in early life and 88.5 years for those with high idea density in early life. Low linguistic ability in early life may reflect suboptimal cognitive and neurological development that may increase susceptibility to aging-related declines and disease processes, resulting in a higher mortality rate late in life. Overall, low linguistic ability and its correlates in early life may place potent limits on the longevity of individuals.