The dominant-subthalamic nucleus phenomenon in bilateral deep brain stimulation for Parkinson's disease: Evidence from a gait analysis study

BackgroundIt has been suggested that parkinsonian [Parkinson’s disease (PD)] patients might have a “dominant” (DOM) subthalamic nucleus (STN), whose unilateral electrical stimulation [deep brain stimulation (DBS)] could lead to an improvement in PD symptoms similar to bilateral STN-DBS.ObjectivesSince disability in PD patients is often related to gait problems, in this study, we wanted to investigate in a group of patients bilaterally implanted for STN-DBS: (1) if it was possible to identify a subgroup of subjects with a dominant STN; (2) in the case, if the unilateral stimulation of the dominant STN was capable to improve gait abnormalities, as assessed by instrumented multifactorial gait analysis, similarly to what observed with bilateral stimulation.MethodsWe studied 10 PD patients with bilateral STN-DBS. A clinical evaluation and a kinematic, kinetic, and electromyographic (EMG) analysis of overground walking were performed—off medication—in four conditions: without stimulation, with bilateral stimulation, with unilateral right or left STN-DBS. Through a hierarchical agglomerative cluster analysis based on motor Unified Parkinson’s Disease Rating Scale scores, it was possible to separate patients into two groups, based on the presence (six patients, DOM group) or absence (four patients, NDOM group) of a dominant STN.ResultsIn the DOM group, both bilateral and unilateral stimulation of the dominant STN significantly increased gait speed, stride length, range of motion of lower limb joints, and peaks of moment and power at the ankle joint; moreover, the EMG activation pattern of distal leg muscles was improved. The unilateral stimulation of the non-dominant STN did not produce any significant effect. In the NDOM group, only bilateral stimulation determined a significant improvement of gait parameters.ConclusionIn the DOM group, the effect of unilateral stimulation of the dominant STN determined an improvement of gait parameters similar to bilateral stimulation. The pre-surgical identification of these patients, if possible, could allow to reduce the surgical risks and side effects of DBS adopting a unilateral approach

Development of a laboratory test procedure for the evaluation of potential gaseous emissions of asphalt rubber bituminous mixtures

The superior performance of bituminous mixtures containing crumb rubber from end-of-life tyres has been widely documented from a structural and functional point of view. However, potential impact of the use of crumb rubber on the health of workers in pavement construction sites has been the subject of a limited number of investigations, with a consequent gap in currently available technical knowledge. Following previous research work focused on the chemical analysis of fumes sampled on site, in this paper the Authors present results obtained in the development of a laboratory test procedure for the evaluation of gaseous emissions of asphalt rubber bituminous mixtures in standard, controlled conditions unaffected by site-specific factors. The investigation included monitoring of emissions at the paver's driving seat and at the screed during the laying of gap-and dense-graded wearing course mixtures in three different sites. Laboratory tests were performed by following a fume-generation protocol and by measuring the contents of volatile organic compounds and polycyclic aromatic hydrocarbons in produced emissions. Comparison of results derived from laboratory and field data was carried out in absolute terms and within a carcinogenic risk assessment model. It was found that the proposed laboratory procedure yields emissions which in most cases are similar to those recorded on site at the paver's screed and that lead to a conservative risk estimat

Deep Brain Stimulation of the subthalamic nucleus does not negatively affect social cognitive abilities of patients with Parkinson's disease

Abstract Bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a treatment option for patients with advanced idiopathic PD successful at alleviating disabling motor symptoms. Nevertheless, the effects of STN-DBS on cognitive functions remain controversial and few studies have investigated modification of social cognitive abilities in patients with PD treated with STN-DBS. Here we expanded the typically-investigated spectrum of these abilities by simultaneously examining emotion recognition, and both affective and cognitive Theory of Mind (ToM). By means of a cross-sectional study, 20 patients with PD under dopaminergic replacement therapy, 18 patients with PD treated with STN-DBS, and 20 healthy controls performed the Ekman 60-Faces test, the full version of the Reading the Mind in the Eyes test, and the Protocol for the Attribution of Communicative Intentions. There were no differences between the PD groups (treated and not treated with STN-DBS) on any of the social cognitive tests. Our results suggest that patients with PD who are treated with STN-DBS do not experience detrimental effects on their social cognitive abilities. The present study, the first one examining a wide spectrum of social cognitive abilities after DBS of the STN, suggests that this surgical procedure can be considered safe from this standpoint