Stereotactic neurosurgical lesions in a variety of brain sites have proved helpful for many patients who remain disabled with Obsessive Compulsive Disorder (OCD) in spite of conventional therapies. Some studies suggest that lesions in the anterior limbs of the internal capsules (anterior capsulotomy) may be the most effective of these procedures. Stereotactic lesions in the nucleus ventralis intermedius (VIM) of the thalamus are beneficial in the treatment of tremors which do not respond to medical therapy. For these disorders, electrical simulation in the would-be lesion site has proved equally effective. This suggests that electrical stimulation might also be a viable substitute for surgical lesions in OCD. If so, this would be preferable for a number of reasons. Although adverse effects of neurosurgical therapy of OCD are minimal, irreversible destruction of brain tissue does occur at the site of the lesions, and, in addition we have found postoperative increase in third ventricle volume as well as reduction in volume of several cell body nuclei, including thalamus, caudate nuclei, and (in 2 of 5 subjects) hippocampi. Subtle memory difficulties have also been noted in some patients. In contrast, any changes due to electrical stimulation are completely reversible on discontinuation of the stimulation. We propose a pilot study to determine whether more extensive studies are warranted to test the safety and effectiveness of deep brain stimulation (DBS) as a substitute for anterior capsulotomy and, if so, to begin determining optimal stimulation parameters. Subjects will be five patients with OCD refractory to established therapies, who would otherwise be candidates for anterior capsulotomy. After preoperative diagnostic and baseline studies, an electrode array will be placed stereotactically in the anterior limb of each internal capsule and connected to a subcutaneous pulse generator. After surgery the DBS system will be tested in-hospital """"""""open label"""""""" to assess for side effects and complications, to identify possible immediate therapeutic effects, and to search for optimum stimulation parameters. Subsequently, as outpatients, each patient will undergo alternating periods of several weeks each, in which stimulation will alternately be turned on and off in a double blind design in order to verify any apparent benefits and to test for possible benefits of prolong stimulation. Symptom severity and impairment scores will be given the choice of continued stimulation, anterior capsulotomy, or further conventional therapy. If DBS proves effective, future studies combining it with imaging and other studies may shed additional light on the mechanisms of OCD. Analogous studies of the effectiveness of DBS at other common lesion sites would also be indicated, as would assessment of the effectiveness of DBS for other psychiatric disorders for which stereotactic lesions are helpful.
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