Deep-brain stimulation of the nucleus accumbens in obsessive compulsive disorder: clinical, surgical and electrophysiological considerations in two consecutive patients

Franzini, A., Messina, G., Gambini, O., Muffatti, R., Scarone, S., Cordella, R., & Broggi, G. (2010). Deep-brain stimulation of the nucleus accumbens in obsessive compulsive disorder: clinical, surgical and electrophysiological considerations in two consecutive patients. Neurological Sciences, 31(3), 353-359. doi:10.1007/s10072-009-0214-8

The purpose of this study was to determine the effectiveness of deep brain stimulation (DBS) in treating obsessive compulsive disorder (OCD). OCD is a condition that can impair function socially, cognitively, and interpersonally. Some cases of OCD are extremely severe and are also resistant to drugs. In this study the nucleus accumbens was stimulated in order to help localize the target. In the past electrical brain stimulation was used to treat behavioral disorders and in conditions in which chronic pain was prevalent. DBS became accepted after it was used to treat Parkinson’s disease and other movement disorders. For this study twenty-two patients were evaluated over a period of time in order to determine if they met the criteria in order to receive DBS surgery. The inclusion criteria was as follows: “severe chronic form of treatment-resistant OCD with duration of illness of at least 5 years without remission. Treatments with maximum tolerate dose of at least four out of clomipramine, fluvoxamine, sertraline, paroxetine, fluoxetine for at least 3 months, augmentation strategies with at least two out of lithium, clonazepam, atypical antipsychotics, ECT; psychotherapy simultaneously with pharmacotherapy. A Yale Brown Obsessive Compulsive Scale (Y-BOCS) score of  >30/40 and a Global Assessment of Functioning (GAF) Score less than 45 as an index of OCD severity were required to consider the option of surgical therapy.” Three of the patients met the criteria, but two of them agreed to have the DBS surgery. Both of these patients, Patient 1 and Patient 2, were male. Patient one was a 33 year old who had been suffering from OCD since he was 16 years of age. Patient 2 was a 41 year old who had been suffering from OCD since he was 15 years of age.

After the procedure was fully explained, the patients gave their consent for the surgical procedure. The researchers obtained MRI brain images along with T1, T2 and IR brain images before the operation began. In order to locate the coordinates of the nucleus acucumbens a Leksell G frame and a CT scan were used together and compared. On each side, 3.5 cm lateral to the midline, two coronal burr holes were made and then a cannula was inserted through the holes 10mm from the target. The cannula was used to guide the placement for the electrode. Two pulse generators were implanted into the subclavian region for both patients. In order to confirm that the electrodes were positioned correctly, a CT scan was merged with a brain MR scan. The results showed, after a 2 year follow up that both patients slowly improved in their obsessive-compulsive symptoms and in their abilities to function. Patient 1’s improvement mostly came after the first year of stimulation and then remained stable while  Patient 2’s improvement came after 22 months.