Use of Transcranial Direct Current Stimulation (tDCS) Coupled With Constraint Induced Movement Therapy in Stroke Patient: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Use of Transcranial Direct Current Stimulation (tDCS) Coupled With Constraint Induced Movement Therapy in Stroke Patient (NCT01143649), a randomized na study. The primary outcome is Jebsen Taylor Hand Function Test.

2. Clinical Question

The study’s stated rationale was to examine whether noninvasive brain stimulation added benefit to motor learning alone in stroke patients. Its hypothesis specified greater motor-function improvement with active tDCS plus CIMT than with sham tDCS plus CIMT. That is the trial question; it is not itself evidence that the hypothesized difference occurred.

The randomized comparison is the relevant contrast for interpreting the outcome. Both arms received CIMT, while the stimulation condition differed. Accordingly, the posted comparison concerns the added contribution of active rather than sham tDCS in the context of CIMT. It does not compare CIMT with no therapy, and it does not isolate the effects of tDCS in the absence of CIMT. The registry record does not report a separate primary-outcome comparison for the healthy-participant descriptions.

3. Trial Design

The registry record describes a randomized, double-masked, parallel trial and lists an enrollment of 44. The study is marked completed, with a phase designation of NA. The sponsor is Spaulding Rehabilitation Hospital. The recorded study start is 2010-04, and primary completion is recorded as 2011-04.

The primary outcome was collected in the stroke study, designated Experiment 1 in the outcome description. The two posted outcome arms are tDCS + CIMT and Sham tDCS + CIMT, with 7 participants reported in each arm. The intervention descriptions specify 5 stimulation sessions over the primary motor cortex for stroke participants, paired with the first 40 minutes of CIMT. CIMT is described as 10 consecutive sessions Monday-Friday.

The record also contains descriptions of healthy-participant experiments involving active and sham tDCS with CIMT, and active and sham transcranial alternating current stimulation (tACS). Some of those descriptions refer to a single session, and the tACS descriptions state that active and sham order was randomized. Those descriptions are not the source of the posted primary endpoint: the registry explicitly says the Jebsen Taylor Hand Function Test was performed only in the stroke study.

The enrollment figure and the group counts attached to the primary outcome describe different aspects of the record and should not be treated as interchangeable. The registry record does not explain how enrollment relates to the stroke outcome groups and the several healthy-participant descriptions. It also does not report the randomization sequence method, concealment procedures, who was masked, or how masking was maintained. The term double-masked is recorded, but the masked parties are not identified in the registry record. More detail about the trial’s conduct is therefore not available from the posted record.

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: The Jebsen Taylor Hand Function Test was only performed in the stroke study (Experiment 1).

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.

6. Primary Endpoint

The registry lists the primary outcome as Jebsen Taylor Hand Function Test, measured over 2 weeks.

The primary endpoint was the Jebsen Taylor Hand Function Test, measured in seconds, with the registry record listing a 2 weeks timeframe. The test evaluates hand function in real-life activities by measuring the time required to perform 7 different tasks. The description says the non-constrained hand was used for the assessments and that the task times were summed for analysis.

A timed task measure represents performance through completion time: a shorter time means the tasks were completed more quickly. The endpoint therefore captures a particular aspect of hand function under the test conditions. It is not a direct measure of every dimension of motor function, daily activity, independence, or quality of life. The record does not give further details about the timing of the 2-week assessment relative to the intervention schedule.

The posted results give means and standard errors for the two stroke groups. The tDCS + CIMT group has a mean of 68.0 seconds and a standard error of 34.0; the Sham tDCS + CIMT group has a mean of 80.0 seconds and a standard error of 42.0. Each outcome group is reported with 7 participants. These are group summaries, not individual observations. The registry record does not provide a confidence interval or a reported inferential test for the difference between groups.

Using a timed, task-based endpoint makes the outcome interpretable in terms of performance speed on the specified activities. At the same time, interpretation is limited to what this test measures and to the assessment conditions described in the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a group mean describe?

