For the last dozen years, it's been known that young people who follow the stylistic advice of Strunk & White are more likely to get Alzheimer's disease when they get old. Well, at least, in a cohort of nuns,
Low idea density and low grammatical complexity in autobiographies written in early life were associated with low cognitive test scores in late life. Low idea density in early life had stronger and more consistent associations with poor cognitive function than did low grammatical complexity. Among the 14 sisters who died, neuropathologically confirmed Alzheimer's disease was present in all of those with low idea density in early life and in none of those with high idea density.
And if you look into what "idea density" means, you'll see that many aspects of Strunkish writing style, especially avoidance of adjectives and adverbs, are precisely designed to lower it. (For details and links, see "Writing style and dementia", 12/3/2004; and "Miers dementia unlikely", 10/21/2005.)
Now there's a new chapter in the story, based on looking for physical symptoms of Alzheimer's in living nuns using positron emission tomography (PET) brain imaging, rather than relying on post-mortem examination of the brains of dead ones ("Can Language Skills Ward Off Alzheimer's? A Nuns' Study", Time, 7/9/2009).
The recent journal article under discussion is D. Iacono et al., "The Nun Study. Clinically silent AD, neuronal hypertrophy, and linguistic skills in early life", Neurology, published online 7/8./2009.
Background: It is common to find substantial Alzheimer disease (AD) lesions, i.e., neuritic β-amyloid plaques and neurofibrillary tangles, in the autopsied brains of elderly subjects with normal cognition assessed shortly before death. We have termed this status asymptomatic AD (ASYMAD). We assessed the morphologic substrate of ASYMAD compared to mild cognitive impairment (MCI) in subjects from the Nun Study. In addition, possible correlations between linguistic abilities in early life and the presence of AD pathology with and without clinical manifestations in late life were considered.
Methods: Design-based stereology was used to measure the volumes of neuronal cell bodies, nuclei, and nucleoli in the CA1 region of hippocampus (CA1). Four groups of subjects were compared: ASYMAD (n = 10), MCI (n = 5), AD (n = 10), and age-matched controls (n = 13). Linguistic ability assessed in early life was compared among all groups.
Results: A significant hypertrophy of the cell bodies (+44.9%), nuclei (+59.7%), and nucleoli (+80.2%) in the CA1 neurons was found in ASYMAD compared with MCI. Similar differences were observed with controls. Furthermore, significant higher idea density scores in early life were observed in controls and ASYMAD group compared to MCI and AD groups.
Conclusions: 1) Neuronal hypertrophy may constitute an early cellular response to Alzheimer disease (AD) pathology or reflect compensatory mechanisms that prevent cognitive impairment despite substantial AD lesions; 2) higher idea density scores in early life are associated with intact cognition in late life despite the presence of AD lesions.
See also William E. Klunk et al., "Amyloid Imaging with PET in Alzheimer’s Disease, Mild Cognitive Impairment, and Clinically Unimpaired Subjects", chapter 6 in Dan Silverman (Ed.) PET in the Evaluation of Alzheimer's Disease and Related Disorders, 2009.