Individual white matter bundle trajectories are associated with deep brain stimulation response in obsessive-compulsive disorder

Abstract

Background: The ventral anterior limb of the internal capsule (vALIC) is a target for deep brain stimulation (DBS) in obsessive-compulsive disorder (OCD). Conventional surgical planning is based on anatomical landmarks. Objective/hypothesis: We hypothesized that treatment response depends on the location of the active DBS contacts with respect to individual white matter bundle trajectories. This study thus aimed to elucidate whether vALIC DBS can benefit from bundle-specific targeting. Methods: We performed tractography analysis of two fiber bundles, the anterior thalamic radiation (ATR) and the supero-lateral branch of the medial forebrain bundle (MFB), using diffusion-weighted magnetic resonance imaging (DWI) data. Twelve patients (10 females) who had received bilateral vALIC DBS for at least 12 months were included. We related the change in OCD symptom severity on the Yale-Brown obsessive-compulsive scale (Y-BOCS) between baseline and one-year follow-up with the distances from the active contacts to the ATR and MFB. We further analyzed the relation between treatment response and stimulation sites in standard anatomical space. Results: We found that active stimulation of the vALIC closer to the MFB than the ATR was associated with better treatment outcome (p ¼ 0.04; r 2 ¼ 0.34). In standard space, stimulation sites were largely overlapping between treatment (non)responders, suggesting response is independent of the anatomically defined electrode position. Conclusion: These findings suggest that vALIC DBS for OCD may benefit from MFB-specific implantation and highlight the importance of corticolimbic connections in OCD response to DBS. Prospective investigation is necessary to validate the clinical use of MFB targeting.

Toward a unified connectomic target for deep brain stimulation in obsessive-compulsive disorder

“…This potentially misleading nomenclature of the surgical sl-MFB target has suggested that results in two previous OCD studies would be conflicting, while anatomically, their results agreed. Both studies favored a similarly defined tract within the ALIC, which was referred to as sl-MFB in one study 65 and as anterior thalamic radiation in the second 30 . To readers, this suggested conflicting results while they were actually confirmatory (based on the location of both tracts within the ALIC).…”

Distance to white matter trajectories is associated with treatment response to internal capsule deep brain stimulation in treatment-refractory depression

“…Based on the work on sIMFB stimulation and our previous finding that proximity of stimulation to sIMFB was related to treatment response in OCD ( Liebrand et al, 2019 ), we hypothesize that stimulation more proximal to the slMFB within the ALIC is also beneficial for treatment response in TRD. However, a possible role of the ATR and thalamus cannot be ruled out, given reported structural changes within the thalamus ( Kempton, 2011 ), and hyperactivity of the pulvinar nucleus in MDD patients ( Hamilton et al, 2012 ).…”

The Use of Tractography-Based Targeting in Deep Brain Stimulation for Psychiatric Indications

“…Three recent studies have suggested that the VTApp within ALIC (which may represents the hyperdirect cortical-STN connection), may be a critical fiber tract leading to clinical response in DBS for OCD (Baldermann et al, 2019;Liebrand et al, 2019;Li et al, 2020). ALIC fibers associated with a good outcome have been postulated to run dorsal to the NAc, near the bed nucleus of the stria terminalis, entering the ventral part of the thalamus at the border of the anterior and inferior thalamic peduncle (Baldermann et al, 2019).…”