Priming Expectations and Motor Learning With tDCS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Priming Expectations and Motor Learning With tDCS (NCT06039605), a randomized na study. The primary outcome is Performance on Motor Task One Week After Final Training Session.

2. Clinical Question

3. Trial Design

The study is titled “Priming Expectations and Motor Learning With tDCS,” with the official title “Effects of Modulating Expectations About Noninvasive Brain Stimulation on Motor Learning.” The registry describes a randomized, double-masked, parallel-group study. Its phase is listed as NA, and the status is COMPLETED. Arizona State University is listed as the sponsor. The registry record lists enrollment of 140, with a start date of 2023-10-23 and primary completion on 2025-04-16.

There are four arm descriptions. Control received motor training only. The other groups received motor training with tDCS, with two groups reading different information about tDCS before training and stimulation. The tDCS1 description says participants received either sham or active stimulation concurrently with training. The available tDCS1 description of the sham procedure ends partway through its description, so the full stimulation schedule cannot be reconstructed from the registry text. Details about how participants were assigned to the sham or active stimulation condition within that arm are not reported in the registry record.

The stated motor-training schedule for Control was 10 trials per day across 3 days, followed by 2 trials at a one-week follow-up. The primary endpoint uses the average of two task trials at the Day 10 follow-up. The task involves moving two raw kidney beans at a time from a start cup to three target cups as quickly as possible, requiring multijoint coordination and limb reversal. The registry record also lists secondary measures of performance during training, dwell time, peak reach velocity, expectations, and post-stimulation symptoms. It does not report the original statistical plan, the rationale for the enrollment target, or the allocation details beyond randomized parallel assignment.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: All subjects who were randomized, completed the study and had no missing Day 1 expectancy data.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: All subjects who were randomized, completed the study and had no missing Day 1 expectancy data.

6. Primary Endpoint

The registry lists the primary outcome as Performance on Motor Task One Week After Final Training Session, measured over One-Week Follow-Up visit (Day 10).

The primary endpoint is performance on the motor task one week after the final training session, at the One-Week Follow-Up visit (Day 10). Each participant’s measure is described as the average of two timed trials. Time is recorded in seconds, and the registry specifies a mean as the summary measure, with standard deviation as the measure of spread.

The task asks participants to spoon two raw kidney beans at a time from a center proximal start cup to three distal target cups as quickly as possible. It is intended to assess multijoint coordination and limb reversal. Because the task is timed, a lower value represents less time taken to complete the task; however, the analysis must still be interpreted in light of the uncertainty around the group contrast.

A follow-up endpoint addresses performance after the training period rather than performance only during practice. That makes it relevant to the stated interest in motor learning and retention at the one-week visit. The registry record defines the primary analysis population as all subjects who were randomized, completed the study, and had no missing Day 1 expectancy data. It does not report further details about handling missing primary outcome values or explain why the Day 1 expectancy condition is part of the population definition.

7. Results Posted in the Registry

• tDCS1: mean 48.02 versus 48.50 on control; difference -0.48 (95% CI -3.77 to 2.81), standardized effect d = -0.08; z-test p = 0.775.
• tDCS2: mean 47.14 versus 48.50 on control; difference -1.36 (95% CI -4.89 to 2.17), standardized effect d = -0.20; z-test p = 0.450.
• tDCS3: mean 47.23 versus 48.50 on control; difference -1.27 (95% CI -4.81 to 2.27), standardized effect d = -0.18; z-test p = 0.482.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Change in Motor Performance Over the Course of Training

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • tDCS1: mean -0.09 versus 0.45 on control; difference -0.54 (95% CI -1.77 to 0.69), standardized effect d = -0.23; z-test p = 0.390.
  • tDCS2: mean 0.04 versus 0.45 on control; difference -0.41 (95% CI -1.62 to 0.80), standardized effect d = -0.18; z-test p = 0.506.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS1 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS2 and the control. The interval gives the range of effects that remain compatible with the data.

