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Cited by 13Transcranial Magnetic Stimulation StudiesCognitive Abilities and TestingDementia and Cognitive Impairment Research

Primary outcome from the augmenting cognitive training in older adults study (ACT): A tDCS and cognitive training randomized clinical trial

Open access
Hausman, Hanna K., Alexander, Gene E., Cohen, Ronald, Marsiske, Michael, DeKosky, Steven T., Hishaw, Georg A., O'Shea, Andrew, Kraft, Jessica N. +3 more·2023·Brain Stimulation
DOI 10.1016/j.brs.2023.05.021PMC PMC10436327
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Abstract

BACKGROUND: There is a need for effective interventions to stave off cognitive decline in older adults. Cognitive training has variably produced gains in untrained tasks and daily functioning. Combining cognitive training with transcranial direct current stimulation (tDCS) may augment cognitive training effects; however, this approach has yet to be tested on a large-scale. OBJECTIVE: This paper will present the primary findings of the Augmenting Cognitive Training in Older Adults (ACT) clinical trial. We hypothesize that receiving active stimulation with cognitive training will result in greater improvements on an untrained fluid cognition composite compared to sham following intervention. METHODS: 379 older adults were randomized, and 334 were included in intent-to-treat analyses for a 12-week multidomain cognitive training and tDCS intervention. Active or sham tDCS was administered at F3/F4 during cognitive training daily for two weeks then weekly for 10 weeks. To assess the tDCS effect, we fitted regression models for changes in NIH Toolbox Fluid Cognition Composite scores immediately following intervention and one year from baseline controlling for covariates and baseline scores. RESULTS: Across the entire sample, there were improvements in NIH Toolbox Fluid Cognition Composite scores immediately post-intervention and one year following baseline; however, there were no significant tDCS group effects at either timepoint. CONCLUSIONS: The ACT study models rigorous, safe administration of a combined tDCS and cognitive training intervention in a large sample of older adults. Despite potential evidence of near-transfer effects, we failed to demonstrate an additive benefit of active stimulation. Future analyses will continue to assess the intervention's efficacy by examining additional measures of cognition, functioning, mood, and neural markers.

AI snapshot

Written from the paper’s full text.

TL;DR

In the ACT randomized clinical trial, 334 older adults received 12 weeks of multidomain cognitive training with active or sham tDCS, and the primary intent-to-treat analysis found no significant additive tDCS effect on NIH Toolbox Fluid Cognition Composite change post-intervention or at one year. The whole sample improved on the Fluid Cognition Composite, with mean changes of 4.6 points post-intervention and 4.7 points at one year.

Key findings

  • Across the entire sample, NIH Toolbox Fluid Cognition Composite scores improved significantly from baseline to post-intervention (mean T2−T1 change = 4.6) and from baseline to one-year (mean T3−T1 change = 4.7).
  • Active versus sham tDCS did not significantly predict changes in Fluid Cognition Composite scores from baseline to post-intervention or from baseline to one-year after controlling for demographics, adherence, and baseline scores.
  • Adherence was 76.9% for stimulation and 72.5% for cognitive training, with no significant differences between tDCS groups; blinding questionnaires also showed no significant group differences in predicting treatment condition.
  • In the phase 2 sample only, the active group showed a 1.57-point greater improvement in Fluid Cognition Composite from baseline to one-year compared with sham (p = 0.03); this effect was larger but non-significant in complete-case sensitivity analysis (estimate = 1.72, p = 0.11).

Methods

  • Adaptive two-phase randomized clinical trial at the University of Florida and University of Arizona: 379 participants were randomized, and 334 who received cognitive training were included in intent-to-treat analyses. Phase 1 randomized 87 participants to four arms; phase 2 randomized remaining participants to cognitive training with active or sham tDCS.
  • Intervention: approximately 40 hours of BrainHQ computerized cognitive training over 12 weeks; active or sham tDCS was administered at F3 (cathode)/F4 (anode) at 2 mA for 20 minutes during cognitive training daily for two weeks, then weekly for 10 weeks. Sham received 2 mA only during the first 30 seconds.
  • Primary outcome was the NIH Toolbox Fluid Cognition Composite at baseline, post-intervention, and one year. Intent-to-treat regression models tested tDCS group effects on change scores with covariates age, sex, clinical site, and baseline composite scores; formal inference combined phase 1 (N=42) and phase 2 (N=292) p-values via inverse-normal combination.

