Despite the rise in literacy, 773 million of the global population is estimated to be illiterate. The rate of illiteracy is even higher among women and older adults (OA). Literacy has been well documented to impact cognitive skills, and most neuropsychological tests developed are for individuals with higher education. Moreover, there is sparse research on cognitive process and performance of illiterate individuals across cognitive domains.

Per a 2011 census, the illiteracy rate in the Indian older adult population was as high as 56%, and within this group, women and older adults in rural regions were especially vulnerable. Thus, it is important to understand cognitive performance of illiterate Indian older adult population, especially when they are being assessed for neurodegenerative disorders.

This study used subset of data from Harmonized Longitudinal Aging Study of India, Diagnostic Assessment of Dementia (LASI DAD), which was developed by the Gateway to Global Aging Data. A sample of cognitive healthy OA (n = 715) was selected based on Hindi Mental Status Exam score of >19 and a Clinical Dementia Rating Scale of 0 (literate = 419, illiterate = 296). Given the heterogeneity of the population, adapted cognitive instruments were used. This study compared memory performances, using word list and constructional praxis with delayed recall tasks, of OA based on their literacy status (illiterate vs. literate).

Literate cognitive healthy OA (M = 15.27, SD = 3.9) learned more words over three trials than illiterate OA (M = 12.17, SD = 3.7) on a world list task, a statistically significant difference (M = 3.1, 95% CI [2.5, 3.6], t (713) = 10.62, p<0.05. Literate OA (M = 8.7, SD = 2.2) had higher scores on task of copy of simple geometrical figures than illiterate OA (M = 5.3, SD = 2.8), a statistically significant difference (M = 3.3, 95% CI [2.9, 3.7], t (713) = 7.1, p<0.05. Literate OA (M = 4.5, SD = 1.8) also recalled more words than illiterate OA (M = 3.6, SD = 2.1) after a delay. Recall of geometric figures after a delay was higher for literate OA (M = 5, SD = 2.9) as well compared to illiterate OA (M = 2.4, SD = 2.5).

Conclusion: In a sample of cognitively healthy Indian older adults, literate OA consistently performed better than illiterate OA on both verbal and nonverbal memory measures. This is consistent with past literature which shows that illiterate individuals take longer to learn verbal information and have lower recall. Additionally, use of geometric figure may be complicated for these individuals. These are important considerations when assessing an OA for memory problems with low or no education. Next steps would be to look at differences across other cognitive domains and also examining if cognitive differences exist in illiterate OA based on gender.