Evaluation of 1 Hz/20 Hz bilateral rTMS effects on cognitive performance in patients with major depressive disorder using thinc-it

      Background: This study evaluates the cognitive performance of 943 patients (nmales = 330) primarily diagnosed with MDD, using THINC-it subtests: (Choice Reaction Time Identification Task (CRT), One-Back Test (NBack), Digit Symbol Substitution Test (DSST), Trail Making Test-Part B (TMT) and Perceived Deficits Questionnaire for Depression-5-item (PDQ-5-D)) before and after an acute course of rTMS in a natural, clinical setting.
      Methods: Patients received 30-36 bilateral rTMS sessions (M = 35.92, SD = 0.51) with 1 Hz delivered to the right dorsolateral prefrontal cortex (dlPFC) for 360 pulses, followed by left dlPFC stimulation at 20 Hz for 1200 pulses. PHQ-9 and GAD-7 outcome measures and the THINC-it tool were administered before and after an acute course of rTMS in a naturalistic, clinical setting.
      Results: Overall, significant objective improvements appeared on the CRT, NBack, DSST, and TMT components of the THINC-it, with effect sizes in the range of 0.05-0.49. Significant objective improvements also appeared on the PDQ-5-D score, with an effect size at 0.84. Notably, the degree of improvement in overall THINC-it score did not correlate significantly to the degree of improvement in either the PHQ-9 score or the GAD-7 score. Among non-responders on the PHQ-9 (<50% improvement) (25.66%, nNR = 242), there were significant improvements in scores on all 5 THINC-it subtests, suggesting some independence of the effects of rTMS on cognition from those on clinical symptoms.
      Conclusions: This study suggests rTMS had no negative impact or detrimental effects on cognition. Mild-to-moderate improvements in task performance and larger improvements in subjective cognitive function ensued following rTMS, independent of improvement in clinical symptoms. rTMS appears not to worsen cognition but may slightly improve executive functioning, working memory, attention, and processing speeds.
      Keywords: rTMS, MDD, THINC-it, Cognition