A brain network for deep brain stimulation induced cognitive decline in Parkinson's disease

Reich et al. show that DBS-induced cognitive decline is associated with connectivity between the stimulation site and a specific brain network implicated in lesion-induced memory impairment. Transforming this network into a heat map can help identify DBS patients at risk of delayed-onset side-effects and guide reprogramming efforts.Deep brain stimulation is an effective treatment for Parkinson's disease but can be complicated by side-effects such as cognitive decline. There is often a delay before this side-effect is apparent and the mechanism is unknown, making it difficult to identify patients at risk or select appropriate deep brain stimulation settings. Here, we test whether connectivity between the stimulation site and other brain regions is associated with cognitive decline following deep brain stimulation. First, we studied a unique patient cohort with cognitive decline following subthalamic deep brain stimulation for Parkinson's disease (n = 10) where reprogramming relieved the side-effect without loss of motor benefit. Using resting state functional connectivity data from a large normative cohort (n = 1000), we computed connectivity between each stimulation site and the subiculum, an a priori brain region functionally connected to brain lesions causing memory impairment. Connectivity between deep brain stimulation sites and this same subiculum region was significantly associated with deep brain stimulation induced cognitive decline (P < 0.02). We next performed a data-driven analysis to identify connections most associated with deep brain stimulation induced cognitive decline. Deep brain stimulation sites causing cognitive decline (versus those that did not) were more connected to the anterior cingulate, caudate nucleus, hippocampus, and cognitive regions of the cerebellum (P-FWE < 0.05). The spatial topography of this deep brain stimulation-based circuit for cognitive decline aligned with an a priori lesion-based circuit for memory impairment (P = 0.017). To begin translating these results into a clinical tool that might be used for deep brain stimulation programming, we generated a 'heatmap' in which the intensity of each voxel reflects the connectivity to our cognitive decline circuit. We then validated this heat map using an independent dataset of Parkinson's disease patients in which cognitive performance was measured following subthalamic deep brain stimulation (n = 33). Intersection of deep brain stimulation sites with our heat map was correlated with changes in the Mattis dementia rating scale 1 year after lead implantation (r = 0.39; P = 0.028). Finally, to illustrate how this heat map might be used in clinical practice, we present a case that was flagged as 'high risk' for cognitive decline based on intersection of the patient's deep brain stimulation site with our heat map. This patient had indeed experienced cognitive decline and our heat map was used to select alternative deep brain stimulation parameters. At 14 days follow-up the patient's cognition improved without loss of motor benefit. These results lend insight into the mechanism of deep brain stimulation induced cognitive decline and suggest that connectivity-based heat maps may help identify patients at risk and who might benefit from deep brain stimulation reprogramming

Prospect of cell therapy for Parkinson's disease

The hallmark of Parkinson's disease is on-going degeneration of dopaminergic neurons in the substantia nigra, which may be due to various etiologies. Various approaches to alleviate symptoms are available, such as life-long pharmacological intervention, deep brain stimulation, and transplantation of dopaminergic neuron-containing fetal tissue. However, each of these approaches has a disadvantage. Several studies have shown that various kinds of stem cells, induced pluripotent stem cells, and other cells can differentiate into dopaminergic neurons and may be promising for treating Parkinson's disease in the future. Therefore, this review addresses those cells in terms of their prospects in cell therapy for Parkinson's disease. In addition, the need for safety and efficacy studies, various cell delivery modes and sites, and possible side effects will be discussed

Management of Severe Asthma: a European Respiratory Society/American Thoracic Society Guideline.

This document provides clinical recommendations for the management of severe asthma. Comprehensive evidence syntheses, including meta-analyses, were performed to summarise all available evidence relevant to the Task Force's questions. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach and the results were summarised in evidence profiles. The evidence syntheses were discussed and recommendations formulated by a multidisciplinary Task Force of asthma experts, who made specific recommendations on 6 specific questions. After considering the balance of desirable and undesirable consequences, quality of evidence, feasibility, and acceptability of various interventions, the Task Force made the following recommendations: 1) Suggest using anti-IL5 and anti IL-5Rα for severe uncontrolled adult eosinophilic asthma phenotypes; 2) suggest using blood eosinophil cut-point of ≥150/μL to guide anti-IL5 initiation in adult patients with severe asthma; and 3) Suggest considering specific eosinophil (≥260/μL) and FeNO (≥19.5 ppb) cutoffs to identify adolescents or adults with the greatest likelihood or response to anti-IgE therapy; 4) Suggest using inhaled tiotropium for adolescents and adults with severe uncontrolled asthma despite GINA step 4-5 or NAEPP step 5 therapies; 5) Suggest a trial of chronic macrolide therapy to reduce asthma exacerbations in persistently symptomatic or uncontrolled patients on GINA step 5 or NAEPP step 5 therapies, irrespective of asthma phenotype; 6) Suggest using anti-IL4/13 for adult patients with severe eosinophilic asthma, and for those with severe corticosteroid-dependent asthma regardless of blood eosinophil levels. These recommendations should be reconsidered as new evidence becomes available