Normative Cognitive Scores in Western India, Stratified by Age, Rurality, Cognitive Domains, and Psychiatric Comorbidity.

Abstract

Indian ethnic and educational diversities necessitate obtaining normative cognitive data in different populations. We aimed to evaluate cognitive scores using a Marathi translation of the Kolkata cognitive battery (KCB) and to study the association of KCB components with depression and sociodemographic variables. We studied 2,651 individuals aged ≥40 years without preexisting neuropsychiatric conditions from urban (Mumbai) and rural districts of Maharashtra. For each component of KCB, the lowest 10th percentile score was used to define cognitive impairment. We studied 1,435 (54%) rural and 1,216 (46%) urban residents equally divided by gender (1,316 women and 1,335 men), average age 54 years. KCB scores were significantly lower with female sex, older age, illiteracy, and depression. The largest effect sizes attributable to these factors were in the domains of calculation (gender), visuoconstructional ability (VCA) (rurality), and verbal fluency (VF) (depression). Scores remained significantly lower in rural residents after controlling for age, sex, and education, particularly for VCA, immediate recall, and calculation. This Marathi KCB, having been validated on large urban as well as rural samples, may be used to study cognition in Marathi-speaking populations with appropriate cutoffs tailored to the degree of urbanization of the population.