sábado, 23 de dezembro de 2017

Tecnologia permite estender duração das baterias dos neuroestimuladores

23 Dez, 2017 | Os doentes com Parkinson e outras doenças do movimento, operados ao cérebro para controlar os sintomas incapacitantes, vão ser sujeitos a menos cirurgias. Uma nova tecnologia permite estender por mais seis anos a duração das baterias dos neuroestimuladores, o que previne também mais infeções.

Veja vídeo Aqui.

Não me perguntem mais, pois a matéria inexplica o tipo de procedimento que é feito e não consegui maiores informações!

quinta-feira, 21 de dezembro de 2017

A estimulação do cérebro profundo pode ser segura na demência de Parkinson

December 20, 2017 - Deep-brain stimulation of a novel brain region can be safely performed in patients with Parkinson's disease dementia, and although it may not improve cognition, it does appear to have benefits on other Parkinson's symptoms, a new study suggests.

"This was a proof-of-concept study. We have demonstrated that it is possible to use deep-brain stimulation safely in patients with Parkinson's disease dementia by targeting different areas of the brain," senior author, Thomas Foltynie, MD, the National Hospital for Neurology and Neurosurgery, London, United Kingdom, told Medscape Medical News.

"We didn't see an improvement in cognition as hoped for, but we did show benefits on movement symptoms and on hallucinations. These results open up the possibility of using deep-brain stimulation in this population for whom it has so far not been recommended."

The study was published in JAMA Neurology on December 18.

Dr Foltynie explained that deep-brain stimulation treatment in Parkinson's is known to help with the movement issues characteristic of the disease, but stimulation of the usual target — the subthalamic nucleus — also carries a risk of upsetting other brain functions, including cognition, so it is not performed in patients with Parkinson's dementia.

For the current study, the researchers targeted a different part of the brain: the nucleus basalis of Meynert. "Animal studies have suggested that stimulation of this area leads to an increase in acetylcholine throughout critical regions of the brain and improves memory, and there has been a case report in which brain stimulation of the nucleus basalis of Meynert showed a striking increase in cognitive performance in a dementia patient," Dr Foltynie said. "This part of the brain represents a novel target, and we wanted to pursue this further."

The nucleus basalis of Meynert is just below another region of the brain, the globus pallidus, which has also been used as a target for deep-brain stimulation. "Stimulation of the globus pallidus is also associated with benefits on movement in Parkinson's and is more forgiving in terms of cognitive issues, so in our study we placed the stimulation electrodes so that they went through both the globus pallidus and the nucleus basalis of Meynert, with contacts in both sites. These were activated separately so we could discern which region was associated with any effects seen," Dr Foltynie noted.

"Our hypothesis was that by selecting new regions as targets for deep-brain stimulation we may be able help patients with Parkinson dementia with both movement and cognition symptoms."

The randomized, double-blind, crossover clinical trial involved six patients (average age, 65 years) with Parkinson's disease dementia who underwent surgery for electrode implantation and were assigned to receive either low-frequency (20-Hz) active stimulation to the nucleus basalis of Meynert or sham stimulation for 6 weeks, followed by the opposite treatment for 6 weeks.

Results showed that surgery and stimulation were well tolerated by all six patients, with no serious adverse events during the trial. No consistent improvements were observed in the primary cognitive outcomes or in results of resting state functional MRI.

However, scores on the Neuropsychiatric Inventory improved by 5 points with the stimulation. This improvement was driven primarily by a reduction in hallucinations subscale scores in two patients.

In the paper, the researchers report that the two patients with hallucinations both experienced "near-complete cessation of visual hallucinations after surgery when nucleus basalis of Meynert stimulation was turned on, followed by a resurgence of hallucinations when stimulation was subsequently turned off."

Dr Foltynie elaborated: "Two patients with quite troublesome hallucinations showed a dramatic improvement. This was an unexpected benefit. However, this was a secondary outcome, and we have to be cautious about overinterpreting these observations. But I would say it is something to be investigated in future studies."

Three patients showed improvement in levodopa-induced dyskinesias during on-stimulation.

The researchers suggest this may be explained by spread of current from the nucleus basalis of Meynert to the overlying globus pallidus. They add that conventional deep-brain stimulation of the globus pallidus for dyskinesia control in Parkinson disease is delivered at high frequency, "so the finding that low-frequency stimulation directed toward the nucleus basalis of Meynert also attenuated dyskinesias warrants further study."

Dr Foltynie noted that two patients went on to receive long-term stimulation of the globus pallidus and showed clear movement benefits.

He explained that deep-brain stimulation works best for the Parkinson's symptoms of slowness, stiffness, and tremor but does not have much impact on balance and freezing. It is appropriate for only a small percentage of patients with Parkinson's disease — probably less than 10%.

