Age-Related Repetitive Transcranial Magnetic Stimulation Effects on Executive Function in Depression: A Systematic Review

Objective: The aims of the current review were to: 1) examine whether the rTMS effects on executive function increase as age advances; 2) to examine the potential of rTMS to remediate executive function in older depressed patients; and 3) to assess the relationship between the executive function and mood benefits from rTMS in depression. Methods: Randomized or matched-groups, blind, sham-controlled studies (12 studies, 347 participants) on excitatory rTMS applied to left DLPFC in depression were reviewed. Results: A series of meta-regressions found no evidence of greater rTMS effects on executive functions as age advances. Similarly, meta-analyses showed no significant rTMS effects on executive functions in older depressed individuals. However, meta-regression analyses showed that the size of the executive function benefits from rTMS in depression are positively related to the effect size of mood symptom reduction. Despite its correlational nature, this finding is consistent with the idea that improvement in executive function may play a critical role in depression recovery. Conclusions: The authors consider these findings preliminary because of the modest number of available studies. Based on a qualitative review, the authors describe methodologic modifications that may increase rTMS efficacy for both executive functions and mood in late-life depression.