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Cognitive function, mental decline, and rural‐living effects on brain structure in an elderly Indian population
Author(s) -
Keller Brenton James,
Jovicich Jorge,
Lee Jinkook,
Toga Arthur W.
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.038427
Subject(s) - subiculum , cognition , neuropsychology , middle temporal gyrus , population , middle frontal gyrus , dementia , cognitive decline , lateralization of brain function , superior frontal gyrus , brain size , medicine , psychology , audiology , psychiatry , neuroscience , dentate gyrus , hippocampus , radiology , magnetic resonance imaging , environmental health , disease
Background Age‐related cognitive decline is widely documented, but with substantial individual differences that are not yet understood (Vaque‐Alcazar et al., 2017). Using the recently collected neuroimaging data from the Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India (LASI‐DAD), we investigate the associations between cognitive function (global cognition score), mental decline (JORM IQCODE), and rural‐living on brain structure. Methods A total of 103 subjects (female = 46, age = 68 ± 6 years) were studied from three clinical 3T MRI centers using the ADNI 3 MRI protocol (NIMHANS, Bangalore, N = 52, NM Medical, Mumbai, N = 23, and Institute of Kolkata N = 28). Brain morphometry data was studied with Freesurfer using volumetric ROI‐analysis and vertex‐based cluster‐corrected structural analysis. A global cognition score was derived by aggregating all cognitive tests administered, which included a set of common neuropsychological test battery from the Harmonized Cognitive Assessment Project protocol (HCAP) (Weir et al., 2016), as well as additional tests suitable for illiterate and innumerate population in India (Lee et al., 2019). Results ROI‐based morphometry analyses identified the hippocampus (subiculum and CA4, 3‐5%) and pars orbitalis (4‐6%) volume as having a positive correlation with global cognition score. Left hemisphere rostal middle frontal gyrus and right hemisphere postcentral gyrus area were also found to be positively associated with global cognition scores. In comparison, healthy status according to JORM IQCODE was positively correlated with right hemisphere rostral middle frontal gyrus thickness. Other significant clusters, including bilateral superior frontal gyrus and superior temporal gyrus thickness were found to be positively associated with JORM IQCODE healthy scores, while also showing colocalized area reductions in those with healthy JORM IQCODE scores. Similar to JORM IQCODE, rural‐living was also found to increase thickness in bilateral superior frontal gyrus. Conclusions Through the use of an intensive structural MRI protocol and neuropsychological test battery, we examined factors influencing brain morphometry. Of note, this study is the first to examine the effects of general cognition, respondent‐based memory assessment, and rural‐living on brain structure in an elderly Indian population.