Average Dwell Time

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • tDCS1: mean 18.02 versus 18.39 on control; difference -0.37 (95% CI -2.48 to 1.74), standardized effect d = -0.09; z-test p = 0.732.
  • tDCS2: mean 17.90 versus 18.39 on control; difference -0.49 (95% CI -2.62 to 1.64), standardized effect d = -0.11; z-test p = 0.653.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS1 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS2 and the control. The interval gives the range of effects that remain compatible with the data.

Average Peak Reach Velocity

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • tDCS1: mean 0.11 versus 0.16 on control; difference -0.05 (95% CI -0.14 to 0.04), standardized effect d = -0.33; z-test p = 0.295.
  • tDCS2: mean 0.12 versus 0.16 on control; difference -0.04 (95% CI -0.14 to 0.06), standardized effect d = -0.23; z-test p = 0.433.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS1 and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between tDCS2 and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover different aspects of motor performance and expectations. They include performance over training, dwell time, peak reach velocity, changes and variability in tDCS expectations, post-tDCS symptom questionnaire score, and tDCS expectation scores. The posted continuous summaries and recalculated comparisons cover only some of these measures; reported analyses are not listed for the secondary outcomes.

Across the posted secondary comparisons, the estimates do not provide a consistent pattern of clearly separated group means. The uncertainty around the recalculated contrasts is substantial, and the recorded measures capture different features of performance rather than repeated versions of the primary task-time outcome. They should therefore be treated as complementary descriptions, not as independent confirmation of a single primary finding.

The primary endpoint concerns timed task performance at the one-week follow-up. Training-course performance and movement measures at follow-up can offer context about the process or components of task performance, but they do not replace the primary outcome. Expectation measures address a proposed pathway of the study, while symptom scores address a different outcome domain. A pattern in one measure would not automatically establish a corresponding effect on another.

Unadjusted secondary comparisons carry less weight because the registry record does not report a prespecified hierarchy or multiplicity adjustment. With many outcomes and contrasts, some estimates can appear unusual by chance. Also, no reported analyses are listed for these secondary outcomes, so the recalculated comparisons are not evidence of a sponsor-confirmed model. Interpretation should emphasize the overall uncertainty and the distinct roles of the measures rather than selecting individual estimates as decisive.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Change in Motor Performance Over the Course of Training
• Change in tDCS Expectations From Day 1 to Day 10
• Average Dwell Time
• Average Peak Reach Velocity
• Variability in Transcranial Direct Current Stimulation Expectations
• Post-tDCS Symptom Questionnaire Score
• tDCS Expectation Scores

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a time in seconds, summarized as a mean for each arm. A mean expresses the average measured task time in a group. The standard deviation describes how spread out individual measurements are around that group mean. It is not the same as the uncertainty in the mean or in a difference between means.

What is the group contrast?

The recalculated comparisons use Control as the reference and report a mean difference for each tDCS group. The estimate is the tDCS group mean minus the Control mean, consistent with the displayed values. A negative estimate therefore means the observed average time was lower in the tDCS group; a positive estimate would mean it was higher. The contrast describes the difference between group averages, not the change experienced by every participant and not an individual-level prediction.

The comparisons are unadjusted recalculations from posted summary statistics. They do not account for covariates or other model terms. The registry record does not report a sponsor inferential analysis for the primary outcome, and its original statistical model is not reported in the registry record. The recalculations should therefore be read as a transparent summary comparison rather than as a reconstruction of an undocumented analysis.

What does a confidence interval describe?

A confidence interval gives a range of values compatible with the observed estimate under the assumptions of the method used. It communicates uncertainty around the estimated mean difference. A narrower interval is more precise; a wider interval is less precise. If an interval includes zero, the data do not distinguish the estimated contrast from no difference at the corresponding confidence level. That does not mean the true difference is exactly zero, and it does not prove that groups are equivalent.

The reported primary intervals all include zero. Their interpretation is especially important because the point estimates alone might otherwise be mistaken for evidence that the intervention groups had meaningfully shorter task times. The intervals also include values on the other side of zero, so the observed data are compatible with differences in either direction. The registry record does not identify a clinically important difference in seconds, so the practical importance of any value within these intervals cannot be determined from the record.