Limitations

  • The paper states that the trial primarily consisted of Non-Hispanic or Latinx and White individuals, limiting generalizability to systemically marginalized populations; it also notes that no data were collected at the two-week timepoint, so temporal tDCS effects could not be explored, and that the same tDCS parameters across all participants may not have optimized current delivery given anatomical variability.
  • The paper states that the selected NIH Toolbox Fluid Cognition Composite may not have been as sensitive to tDCS effects as single-domain tests, and that cognitive training adherence was modeled as a binary variable, not accounting for the range of training levels completed.
  • The paper states that it is difficult to determine how much of the whole-sample improvement relates to cognitive training versus practice effects; the text also makes evident that the phase 2 one-year tDCS effect was not significant in complete-case sensitivity analysis and was not the primary combined-sample result.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.brs.2023.05.021

Cites

81 of 81 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

55 of 77 cited sources checked · 33 supported · 2 flagged · accuracy not yet measured

  • Premisecitation

    Post-intervention cognitive gains have been associated with increases in resting-state functional connectivity.

    “Finally, post-intervention cognitive gains have been associated with increases in resting-state functional connectivity [36–37], suggesting that this intervention may adaptively modify communication within brain networks vulnerable to aging.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [36] Antonenko, 2018, Neuronal and behavioral effects of multi-day brain stimulation and memory training, Neurobiol Aging source
    • cites [37] Nissim, 2019, Effects of in-scanner bilateral frontal tDCS on functional connectivity of the working memory network in older adults, Front Aging Neurosci source

      The Analytical Approach says the connectivity analysis captured N-Back task periods, not rest periods. The Results (Post > Baseline) report no significant post-stimulation connectivity increase, and the Discussion says the study found no statistically significant behavioral improvement. The paper therefore does not report the claimed association between post-intervention cognitive gains and increased resting-state connectivity. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisecitation

    Applying tDCS while an individual is engaging in an active task is thought to result in induced cortical plastic changes primarily in the brain areas functionally relevant for task execution.

    “Further, applying tDCS while an individual is engaging in an active task is thought to result in induced cortical plastic changes primarily in the brain areas functionally relevant for task execution [29].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [29] Pisoni, 2018, Cognitive enhancement induced by anodal tDCS drives circuit-specific cortical plasticity, Cerebr Cortex source
  • Premisecitation

    Findings for transfer effects of cognitive training on untrained cognitive domains and daily functioning are less consistent.

    “While a variety of cognitive training studies have identified post-intervention gains on trained tasks and on tasks within similar domains [13–15], findings for transfer effects on untrained cognitive domains and daily functioning are less consistent, presenting a need to improve the efficacy of cognitive training interventions in producing clinically meaningful outcomes [11, 15–18].”
    Quote in the paperSubstantial claim3 of 5 sources checked
    • cites [11] Rebok, 2014, Ten-year effects of the advanced cognitive training for independent and vital elderly cognitive training trial on cognition and everyday functioning in older adults, J Am Geriatr Soc source
    • cites [15] Sala, 2019, Near and far transfer in cognitive training: a second-order meta-analysis, Collabra Psychol source
    • cites [16] Jaeggi, 2008, Improving fluid intelligence with training on working memory, Proc Natl Acad Sci USA source

      The Abstract says that gains on trained tasks can be dramatic while transfer to other tasks or domains remains rare, supporting the claim about inconsistent transfer to untrained domains. The paper does not address transfer to daily functioning; its Materials and Methods describe cognitive tests as the transfer measures. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [17] Melby-Lervåg, 2016, Working memory training does not improve performance on measures of intelligence or other measures of “far transfer”: evidence from a meta-analytic review, Perspect Psychol Sci source

      The Discussion reports gains on similar working-memory tasks but no convincing transfer to untrained cognitive skills such as reading comprehension and arithmetic. This supports the claim about uncertain transfer to other cognitive domains, but the review concerns working-memory training specifically and does not assess daily functioning as a distinct outcome. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [18] Redick, 2013, No evidence of intelligence improvement after working memory training: a randomized, placebo-controlled study, J Exp Psychol Gen source
  • Premisecitation

    tDCS is a promising non-invasive technique for inducing neuroplastic changes in the brain.

