Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Apr 4;12(1):51-59.
doi: 10.1159/000520879. eCollection 2022 Jan-Apr.

Discrepancy in Fluid and Crystallized Intelligence: An Early Cognitive Marker of Dementia from the LASI-DAD Cohort

Swati Bajpai  1 , Ashish Dutt Upadhayay  2 , Joyita Banerjee  1 , Avinash Chakrawarthy  1 , Prashun Chatterjee  1 , Jinkook Lee  3 , Aparajit Ballav Dey  1
Affiliations

Discrepancy in Fluid and Crystallized Intelligence: An Early Cognitive Marker of Dementia from the LASI-DAD Cohort

Swati Bajpai et al. Dement Geriatr Cogn Dis Extra. .

Abstract

Background: Cognitive aging is a complex phenomenon, which comprises various cognitive skills, broadly categorized into fluid and crystallized intelligence. Crystallized intelligence (gc) tends to be maintained, as opposed to fluid intelligence (gf), which tends to decline rapidly with age. The association of the two with cognitive decline remains a matter of conjecture requiring further research.

Aim: The aim of the study was to identify the variables of gc and gf from a population data of Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD) study and investigate its relationship with the onset of cognitive impairment using discrepancy analysis against neuropsychological tests.

Methods: This analysis of data from LASI-DAD study was carried out on a sample of 3,223 participants. They were assessed on extensive thirteen cognitive tests and one subjective test of cognition. Standardized score was used for discrepancy analysis. Fluid ability minus crystallized ability was used to assess the cognitive impairment. Any statistical significance with the score difference >0.99 SD was defined as a presence of cognitive decline. Hindi Mental Status Examination (HMSE) and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) were used as gold standard.

Results: With increased discrepancy score, each cognitive parameter score declined which was found to be statistically significant. In HMSE (Normal = 25.81 ± 3.39; Impaired = 23.17 ± 3.54; p = <0.001), there was a drop of 2 point scores in identifying cognitive impairment in the population sample as per the gold standard. A similar trend was evident in other neurocognitive domains as well.

Conclusion: Crystallized-fluid intelligence discrepancy analysis has a strong potential in predicting the onset of cognitive decline ahead of time, facilitating early intervention.

Keywords: Cognitive impairment; Crystallized intelligence; Discrepancy analysis; Fluid intelligence; LASI-DAD.

PubMed Disclaimer

Conflict of interest statement

The authors have no potential conflicts of interest to disclose.

Figures

Fig. 1
Fig. 1
Graphical representation of fluid and crystallized ability scores across the age-groups.
Fig. 2
Fig. 2
Trend of discrepancy scores in memory domain in total population group (a) and derived pure normal sample (b) on discrepancy analysis.
See this image and copyright information in PMC

References

    1. World Health Organization . World report on ageing and health. World Health Organization; 2015. Oct 22,
    1. Rodriguez FS, Lachmann T. Systematic review on the impact of intelligence on cognitive decline and dementia risk. Front Psychiatry. 2020;11:658. - PMC - PubMed
    1. Lezak MD, Howieson DB, Loring DW, Fischer JS. Neuropsychological assessment. USA: Oxford University Press; 2004.
    1. Mazzonna F, Peracchi F. Oxford research encyclopedia of economics and finance. Oxford University Press; 2018. The economics of cognitive aging.
    1. Schneider WJ, McGrew KS. The Cattell-Horn-Carroll theory of cognitive abilities. The Guilford Press; 2018.