Association between the Japanese version of the Montreal Test of Cognitive Abilities scores and intra-individual variability in reaction time: A one-year analysis

Early detection is a critical issue in dementia prevention. This study utilizes intra-individual variability in reaction time (IIV-RT) as an indicator of cognitive function. By analyzing data over a one-year period, we examine the association between IIV-RT and the Japanese version of the Montreal Test of Cognitive Abilities (MoCA-J), a cognitive screening test. In all, 36 community-dwelling older adults (mean age: 72.3 ± 3.6 years; 29 men and seven women) were included. IIV-RT was measured using a go/no-go task, which assesses inhibitory function. Cognitive function was assessed using the MoCA-J. In addition, neuropsychological tests, namely the Trail Making Test Parts A and B and Verbal fluency test, were conducted. Data on IIV-RT and MoCA-J were collected one year later, and Pearson's correlation analyses were conducted on the changes in each measure. In addition, a linear mixed-effects model was used to analyze the longitudinal association between IIV-RT and MoCA-J. Correlation analysis revealed a significant negative correlation between changes in IIV-RT and MoCA-J scores (r = -0.382, p = 0.02). The mixed-effects model also showed a significant association between IIV-RT and MoCA-J scores (β = -0.25, p < 0.001). The results of this study indicate that IIV-RT has potential for use as a complementary tool for self-monitoring in non-clinical settings. As this study was conducted in Japan, the findings may reflect characteristics specific to Japanese culture. Future studies should consider replicating the study in different cultural contexts to enhance the generalizability of the results.