A recent study published in JAMA Psychiatry suggests that cognitive remediation (CR) combined with transcranial direct current stimulation (tDCS) may help slow cognitive decline in older adults at high risk, particularly those with remitted major depressive disorder (rMDD) or mild cognitive impairment (MCI). Conducted by Dr. Tarek K. Rajji and his team at the Campbell Family Mental Health Research Institute in Toronto, the study involved 486 older adults, with 375 completing at least one session of the intervention.

This trial focused on older adults with a history of rMDD, MCI, or both, utilizing CR and tDCS targeting the prefrontal cortex. During the median follow-up period of 48.3 months, participants receiving the combined therapy demonstrated a statistically significant slowing in cognitive decline (adjusted z score difference at 60 months: 0.21; 95% confidence interval: 0.07 to 0.35). However, immediate cognitive improvements were not observed at the two-month mark in the primary analysis (adjusted z score difference: 0.06; 95% confidence interval: -0.006 to 0.12).

Though the intervention showed limited effectiveness in delaying progression from normal cognition to MCI or from MCI to dementia (hazard ratio: 0.66; 95% confidence interval: 0.40 to 1.08), specific cognitive domains, including executive function and verbal memory, showed positive effects. The study also found that participants without the APOE ε4 gene variant and those with a history of rMDD exhibited stronger benefits from the therapy.

"Our trial demonstrated the efficacy of a combined therapy of CR and tDCS in slowing cognitive decline in a high-risk sample," the authors concluded, highlighting the potential of this approach for older adults vulnerable to cognitive decline.

Notably, several authors of the study disclosed affiliations with the biopharmaceutical industry, which underscores the importance of ongoing research to independently validate these findings.