Cognitive remediation plus electrical stimulation delays cognitive decline

Cognitive decline in older adults with remitted major depressive disorder (rMDD) appears to be slower when they receive cognitive remediation (CR) plus transcranial direct current stimulation (tDCS), according to a study.

The study included 375 participants (mean age 72.2 years, 62 percent female) with rMDD, mild cognitive impairment (MCI), or both. These participants were randomly assigned to receive the active intervention (CR plus tDCS, n=188) or the sham intervention (n=187) 5 days per week for 8 weeks (acute phase), followed by 5-day “boosters” every 6 months until the study end or a participant progressed from normal cognitive status to MCI or from MCI to dementia.

Change in global composite cognitive score at month 60 was evaluated as the primary outcome. Secondary outcomes included changes in six cognitive domains, moderating effect of the diagnosis, moderating effect of APOE ε4 status, change in composite score at month 2, and progression to MCI or dementia over time. Assessments were conducted at baseline, at month 2, and yearly from baseline for 3 to 7 years.

Over a median follow-up of 48.3 months, the active intervention was associated with slower cognitive decline at month 60 in older adults with rMDD or MCI compared with sham intervention (adjusted z-score difference, 0.21, 95 percent confidence interval [CI], 0.07–0.35; likelihood ratio test [LRT] p=0.006).

However, the active intervention did not improve cognition at month 2 relative to the sham intervention (adjusted z-score difference, 0.06, 95 percent CI, −0.006 to 0.12). Likewise, the active intervention had a weak and nonsignificant effect in terms of delaying progression from normal cognition to MCI or MCI to dementia (hazard ratio, 0.66, 95 percent CI, 0.40–1.08; p=0.10).

The active intervention had significant treatment effects for executive function (LRT p=0.04) and verbal memory (LRT p=0.02) and interactions with diagnosis (p=0.01) and APOE ε4 (p<0.001), showing a larger effect among participants with rMDD and in noncarriers of APOE ε4.