Bilateral implantation in globus pallidus internus and in subthalamic nucleus in Parkinson's disease.

Introduction. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and of the pars interna of Globus Pallidus (GPi) is used to improve parkinsonian symptoms and attenuate levodopa-induced motor complications in Parkinson's disease (PD) (DBS for PD study group, 2001). It is still not clear what the best anatomic structures to stimulate are or what the physiologic effects of DBS are. Most of the studies regarding DBS for parkinsonian symptoms have been conducted in patients with STN implantation, and these studies reported significant improvement in motor function with a relatively low rate of complication. The large experience of ablative surgery associated with the DBS experience of some groups worldwide indicate that GPi is a possible and very promising target for the management of parkinsonian symptoms. Surgical procedures have become safer and it is now possible, in selected cases, to target both structures in the same patient by means of the stereotactic system, "3P Maranello" (CLS-SRL, Italy). Using this system we were able to evaluate the clinical effects of simultaneous stimulation of both STN and GPi as well as evaluate the effects of isolated stimulation of each target. As it is known that there is a high intersubject variability of DBS, it seems relevant to test all different combinations of DBS in the same patient. Methods. We assessed the effects of DBS in 13 cases of PD, immediately after (30 min) stimulation and during chronic stimulation (weeks or months). Patients fell into two groups. The first (n = 7) responded to both GPi and STN stimulation equally. The second group (n = 6) was preferentially stimulated with only one target (STN = 5, GPi = 1). Results. There was a good reduction in levodopa treatment following surgery. Most patients remained were chronically treated with bilateral stimulation of both targets. Conclusion. We conclude that DBS of STN and GPi was effective, with most patients treated chronically with both targets stimulated

Theory of mind: A clue for the interpretation of functional movement disorders

Objectives: Functional movement disorders (FMD) refer to a heterogeneous group of manifestations incongruent with known neurological diseases. Functional neuroimaging studies in FMD indicate the overlap between cerebral regions in which abnormal activation occurs and those considered crucial for theory of mind (ToM), the ability to attribute mental states. The aim of this study was to explore whether FMD might be related to ToM disorders to the extent that they reduce the ability to make inferences about the mental states underlying motor behaviour during social interaction. Materials & Methods: Eighteen subjects with FMD and 28 matched healthy controls (HC) were given a ToM battery. The severity of FMD was rated by the Simplified-FMD Rating Scale (S-FMDRS). Dissociative symptoms were evaluated by the Dissociative Experiences Scale (DES-II). Results: FMD scored worse than the HC in most ToM tasks: second-order False Beliefs (p =.005), Faux-Pas Recognition Test (p <.001) and Reading the Mind in the Eyes Test (p =.020); control questions elicited normal scores. The DES-II indicated dissociative-borderline psychopathology and negatively correlated with accuracy on the second-order False Belief (Spearman's rho = −.444; p =.032); the positive correlation between DES-II and severity of motor symptoms (S-FMDRS) approached significance (Spearman's rho test =.392; p =.054). ToM disorders were not correlated with S-FMDRS, due to the typical variability in FMD over time with regard to the severity of symptoms and the district of body involved. Conclusions: Our results are consistent with the hypothesis that FMD are related to ToM deficits, and future studies are needed to define the specific nature of this relationship