The clinical application of DBS has become manifold and there has been a tremendous growth in DBS technology in the last few decades making it safer and user friendly. The earlier concept of its ...delayed application in motor fluctuations of Parkinson's disease has been replaced by Class-I evidence of EARLY-STIM trial in 2013, leading to its FDA approval to be used in early-stage despite criticism. Various studies have provided evidence of beneficial effects of bilateral STN-DBS on both motor as well as nonmotor symptoms and different new targets such as the pedunculopontine nucleus, posterior subthalamic area or caudal zona incerta, centromedian-parafascicular complex, and substantia nigra pars reticulata have now become a new area of interest in addition to the subthalamic nucleus and globus pallidus internus for the alleviation of both motor and nonmotor symptoms of Parkinson's disease. New data has confirmed that the DBS is clinically as effective and safe in elderly patients as it is in younger ones. Technological advances like current steering, directional leads, and closed-loop DBS are directed towards reducing the stimulation-induced adverse effects and preservation of the battery life for a longer period. Results of the long-term efficacy of DBS on Parkinson's disease are now available. These have shown that as the motor benefit continues, the clinical progression of Parkinson's disease also continues. We plan to discuss all these in this paper.
Increased 4–12 Hz oscillatory activity in the cortico-basal ganglia-thalamo-cortical (CBGTC) loop is reported in dystonia. Coherence analysis is a measure of linear coupling between two signals, ...revealing oscillatory activity drives that are common across motor units. By performing coherence analysis, activity of the CBGTC-loop can be measured with modalities like local field potentials (LFPs), electromyography (EMG), and electro-encephalography (EEG). The aim of this study is to perform a systematic review on the use of coherence analysis for clinical assessment and treatment of dystonia.
A systematic review was performed on a search in Embase and PubMed on June 28th, 2023. All studies incorporating coherence analysis and an adult dystonia cohort were included. Three authors evaluated the eligibility of the articles. Quality was assessed using the QUADAS-2 checklist.
A total of 41 articles were included, with data of 395 adult dystonia patients. In the selected records, six different types of coherence were investigated: corticocortical, corticopallidal, corticomuscular, pallidopallidal, pallidomuscular, and intermuscular coherence. Various types of 4–12 coherence were found to be increased in all dystonia subtypes.
There is increased 4–12 Hz coherence found between the cortex, basal ganglia, and affected muscles in all dystonia subtypes. However, the relationship between 4-12 Hz coherence and the dystonic clinical state has not been established. DBS treatment leads to a reduction of 4–12 Hz coherence. In combination with the results of this review, the 4–12 Hz frequency band can be used as a promising phenomenon for the development of a biomarker.
Feedback control of deep brain stimulation (DBS) in Parkinson's disease has great potential to improve efficacy, reduce side effects, and decrease the cost of treatment. In this, the timing and ...intensity of stimulation are titrated according to biomarkers that capture current clinical state. Stimulation may be at standard high frequency or intelligently patterned to directly modify specific pathological rhythms. The search for and validation of appropriate feedback signals are therefore crucial. Signals recorded from the DBS electrode currently appear to be the most promising source of feedback. In particular, beta-frequency band oscillations in the local field potential recorded at the stimulation target may capture variation in bradykinesia and rigidity across patients, but this remains to be confirmed within patients. Biomarkers that reliably reflect other impairments, such as tremor, also need to be established. Finally, whether brain signals are causally important needs to be established before stimulation can be specifically patterned rather than delivered at empirically defined high frequency.
This review article provides a brief historical perspective on the use of DBS for tremor, reviews the various etiologies for tremor that can be effectively managed with DBS therapy, discusses the DBS ...targets that have been used for suppression of tremor, and reviews in detail important aspects of DBS surgical technique, including significant technological advances over the past several years that, when applied, can substantially improve the outcomes of DBS for tremor.
This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.
•Brief historical perspective on the use of DBS for tremor.•Review of the various tremor etiologies effectively managed with DBS.•Discussion of DBS targets used for suppression of tremor.•Detailed review of important aspects of DBS surgical technique.•Review of recent technological advances that can improve outcomes of DBS for tremor.
