Cognitive Outcome After Deep Brain Stimulation for Refractory Obsessive-Compulsive Disorder: A Systematic Review.

INTRODUCTION: Deep brain stimulation (DBS) is an effective treatment for refractory obsessive-compulsive disorder (OCD). Neuropsychological assessment contributes to DBS treatment in several ways: it monitors the cognitive safety of the treatment, identifies beneficial or detrimental cognitive side effects, and it could aid to explain variability in treatment outcome, and possibly the treatment's working mechanism(s). BACKGROUND: This systematic review assessed the cognitive safety of DBS for OCD and explored whether changes in cognitive function may help explain its working mechanism(s). MATERIALS AND METHODS: EMBASE, PubMed/Medline, Psycinfo, and the Cochrane Library were systematically searched for studies reporting cognitive outcomes following DBS for OCD. Searches were completed in November 2020. Included studies were appraised for study design and quality according to National Heart, Lung, and Blood Institute (NHLBI) quality assessment tools. RESULTS: Five randomized controlled trials and ten observational studies comprising a total of 178 patients were analyzed collectively. Variable outcomes of DBS were observed in the domains of attention, memory, executive functioning, and in particular, cognitive flexibility. CONCLUSION: Although individual studies generally do not report cognitive deterioration after DBS for OCD, the variability of study designs and the multitude of cognitive measures used precluded a meta-analysis to confirm its safety and recognition of a cognitive pattern through which the efficacy of DBS for OCD might be explained. In the future, prospective studies should preferably include a standardized neuropsychological assessment battery specifically addressing executive functioning and have a longer-term follow-up in order to demonstrate the cognitive safety of the procedure. Such prospective and more uniform data collection may also contribute to our understanding of the working mechanisms of DBS in OCD.

Surgical and Hardware-Related Adverse Events of Deep Brain Stimulation: A Ten-Year Single-Center Experience.

INTRODUCTION: Although deep brain stimulation (DBS) is effective for treating a number of neurological and psychiatric indications, surgical and hardware-related adverse events (AEs) can occur that affect quality of life. This study aimed to give an overview of the nature and frequency of those AEs in our center and to describe the way they were managed. Furthermore, an attempt was made at identifying possible risk factors for AEs to inform possible future preventive measures. MATERIALS AND METHODS: Patients undergoing DBS-related procedures between January 2011 and July 2020 were retrospectively analyzed to inventory AEs. The mean follow-up time was 43 ± 31 months. Univariate logistic regression analysis was used to assess the predictive value of selected demographic and clinical variables. RESULTS: From January 2011 to July 2020, 508 DBS-related procedures were performed including 201 implantations of brain electrodes in 200 patients and 307 implantable pulse generator (IPG) replacements in 142 patients. Surgical or hardware-related AEs following initial implantation affected 40 of 200 patients (20%) and resolved without permanent sequelae in all instances. The most frequent AEs were surgical site infections (SSIs) (9.95%, 20/201) and wire tethering (2.49%, 5/201), followed by hardware failure (1.99%, 4/201), skin erosion (1.0%, 2/201), pain (0.5%, 1/201), lead migration (0.52%, 2/386 electrode sites), and hematoma (0.52%, 2/386 electrode sites). The overall rate of AEs for IPG replacement was 5.6% (17/305). No surgical, ie, staged or nonstaged, electrode fixation, or patient-related risk factors were identified for SSI or wire tethering. CONCLUSIONS: Major AEs including intracranial surgery-related AEs or AEs requiring surgical removal or revision of hardware are rare. In particular, aggressive treatment is required in SSIs involving multiple sites or when Staphylococcus aureus is identified. For future benchmarking, the development of a uniform reporting system for surgical and hardware-related AEs in DBS surgery would be useful.

Deep brain stimulation of the anterior nucleus of the thalamus for drug-resistant epilepsy.

Despite the use of first-choice anti-epileptic drugs and satisfactory seizure outcome rates after resective epilepsy surgery, a considerable percentage of patients do not become seizure free. ANT-DBS may provide for an alternative treatment option in these patients. This literature review discusses the rationale, mechanism of action, clinical efficacy, safety, and tolerability of ANT-DBS in drug-resistant epilepsy patients. A review using systematic methods of the available literature was performed using relevant databases including Medline, Embase, and the Cochrane Library pertaining to the different aspects ANT-DBS. ANT-DBS for drug-resistant epilepsy is a safe, effective and well-tolerated therapy, where a special emphasis must be given to monitoring and neuropsychological assessment of both depression and memory function. Three patterns of seizure control by ANT-DBS are recognized, of which a delayed stimulation effect may account for an improved long-term response rate. ANT-DBS remotely modulates neuronal network excitability through overriding pathological electrical activity, decrease neuronal cell loss, through immune response inhibition or modulation of neuronal energy metabolism. ANT-DBS is an efficacious treatment modality, even when curative procedures or lesser invasive neuromodulative techniques failed. When compared to VNS, ANT-DBS shows slightly superior treatment response, which urges for direct comparative trials. Based on the available evidence ANT-DBS and VNS therapies are currently both superior compared to non-invasive neuromodulation techniques such as t-VNS and rTMS. Additional in-vivo research is necessary in order to gain more insight into the mechanism of action of ANT-DBS in localization-related epilepsy which will allow for treatment optimization. Randomized clinical studies in search of the optimal target in well-defined epilepsy patient populations, will ultimately allow for optimal patient stratification when applying DBS for drug-resistant patients with epilepsy.

Network analysis in Gamma Knife capsulotomy for intractable obsessive-compulsive disorder.

Introduction: Gamma-knife Ventral Capsulotomy (GVC) has been suggested as an efficacious treatment for a subset of patients with treatment refractory obsessive compulsive disorder (OCD). Research question: The goal of this study was to investigate neural correlates of GVC and investigate the predictive value of white matter tracts that are known to be associated with clinical outcome to Deep Brain Stimulation (DBS). Material and methods: MR images of 8 treatment-refractory OCD patients with a minimum follow-up of 3-years who underwent GVC were used to correlate lesion characteristics with symptom improvement. This exploratory study investigated relations between differences in cortical grey matter structure and subcortical structures before and after GVC for responding and non-responding patients (n â€‹= â€‹6). Normative diffusion MRI- based tractography was used to determine networks associated with successful lesions. Results: The mean total Y-BOCS reduction was 19.6 after three years, resulting in a response rate of 63%.The strongest correlation with symptom improvement was found for a decrease of the left ventral diencephalon volume (r â€‹= â€‹-0.83, p â€‹= â€‹0.039). Discriminative tractography suggest streamlines connecting the prefrontal cortex with the subthalamic nucleus to be associated with clinical response. However, results could not be validated either implicating interpatient anatomical variability or reflecting the relative small sample size as a limitation. Discussion/Conclusion: Taken together, the present study highlights the efficacy of GVC in patients with treatment-refractory OCD. Our results are suggestive of GVC treatment efficacy being mediated by the involvement of a subpart of the ALIC connecting the PFC and the STN.