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Parkinson's disease (PD) is the second most common neurodegenerative disorder. Despite its high frequency the etiology is still unclear; several lines of evidence show that an inflammatory process is implicated in the pathogenesis of this disorder; where activation of brain microglia plays a central role in the damage of dopaminergic neurons of the substantia nigra. Such inflammation has been attributed to the toxic effect of aggregated α-synuclein; however, evidence also implicates an altered gut microbiota (dysbiosis) through the systemic release of endotoxins such as lipopolysaccharide and other metabolic products. This exposure may be enhanced by increased permeability of the intestinal ("leaky gut") and the blood brain barrier; enhancing the entrance of microbiota-produced substances into the central nervous system. In this manuscript, we explore the evidence from clinical and basic science implicating microglia activation by gut dysbiosis and how this phenomenon may impact in the symptomatology and progression of PD., (Copyright © 2020 IBRO. Published by Elsevier Ltd. All rights reserved.)

Background: Tremor is a known side-effect of anticonvulsants, particularly of valproate. However, there is a dearth of information regarding detailed clinical features and functional impact of valproate-induced tremor., Methods: We studied a cohort of patients treated with anticonvulsants for neurological disorders, through blinded evaluations using the Clinical Rating Scale for Tremor (CRST); we compared the frequency, severity and functional impact of drug-induced tremor between patients treated with valproate and those treated with other anticonvulsants., Results: From a cohort of 218 consecutive patients, 171 were fully evaluated; 118 patients were taking valproate alone or combined with other anticonvulsants and 53 patients were taking other anticonvulsants. Mean age (±SD) at evaluation of the cohort was 32 ± 13 years, females represented 55.6% of cases. Tremor was more frequently observed in patients taking valproate particularly postural upper limb tremor: 49% vs. 15% (right-side) (P < 0.001) and 48.3% vs. 13.2% (left-side), (P < 0.001); had a higher total CRST score: 12.14 vs. 3.06 (P < 0.001), and required more frequently treatment for drug-induced tremor: 23.7% vs. 5.6% (P=0.005) compared with patients taking other anticonvulsants. Among 118 patients taking valproate, women had a higher total CRST score compared with men: 14.54 ± 14.9 vs. 9.56 ± 9.55 (P=0.034). A weak correlation between the total CRST score, dose per Kg of valproate and serum levels of valproate were observed., Conclusions: Tremor is frequently observed in patients taking valproate and is severe enough to require treatment in about 24% of cases., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: Traditionally, deep brain stimulation (DBS) for movement disorders (MDs) is provided using stimulation frequencies equal to or above 100 Hz. However, recent evidence suggests that relatively low-frequency stimulation (LFS) below 100 Hz is an option to treat some patients with MDs., Objectives: We aimed to review the clinical and pathophysiological evidence supporting the use of stimulation frequencies below 100 Hz in different MDs., Results: Stimulation of the subthalamic nucleus at 60 Hz has provided benefit in gait and other axial symptoms such as swallowing and speech. Stimulation of the pedunculopontine nucleus between 20 and 45 Hz can provide benefit in freezing of gait, cognition, and sleep quality in select patients with Parkinson's disease. Stimulation of the globus pallidus internus below 100 Hz in patients with dystonia has provided benefit at the beginning of the therapy, although progressively higher stimulation frequencies seem to be necessary to maintain the clinical benefit. Relative LFS can lower energy requirements and reduce battery usage-a useful feature, particularly in patients treated with high current energy., Conclusions: DBS at frequencies below 100 Hz is a therapeutic option in select cases of Parkinson's disease with freezing of gait and other axial symptoms, and in select patients with dystonia and other hyperkinetic movements, particularly those requiring an energy-saving strategy., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Deep brain stimulation represents a major advance in the treatment of several types of movement disorders. However, during stimulation new movement disorders may emerge, thus limiting the positive effects of this therapy. These movement disorders may be induced by: 1) stimulation of the targeted nucleus, 2) stimulation of surrounding tracts and nuclei, and 3) as a result of dose adjustment of accompanying medications, such as reduction of dopaminergic drugs in patients with Parkinson's disease. Various dyskinesias, blepharospasm, and apraxia of eyelid opening have been described mainly with subthalamic nucleus stimulation, whereas hypokinesia and freezing of gait have been observed with stimulation of the globus pallidus internus. Other deep brain stimulation-related movement disorders include dyskinesias associated with stimulation of the globus pallidus externus and ataxic gait as a side effect of chronic bilateral stimulation of the ventral intermediate nucleus of thalamus. These movement disorders are generally reversible and usually resolved once the stimulation is reduced or turned off. This, however, typically leads to loss of benefit of the underlying movement disorder which can be re-gained by using different contacts, changing targets or stimulation parameters, and adjusting pharmacological therapy. New and innovative emerging technologies and stimulation techniques may help to prevent or overcome the various deep brain stimulation-induced movement disorders. In this review we aim to describe the clinical features, frequency, pathophysiology, and strategies for treatment of these iatrogenic movement disorders., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Corticobasal degeneration (CBD) is a neurodegenerative, sporadic disorder of unknown cause. Few familial cases have been described., Objective: We aim to characterize the clinical, imaging, pathological and genetic features of two familial cases of CBD., Methods: We describe two first cousins with CBD associated with atypical MRI findings. We performed exome sequencing in both subjects and in an unaffected first cousin of similar age., Results: The cases include a 79-year-old woman and a 72-year-old man of Native American and British origin. The onset of the neurological manifestations was 74 and 68 years respectively. Both patients presented with a combination of asymmetric parkinsonism, apraxia, myoclonic tremor, cortical sensory syndrome, and gait disturbance. The female subject developed left side fixed dystonia. The manifestations were unresponsive to high doses of levodopa in both cases. Extensive bilateral T1-W hyperintensities and T2-W hypointensities in basal ganglia and thalamus were observed in the female patient; whereas these findings were more subtle in the male subject. Postmortem examination of both patients was consistent with corticobasal degeneration; the female patient had additional findings consistent with mild Alzheimer's disease. No Lewy bodies were found in either case. Exome sequencing showed mutations leading to possible structural changes in MRS2 and ZHX2 genes, which appear to have the same upstream regulator miR-4277., Conclusions: Corticobasal degeneration can have a familial presentation; the role of MRS2 and ZHX2 gene products in CBD should be further investigated., (Copyright © 2013 Elsevier Ltd. All rights reserved.)