OCD-bezogene Aktivitätsmodulation während der Nacc/ALIC-Tiefenhirnstimulation

Deep brain stimulation (DBS) is an established therapy for therapy-resistant psychiatric disorders, such as obsessive-compulsive disorder (OCD). Although it is generally recognized that the phenomenology of OCD symptoms is rooted in hyperactivity of the prefrontal cortex, the precise neural correlates are still poorly understood, as are the neurophysiological effects of DBS in OCD. Our aim was to uncover electrophysiological markers of OCD during a paradigm of symptom provocation.

We recorded bipolar local field potential (LFP) data from implanted leads in six patients with OCD who underwent Nucleus accumbens/ Anterior Limb of the Internal Capsule (Nacc/ALIC) DBS, using the Percept PC system. Recordings were performed under a confrontation test condition in which patients were shown patient-adapted pictures with negative-, positive- and neutral-obsession-related content. Afterwards, patients were asked to rate if the picture provoked OCD symptoms and their emotional arousal (from 1 to 5) and the valence (from 1 to 5 – negative vs positive). This paradigm was conducted during active DBS. Afterwards, OCD-related spectral power LFP was calculated.

Our study showed increase in low-frequency power (2-6 Hz) after stimulus onset (i.e., picture) compared to baseline starting, which lasted around 1000 ms. This low power changes is visible for both conditions (negative- and positive obsession-related pictures) and both hemispheres (p<0.05). Nevertheless, the effect is more pronounced for the left hemisphere compared to the right hemisphere. Moreover, there is a difference between symptom-provoking vs symptom-provoking event-related low frequency power only in the left hemisphere, with more increased power for symptomatic negative-obsession-related content pictures.

The present study is the first to report postoperative LFP data acquired with the fully-implanted DBS system Percept PC in Nac/ALIC DBS for OCD patients. Our findings suggest that an increase in low-frequency activity of a broad area in the Nac/ALIC in patients with OCD may contribute to generation of obsessions and possibly eventually the compulsion and anxiety phenomenology. Increased low-frequency activity before the onset of a compulsion might function as an electrophysiological marker for closed-loop DBS for OCD.