    “Transcranial direct current stimulation (tDCS) is a promising non-invasive technique for inducing neuroplastic changes in the brain [19–20].”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [19] Stagg, 2011, Physiological basis of transcranial direct current stimulation, Neurosciences source
    • cites [20] Zheng, 2011, Effects of transcranial direct current stimulation (tDCS) on human regional cerebral blood flow, Neuroimage source
  • Premisecitation

    Subtle functional changes are associated with an increased risk of conversion from normal aging to mild cognitive impairment and dementia.

    “Subtle functional changes are associated with an increased risk of conversion from “normal aging” to mild cognitive impairment and dementia [5–7].”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [5] Chen, 2017, Progression from normal cognition to mild cognitive impairment in a diverse clinic- and community-based elderly cohort, Alzheimers Dement source
    • cites [6] Farias, 2013, Longitudinal trajectories of everyday function by diagnostic status, Psychol Aging source

      The Discussion says subtle everyday-function changes were detectable in cognitively normal people who later developed MCI or dementia. The Results found worse baseline function among those who later developed dementia, but the difference for those who developed MCI was only a nonsignificant trend (p = .12). Thus the paper suggests, rather than firmly establishes, the claimed association for conversion to MCI. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [7] Lau, 2015, Early cognitively based functional limitations predict loss of independence in instrumental activities of daily living in older adults, J Int Neuropsychol Soc source
  • Classified as probably not a substantial claim. 22
  • May combine two claims. 16

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    The ACTIVE study found that cognitive training groups demonstrated improvements on trained tasks which remained over time and evidence of transfer to functional tasks.

    “The Advanced Cognitive Training in Vital Elderly (ACTIVE) study examined the longitudinal effects of cognitive training in 2,832 older adults [10]. Cognitive training groups demonstrated improvements on trained tasks which remained over time and evidence of transfer to functional tasks [10–12].”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [10] Ball, 2002, Effects of cognitive training interventions with older adults: a randomized controlled trial, J Am Med Assoc source

      The Results and Comment sections support lasting improvements in the trained cognitive abilities. But the Abstract states that no training effects on everyday functioning were detected at two years, and the Comment explicitly describes an absence of transfer to real-world outcomes. The claim’s assertion of evidence of transfer to functional tasks is therefore contrary to this paper’s finding; page numbers were not supplied in our copy. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [11] Rebok, 2014, Ten-year effects of the advanced cognitive training for independent and vital elderly cognitive training trial on cognition and everyday functioning in older adults, J Am Geriatr Soc source
    • cites [12] Ball, 2010, Cognitive training decreases motor vehicle collision involvement among older drivers, J Am Geriatr Soc source

  • May combine two claims.

    Premisecitation

    Changes in cortical excitability and improvements in behavior induced by tDCS have been reported to persist long after the stimulation period.

    “Importantly, changes in cortical excitability and improvements in behavior induced by tDCS have been reported to persist long after the stimulation period [25–28].”
    Quote in the paperSubstantial claim3 of 4 sources checked
    • cites [25] Nitsche, 2001, Sustained excitability elevations induced by transcranial DC motor cortex stimulation in humans, Neurology source
    • cites [26] Stagg, 2013, Widespread modulation of cerebral perfusion induced during and after transcranial direct current stimulation applied to the left dorsolateral prefrontal cortex, J Neurosci source

      The Introduction reports behavioral aftereffects lasting at least three months, supporting the claim that behavioral effects can persist well beyond stimulation. The Discussion and “Brain perfusion changes after stimulation” section report cortical-excitability changes in the immediate poststimulation period, but do not establish that those changes persist long after stimulation. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [27] Fritsch, 2010, Direct current stimulation promotes BDNF-dependent synaptic plasticity: potential implications for motor learning, Neuron source
    • cites [28] Rroji, 2015, Anodal tDCS over the primary motor cortex facilitates long-term memory formation reflecting use-dependent plasticity, PLoS One source

  • May combine two claims.

    Premisecitation

    Prior studies found a small 2.7-point gain on the Fluid Cognition Composite standard scores with 3-5 weeks between administrations, but no practice effects with 15 months between administrations.

