A pilot randomized sham controlled trial of bilateral iTBS for depression and executive function in older adults.

INTRODUCTION: Executive function deficits (EFD) in late life depression (LLD) are associated with poor outcomes. Dysfunction of the cognitive control network (CCN) has been posited in the pathophysiology of LLD with EFD. METHODS: Seventeen older adults with depression and EFD were randomized to iTBS or sham for 6 weeks. Intervention was delivered bilaterally using a recognized connectivity target. RESULTS: A total of 89% (17/19) participants completed all study procedures. No serious adverse events occurred. Pre to post-intervention change in mean Montgomery-Asberg-depression scores was not different between iTBS or sham, p = 0.33. No significant group-by-time interaction for Montgomery-Asberg Depression rating scale scores (F 3, 44  = 0.51; p = 0.67) was found. No significant differences were seen in the effects of time between the two groups on executive measures: Flanker scores (F 1, 14  = 0.02, p = 0.88), Dimensional-change-card-sort scores F 1, 14  = 0.25, p = 0.63, and working memory scores (F 1, 14  = 0.98, p = 0.34). The Group-by-time interaction effect for functional connectivity (FC) within the Fronto-parietal-network was not significant (F 1, 14  = 0.36, p = 0.56). No significant difference in the effect-of-time between the two groups was found on FC within the Cingulo-opercular-network (F 1, 14  = 0, p = 0.98). CONCLUSION: Bilateral iTBS is feasible in LLD. Preliminary results are unsupportive of efficacy on depression, executive function or target engagement of the CCN. A future Randomized clinical trial requires a larger sample size with stratification of cognitive and executive variables and refinement in the target engagement.

iTBS to Relieve Depression and Executive Dysfunction in Older Adults: An Open Label Study.

BACKGROUND: Executive Function Deficits (EFD) accompany depression and are associated with poor outcomes in older adults. We examined whether Intermittent Theta Burst Stimulation (iTBS) could improve depression with EFD. METHODS: Thirteen geriatric patients with depression and EFD were enrolled. Open label iTBS was delivered bilaterally over the dorso-lateral-prefrontal-cortex for four weeks. RESULTS: Montgomery Asberg Depression Scale scores improved significantly from baseline to treatment-end, mean change in score = 11.82 points, 95% CI = 8.3, 15.4. The Flanker Inhibitory control and attention test showed significant improvement in executive function from baseline to treatment-end, mean change in score = -7.73, 95% CI ( -13.54, -1.92). Side effects included twitching in facial muscles (n = 11), headaches (n = 10) and stimulation discomfort (n = 4). LIMITATIONS: Small sample size and lack of a sham comparator. CONCLUSION: iTBS improved depression with EFD in older adults. Side effects appeared higher than in previous iTBS studies.