TABLE 1.
Summary of Studies from Systematic Review
| Author | Study design (number of patients) | Follow-up (mo) | DBS target | Major findings | Level of Evidence | GRADECategory |
|---|---|---|---|---|---|---|
| Luyten 201630 | Double-blind RCT with cross-over (24) | 48-171 | BNST/ALIC | BNST/ALIC stimulation is safe and significantly decreased obsessions, compulsions, and associated anxiety and depressive symptoms, and improves global functioning in a blinded crossover trial (n = 17), after 4 yr (n = 18), and at last follow-up (up to 171 mo, n = 24). Only 17 of 24 patients participated in the randomized phase. | II | High |
| Mallet 200848 | Multicenter double-blind RCT with crossover (17) | 10 | STN | STN DBS had significantly lower Y-BOCS (19 ± 8 vs 28 ± 7; P = .01) and higher GAF (56 ± 14 vs 43 ± 8, P = .005) compared to sham. Depression and anxiety were not modified by stimulation. | I | High |
| Polosan 201949 | Double-blind RCT (10) | 5-71 | STN | Patients underwent double-blind, randomized on and off STN DBS and degrees of valence and arousal were assessed in response to images. STN stimulation increased positive ratings and decreased negative ratings. Postoperative Y-BOCS baseline scores at the time of the study were reduced by 41% ± 28% in this population when compared to preoperative scores. | III | High |
| Barcia 201834 | Double-blind RCT (7) | 3 | NAc (contacts 0-1) Caudate (contacts 2-3) | Six patients were responders, with median 50% symptomatic reduction from each patient's best contact; located at the caudate in 4 cases and NAc in 2 cases. The locus for best contact correlated with an index derived by combining fMRI responses to prevailing symptom provocation and prefronto-cortico-striatal projections defined by probabilistic tractography. | II | High |
| Tyagi 201928 | Double-blinded RCT (6) | 9 | STN or VC/VS | DBS at each site significantly and equivalently reduced OCD symptoms with little additional gain following combined stimulation. Anteromedial STN significantly improved cognitive flexibility, whereas VC/VS had a greater effect on mood. There was no further improvement following CBT, reflecting a floor effect of DBS on OCD. | III | High |
| Abelson 200546 | Double-blind RCT (4) | 7 | ALIC/NAc | The patients underwent a 12-wk double-blind testing phase consisting of 4 consecutive 3-wk blocks of randomized on-off stimulation (2 off, 2 on in a randomized order), followed by an open-ended, open-label stimulation period. One of four patients achieved significant improvement in symptoms during the double-blind phase, and an additional patient achieved significant improvement during the open phase. | III | High |
| Denys 201029 | Randomized, double-blind, cross-over study (16) | 21 | NAc | In the open phase, Y-BOCS decreased by 46%, from 33.7 ± 3.6 at baseline to 18.0 ± 11.4 after 8 mo (P = .001). 9/16 patients were responders, with Y-BOCS decrease of 23.7 ± 7.0 (72%). In the double-blind, sham-controlled phase (n = 14), Y-BOCS difference between active and sham was 8.3 ± 2.3 (25%; P = .004). Depression and anxiety decreased significantly. | II | High |
| Goodman 20101 | Randomized, double-blind, staggered-onset pilot study (6) | 12 | Ventral ALIC and VC | At 12 mo, 4 of 6 (66.7%) were found to be responders. Patients did not improve during sham. Depressive symptoms improved significantly in the group overall; global functioning improved in the 4 responders. Stimulation interruption led to rapid but reversible induction of depressive symptoms in 2 cases. | III | High |
| Tsai 201433 | Double-blind prospective observational study (4) | 15 | VC/VS | At 15 mo, there was a 33.06% decrease in OCD severity (Y-BOC score 24.3 ± 9.1, P = .001), 32.51% decrease in depression severity (HDRS score 24.5 ± 11.1, P = .005). WAIS-III was 106 at baseline and 102 at 12-mo follow-up. | II | Moderate |
| Greenberg 201041 | Multicenter case series (26) | 96 | VC/VS | Y-BOCS decreased to 20.9 ± 2.4 at 36 mo with improvement apparent by 3 mo (21.0 ± 1.8). On average, there was 12.5 ± 1.4 point decrease between baseline and treatment phases (c2 = 19.59; P < .001). Responder rate increased from 28% at 1 mo (7 of 25) to 61.5% (16 of 26) at last follow-up. Overall, 73% of patients had > 25% Y-BOCS improvement at last follow-up. | III | Moderate |
| Liebrand 201935 | Case series (12) | 12 | Ventral ALIC | Active stimulation of the ventral ALIC closer to the medial forebrain bundle than the anterior thalamic radiation was associated with better treatment outcome. | III | Moderate |
| Hartmann 201637 | Case series (6) | 24 | NAc/ALIC | Two patients were responders, and two partial responders. Modulation of the right anterior middle frontal gyrus was associated with excellent response. In contrast, non-responders showed high activation in the orbital part of the right inferior frontal gyrus. | III | Moderate |
| Lee 201917 | Case series (5) | 12 | ITP | All patients were considered responders at 1 yr (52% Y-BOCS reduction; range 39%-73%) and last follow-up (54% improvement, range 38%-85%). | III | Moderate |
| Roh 201242 | Case series (4) | 24 | Ventral ALIC and VS | All 4 patients were responders with improvement of 59.7 ± 14.6% after 24 mo. At 3 mo, depression decreased ≥ 42% from baseline. At 24 mo, HDRS scores decreased by 50%. | III | Moderate |
