Pepijn van den Munckhof

Deep Brain Stimulation of the Nucleus Accumbens for Treatment-Refractory Obsessive-Compulsive Disorder

CONTEXT Obsessive-compulsive disorder (OCD) is a chronic psychiatric disorder that affects 2% of the general population. Even when the best available treatments are applied, approximately 10% of patients remain severely afflicted and run a long-term deteriorating course of OCD. OBJECTIVE To determine whether bilateral deep brain stimulation of the nucleus accumbens is an effective and safe treatment for treatment-refractory OCD. DESIGN The study consisted of an open 8-month treatment phase, followed by a double-blind crossover phase with randomly assigned 2-week periods of active or sham stimulation, ending with an open 12-month maintenance phase. SETTING Academic research. Patients Sixteen patients (age range, 18-65 years) with OCD according to DSM-IV criteria meeting stringent criteria for refractoriness to treatment were included in the study. INTERVENTIONS Treatment with bilateral deep brain stimulation of the nucleus accumbens. MAIN OUTCOME MEASURES Primary efficacy was assessed by score change from baseline on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Responders were defined by a score decrease of at least 35% on the Y-BOCS. RESULTS In the open phase, the mean (SD) Y-BOCS score decreased by 46%, from 33.7 (3.6) at baseline to 18.0 (11.4) after 8 months (P < .001). Nine of 16 patients were responders, with a mean (SD) Y-BOCS score decrease of 23.7 (7.0), or 72%. In the double-blind, sham-controlled phase (n = 14), the mean (SD) Y-BOCS score difference between active and sham stimulation was 8.3 (2.3), or 25% (P = .004). Depression and anxiety decreased significantly. Except for mild forgetfulness and word-finding problems, no permanent adverse events were reported. CONCLUSION Bilateral deep brain stimulation of the nucleus accumbens may be an effective and safe treatment for treatment-refractory OCD. CLINICAL TRIAL REGISTRATION isrctn.org Identifier: ISRCTN23255677.

Subthalamic nucleus versus globus pallidus bilateral deep brain stimulation for advanced Parkinson's disease (NSTAPS study): a randomised controlled trial

BACKGROUND Patients with advanced Parkinsons disease often have rapid swings between mobility and immobility, and many respond unsatisfactorily to adjustments in pharmacological treatment. We assessed whether globus pallidus pars interna (GPi) deep brain stimulation (DBS) gives greater functional improvement than does subthalamic nucleus (STN) DBS. METHODS We recruited patients from five centres in the Netherlands who were aged 18 years or older, had idiopathic Parkinsons disease, and had, despite optimum pharmacological treatment, at least one of the following symptoms: severe response fluctuations, dyskinesias, painful dystonias, or bradykinesia. By use of a computer-generated randomisation sequence, we randomly assigned patients to receive either GPi DBS or STN DBS (1:1), applying a minimisation procedure according to drug use (levodopa equivalent dose <1000 mg vs ≥1000 mg) and treatment centre. Patients and study assessors (but not those who assessed adverse events) were masked to treatment allocation. We had two primary outcomes: functional health as measured by the weighted Academic Medical Center Linear Disability Scale (ALDS; weighted by time spent in the off phase and on phase) and a composite score for cognitive, mood, and behavioural effects up to 1 year after surgery. Secondary outcomes were symptom scales, activities of daily living scales, a quality-of-life questionnaire, the occurrence of adverse events, and drug use. We used the intention-to-treat principle for all analyses. This trial is registered with www.controlled-trials.com, number ISRCTN85542074. FINDINGS Between Feb 1, 2007, and March 29, 2011, we enrolled 128 patients, assigning 65 to GPi DBS and 63 to STN DBS. We found no statistically significant difference in either of our primary outcomes: mean change in weighted ALDS (3·0 [SD 14·5] in the GPi group vs 7·7 [23·2] in the STN group; p=0·28) and the number of patients with cognitive, mood, and behavioural side-effects (36 [58%] of 62 patients in the GPi group vs 35 [56%] of 63 patients in the STN group; p=0·94). Secondary outcomes showed larger improvements in off-drug phase in the STN group compared with the GPi group in the mean change in unified Parkinsons disease rating scale motor examination scores (20·3 [16·3] vs 11·4 [16·1]; p=0·03), the mean change in ALDS scores (20·3 [27·1] vs 11·8 [18·9]; p=0·04), and medication (mean levodopa equivalent drug reduction: 546 [SD 561] vs 208 [521]; p=0·01). We recorded no difference in the occurrence of adverse events between the two groups. Other secondary endpoints showed no difference between the groups. INTERPRETATION Although there was no difference in our primary outcomes, our findings suggest that STN could be the preferred target for DBS in patients with advanced Parkinsons disease. FUNDING Stichting Internationaal Parkinson Fonds, Prinses Beatrix Fonds, and Parkinson Vereniging.

