Non-invasive Brain Stimulation in Alzheimer's Disease and Mild Cognitive Impairment—A State-of-the-Art Review on Methodological Characteristics and Stimulation Parameters

Abstract

Background: Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been proposed as a new therapeutic way to enhance the cognition of patients with dementia. However, serious methodological limitations appear to affect the estimates of their efficacy. We reviewed the stimulation parameters and methods of studies that used TMS or tDCS to alleviate the cognitive symptoms of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Moreover, we evaluated the risk of bias in these studies. Our aim was to highlight the current vulnerabilities of the field and to formulate recommendations on how to manage these issues when designing studies.Methods: Electronic databases and citation searching were used to identify studies administering TMS or tDCS on patients with AD or MCI to enhance cognitive function. Data were extracted by one review author into summary tables with the supervision of the authors. The risk of bias analysis of randomized-controlled trials was conducted by two independent assessors with version 2 of the Cochrane risk-of-bias tool for randomized trials.Results: Overall, 36 trials were identified of which 23 randomized-controlled trials underwent a risk of bias assessment. More than 75% of randomized-controlled trials involved some levels of bias in at least one domain. Stimulation parameters were highly variable with some ranges of effectiveness emerging. Studies with low risk of bias indicated TMS to be potentially effective for patients with AD or MCI while questioned the efficacy of tDCS. Conclusions:The presence and extent of methodical issues affecting TMS and tDCS research involving patients with AD and MCI were examined for the first time. The risk of bias frequently affected the domains of the randomization process and selection of the reported data while missing outcome was rare. Unclear reporting was present involving Holczer et al.NIBS in Dementia: Methodological Issues randomization, allocation concealment, and blinding. Methodological awareness can potentially reduce the high variability of the estimates regarding the effectiveness of TMS and tDCS. Studies with low risk of bias delineate a range within TMS parameters seem to be effective but question the efficacy of tDCS.

Síndrome De West Com Suspeita De Correlação Com Citomegalovirose Congênita: Relato De Caso

“…Destaca-se o uso potencial de TECNI para melhorar funções neuropsiquiátricas em tarefas cognitivas, humor e cognição social (DONG et al, 2018). Estudos recentes demonstraram de forma favorável que TECNI melhorou a memória e atenção de idosos com CCL (BIRBA et al, 2017;HOLCZER et al, 2020). Já as utilizadas no tratamento da DA, causaram melhorias associadas à estimulação na memória e funções cognitivas específicas (ZHAO et al, 2017;CHANG et al, 2018;HOLCZER et al, 2020;WEILER et al, 2020).…”

“…Estudos recentes demonstraram de forma favorável que TECNI melhorou a memória e atenção de idosos com CCL (BIRBA et al, 2017;HOLCZER et al, 2020). Já as utilizadas no tratamento da DA, causaram melhorias associadas à estimulação na memória e funções cognitivas específicas (ZHAO et al, 2017;CHANG et al, 2018;HOLCZER et al, 2020;WEILER et al, 2020). Ademais, a estimulação direcionada a várias regiões do cérebro ou combinada com outros tratamentos, parece produzir efeitos mais positivos (CHANG et al, 2018).…”

Deep Brain Stimulation for Alzheimer's Disease: Stimulation Parameters and Potential Mechanisms of Action

“…The severity of AD and the limitations of drug therapy have spurred the development of research on non-drug therapies (Cummings et al, 2014 ; Aldehri et al, 2018 ). A series of physical therapy methods, including electrical stimulation and magnetic stimulation, are gradually being applied in the field of neurological diseases (Li et al, 2015 ; Temel and Jahanshahi, 2015 ; Zhou et al, 2018 ; Holczer et al, 2020 ).…”

Modulating brain networks associated with cognitive deficits in Parkinson’s disease

“…The safety of tDCS has been assessed and documented elsewhere (Bikson et al 2016 ). The clinical efficiency of tDCS has been successfully assessed on different neurological conditions, such as AD and mild cognitive impairment (MCI) (Holczer et al 2020 ), attention-deficit hyperactivity disorder (Salehinejad et al 2020 ), depression (Palm et al 2016 ), and PD motor symptoms (Manenti et al 2018 ; Lee et al 2019 ), as well as in healthy working memory (Mancuso et al 2016 ). The structure of this review is split into three sections.…”