"There is a window of opportunity — we don't use it in early disease as symptoms can be well controlled with medication and we wouldn't want to expose these patients to the risk of surgery. But when patients start to become refractory to dopamine therapies, deep-brain stimulation can still show a benefit. Although when patients deteriorate further then it too will become ineffective."

He noted that it is easier to place the electrodes correctly in the younger brain, where there hasn't been too much shrinkage. "The best candidates are patients with early-onset Parkinson's disease — those in their 50s or 60s — who could have benefit for up to 10 years. While not many of these younger patients will have Parkinson's dementia, there will be some who do and our study opens up this therapy to them. "

He cautioned, however, that such treatment should still be viewed as experimental and should be performed only at one of the specialist centers with particular expertise in deep-brain stimulation.

What Now for Deep-Brain Stimulation in Dementia?
Dr Foltynie said the future for deep-brain stimulation in dementia is uncertain. "A Canadian group is looking at targeting stimulation to the fornix area of the brain in Alzheimer's, but their results have not been encouraging either. Other research has suggested that while high-frequency stimulation in the subthalamic nucleus makes dementia worse, using low-frequency stimulation may show some benefit, and further research on this approach is ongoing," he reported.

In an accompanying editorial, Wissam Deeb, MD, Michael S. Okun, MD, and Leonardo Almeida, MD, Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, state: "Although the primary outcome of this study was not met, these results challenge the consensus in the field that DBS [deep-brain stimulation] is contraindicated in PDD [Parkinson's disease dementia]."

They add: "The authors provide evidence for the safety and the tolerability of nucleus basalis of NBM [Meynert] DBS, albeit in a small number of patients. There will need to be more work to refine the target and trajectory, as well as programming strategies (duty cycle, frequency, and pulse shapes). The findings from the current study will require replication in larger cohorts. Finally, this and future DBS studies in Parkinson's disease dementia could provide insights into the cholinergic network underpinning cognitive dysfunction."

This study was funded by a grant from the Brain Research Trust and was sponsored by University College London. Dr Foltynie reports receiving honoraria from Medtronic, St Jude Medical, Profile Pharma, Bial, AbbVie Pharmaceuticals, UCB Pharmaceuticals, and Oxford Biomedica.

JAMA Neurol. Published December 18, 2017. Full text, Editorial. Fonte: MedScape.

terça-feira, 12 de dezembro de 2017

A estimulação cerebral profunda melhora a sobrevivência na doença de Parkinson

December 12, 2017 - A estimulação cerebral profunda pode ajudar a reter a função motora e, por sua vez, prolongar a vida em pacientes com doença de Parkinson.

O uso de estimulação cerebral profunda (DBS) em pacientes com doença de Parkinson (DP) pode resultar em uma modesta melhora na sobrevivência, de acordo com uma análise retrospectiva dos dados administrativos de Veterans Affairs e Medicare publicados em Movement Disorders.

Os dados do paciente foram retirados dos arquivos de reivindicações do Veterans Affairs e do Center for Medicare e Medicaid Services. Os pesquisadores usaram a pontuação de propensão para combinar veteranos com DP submetidos a DBS (n = 611) versus veteranos que não passaram por DBS (n = 611) durante 2008 a 2013 para determinar o efeito da terapia sobre os resultados de mortalidade.

De acordo com os achados, os pacientes submetidos a DBS experimentaram uma sobrevida significativamente maior do que os pacientes que não receberam DBS (média, 2291,1 [erro padrão = 46,4] dias [6,3 anos] versus 2063,8 [erro padrão = 47,7] dias [5,7 anos], respectivamente; P = .006; índice de risco 0,69; IC 95%, 0,56-0,85). Durante o seguimento, significativamente menos pacientes no grupo DBS contra o grupo não DBS morreram (168 [27,5%] versus 214 [35,0%], respectivamente, P = 0,002).

Não houve diferença significativa entre o DBS e nenhum DBS em relação à idade média à morte (76,5 e 75,9, respectivamente, P = 0,67). Além disso, os pacientes gerenciados com DBS apresentaram uma chance de mortalidade de 31% menos que os participantes submetidos à administração médica (P =.0004).

Uma vez que este era um estudo retrospectivo de reivindicações e dados administrativos, os pesquisadores não podiam se ajustar completamente para diferenças não observadas, o que poderia ter afetado a sobrevivência. Além disso, este estudo é ainda limitado, na medida em que os pesquisadores não levaram em consideração cada uma a duração da DP de cada paciente, os tipos de medicamentos utilizados e a função motora ou a fase de doença de cada indivíduo.