How should the p-values be read?

The p-values are unadjusted. In general, a p-value measures how unusual data at least as incompatible with a specified null model would be if that model were true, under the analysis assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of a difference. A larger p-value does not prove no effect. Here, p-values accompany estimates and confidence intervals; the estimates and their uncertainty are essential to interpretation.

Because several groups are compared with the same Control group, the comparisons are related. Testing multiple contrasts can increase the chance of at least one apparently notable result by chance if no adjustment or prespecified testing strategy is used. The registry record does not report how multiplicity was handled. The recalculated p-values should not be treated as adjusted evidence, and they should not be ranked as if they were independent trials.

Why do group sizes and spread matter?

Precision depends on the amount of information in the comparison, including the number of observations and the variability of measurements. Larger within-group spread generally makes a mean difference harder to estimate precisely when other features are similar. The arm summaries report standard deviations, and the comparison calculations use them. The primary outcome population is defined by randomization, completion, and availability of Day 1 expectancy data; the registry record does not explain missing-data handling beyond that definition.

General statistical explanation: estimates based on finite samples vary from sample to sample. Confidence intervals represent this sampling uncertainty under their model assumptions, but they do not automatically account for selection bias, measurement problems, incomplete follow-up, or unreported analysis choices. A randomized design can support comparison of assigned groups, but the interpretation still depends on conduct, outcome availability, masking, and analysis details. Several of those details are not reported in the registry record.

The posted recalculations use simple unadjusted comparisons, while the original trial’s own statistical plan is not reported in the registry record. No reported analysis entries are available for the listed secondary outcomes. These limitations mean that the descriptive summaries are informative about the observed sample, but the record does not establish that every outcome was analyzed according to a prespecified model or testing hierarchy.

11. Confidence Intervals and Precision

The primary mean-difference intervals are wide enough to include zero and values on either side of zero. For tDCS1 versus Control, the estimate is -0.48 seconds with a 95% confidence interval from -3.772 to 2.812. For tDCS2 versus Control, the estimate is -1.36 seconds with an interval from -4.89 to 2.17. For tDCS3 versus Control, the estimate is -1.27 seconds with an interval from -4.809 to 2.269.

These ranges show that the point estimates are uncertain. For each contrast, the data are compatible with a lower average time in the tDCS group, little or no difference, or a higher average time. The intervals do not establish equivalence, because the registry record does not report a prespecified equivalence margin. It also does not report a threshold for what would count as an important difference in task time, so clinical or practical importance cannot be judged from the intervals alone.

Precision is distinct from statistical significance. The interval communicates a range of plausible contrasts under the recalculation’s assumptions, while the p-value summarizes evidence relative to a null model. Neither statistic provides a probability that a treatment works. The registry record does not report a sponsor analysis for these primary contrasts, so the recalculated intervals should be read as unadjusted estimates based on the posted arm-level means and standard deviations.

The group standard deviations and outcome counts are relevant to the uncertainty, but they cannot resolve limitations in the record such as missing-data handling, the original model, or the method used to address multiple comparisons. In general, a confidence interval is most informative when considered together with the study design, the analysis population, measurement quality, and the importance of differences across the interval.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total participants across the study. The registry’s planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It sets the effect to detect as a stated fraction of the observed effect. The trial’s own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column means the number of participants per arm the illustration estimates would be needed for an 80% chance of detecting the specified effect under those planning assumptions, if that effect and model were correct. The 90% power column gives the corresponding planning count for a 90% chance. These percentages describe prospective design targets, not the probability that the trial’s findings are true. They are not observed power.

Planning for 100% of the observed effect uses the observed estimate as the target effect. Planning for 75% or 50% of the observed effect assumes a smaller target difference. Smaller effects are harder to distinguish from sampling variation, so the illustration calls for more participants per arm as the target effect gets smaller. The displayed figures vary by contrast because the observed effect estimates vary.