    “Findings revealed a small 2.7-point gain with 3–5 weeks between administrations [44], yet no practice effects with 15 months between administrations [45].”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [44] Parsey, 2021, Utility of the iPad NIH Toolbox cognition battery in a clinical trial of older adults, J Am Geriatr Soc source

      The Results > Test-Retest Characteristics section reports a significant increase in Fluid Composite scores between visits averaging 28.4 days apart, consistent with a gain after roughly four weeks. Our copy does not give the claimed 2.7-point gain. The 15-month finding is attached to a different citation in the citing sentence and is not judged here; page numbers are unavailable in our copy. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [45] Scott, 2019, Psychometric properties of the NIH Toolbox cognition battery in healthy older adults: reliability, validity, and agreement with standard neuropsychological tests, J Int Neuropsychol Soc source

  • May combine two claims.

    Premisecitation

    Fluid cognitive abilities (e.g., processing speed, attention, executive functioning) decline in late life and can negatively impact older adults' ability to manage day-to-day tasks.

    “While crystallized cognition (e.g., acquired knowledge, vocabulary) is relatively preserved in late life, older adults’ ability to successfully manage day-to-day tasks can be negatively impacted by prototypical declines in fluid cognitive abilities (e.g., processing speed, attention, executive functioning) [2–4].”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [2] Salthouse, 2000, Aging and measures of processing speed, Biol Psychol source
    • cites [3] Salthouse, 2010, Selective review of cognitive aging, J Int Neuropsychol Soc source

      In “What Cognitive Variables and Abilities Are Affected?” (page unavailable), the review describes relatively preserved vocabulary and general information alongside age-related declines in processing efficiency and neuropsychological test performance. It does not establish that these declines impair older adults’ management of day-to-day tasks, and it cautions that speed is distinct from fluid ability in psychometric classifications. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [4] Murman, 2015, The impact of age on cognition, Semin Hear source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The principal mechanism of tDCS involves a subtle alteration of a neuron's resting membrane potential affecting the neuron's probability of firing.

    “The principal mechanism of action involves a subtle alteration of a neuron’s resting membrane potential affecting the neuron’s probability of firing [22].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [22] Nitsche, 2000, Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation, J Physiol source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In younger adults, applying 2mA of current for 20 minutes to the motor cortex increases cortical excitability underneath both the anode and cathode.

    “In younger adults, applying 2mA of current for 20 minutes to the motor cortex increases cortical excitability underneath both the anode and cathode [55, 56].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [55] Batsikadze, 2013, Partially non-linear stimulation intensity-dependent effects of direct current stimulation on motor cortex excitability in humans, J Physiol source
    • cites [56] Mosayebi Samani, 2019, Titrating the neuroplastic effects of cathodal transcranial direct current stimulation (tDCS) over the primary motor cortex, Cortex source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Teixeira-Santos and colleagues (2022) demonstrated that intervention-related improvements on near-transfer tasks predicted improvements on an untrained reasoning task, suggesting that far-transfer effects are directly related to the enhancement of the trained construct.

    “Similarly, Teixeira-Santos and colleagues (2022) demonstrated that intervention-related improvements on near-transfer tasks predicted improvements on an untrained reasoning task, suggesting that far-transfer effects are directly related to the enhancement of the trained construct [46].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [46] Teixeira-Santos, 2022, Working memory training coupled with transcranial direct current stimulation in older adults: a randomized controlled experiment, Front Aging Neurosci source

      Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Booster stimulation sessions offer promising therapeutic effects in individuals with fibromyalgia and drug cravings.

    “Booster stimulation sessions offer promising therapeutic effects in individuals with fibromyalgia and drug cravings [52,53].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [52] Kang, 2020, Effects of add-on transcranial direct current stimulation on pain in Korean patients with fibromyalgia, Sci Rep source
    • cites [53] Shariatirad, 2016, Cumulative and booster effects of tdcs sessions on drug cravings, lapse, and cognitive impairment in methamphetamine use disorder: a case study report, Am J Addict source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Adults ages 50-65 experience increased excitability underneath the cathode at 2mA/20min motor cortex parameters.

