Repetitive TMS (rTMS) of left DLPFC was approved by the US Food and Drug Administration (FDA) in 2008 as a therapy TRD, and this was extended to the equally effective iTBS protocol in 2018.
Dysfunctional connectivity between the left DLPFC and subgenual anterior cingulate cortex (sgACC) has been implicated in the pathogenesis of depression. It has been hypothesized that rTMS-induced neuroplasticity in left DLPFC modifies functional connectivity between left DLPFC and sgACC, normalizing the underlying brain circuit dysfunction.
A recent development has been a move towards "accelerated" rTMS protocols with more than one session per day. Recently, two studies reported promising results for the Stanford Accelerated Intelligent Neuromodulation Treatment (SAINT) protocol for TRD.
The aim of the COMPACT trial is to introduce and test a novel accelerated iTBS therapy for TRD that is designed to significantly expand existing work on accelerated iTBS.
The novel CoMPACT protocol utilizes high frequency bursts to produce a strong "acceleration" effect, securing therapeutic efficacy and clinical feasibility.
The COMPACT protocol consists of five iTBS sessions per day (rather than 10 sessions per day as given in the "SAINT" protocol) over five consecutive days to increase feasibility. In addition to accelerated iTBS of left DLPFC, the invetigators will test clinical efficacy of a novel parietal target, the left IPL. The investigators hypothesize that accelerated iTBS of the area in left IPL that shows a strong negative functional connectivity with the sgACC will be also highly effective in treating TRD compared to the accelerated sham protocol.
Anatomically guided personalized targeting and dosing will be based on E-field modeling informed by the individual cortical anatomy revealed by the patient's structural brain MRI.
Patients with TRD are recruited from psychiatric departments in Copenhagen. Information material with contact details for the project will be available in waiting rooms at the outpatient clinics so that potential participants can contact the project themselves. Furthermore, we will recruit by advertising via Trialtree.dk After inclusion, participants will undergo a baseline assessment (T0) that includes evaluating depression severity and several widely used psychiatric rating scales measuring anhedonia, cognitive deficits, and treatment-related adverse effects. A list of the tests included can be found in the "Outcome" section.
Within two weeks after T0, patients will undergo 5 days of active iTBS targeting either the left DLPFC or the left IPL, or a sham intervention on the left DLPFC or IPL, for a total of 25 sessions. During the first and last day of intervention week, EEG will be used recorded before, during and after first and last iTBS sessions. This helps to investigate acute changes in the cortical activity patterns induced by a single iTBS and the cumulative functional effects on cortical activity caused by the CoMPACT protocol.
Moreover, EEG response to a single and multi TMS pulse, so-called transcranial evoked potentials (TEPs), will be measured before and after iTBS session. This will allow us to explore how high-frequency burst iTBS modulates cortical excitation and inhibition in targeted regions and its potential correlation with clinical response. Online EEG monitoring during iTBS will be performed can also be used to document safety and capture brain activity during the periods separating consecutive iTBS trains.
The antidepressive effects of the intervention (Hamilton Depression Rating Scale as primary outcome) will be assessed, within 3 days after the last session. The rest of the clinical tests will be performed within 5 days after end of treatment (T1). The long-term effect on symptom of depression and other clinical effect will be tested after 4 weeks (T2) and at potential 6 months follow-up.
Assessments at T0 and T1 will also include structural (T1 and T2 weighted sequences), diffusion sensitive MRI, resting-state, and task-based functional MRI (fMRI). Task-related fMRI will reveal how the active CoMPACT intervention modifies brain activity and connectivity within key brain networks compared to sham COMPACT. Cognitive performance will be also probed using a selected set of cognitive tests at T0, T1 and T2.Referral to standard TMS therapy for non-responders:
If patients have not entered remission (i.e. a score less than 7 on HDS-17) immediately after the end of COMPACT treatment or at visit T1, they will be offered standard TMS treatment. A treatment that is approved for general clinical use in psychiatric wards and elsewhere.
Data will be collected at the participating sites in the Capital Region of Denmark (RegionH). After end of trial and final data analysis, anonymized trial-related data and methods will be made available to other researchers through public databases after publication of the main clinical outcome paper in accordance with Danish law.