Embora a DP seja progressiva e continue a resultar em piora da cognição, marcha e fala, os dados do estudo sobre pacientes que recebem DBS "sugerem que pode haver uma vantagem em manter a função motora". Original em inglês, tradução Google, revisão Hugo. Fonte: Neurology Advisor.

Veja também Aqui.

segunda-feira, 11 de dezembro de 2017

Boston Scientific recebe a aprovação da US FDA para o sistema de estimulação cerebral profunda Vercise ™

Boston Scientific Receives U.S. FDA Approval for the Vercise™ Deep Brain Stimulation System
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SOURCE Boston Scientific Corporation

Platform Offers Physicians Advanced Technology to Treat Symptoms of Parkinson's disease

MARLBOROUGH, Mass., Dec. 11, 2017 /PRNewswire/ -- Boston Scientific Corporation (NYSE: BSX) today announced that it has received approval from the U.S. Food and Drug Administration (FDA) for the Vercise™ Deep Brain Stimulation (DBS) System. DBS is used to treat the symptoms of Parkinson's disease (PD), a degenerative condition that affects more than one million people in the United States and 10 million worldwide.1 DBS works by stimulating a targeted region of the brain through implanted leads that are powered by a device called an implantable pulse generator (IPG). (segue...) Fonte: wboc.

Inibição neuronal e plasticidade sináptica dos neurônios dos gânglios basais na doença de Parkinson


11 December 2017 - A estimulação cerebral profunda do núcleo subtalâmico é um tratamento eficaz para os sintomas da doença de Parkinson. Os benefícios terapêuticos da estimulação cerebral profunda são dependentes da freqüência, mas os mecanismos fisiológicos subjacentes não são claros. Para promover a terapia de estimulação cerebral profunda, é fundamental uma compreensão dos mecanismos fundamentais. Os objetivos deste estudo foram (i) comparar os efeitos dependentes da freqüência no disparo de células no núcleo subtalâmico e na substância nigra pars reticulata; (ii) quantificar os efeitos dependentes da frequência na plasticidade de curto prazo na substância nigra pars reticulata; e (iii) investigar os efeitos da estimulação contínua de alta freqüência de cadeia longa (comparável à estimulação convencional do cérebro profundo) sobre a plasticidade sináptica. Dois microeletrodos estreitamente espaçados (600 μm) foram avançados para o núcleo subtalâmico (n = 27) e substância nigra pars reticulata (n = 14) de 22 pacientes submetidos a cirurgia de estimulação cerebral profunda para a doença de Parkinson. Os potenciais de campo de disparo celular e evocados foram registrados com um microeletrodo durante os trens de estimulação do microeletrodo adjacente em uma faixa de freqüências (1-100 Hz, 100 μA, 0,3 ms, 50-60 pulsos). Acionamento subtalâmico atenuado com ≥20 Hz (P <0,01) (silenciado a 100 Hz), enquanto a substância nigra pars reticulata diminuiu com ≥ 3 Hz (P <0,05) (silenciado a 50 Hz). Substantia nigra pars reticulata também exibiu um aumento mais prominente no período de silêncio transitório após a estimulação. Os pacientes com períodos de silêncio mais longos após a estimulação de 100 Hz no núcleo subtalâmico tendem a ter um melhor resultado clínico após a estimulação cerebral profunda. A ≥ 30 Hz, o primeiro potencial de campo evocado do trem de estimulação na substância nigra pars reticulata foi potenciado (P <0,05); no entanto, a amplitude média dos potenciais subseqüentes foi atenuada rapidamente (P <0,01). Isso é sugestivo de facilitação sináptica seguido de depressão rápida. As proporções de pulsos em pares calculadas no início do trem revelaram que 20 Hz (P <0,05) era a freqüência mínima necessária para induzir a depressão sináptica. Por fim, a amplitude média dos potenciais de campo evocado durante os impulsos de 1 Hz mostrou potencialização sináptica inibitória significativa após a estimulação de alta freqüência de trem longo (P <0,001) e esses aumentos foram combinados com o aumento da duração da inibição neuronal (P <0,01). O núcleo subtalâmico exibiu um limite de freqüência mais alto para a inibição induzida por estimulação do que a substância nigra pars reticulata provavelmente devido a diferentes razões de GABA: terminais de glutamato no soma e / ou a natureza de seus insumos GABAérgicos (pallual versus estriatal). Sugerimos que o aprimoramento da plasticidade sináptica inibitória e a potencialização e depressão dependentes da freqüência são mecanismos putativos de estimulação cerebral profunda. Além disso, prevemos que os futuros sistemas de estimulação cerebral profunda em circuito fechado (com períodos de estimulação fora da frequência) podem se beneficiar da potencialização sináptica inibitória que ocorre após a estimulação de alta freqüência. Original em inglês, tradução Google, revisão Hugo. Fonte: Academic.