    “Adults ages 50–65 also experience increased excitability underneath the cathode at these parameters, while older adults ages 66–80 demonstrate slight reductions in excitability [57].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [57] Ghasemian-Shirvan, 2022, Age-dependent non-linear neuroplastic effects of cathodal tDCS in the elderly population: a titration study, Brain Stimul source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Applying 2mA to the frontal cortex during an in-scanner working memory task using the F3/F4 montage results in increased functional connectivity between left frontal regions under the cathode during active stimulation in older adults.

    “In contrast, applying 2mA to the frontal cortex during an in-scanner working memory task using the F3/F4 montage results in increased functional connectivity between left frontal regions under the cathode during active stimulation in older adults [37].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [37] Nissim, 2019, Effects of in-scanner bilateral frontal tDCS on functional connectivity of the working memory network in older adults, Front Aging Neurosci source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In a sample of 90 healthy older adults, individuals who received 2mA of stimulation combined with working memory training improved on working memory, processing speed, cognitive flexibility, arithmetic, and functional tasks after one month without contact.

    “For instance, in a sample of 90 healthy older adults, individuals who received 2mA of stimulation combined with working memory training improved on working memory, processing speed, cognitive flexibility, arithmetic, and functional tasks after one month without contact [35].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [35] Stephens, 2016, Older adults improve on everyday tasks after working memory training and neurostimulation, Brain Stimul source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Prior evidence shows enhanced cognitive performance in domains of working memory and episodic memory and evidence of transfer effects following active stimulation with cognitive training in older adults.

    “This is surprising given prior evidence of enhanced cognitive performance in domains of working memory and episodic memory and evidence of transfer effects following active stimulation with cognitive training in older adults [33–36, 46, 47].”
    Quote in the paperSubstantial claim4 of 6 sources checked
    • cites [33] Nissim, 2019, Effects of transcranial direct current stimulation paired with cognitive training on functional connectivity of the working memory network in older adults, Front Aging Neurosci source

      The Discussion reports improved working-memory performance with active stimulation plus cognitive training in older adults, and the Conclusion reports gains on an untrained working-memory task, supporting evidence of transfer. The cited paper does not report an episodic-memory improvement. Page numbers are unavailable in our copy. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [34] Park, 2014, Long-term effects of transcranial direct current stimulation combined with computer-assisted cognitive training in healthy older adults, Neuroreport source
    • cites [35] Stephens, 2016, Older adults improve on everyday tasks after working memory training and neurostimulation, Brain Stimul source

      The Discussion (page unavailable) reports that older adults improved on trained working-memory tasks and that the active 2 mA stimulation group performed better on far-transfer tasks. The Study Design describes working-memory and transfer measures, but our copy does not report an episodic-memory benefit. It also says trained-task improvement occurred regardless of stimulation group. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [36] Antonenko, 2018, Neuronal and behavioral effects of multi-day brain stimulation and memory training, Neurobiol Aging source
    • cites [46] Teixeira-Santos, 2022, Working memory training coupled with transcranial direct current stimulation in older adults: a randomized controlled experiment, Front Aging Neurosci source

      The Results and Conclusion (no page numbers in our copy) report improved working-memory task performance and transfer to short-term memory and reasoning in older adults receiving active stimulation with training. They do not report an episodic-memory outcome; working-memory task performance also improved in the sham-stimulation training group. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [47] Indahlastari, 2021, A systematic review and meta-analysis of transcranial direct current stimulation to remediate age-related cognitive decline in healthy older adults, Neuropsychiatric Dis Treat source

      The Discussion (page unavailable) reports improved working-memory performance in three of four studies pairing tDCS with extended cognitive training. The Results table (page unavailable) also reports a significant effect on a far-transfer task in a study paired with cognitive training. The review reports an episodic-memory benefit from active versus sham stimulation, but does not establish that this benefit followed stimulation paired with cognitive training. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    1-1.5cm electrode shifts can significantly alter current distribution in the brain.

    “For instance, 1–1.5cm electrode shifts can significantly alter current distribution in the brain [54].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [54] Woods, 2015, Effects of electrode drift in transcranial direct current stimulation, Brain Stimul source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Older adults ages 66-80 demonstrate slight reductions in excitability at 2mA/20min motor cortex parameters.

    “Adults ages 50–65 also experience increased excitability underneath the cathode at these parameters, while older adults ages 66–80 demonstrate slight reductions in excitability [57].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [57] Ghasemian-Shirvan, 2022, Age-dependent non-linear neuroplastic effects of cathodal tDCS in the elderly population: a titration study, Brain Stimul source

  • May combine two claims.