For a continuous endpoint such as test time, a mean gives the arithmetic average of the observed values in a group. The registry record reports means of 68.0 seconds for tDCS + CIMT and 80.0 seconds for Sham tDCS + CIMT. These summaries describe the groups’ average task completion times under the recorded assessment conditions. They do not describe every participant, and without individual data they cannot show the range or shape of scores within each group.

The endpoint description says the times for 7 tasks were summed for analysis. That means the posted mean concerns the resulting test score, rather than a separate mean for each task. The record does not report task-level summaries or individual scores.

What does a standard error mean?

A standard error describes the sampling uncertainty of an estimated quantity, such as a group mean. It is not the same as the standard deviation, which describes variation among individual measurements. The posted standard errors are 34.0 seconds for tDCS + CIMT and 42.0 seconds for Sham tDCS + CIMT. They indicate uncertainty around each group mean; they do not directly quantify uncertainty in the contrast between the groups.

To assess a treatment contrast, an analysis would ordinarily estimate the difference between groups and its uncertainty, often using a confidence interval and a test under a stated statistical model. A confidence interval gives a range of effect values compatible with the data and the assumptions of that method. The registry record does not report a confidence interval or a p-value for the primary comparison, so neither can be described as a posted result.

Why does the analysis model matter?

General statistical principle: the method used to compare groups should reflect the trial design and the outcome being analyzed. A simple unadjusted comparison and a model that accounts for baseline values or other variables can produce different estimates and uncertainty. The registry record does not report whether the primary comparison was adjusted, what model was used, or how any repeated measurements were handled. The outcome listing alone does not establish an analysis plan.

The study is described as randomized and parallel, which identifies the broad design of the stroke comparison. Randomization is intended to make treatment assignment independent of prognostic characteristics on average, but it does not guarantee that groups will be identical, especially in a small study. The record does not report baseline characteristics for the two outcome groups, so their comparability cannot be evaluated from the posted results.

How should the posted comparison be read?

The group means can be compared descriptively, with attention to the fact that lower times indicate faster task completion. However, a difference in observed means is not by itself a test result. To support inferential statements, the uncertainty of the between-group estimate and the analysis assumptions would need to be available. Because the registry record does not report those items, the evidence should not be described as statistically significant or non-significant on the basis of these summaries.

General statistical principle: when sample sizes are limited, estimates can be imprecise and can vary substantially across samples. The reported standard errors help communicate uncertainty in each mean, but the registry record does not provide enough information to quantify the precision of the treatment contrast. No new inferential result can be recovered from the posted summaries without making assumptions that the record does not specify.

What is the role of the planning illustration?

The sample-size assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The planning effect is described as a stated fraction of the observed effect. Such an illustration is a planning exercise, not a measure of the trial’s observed power and not evidence that a target sample size was justified in the original protocol. The registry record does not report the trial’s own sample-size justification. Numerical planning results are not stated in the registry record.

General statistical principle: planning calculations depend on assumptions about the effect to detect, variability, allocation, and the chosen error rate. If the assumed effect is based on an observed result, the calculation is conditional on that estimate and does not tell whether the completed study was adequately powered. It should not be interpreted as a probability that the observed result is true.

What cannot be concluded from the available statistics?

The registry record lists no posted analyses for the primary endpoint. It also does not report a prespecified statistical analysis plan, handling of missing data, or an analysis population definition. Without these details, the posted group summaries do not establish the primary treatment-effect estimate, its confidence interval, or the result of a hypothesis test. The appropriate reading is therefore limited to the descriptive means, standard errors, and group counts recorded for the endpoint.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("tDCS + CIMT", "Sham tDCS + CIMT")
n   <- c(7, 7)
m   <- c(68, 80)
sp  <- c(34, 42)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  tDCS + CIMT  7  68.000  89.956  -15.195  151.195
CARM  Sham tDCS + CIMT  7  80.000  111.122  -22.770  182.770

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 3 outcome measures and 0 analyses, and it reports 0 secondary outcomes posted. The primary outcome is identified as the Jebsen Taylor Hand Function Test. No statistical analysis for that endpoint is reported in the registry record, and no secondary outcome result is posted in the information.