Deep brain stimulation restores frontostriatal network activity in obsessive-compulsive disorder

Little is known about the underlying neural mechanism of deep brain stimulation (DBS). We found that DBS targeted at the nucleus accumbens (NAc) normalized NAc activity, reduced excessive connectivity between the NAc and prefrontal cortex, and decreased frontal low-frequency oscillations during symptom provocation in patients with obsessive-compulsive disorder. Our findings suggest that DBS is able to reduce maladaptive activity and connectivity of the stimulated region.

Current Status of Deep Brain Stimulation for Obsessive-Compulsive Disorder: A Clinical Review of Different Targets

Obsessive-compulsive disorder (OCD) is a chronic psychiatric disorder that affects 2% of the general population. Despite optimal cognitive-behavioral and pharmacologic therapy, approximately 10% of patients remain treatment resistant. Currently, deep brain stimulation (DBS) is being investigated as an experimental therapy for treatment-refractory OCD. This review focuses on the efficacy and adverse events of all published DBS targets for OCD: anterior limb of the internal capsule, ventral striatum/ventral capsule, nucleus accumbens, nucleus subthalamicus, and inferior thalamic peduncle. Small studies with various designs indicate an overall average Yale-Brown Obsessive Compulsive Scale score decrease ranging from 6.8 to 31 points. The average overall responder rate is ±50%. The frequency of adverse events seems to be limited. Larger prospective studies including neuroimaging are needed to estimate adequately the true potential of DBS in treatment of OCD and to elucidate its underlying mechanism of action and optimal brain target. We conclude that DBS may be a promising and safe therapy for treatment-resistant OCD.

Directional steering: A novel approach to deep brain stimulation.

Objective: The aim of this study was to investigate whether directional steering through a novel 32-contact electrode is safe and can modulate the thresholds for beneficial and side effects of stimulation. Methods: The study is a single-center, performance and safety study. Double-blind intraoperative evaluations of the thresholds for therapeutic benefit and for side effects were performed in 8 patients with Parkinson disease while stimulating in randomized order in spherical mode and in 4 different steering modes with the 32-contact electrode, and in monopolar mode with a commercial electrode. In addition, simultaneous recordings of local field potentials through all 32 contacts were performed. Results: There were no adverse events related to the experimental device. For 13 of 15 side effects (87%), the threshold could be increased by ≥1 mA while steering in at least one direction in comparison to conventional spherical stimulation, thereby increasing the therapeutic window by up to 1.5 mA. Recording local field potentials through all 32 electrode contacts yielded spatiotemporal information on pathologic neuronal activity. Conclusions: Controlled steering of current through the brain may improve the effectiveness of deep brain stimulation (DBS), allow for novel applications, and provide a tool to better explore pathophysiologic activity in the brain. Classification of evidence: This study provides Class IV evidence that for patients with Parkinson disease, steering DBS current is well tolerated, increases the threshold for side effects, and may improve the therapeutic window of subthalamic nucleus DBS as compared with current standard spherical stimulation.

Top-down-directed synchrony from medial frontal cortex to nucleus accumbens during reward anticipation

The nucleus accumbens and medial frontal cortex (MFC) are part of a loop involved in modulating behavior according to anticipated rewards. However, the precise temporal landscape of their electrophysiological interactions in humans remains unknown because it is not possible to record neural activity from the nucleus accumbens using noninvasive techniques. We recorded electrophysiological activity simultaneously from the nucleus accumbens and cortex (via surface EEG) in humans who had electrodes implanted as part of deep‐brain‐stimulation treatment for obsessive–compulsive disorder. Patients performed a simple reward motivation task previously shown to activate the ventral striatum. Spectral Granger causality analyses were applied to dissociate “top–down” (cortex → nucleus accumbens)‐ from “bottom–up” (nucleus accumbens → cortex)‐directed synchronization (functional connectivity). “Top–down”‐directed synchrony from cortex to nucleus accumbens was maximal over medial frontal sites and was significantly stronger when rewards were anticipated. These findings provide direct electrophysiological evidence for a role of the MFC in modulating nucleus accumbens reward‐related processing and may be relevant to understanding the mechanisms of deep‐brain stimulation and its beneficial effects on psychiatric conditions. Hum Brain Mapp, 2012.