| Park 201945 | Case series (4) | 72 | NAc or ALIC | ALIC and NAc were both found to be safe and effective targets for DBS in refractory OCD patient, though NAc was found to be superior in this study. The 2 NAc patients achieved reductions of 93% and 69% in Y-BOCS scores, while the ALIC patients experienced reductions of 55% and 50%. | III | Moderate |
| Nair 201452 | Case series (4) | 4 | Anteromedial GPi | All 4 patients experienced dramatic benefit in their motor and vocal tics. Two patients experienced complete resolution of their OCD symptoms with the other two having > 85% reduction in their OCI scores. | III | Moderate |
| Huff 201043 | Double-blind sham-controlled crossover study (10) | 12 | Unilateral right NAc (contacts 0-1) Ventral ALIC (contacts 2-3) | Y-BOCS decreased significantly from 32.2 ± 4.0 to 25.4 ± 6.7 after 12 mo (P = .012). 5/10 patients showed at least partial response (≥25%) and one had > 35% response. Depression, GAF, and QoL improved within 1 yr. | II | Low |
| Rauch 200632 | Case-control, cross-sectional study (6) | 3 | VC/VS | All six participants had decreased Y-BOCS: 28.4 ± 16.7%. Y-BOCS improvement was not correlated with the magnitude of PET activation | III | Low |
| Greenberg 200618 | Case series (8) | 36 | VC/VS | Y-BOCS decreased from 34.6 ± 0.6 to 22.3 ± 2.1 at 36 mo. 4/8 patients were responders. Two patients had Y-BOCS decline between 25% and 35%. GAF improved from 36.6 ± 1.5 to 53.8 ± 2.5 at 36 mo. Depression, anxiety, self-care, independent living, and work, school, and social functioning also improved. | III | Low |
| Mantione 201538 | Case-control study (16 DBS; 14 controls) | 8 | NAc | In the DBS group, OCD, anxiety and depressive symptoms improved significantly during the open phase. They experienced mean decreases of 15.7 ± 10.8 points on the Y-BOCS, 10.7 ± 8.1 points on the HARS, and 9.0 ± 6.2 points on the HDRS. In the control group (medical management), OCD, anxiety and depressive symptoms remained unchanged. | III | Low |
| Huys 201939 | Case series (20) | 12 | NAc/ALIC | ALIC-NAc DBS significantly decreased OCD symptoms (33% Y-BOCS reduction, 40% full responders) and improved global functioning without loss of efficacy over 1 yr. No significant changes were found in depressive or anxiety symptoms. 35% of patients reported a sudden increase in anxiety and anhedonia after acute cessation of stimulation. | III | Low |
| Farrand 201844 | Case series (7) | 31 (range: 8-54) | NAc or BNST | All patients showed improvement on symptom severity rating scales. Three responders with other four showing responses between 7% and 20%. | III | Low |
| Jimenez 201350 | Case series (6) | 12 | ITP | ITP DBS decreased Y-BOCS (51%) and increased GAF to 68% (P = .026) at 1 yr. HDRS for the only patient with major depression went from 42 to 6. | III | Low |
| Maarouf 201651 | Case series (3) | 3.7-34.6 | MD/VA | Continuous thalamic stimulation yielded no significant improvement in OCD symptom severity. Over the course of thalamic DBS, only one patient was a partial responder. BDI scores dropped 46% in the de novo group; anxiety symptoms improved by up to 34%. Of note, one patient had follow-up less than 3 mo and was excluded from analysis. | III | Low |
| Gabriels 200336 | Case series (3) | 12 | ALIC | Two patients with Y-BOCS decrease of 12 and 23 points. Total Maladjustment Score on BPRS reduced by 44 and 59%. | III | Low |
| Guehl 200847 | Case series (3) | 12 | Caudate Nucleus | Electrophysiological unit recordings were performed followed by implantation of a chronic DBS electrode in the caudate nucleus of 3 patients. DBS of the caudate nucleus produced a 35% to 60% reduction in Y-BOCS score. The findings of this study suggest that caudate hyperactivity contributes to the manifestation of obsessions. | III | Low |
| Baldermann 201940 | Case series (22) | 12 | NAc/ALIC | After 12 mo, Y-BOCS decreased significantly by 30.4 ± 20.1%. No significant correlation between age at surgery or preoperative baseline symptom severity with clinical outcome. Models of optimal connectivity successfully cross-predicted clinical outcomes. Degree of connectivity between stimulation sites and medial and lateral prefrontal cortices significantly predicted clinical improvement. | III | Very Low |
| Sturm 200312 | Case series (4) | 24-30 | NAc | Significant improvement in OCD and anxiety symptoms in 3 of 4 | III | Very Low |
Randomized controlled trial (RCT); Yale-Brown Obsessive Compulsive Scale (Y-BOCS); Responders (≥35% Y-BOCS reduction); Partial responders (25-35% Y-BOCS reduction); Brief Psychiatric Rating Scale (BPRS); Profile of Mood States (POMS); Hamilton Depression Rating Scale (HDRS); Hamilton Anxiety Rating Scale (HARS); Global Assessment of Functioning (GAF) Scale; Beck Depression Inventory (BDI); State and Trait Anxiety Inventory (STAI); Modular System of Quality of Life (MSLQ); quality of life (QoL); Clinical Global Impression (CGI); Short Form Health Survey (SF-36); Montgomery-Asberg Depression Rating Scale (MADRS); Yale Global Tic Severity Scale (YGTSS); Obsessive Compulsive Inventory (OCI); Wechsler Adult Intelligence Scale-Third Edition (WAIS-III); Montreal Cognitive Assessment (MoCA); Oxford Happiness Questionnaire (OHQ); Warwick-Edinburgh Mental Well-Being Scale (WEMWBS); Sheehan Disability Scale (SDS); HDRS; HAMS; Brown Assessment of Beliefs Scale (BABS).