    Premisecitation

    Female older adults receive higher current density in targeted regions than their male counterparts, mediated by sex differences in brain structure.

    “Mediated by sex differences in brain structure, female older adults receive higher current density in targeted regions than their male counterparts [64], which may partly explain these discrepancies given the male-dominated active stimulation group in phase 1.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [64] Bhattacharjee, 2022, Sex difference in tDCS current mediated by changes in cortical anatomy: a study across young, middle and older adults, Brain Stimul source

  • May combine two claims.

    Findingown data

    In sensitivity analyses, the phase 2 one-year tDCS effect was larger but non-significant in the smaller sample of completed cases (estimate = 1.72, p = 0.11).

    “Sensitivity analyses revealed largely no differences between ITT and complete case analyses except that this phase 2 one-year tDCS effect is larger but non-significant in the smaller sample of completed cases (estimate = 1.72, p = 0.11; Table A.4).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Average ratings for each stimulation sensation were largely between 0 and 1 on a 10-point scale.

    “Notably, average ratings for each sensation were largely between 0 and 1 on a 10-point scale.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the present paper, there were improvements on the NIH Toolbox Fluid Cognition Composite immediately following the intervention that were maintained one year after baseline.

    “In the present paper, there were improvements on the NIH Toolbox Fluid Cognition Composite immediately following the intervention that were maintained one year after baseline; however, we failed to demonstrate an additive benefit of receiving active stimulation during cognitive training.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Participants, interventionists, and outcome assessors were blinded to the tDCS condition assigned.

    “Participants, interventionists, and outcome assessors were blinded to the tDCS condition assigned.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Intent-To-Treat (ITT) analyses were performed to assess the effect of tDCS on changes in FCC from baseline to post-intervention and from baseline to one-year.

    “Intent-To-Treat (ITT) analyses were performed to assess the effect of tDCS on changes in FCC from baseline to post-intervention and from baseline to one-year, with missing outcomes predicted by regression models that include demographic and baseline characteristics.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    There were no significant differences in predicting treatment condition or confidence in predictions between active and sham groups for both participant and experimenter blinding questionnaires.

    “There were no significant differences in predicting treatment condition or confidence in predictions between active and sham groups for both the participant and experimenter blinding questionnaires (Tables 3, 4).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The clinical trial statistician performed randomization procedures using a permuted block randomization with block sizes of 8 and 12 and study site as a stratification factor.

    “The clinical trial statistician performed randomization procedures using a permuted block randomization with block sizes of 8 and 12 and study site as a stratification factor.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The ACT study provides a foundational framework for the rigorous application of tDCS on a large scale.

    “As the largest randomized clinical trial in tDCS to date, the ACT study provides a foundational framework for the rigorous application of tDCS on a large scale and sheds light on the effects of tDCS combined with cognitive training in older adults.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The ACT study is the largest randomized clinical trial in tDCS to date.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    There is an increasing need for interventions to avert age-related cognitive decline in older adults.

    “With a growing older adult population, there is an increasing need for interventions to avert age-related cognitive decline [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] Ortman, 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductown data

    There were no significant baseline differences between tDCS groups in demographics, medical history, NACC UDS domain scores, Brain HQ Cognitive Training assessment composite, depression, or FCC scores.

    “There were no significant baseline differences between tDCS groups in demographics, reports of medical history, NACC UDS domain scores, the Brain HQ Cognitive Training assessment composite, depression, or FCC scores (Tables 1 and 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The present null findings are likely due to a true small tDCS effect as opposed to insufficient power to detect an effect.

    “As such, the present null findings are likely due to a true small tDCS effect as opposed to insufficient power to detect an effect.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Inter-individual differences in cognitive training engagement may have impacted response to stimulation.

    “While we demonstrated overall improvements on the primary outcome using this training paradigm, inter-individual differences in cognitive training engagement may have impacted response to stimulation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    In phase 1, there were significantly more males in the active tDCS group and females in the sham tDCS group, while sex distribution was balanced across conditions in phase 2.

    “In phase 1, there were significantly more males in the active tDCS group and females in the sham tDCS group, while sex distribution was balanced across conditions in phase 2.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    In non-pathological older adults, active stimulation combined with cognitive training may allow for better maintenance of cognitive functioning over time.