Deep Brain Stimulation Induces Striatal Dopamine Release in Obsessive-Compulsive Disorder

BACKGROUND Obsessive-compulsive disorder is a chronic psychiatric disorder related to dysfunctional dopaminergic neurotransmission. Deep brain stimulation (DBS) targeted at the nucleus accumbens (NAc) has recently become an effective treatment for therapy-refractory obsessive-compulsive disorder, but its effect on dopaminergic transmission is unknown. METHODS We measured the effects of NAc DBS in 15 patients on the dopamine D2/3 receptor availability in the striatum with [(123)I]iodobenzamide ([(123)I]IBZM) single photon emission computed tomography. We correlated changes in [(123)I]IBZM binding potential (BP) with plasma levels of homovanillic acid (HVA) and clinical symptoms. RESULTS Acute (1-hour) and chronic (1-year) DBS decreased striatal [(123)I]IBZM BP compared with the nonstimulated condition in the putamen. BP decreases were observed after 1 hour of stimulation, and chronic stimulation was related to concurrent HVA plasma elevations, implying DBS-induced dopamine release. BP decreases in the area directly surrounding the electrodes were significantly correlated with changes in clinical symptoms (45% symptom decrease). CONCLUSIONS NAc DBS induced striatal dopamine release, which was associated with increased HVA plasma levels and improved clinical symptoms, suggesting that DBS may compensate for a defective dopaminergic system.

Deep Brain Stimulation of the Ventral Anterior Limb of the Internal Capsule for Treatment-Resistant Depression: A Randomized Clinical Trial.

IMPORTANCE Patients with treatment-resistant depression (TRD) do not respond sufficiently to several consecutive treatments for major depressive disorder. Deep brain stimulation (DBS) is a promising treatment for these patients, but presently placebo effects cannot be ruled out. OBJECTIVE To assess the efficacy of DBS of the ventral anterior limb of the internal capsule (vALIC), controlling for placebo effects with active and sham stimulation phases. DESIGN, SETTING, AND PARTICIPANTS Twenty-five patients with TRD from 2 hospitals in the Netherlands were enrolled between March 22, 2010, and May 8, 2014. Patients first entered a 52-week open-label trial during which they received bilateral implants of 4 contact electrodes followed by optimization of DBS until a stable response was achieved. A randomized, double-blind, 12-week crossover phase was then conducted with patients receiving active treatment followed by sham or vice versa. Response and nonresponse to treatment were determined using intention-to-treat analyses. INTERVENTIONS Deep brain stimulation targeted to the vALIC. MAIN OUTCOMES AND MEASURES The change in the investigator-rated score of the 17-item Hamilton Depression Rating Scale (HAM-D-17) was the main outcome used in analysis of the optimization phase. The primary outcome of the crossover phase was the difference in the HAM-D-17 scores between active and sham DBS. The score range of this tool is 0 to 52, with higher scores representing more severe symptoms. Patients were classified as responders to treatment (≥50% decrease of the HAM-D-17 score compared with baseline) and partial responders (≥25 but <50% decrease of the HAM-D-17 score). RESULTS Of 25 patients included in the study, 8 (32%) were men; the mean (SD) age at inclusion was 53.2 (8.4) years. Mean HAM-D-17 scores decreased from 22.2 (95% CI, 20.3-24.1) at baseline to 15.9 (95% CI, 12.3-19.5) (P = .001), Montgomery-Åsberg Depression Rating Scale scores from 34.0 (95% CI, 31.8-36.3) to 23.8 (95% CI, 18.4-29.1) (P < .001), and Inventory of Depressive Symptomatology-Self-report scores from from 49.3 (95% CI, 45.4-53.2) to 38.8 (95% CI, 31.6-46.0) (P = .005) in the optimization phase. Following the optimization phase, which lasted 51.6 (22.0) weeks, 10 patients (40%) were classified as responders and 15 individuals (60%) as nonresponders. Sixteen patients entered the randomized crossover phase (9 responders [56%], 7 nonresponders [44%]). During active DBS, patients scored significantly lower on the HAM-D-17 scale (13.6 [95% CI, 9.8-17.4]) than during sham DBS (23.1 [95% CI, 20.6-25.6]) (P < .001). Serious adverse events included severe nausea during surgery (1 patient), suicide attempt (4 patients), and suicidal ideation (2 patients). CONCLUSIONS AND RELEVANCE Deep brain stimulation of the vALIC resulted in a significant decrease of depressive symptoms in 10 of 25 patients and was tolerated well. The randomized crossover design corroborates that vALIC DBS causes symptom reduction rather than sham. TRIAL REGISTRATION trialregister.nl Identifier: NTR2118.