Introdução/Objetivo: No Mundo em 2019, Presume-me que 58 milhões de pessoas tenham a infecção cônica pelo HCV, anualmente ocorram 1,5 milhões de novos casos. A Organização Mundial de Saúde (OMS), tem ...como meta a eliminação das hepatites virais como ameaça a saúde pública até 2030. Para alcançar os objetivos devem ser adotadas estratégias que explorem novas oportunidades, como o diagnóstico. Dando prioridade ao desenvolvimento de testes diagnóstico de tecnologia simples, que alcance áreas remotas e população de difícil acesso, permitindo orientar as decisões médicas. O uso de Dried Blood Spot (DBS) oferece mais conveniência e simplificação na logística para coleta, armazenamento e transporte. A Região Amazônica, por ter um perfil endêmico para a hepatite C, e ter uma logística de pessoas e insumos feitos por via fluvial foi o cenário ideal para aplicabilidade desse estudo. O objetivo do trabalho é analisar o desempenho de testes para detectar e quantificar a carga viral em amostras de sangue seco em papel filtro em comparação com amostras de plasma de pacientes infectados com HCV. Métodos: Foram analisadas amostras de 67 pacientes, de dois municípios do Amazonas. O protocolo do estudo foi aprovado pelo Comitê de Ética e Pesquisa da FMT-HVD. Para cada paciente foi realizada coleta de 8 mL de sangue venoso e sangue capilar por punção digital impregnando o sangue nos círculos de 1,0 cm de diâmetro (∼80 µL) cada, no DBS. As amostras foram processadas utilizando os protocolos de modo aberto para extração e amplificação do DNA. Resultados: Um total de 67 amostras pareadas de plasma e DBS capilar foram coletadas de pacientes com sorologia anti-HCV reagente e sem uso de tratamento antiviral. Oito amostras não apresentaram amplificação do RNA de HCV e 59 amostras houve a detecção de RNA de HCV em plasma e DBS capilar, resultando em uma concordância qualitativa geral de 100%. Comparando as cargas virais plasmáticas de RNA do HCV e as cargas virais capilares DBS, mostrou o R2 = 0,746. Conclusão: Os resultados mostram que o uso do DBS é satisfatório no diagnóstico molecular da hepatite viral C, apresentando uma forte correlação e alta sensibilidade, além disso o seu uso pode reduzir os custos associados a coleta, armazenamento e transporte.
Electrical stimulation of the subthalamic nucleus (STN) is clinically employed to ameliorate several symptoms of manifest Parkinson's Disease (PD). Stimulation parameters utilized by chronically ...implanted pulse generators comprise biphasic rectangular short (60-100µsec) pulses with a repetition frequency between 130 and 180 Hz. A better insight into the effect of electrical stimulation parameters could potentially reveal new possibilities for the improvement of Deep Brain Stimulation (DBS) as a treatment. To this end, we employed single-sided 6-hydroxidopamine (6-OHDA) lesioning of the Medial Forebrain Bundle (MFB) in rats to systematically investigate alternative stimulation parameters. These hemi-parkinsonian (hemi-PD) rats underwent individualized, ipsilateral electrical stimulation to the STN of the lesioned hemisphere, while the transiently-induced contralateral rotational behavior was quantified to assess the effect of DBS parameter variations. The number of induced rotations during 30 seconds of stimulation was strongly correlated with the amplitude of the stimulation pulses. Despite a general linear relation between DBS frequency and rotational characteristics, a plateau effect was observed in the rotation count throughout the clinically-used frequency range. Alternative waveforms to the conventional biphasic rectangular (Rect) pulse shapes Triangular (Tri), Sinusoidal (Sine) and Sawtooth (Lin.Dec.) required higher charges per phase to display similar behavior in rats as compared to the conventional pulse shape. The Euclidean Distance (ED) was used to quantify similarities between different angular trajectories. Overall, our study confirmed that the effect of different amplitude and frequency parameters of STN-DBS in the hemi-PD rat model was similar to those in human PD patients. This shows that induced contralateral rotation is a valuable readout in testing stimulation parameters. Our study supports the call for more pre-clinical studies using this measurement to assess the effect of other DBS parameters such as pulse-width and interphase intervals.
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