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Abstract(s)
Introdução: A doença de Alzheimer representa a causa de demência mais prevalente
a nível mundial, com instalação de sintomas neurológicos, motores e até psiquiátricos.
As terapêuticas disponíveis têm demonstrado insucesso em prevenir ou tratar a doença.
A estimulação magnética transcraniana tem demonstrado resultados terapêuticos
promissores em várias doenças neuropsiquiátricas. O objetivo desta revisão sistemática
é avaliar a eficácia desta intervenção em produzir alterações mensuráveis, com potencial
para atrasar ou reverter a progressão da doença de Alzheimer.
Métodos: Foi realizada uma pesquisa nas bases eletrónicas PubMed/MEDLINE e
EMBASE para encontrar estudos em humanos ou modelos animais/celulares com
aplicação de estimulação magnética transcraniana, analisando modificações
mensuráveis – neuroquímicas, neuroanatómicas, imagiológicas ou neurofisiológicas. Os
títulos e resumos dos artigos encontrados foram analisados, procedendo-se à seleção dos
artigos relevantes para leitura integral. Posteriormente, foram selecionados os artigos
pertinentes para a inclusão na síntese qualitativa. O risco de viés de cada artigo foi
avaliado com recurso ao programa Review Manager.
Resultados: Foram incluídos três ensaios clínicos com doentes humanos e três artigos
de investigação básicos com modelos animais. Nos primeiros, a estimulação magnética
transcraniana repetitiva provocou uma redução da inibição transcalosal e a indução de
hipoconectividade na default mode network, quando a estimulação foi aplicada no
córtex pré-frontal dorsolateral. A estimulação do precúneo originou o aumento da
atividade neuronal na mesma rede. Já nos artigos com modelos animais, as estimulações
magnéticas transcranianas repetitiva e theta burst levaram à diminuição da apoptose e
aumento dos fatores neurotróficos, à diminuição da fosforilação da proteína tau e à
recuperação da potenciação de longa duração.
Discussão: A estimulação aparenta diminuir a síndrome de desconexão interhemisférica e recuperar a potenciação de longa duração além de promover a neurogénese
e reduzir os níveis de tau fosforilada e o beta-amiloide. O seu efeito na default mode
network é mais contraditório, com evidencias de ativação de áreas com atividade
diminuída por um lado, assim como, por outro lado, de reduzir a hiperativação de outras
áreas. Não é claro qual o tipo de estimulação com maior eficácia, no entanto, existe uma revisão sistemática sobre estimulação magnética transcraniana na demência
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alguma tendência para a verificação de efeitos mais significativos com frequências
superiores.
Conclusão: A estimulação magnética transcraniana parece ter o potencial de causar
alterações mesuráveis, tanto em humanos como em modelos animais, verificando-se
estas alterações em determinados mecanismos fisiopatológicos já estabelecidos da
doença, assim como noutros menos explorados. Deste modo, esta revisão sistemática
permitiu compreender alguns dos principais efeitos desta intervenção, mas também
evidenciar algumas dúvidas que se mantêm e carecem maior enfoque por parte dos
investigadores.
Introduction: Alzheimer's disease is the most common type of dementia worldwide, with the onset of neurological, motor, and even psychiatric symptoms. The available therapies have failed in preventing or treating the disease. Transcranial magnetic stimulation has shown promising therapeutic results in several neuropsychiatric diseases. The objective of this systematic review is to assess the effectiveness of this intervention in producing measurable changes, with the potential to delay or reverse the progression of Alzheimer's disease. Methods: A literature search was carried out on the PubMed/MEDLINE and EMBASE databases to find studies in humans, animals, or cell models, with the application of transcranial magnetic stimulation, analyzing measurable neurochemical, neuroanatomical, imaging, or neurophysiological changes. The titles and abstracts of the articles found were scrutinized, proceeding to the selection of relevant articles for full reading. Subsequently, articles were selected to be included in the qualitative synthesis. The risk of bias for each article was assessed using the Review Manager program. Results: Three clinical trials with human patients and three basic research articles with animal models were included. In the former, repetitive transcranial magnetic stimulation caused a reduction in transcallosal inhibition and the induction of hypoconnectivity within the default mode network when stimulation was applied to the dorsolateral prefrontal cortex. When applied in the precuneus, stimulation caused an increase in neuronal activity in this same network. In the research articles, repetitive and theta burst transcranial magnetic stimulation led to decreased apoptosis and increased neurotrophic factors, decreased tau protein phosphorylation and recovered long-term potentiation. Discussion: Transcranial magnetic stimulation appears to decrease inter-hemispheric disconnection syndrome and recover long-term potentiation, in addition to promoting neurogenesis and reducing levels of phosphorylated tau protein and amyloid beta. Its effect on the default mode network is more contradictory, with evidence of increased activity in previously deactivated areas, as well as reduced hyperactivation of other areas. It is not clear which type of stimulation is most effective, however, there is some tendency for more significant effects at higher frequencies Conclusion: Transcranial magnetic stimulation appears to have the potential to cause measurable changes, both in humans and in animal models, with these changes occurring in certain pathophysiological mechanisms of the disease that are already established, as well as in others less explored. This way, this systematic review heightened our comprehension about some of the main effects of this intervention, but also highlighted some remaining doubts and the areas that lack a greater focus from researchers.
Introduction: Alzheimer's disease is the most common type of dementia worldwide, with the onset of neurological, motor, and even psychiatric symptoms. The available therapies have failed in preventing or treating the disease. Transcranial magnetic stimulation has shown promising therapeutic results in several neuropsychiatric diseases. The objective of this systematic review is to assess the effectiveness of this intervention in producing measurable changes, with the potential to delay or reverse the progression of Alzheimer's disease. Methods: A literature search was carried out on the PubMed/MEDLINE and EMBASE databases to find studies in humans, animals, or cell models, with the application of transcranial magnetic stimulation, analyzing measurable neurochemical, neuroanatomical, imaging, or neurophysiological changes. The titles and abstracts of the articles found were scrutinized, proceeding to the selection of relevant articles for full reading. Subsequently, articles were selected to be included in the qualitative synthesis. The risk of bias for each article was assessed using the Review Manager program. Results: Three clinical trials with human patients and three basic research articles with animal models were included. In the former, repetitive transcranial magnetic stimulation caused a reduction in transcallosal inhibition and the induction of hypoconnectivity within the default mode network when stimulation was applied to the dorsolateral prefrontal cortex. When applied in the precuneus, stimulation caused an increase in neuronal activity in this same network. In the research articles, repetitive and theta burst transcranial magnetic stimulation led to decreased apoptosis and increased neurotrophic factors, decreased tau protein phosphorylation and recovered long-term potentiation. Discussion: Transcranial magnetic stimulation appears to decrease inter-hemispheric disconnection syndrome and recover long-term potentiation, in addition to promoting neurogenesis and reducing levels of phosphorylated tau protein and amyloid beta. Its effect on the default mode network is more contradictory, with evidence of increased activity in previously deactivated areas, as well as reduced hyperactivation of other areas. It is not clear which type of stimulation is most effective, however, there is some tendency for more significant effects at higher frequencies Conclusion: Transcranial magnetic stimulation appears to have the potential to cause measurable changes, both in humans and in animal models, with these changes occurring in certain pathophysiological mechanisms of the disease that are already established, as well as in others less explored. This way, this systematic review heightened our comprehension about some of the main effects of this intervention, but also highlighted some remaining doubts and the areas that lack a greater focus from researchers.
Description
Keywords
Alzheimer Demência Disfunção Cognitiva Estimulação Magnética Transcraniana Neuromodulação Revisão Sistemática