These calculations are illustrations, not evidence about the adequacy of the original trial’s design. They depend on assumptions about allocation, significance level, distributional approximation, and target effect. They do not account for unreported features such as missing outcomes, multiplicity, or any original analysis model. They should not be interpreted as a retrospective claim about whether the study was powered for its original objectives.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.480; pooled standard deviation σ = 6.213.
2. n = 2 × (1.96 + 0.842)² × 6.213² / -0.480² = 2,629.6, rounded up to 2,630 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.479999999999997                      # observed difference in means
sigma <- 6.21252122732792                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(6039605)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 2,630 (80% power), 3,521 (90% power)
 75% of observed effect: n per arm = 4,675 (80% power), 6,259 (90% power)
 50% of observed effect: n per arm = 10,519 (80% power), 14,082 (90% power)
power.t.test: 2630.6 
Simulated power at n = 2,630 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists several primary comparisons against Control and multiple secondary outcomes. It does not report a multiplicity adjustment, a prespecified order for testing outcomes, or a rule for interpreting findings across the outcome set. Without such a plan, repeated testing can make isolated small p-values less persuasive as confirmatory evidence. The recalculated p-values are unadjusted, and no adjusted values should be inferred from them.

The primary population is described as all subjects who were randomized, completed the study, and had no missing Day 1 expectancy data. This is a specific analysis-population definition. It is not enough to determine whether all randomized participants were included in the primary comparison, because the registry record does not report the flow from randomization through completion or the number excluded for missing expectancy data. It also does not report how missing primary endpoint observations were handled, whether any values were imputed, or whether sensitivity analyses were conducted.

Observed counts differ among posted outcome summaries. Such variation can reflect outcome availability or analysis-population definitions, but the reasons for the differences are not reported in the registry record. It would be inappropriate to infer why particular outcomes have different counts or to assume that missingness was unrelated to outcome or group assignment.

The registry record does not report the trial’s original statistical plan, the model used by the sponsor, interim analyses, or a sample-size justification. Those omissions limit assessment of whether the posted comparisons follow prespecified decisions. The record also does not report a detailed participant flow, protocol deviations, or the treatment of any deviations in analysis. These are important context for interpreting randomized comparisons and for judging how robust results may be to missingness and analytic choices.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event summary reports serious and other adverse events by group. For Control, the number at risk was 25 for each category, with 0 serious and 0 other events reported. For tDCS1, the number at risk was 38 for each category, with 0 serious and 0 other events. For tDCS2, the number at risk was 38 for each category, with 0 serious and 0 other events. For tDCS3, the number at risk was 39 for each category, with 0 serious and 0 other events. Deaths were reported as 0 in every group.

These are the counts recorded in the registry, not evidence that no symptoms or other experiences occurred outside the reported categories. A zero count means no event in that category was recorded in the posted summary for the stated group. The registry record does not give further event terms, severity details for non-serious symptoms, or a fuller account of how adverse events were collected. It separately lists a post-tDCS symptom questionnaire as a secondary outcome, but no result for that measure is included among the posted secondary summaries.

Safety counts should be interpreted in light of the number at risk and the scope of event reporting. They describe this study record and do not establish the absence of risk more broadly.

16. What the Result Does, and Does Not, Mean

The posted results describe average performance on a specific bean-transfer motor task at the one-week follow-up. In the arm summaries, mean times were 48.5 seconds for Control, 48.02 seconds for tDCS1, 47.14 seconds for tDCS2, and 47.23 seconds for tDCS3. The unadjusted recalculated differences from Control were modest in the context of the uncertainty reflected by their confidence intervals, all of which include zero.

This means the posted data do not clearly distinguish the group averages at that follow-up. It does not show that the groups are exactly the same, nor does it establish that tDCS or expectation priming has no effect. The intervals include possible differences in both directions, and the record does not state what magnitude of time difference would be important for this task.

The findings also do not isolate the contribution of expectation priming. The tDCS2 and tDCS3 groups received information before training and stimulation, but those comparisons with Control also differ in receiving tDCS. The record does not report a specific analysis that directly contrasts the two priming approaches or separates expectation effects from stimulation effects. The trial’s design and posted results therefore should not be interpreted as establishing a mechanism.

