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

Deep brain stimulation in the ALIC-BNST region targeting the bed nucleus of stria terminalis in patients with obsessive-compulsive disorder: effects on cognition after 12 months

PURPOSE

The aim of this study was to evaluate cognitive effects 12 months after Deep Brain Stimulation (DBS) of the Bed Nucleus of Stria Terminalis (BNST) in patients with refractory Obsessive-Compulsive Disorder (OCD).

METHODS

Eight patients (5 female; mean ± SD age 36 ± 15) with OCD were included. A neuropsychological test battery covering verbal and spatial episodic memory, executive function, and attention was administered preoperatively and 12 months after surgery. Medical records were used as a source for descriptive data to probe for any changes not covered by standardized checklists and the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), the primary outcome measure.

RESULTS

At 12 months, seven patients showed response to DBS: three were full responders (i.e., Y-BOCS ≥ 35% improvement), and four were partial responders (Y-BOCS 25-34% improvement). Relative to baseline, there was a slight decline on visuo-spatial learning (p = 0.027), and improved performance on the Color-Word Interference inhibition/switching subtest (p = 0.041), suggesting improvement in cognitive flexibility.

CONCLUSIONS

DBS in the BNST for treatment refractory OCD generates very few adverse cognitive effects and improves cognitive flexibility after 12 months of stimulation. The improvement in Y-BOCS and the absence of major cognitive side effects support the BNST as a potential target for DBS in severe OCD.

A brain network for deep brain stimulation induced cognitive decline in Parkinson's disease

Deep brain stimulation is an effective treatment for Parkinson's disease but can be complicated by side-effects such as cognitive decline. There is often a delay before this side-effect is apparent and the mechanism is unknown, making it difficult to identify patients at risk or select appropriate deep brain stimulation settings. Here, we test whether connectivity between the stimulation site and other brain regions is associated with cognitive decline following deep brain stimulation. First, we studied a unique patient cohort with cognitive decline following subthalamic deep brain stimulation for Parkinson's disease (n = 10) where reprogramming relieved the side-effect without loss of motor benefit. Using resting state functional connectivity data from a large normative cohort (n = 1000), we computed connectivity between each stimulation site and the subiculum, an a priori brain region functionally connected to brain lesions causing memory impairment. Connectivity between deep brain stimulation sites and this same subiculum region was significantly associated with deep brain stimulation induced cognitive decline (P < 0.02). We next performed a data-driven analysis to identify connections most associated with deep brain stimulation induced cognitive decline. Deep brain stimulation sites causing cognitive decline (versus those that did not) were more connected to the anterior cingulate, caudate nucleus, hippocampus, and cognitive regions of the cerebellum (PFWE < 0.05). The spatial topography of this deep brain stimulation-based circuit for cognitive decline aligned with an a priori lesion-based circuit for memory impairment (P = 0.017). To begin translating these results into a clinical tool that might be used for deep brain stimulation programming, we generated a 'heat map' in which the intensity of each voxel reflects the connectivity to our cognitive decline circuit. We then validated this heat map using an independent dataset of Parkinson's disease patients in which cognitive performance was measured following subthalamic deep brain stimulation (n = 33). Intersection of deep brain stimulation sites with our heat map was correlated with changes in the Mattis dementia rating scale 1 year after lead implantation (r = 0.39; P = 0.028). Finally, to illustrate how this heat map might be used in clinical practice, we present a case that was flagged as 'high risk' for cognitive decline based on intersection of the patient's deep brain stimulation site with our heat map. This patient had indeed experienced cognitive decline and our heat map was used to select alternative deep brain stimulation parameters. At 14 days follow-up the patient's cognition improved without loss of motor benefit. These results lend insight into the mechanism of deep brain stimulation induced cognitive decline and suggest that connectivity-based heat maps may help identify patients at risk and who might benefit from deep brain stimulation reprogramming.

Psychopathological and neuropsychological outcomes of deep brain stimulation for severe- treatment-resistant obsessive-compulsive disorder: An open-label case series

OBJECTIVE

Deep brain stimulation (DBS) is considered a promising intervention for treatment-resistant obsessive-compulsive disorder (OCD). The present study describes the outcomes of the first DBS procedures for OCD in Iran.

METHODS

Four women patients (age range, 25-35 years) with severe OCD meeting stringent criteria for refractoriness to treatment were selected by Psychosurgery Review Board. DBS electrodes were bilaterally implanted in the internal capsule and nucleus accumbens (NAc). Clinical and neuropsychological assessments were undertaken before and after implantation. The outcomes included Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Hamilton Anxiety Rating Scale (HAM-A), neuropsychological assessments including the Wisconsin Card Sorting Test, Wechsler Memory Scale, and adverse events.

RESULTS

The baseline mean score of the Y-BOCS and HAM-A was 32 ± 6 and 23 ± 14 respectively and decreased to 26 ± 8 and 17 ± 9 after one-year implantation, showing a 19% improvement. Two patients were responders and showed a notable improvement. One patient's score declined 28%, who was not satisfied with DBS results, and one patient worsened under-stimulation. Improvements in the severity of anxiety and cognitive performance were consistent with OCD improvement, and the successfully treated patients showed improvement in anxiety and cognitive performance. No significant cognitive declines were seen. Two patients' suicidal ideation appeared after DBS as an important adverse event.

CONCLUSION

Bilateral DBS of the internal capsule/NAc may be an effective and safe treatment for treatment-refractory OCD. However, there is a need to consider accessibility, high cost, cost-effectiveness, and standardized methodology in future research.