Manuela Pilleri

Background and purpose: For many years deep brain stimulation (DBS) devices relied only on voltage‐controlled stimulation (CV), but recently current‐controlled devices have been developed and approved for new implants as well as for replacement of CV devices after battery drain. Constant‐current (CC) stimulation has been demonstrated to be effective in new implanted parkinsonian and dystonic patients, but the effect of switching to CC therapy in patients chronically stimulated with CV implantable pulse generators (IPGs) has not been assessed. This report shows the results of a consecutive retrospective data collection performed at five Italian centers before and after replacement of constant‐voltage with constant‐current DBS devices, in order to verify the clinical efficacy and safety of this procedure.Methods: Nineteen patients with Parkinson's disease or dystonic syndrome underwent DBS IPG CV/CC replacement. Clinical features and therapy satisfaction were assessed before surgery, 1 week after and 3 and 6 months after replacement. Programming settings and impedances were recorded before removing the CV device and when the CC IPGs were switched on.Results: The clinical outcome of CC stimulation was similar to that obtained with CV devices and remained stable at 3 and 6 months of follow‐up. Impedance values recorded for CV and CC IPGs were similar. Ninety‐five percent of patients and physicians were satisfied with mixed implants. No adverse events occurred after IPG replacement.Conclusion: Replacing CV with CC IPGs is a safe and effective procedure. Longer follow‐up is necessary to better clarify the impact of CC stimulation on clinical outcome after chronic stimulation in CV mode.

Freezing of gait is a common and disabling disorder in advanced Parkinson’s disease (PD). The relationship with dopaminergic medication is complex and often non-linear, thus freezing may occur even when the core parkinsonian features (tremor, rigidity and bradykinesia) appear optimally controlled. We evaluated the effect of Levodopa–carbidopa intrajejunal gel in a group of seven non-demented PD patients with prominent episodes of freezing refractory to adjustments of oral therapy. Clinical assessments were performed in the best “on” state before starting Levodopa–carbidopa intrajejunal gel, while patients were on their standard oral Levodopa (O-LD), and infusion treatment. The main outcome measures were change in freezing of gait (FOG) Questionnaire and UPDRS motor score. FOG Questionnaire and UPDRS subscores related to gait and postural stability significantly improved during Levodopa–carbidopa intrajejunal gel infusion in all patients compared to O-LD treatment. In four out of seven patients, the Levodopa–carbidopa intrajejunal gel dose was equivalent or slightly higher but in three patients was lower compared to O-LD dose recorded at baseline visit. In selected patients, Levodopa–carbidopa intrajejunal gel may improve freezing refractory to oral dopaminergic therapy.

Previous functional neuroimaging studies in Parkinson's disease (PD) patients with impulse control disorders (ICDs) demonstrated dysfunction of the reward network, although the extent of anatomical changes is unclear. The aim of this study was to measure brain cortical thickness and subcortical volumes, and to assess their relationship with presence and severity of symptoms, in PD patients with and without ICDs. We studied 110 PD patients (N = 58 with ICDs) and 33 healthy controls (all negative for ICDs) who underwent an extensive neurological, neuropsychological, and behavioral assessment as well as structural 1.5 Tesla magnetic resonance imaging (MRI). Between‐group differences in brain cortical thickness and subcortical volumes, assessed with the FreeSurfer 5.1 tool, were analyzed. In patients with ICDs, we found significant cortical thinning in fronto‐striatal circuitry, specifically in the right superior orbitofrontal, left rostral middle frontal, bilateral caudal middle frontal region, and corpus callosum, as well as volume reduction in the right accumbens and increase in the left amygdala. Finally, we observed a positive association relationship between severity of impulsive symptoms and left rostral middle frontal, inferior parietal, and supramarginal areas. These results support the involvement of both reward and response inhibition networks in PD patients with ICDs. Moreover, their severity is associated with alterations in brain regions linked with reward and top‐down control networks. Increased understanding of the mechanisms underlying impulsive and compulsive behaviors might help improve therapeutic strategies for these important disorders. © 2015 International Parkinson and Movement Disorder Society