Tolerability and effectiveness of rtms for geriatric patients with treatment-resistant depression in a naturalistic clinic setting

Introduction Repetitive transcranial magnetic stimulation (rTMS) is a known, well-tolerated treatment for geriatric patients experiencing major depressive disorder (MDD) (Dardenne et al., 2017; Sayar et al., 2013). Notably, a recent review of rTMS studies in geriatric populations demonstrated that geriatric patients are frequently underdosed for rTMS, decreasing efficacy rates (Cappon et al., 2022). Current FDA protocol prescribes 90,000 pulses over 4-6 weeks with a frequency of 10Hz and 120% motor threshold (MT) intensity (McClintock et al., 2018). Of the 14 studies reviewed by Cappon et al. (2022), 13 had pulse counts less than FDA protocol dose, and 12 had pulse counts less than 31,500. This study compares the rTMS treatment course and response rates of patients 55 years old and older to patients younger than 55 years old in a treatment-resistant depression clinic at Emory Healthcare in Atlanta, Georgia. Methods A retrospective chart review was conducted on patients who received rTMS March 2017 to June 2022 and consented to use their clinical data for research purposes. All patients received their TMS course at a standardized protocol of 10Hz, 120% MT with a train duration of 4 seconds and an intertrain interval of 15-26 seconds. Descriptive statistics were used to present and visually compare TMS treatment parameters and level of retention between geriatric and non-geriatric patients. A 2 × 3 repeated-measures ANOVA was performed to assess differences in self-reported depression severity on the Beck Depression Inventory-II (BDI-II) throughout treatment course, including pre-treatment, treatment midpoint (session 15) and at the end of treatment (session 30). Results Eighty-nine patients were included in the analyses and divided into two groups based on age: Group 1 (Geriatric): ≥55 years old (n = 42; M = 66.48, SD = 6.16; 71% female), and Group 2 (Non-Geriatric): n = 47; M = 37.40, SD = 9.13; 60% female). With regard to treatment retention, all patients in Group 1 received 3000 pulses per session, with 85.71% of patients completing the current rTMS FDA-approved protocol. 45 patients in Group 2 received 3000 pulses per session, and two patients (4%) received 5000 pulses per session, with 85.11% of patients completing the FDA-approved protocol. With regard to treatment response, 38.1% of patients in Group 1, and 31.9% of patients in Group 2 showed a ≥50% improvement by end of treatment. Consistent with this, measuring change in BDI-II scores across the treatment course, both groups demonstrated significant within-group reductions throughout treatment (ps < .001), Group 1: pre-treatment M = 23.61 (SD = 8.56), session 15 M = 15.78 (SD = 10.38), session 30 M = 14.39 (SD = 10.60); Group 2: pre-treatment M = 28.63 (SD = 10.70), session 15 M = 21.63 (SD = 12.88), session 30 M = 18.13 (SD = 12.77). The between groups’ difference in change in BDI-II total scores was not statistically significant (Wilks’ Lambda = .97, F(2, 71)= 1.09, p= .34, partial eta squared= .03), indicating that the TMS course of geriatric patients (Group 1) was not inferior to the course of non-geriatric patients (Group 2). Conclusions Our data supports that, at adequate dosing, geriatric patients respond consistently with non-geriatric patients and can tolerate the same dosing, with 85% of patients completing the full FDA-approved protocol in each age group. While our overall response rates are somewhat lower than standardized clinical trials reporting on patients with less chronicity (e.g., 41.5% based on scores from the Inventory of Depressive Symptomatology Self Report (IDS-SR), Carpenter et al., 2012), findings highlight the effectiveness of rTMS for patients treated in an unselected, naturalistic outpatient sample. This research was funded by n/a