    “However, it may be the case that in non-pathological older adults, active stimulation combined with cognitive training allows for better maintenance of cognitive functioning over time.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    If active stimulation allows better maintenance, more significant discrepancies in cognitive performance may emerge between active and sham stimulation groups several years after intervention.

    “If so, more significant discrepancies in cognitive performance may emerge between active and sham stimulation groups several years after intervention.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    Those who completed more total minutes or achieved higher difficulty levels may have experienced greater benefits from stimulation.

    “For instance, those who completed more total minutes or achieved higher difficulty levels may have experienced greater benefits from stimulation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Behavioral improvements occur specifically when stimulation is paired with higher demanding tasks.

    “Cognitive training task difficulty may also impact the efficacy of tDCS, as behavioral improvements occur specifically when stimulation is paired with higher demanding tasks [67].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] Gill, 2015, It's the thought that counts: examining the task-dependent effects of transcranial direct current stimulation on executive function, Brain Stimul source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The present cognitive training and tDCS intervention may produce larger effects in individuals with greater cognitive impairment compared to the non-pathological, highly educated sample.

    “However, it may be the case that the present cognitive training and tDCS intervention produces larger effects in individuals with greater cognitive impairment compared to our non-pathological, highly educated sample.”
    Quote in the paperNot a substantial claim
33 of 33

  • The paper relies on this without support.

    A large-scale randomized clinical trial of combined tDCS and cognitive training in older adults is needed.

    “These small studies provide evidence that tDCS may potentiate the effects of cognitive training; however, large-scale randomized clinical trials are needed to further evaluate the intervention’s efficacy.”

  • The paper relies on this without support.

    Studies have yet to examine the efficacy of booster stimulation sessions on maintaining cognitive training gains.

    “However, studies have yet to examine the efficacy of booster stimulation sessions on maintaining cognitive training gains.”

  • The paper relies on this without support.

    Participants tend to habituate to the sensation of tDCS within 30–60 seconds.

    “Participants tend to habituate to the sensation of tDCS within 30–60 seconds.”

  • The paper relies on this without support.

    High blood pressure in the active group has not been shown to be related to effects of stimulation.

    “In particular, there was a greater number of individuals reporting high blood pressure in the active group (Table A.5), which has not been shown to be related to effects of stimulation.”

  • The paper relies on this without support.

    The ACT study is the largest randomized clinical trial in tDCS to date.

    “As the largest randomized clinical trial in tDCS to date, the ACT study provides a foundational framework for the rigorous application of tDCS on a large scale and sheds light on the effects of tDCS combined with cognitive training in older adults.”
5 of 5

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Authors
Hausman, H. K., Alexander, G. E., Cohen, R., Marsiske, M., DeKosky, S. T., Hishaw, G. A., O'Shea, A., Kraft, J. N., Dai, Y., Wu, S., & Woods, A. J.
Affiliations
  • University of Florida Health (US)
  • University of Arizona (US)
Corresponding author
Woods, Adam J.
ORCID
Venue
Brain Stimulation
Publisher
Elsevier BV
Published
2023-05
Volume
16
Issue
3
Pages
904-917
ISSN
  • 1876-4754 (ISSN-L)
  • 1935-861X
DOI
10.1016/j.brs.2023.05.021
PMC
PMC10436327
OpenAlex
W4378473387
Semantic Scholar
86a4f4ee539400d1d8fa4abfa963955bf70e39a2
Cited by
13
References
81
Citations by year
2026: 5 · 2025: 2 · 2024: 6
FWCI
1.34
Type
journal article
Language
en
Open access
Licence
Locations
  • Brain stimulation (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • UA Campus Repository (The University of Arizona) (acceptedVersion, cc-by-nc-nd)
  • PubMed Central (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
National Institute on Aging (P30AG019610, R01AG054077)
Topics
  • Life Sciences › Neuroscience › Neurology › Transcranial Magnetic Stimulation Studies
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
Keywords
transcranial direct current stimulation, cognitive training, older adults, cognitive decline, fluid intelligence, sham stimulation
MeSH terms
Cognitive Training, Aged, Cognition, Humans, Cognitive Dysfunction, Transcranial Direct Current Stimulation

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-28.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

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