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@ARTICLE{Antonenko:267053,
author = {Antonenko, Daria and Fromm, Anna Elisabeth and Thams,
Friederike and Kuzmina, Anna and Backhaus, Malte and
Knochenhauer, Elena and Li, Shu-Chen and Grittner, Ulrike
and Flöel, Agnes},
title = {{C}ognitive training and brain stimulation in patients with
cognitive impairment: a randomized controlled trial.},
journal = {Alzheimer's research $\&$ therapy},
volume = {16},
number = {1},
issn = {1758-9193},
address = {London},
publisher = {BioMed Central},
reportid = {DZNE-2024-00062},
pages = {6},
year = {2024},
abstract = {Repeated sessions of training and non-invasive brain
stimulation have the potential to enhance cognition in
patients with cognitive impairment. We hypothesized that
combining cognitive training with anodal transcranial direct
current stimulation (tDCS) will lead to performance
improvement in the trained task and yield transfer to
non-trained tasks.In our randomized, sham-controlled,
double-blind study, 46 patients with cognitive impairment
(60-80 years) were randomly assigned to one of two
interventional groups. We administered a 9-session cognitive
training (consisting of a letter updating and a Markov
decision-making task) over 3 weeks with concurrent 1-mA
anodal tDCS over the left dorsolateral prefrontal cortex (20
min in tDCS, 30 s in sham group). Primary outcome was
trained task performance (letter updating task) immediately
after training. Secondary outcomes included performance in
tasks testing working memory (N-back task), decision-making
(Wiener Matrices test) and verbal memory (verbal learning
and memory test), and resting-state functional connectivity
(FC). Tasks were administered at baseline, at
post-assessment, and at 1- and 7-month follow-ups (FU). MRI
was conducted at baseline and 7-month FU. Thirty-nine
participants $(85\%)$ successfully completed the
intervention. Data analyses are reported on the
intention-to-treat (ITT) and the per-protocol (PP)
sample.For the primary outcome, no difference was observed
in the ITT (β = 0.1, $95\%-CI$ [- 1.2, 1.3, p = 0.93] or PP
sample (β = - 0.2, $95\%-CI$ [- 1.6, 1.2], p = 0.77).
However, secondary analyses in the N-back working memory
task showed that, only in the PP sample, the tDCS
outperformed the sham group (PP: $\%$ correct, β = 5.0,
$95\%-CI$ [- 0.1, 10.2], p = 0.06, d-prime β = 0.2,
$95\%-CI$ [0.0, 0.4], p = 0.02; ITT: $\%$ correct, β = 3.0,
$95\%-CI$ [- 3.9, 9.9], p = 0.39, d-prime β = 0.1,
$95\%-CI$ [- 0.1, 0.3], p = 0.5). Frontoparietal network FC
was increased from baseline to 7-month FU in the tDCS
compared to the sham group (pFDR < 0.05). Exploratory
analyses showed a correlation between individual memory
improvements and higher electric field magnitudes induced by
tDCS (ρtDCS = 0.59, p = 0.02). Adverse events did not
differ between groups, questionnaires indicated successful
blinding (incidence rate ratio, 1.1, $95\%-CI$ [0.5,
2.2]).In sum, cognitive training with concurrent brain
stimulation, compared to cognitive training with sham
stimulation, did not lead to superior performance
enhancements in patients with cognitive impairment. However,
we observed transferred working memory benefits in patients
who underwent the full 3-week intervention. MRI data pointed
toward a potential intervention-induced modulation of neural
network dynamics. A link between individual performance
gains and electric fields suggested dosage-dependent effects
of brain stimulation. Together, our findings do not support
the immediate benefit of the combined intervention on the
trained function, but provide exploratory evidence for
transfer effects on working memory in patients with
cognitive impairment. Future research needs to explore
whether individualized protocols for both training and
stimulation parameters might further enhance treatment
gains.The study is registered on ClinicalTrials.gov
(NCT04265378). Registered on 7 February 2020.
Retrospectively registered.},
keywords = {Humans / Transcranial Direct Current Stimulation: methods /
Cognitive Training / Memory, Short-Term: physiology /
Cognitive Dysfunction: therapy / Double-Blind Method / Brain
/ Prefrontal Cortex / Electric field simulation (Other) /
Mild cognitive impairment (Other) / Resting-state functional
connectivity (Other) / Subjective cognitive decline (Other)
/ Transcranial direct current stimulation (Other)},
cin = {AG Flöel},
ddc = {610},
cid = {I:(DE-2719)5000081},
pnm = {353 - Clinical and Health Care Research (POF4-353)},
pid = {G:(DE-HGF)POF4-353},
typ = {PUB:(DE-HGF)16},
pmc = {pmc:PMC10782634},
pubmed = {pmid:38212815},
doi = {10.1186/s13195-024-01381-3},
url = {https://pub.dzne.de/record/267053},
}