Results on this task and at this follow-up do not automatically apply to other motor tasks, other time points, or different populations. Nor do the registry’s zero adverse-event counts establish that tDCS is free of adverse effects. They describe only the recorded categories and groups in this study.

Finally, the posted primary comparisons are unadjusted recalculations from summary statistics. The sponsor’s inferential analysis, original model, missing-data strategy, and multiplicity procedure are not reported in the registry record. Interpretation should keep those limitations alongside the estimates rather than treating any one statistic as a complete answer to the study question.

17. Why This Trial Matters Statistically

This study raises a statistical question that is not limited to whether stimulation is active or sham: expectations about stimulation may also shape what participants anticipate and how outcomes are measured. The trial includes two groups that read different information about tDCS before training and stimulation, which makes expectation a central part of the study question. That feature makes clear definitions of comparisons especially important.

The outcome is a measured task time, and the primary result is expressed as a difference in group means. This is a useful setting for distinguishing the observed point estimate from its precision. The estimates favor lower times in the tDCS groups, but the confidence intervals include zero and remain compatible with differences in either direction. Reporting both is essential: a point estimate alone can appear more definitive than the data warrant.

The record also illustrates why multiple outcome domains require a clear analysis strategy. Motor performance, expectations, and symptoms address different questions. If many measures and contrasts are examined without a reported testing hierarchy or multiplicity handling, isolated results should not be treated as definitive confirmation. The absence of reported secondary analyses and missing-data details limits how fully the outcome pattern can be assessed.

Finally, planning illustrations based on observed effects are not evidence of the original study’s design adequacy. They show how a future planning calculation changes with the target effect under stated assumptions, while the original design justification is not reported. Separating prospective planning from retrospective claims about power helps prevent the observed results from being overinterpreted.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record gives an incomplete arm description for tDCS1: the posted sham-stimulation text ends partway through its description. It also does not specify in the available arm details how active and sham stimulation were distributed within the tDCS groups. This limits a detailed reconstruction of the intervention and of the contrasts represented by the posted group summaries.

The primary population definition requires completion and no missing Day 1 expectancy data, but the record does not give participant flow or explain the consequences of that criterion. Outcome counts vary across summaries, and reasons for differences are not reported. The handling of missing endpoint data, protocol deviations, and sensitivity analyses is not reported in the registry record.

There is no reported primary sponsor analysis or original statistical plan in the registry record, and no secondary reported analyses are listed. The recalculated comparisons are unadjusted. The registry record does not report how it handled the multiple primary contrasts and numerous secondary outcomes, or whether the analysis population and models were prespecified.

The primary outcome is a timed task at one follow-up visit. The record does not report a threshold for a practically important time difference, and results from this task cannot establish performance on other tasks or over other time horizons. The posted safety summary gives zero serious and other events in each group but does not provide a fuller account of event collection or symptom results. These limitations constrain interpretation of efficacy, mechanism, generalizability, and safety.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Priming Expectations and Motor Learning With tDCS — NCT06039605.
• Registry record last updated 2026-07-31; status last verified 2026-06.
• Results first posted 2026-07-31.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

The registry record describes a completed randomized, double-masked, parallel-group study sponsored by Arizona State University, with enrollment listed as 140. The study evaluates motor training with tDCS and the role of information intended to prime expectations about tDCS. Control received motor training only; tDCS2 and tDCS3 read different information before receiving the same training and stimulation as tDCS1.

The primary outcome is mean timed motor-task performance at the one-week follow-up, based on two trials. Posted group means are accompanied by unadjusted recalculated comparisons with Control. All three recalculated confidence intervals include zero, and the registry record does not report sponsor inferential analyses or an original statistical plan. Secondary outcomes span training performance, movement measures, expectations, and symptoms; no reported secondary analyses are listed. The adverse-event summary records zero serious events, zero other events, and zero deaths in each group.