Deep brain stimulation for obsessive–compulsive disorders: long-term analysis of quality of life

Objective To evaluate the long-term effects of deep brain stimulation (DBS) on quality of life (QOL) in therapy-refractory obsessive–compulsive disorder (OCD) patients. Design 16 patients who met Diagnostic and Statistical Manual of Mental Disorders (4th ed) (DSM-IV) criteria for OCD and were considered therapy-refractory were treated with DBS. Patients were assessed 1 month before device implantation (T0), at 8 months of active stimulation (T1) and at 3–5 years of active stimulation (T2). QOL was measured with the WHO Quality of Life Scale-Brief Version (WHOQOL-BREF) that covers physical, psychological, social and environmental domains. The study was conducted between April 2005 and January 2011 at the Academic Medical Center, Amsterdam, The Netherlands. Results At T1 and T2, we found significant improvement (p<0.05) in the general score and in the physical, psychological and environmental domains of WHOQOL-BREF. Between T1 and T2, the physical and psychological domains improved further (p<0.05). At T2, the general score improved by a total of 90%, the physical and psychological domains both improved by 39.5% and the environmental domain improved by 16%. The social domain did not change between baseline and follow-up assessments. Conclusions In line with symptom improvement, patients QOL improved in the general score and in three of the four WHOQOL-BREF domains. This suggests that the improvement caused by DBS is not limited to symptom reduction alone, but also has a positive influence on patients’ perception of their physical, psychological, environmental and global QOL. Clinical trial registration http://isrctn.org identifier: ISRCTN23255677.

GPi vs STN deep brain stimulation for Parkinson disease: Three-year follow-up

Objective: To compare motor symptoms, cognition, mood, and behavior 3 years after deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and subthalamic nucleus (STN) in advanced Parkinson disease (PD). Methods: Patients with PD eligible for DBS were randomized to bilateral GPi DBS and bilateral STN DBS (1:1). The primary outcome measures were (1) improvement in motor symptoms in off-drug phase measured with the Unified Parkinson Disease Rating Scale (UPDRS) and (2) a composite score for cognitive, mood, and behavioral effects, and inability to complete follow-up at 36 months after surgery. Results: Of the 128 patients enrolled, 90 were able to complete the 3-year follow-up. We found significantly more improvement of motor symptoms after STN DBS (median [interquartile range (IQR)] at 3 years, GPi 33 [23–41], STN 28 [20–36], p = 0.04). No between-group differences were observed on the composite score (GPi 83%, STN 86%). Secondary outcomes showed larger improvement in off-drug functioning in the AMC Linear Disability Scale score after STN DBS (mean ± SD, GPi 65.2 ± 20.1, STN 72.6 ± 18.0, p = 0.05). Medication was reduced more after STN DBS (median levodopa equivalent dose [IQR] at 3 years, GPi 1,060 [657–1,860], STN 605 [411–875], p < 0.001). No differences in adverse effects were recorded, apart from more reoperations to a different target after GPi DBS (GPi n = 8, STN n = 1). Conclusions: Off-drug phase motor symptoms and functioning improve more after STN DBS than after GPi DBS. No between-group differences were observed on a composite score for cognition, mood, and behavior, and the inability to participate in follow-up. Classification of evidence: This study provides Class II evidence that STN DBS provides more off-phase motor improvement than GPi DBS, but with a similar risk for cognitive, mood, and behavioral complications.