Multiplicity concerns arise when several outcomes, timepoints, or comparisons are tested. General statistical principle: evaluating many hypotheses can increase the chance that at least one result appears noteworthy by chance, so a study may specify how to control or interpret multiple testing. The registry record does not report a multiplicity adjustment or explain whether one was planned. The number of listed outcome measures alone does not establish how many statistical tests were conducted.

The primary endpoint has a stated timeframe of 2 weeks. The record does not report multiple timepoint results for this outcome or indicate whether the posted means are endpoint measurements, changes from baseline, or another summary. It also does not report whether baseline adjustment was planned.

Missing-data handling is not reported in the registry record. The posted group counts describe the outcome summaries, but the record does not state whether any randomized participants lacked measurements, how missing values were treated, or whether the analysis included all randomized participants. An intention-to-treat analysis, a complete-case analysis, or another approach should not be attributed to the trial without documentation.

The registry record does not identify a per-protocol population or provide a detailed analysis-population definition. These omissions limit assessment of how participants were included in the reported summaries and how robust any treatment comparison would be to missing data or analysis choices.

12. Safety Results

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

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 record lists 0 serious adverse events among 7 participants at risk in the tDCS + CIMT - Stroke group and 0 among 7 at risk in the Sham tDCS + CIMT - Stroke group. It also records 0 other adverse events in each of those stroke groups. Separate healthy-participant groups are listed with 10 participants at risk and 0 serious and 0 other adverse events for each listed group.

These are counts in the registry record, not estimates of comparative risk. A zero count in a group means no event of that category was recorded for the participants at risk in that row; it does not establish that the true event probability is zero. The record does not provide confidence intervals for the event counts or a formal safety comparison between groups.

Deaths are not reported in the registry record. No serious adverse-event terms are listed. The adverse-event information should be read within the groups and at-risk counts shown, and not extended to events or participants beyond what is recorded. The registry record does not describe the adverse-event collection method, observation period, or criteria used to classify events.

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

The registry record documents a randomized comparison of active tDCS plus CIMT against sham tDCS plus CIMT in stroke patients, with hand-function test time as the primary outcome. It provides group means, standard errors, and group counts for the outcome at the stated 2 weeks timeframe. Those figures make it possible to describe the posted results, but not to establish the inferential result of the primary comparison.

The mean task time is 68.0 seconds in the active tDCS group and 80.0 seconds in the sham group. Since the test measures time to complete tasks, the lower mean represents quicker average completion in that group. However, the registry record does not report an estimate of the between-group difference, its confidence interval, or a hypothesis-test result. The means therefore do not show whether the observed contrast is distinguishable from sampling variability.

The outcome is specific to the summed time for 7 tasks using the non-constrained hand. It should not be treated as a complete measure of motor function or as a measure of every aspect of everyday performance. The registry record does not report a threshold for a clinically important difference, nor does it provide enough information to interpret the observed contrast as a meaningful change for patients.

The findings also do not answer questions beyond the comparison studied. Both stroke groups received CIMT, so the posted outcome does not compare CIMT with no CIMT. The registry record’s healthy-participant descriptions do not contribute primary outcome results, because the endpoint was recorded only for the stroke study. The described tACS experiments should not be conflated with the stroke tDCS comparison.

In short, the posted results are descriptive and incomplete for judging the study hypothesis. They record observed group summaries, not a confirmed treatment effect. No conclusion about benefit, lack of benefit, or clinical effectiveness can be drawn from the registry record’s primary outcome summaries alone.

14. Why This Trial Matters Statistically

This trial is statistically interesting because its question concerns the incremental contribution of stimulation when both stroke groups receive a rehabilitation procedure. That makes the active-versus-sham contrast central: the comparison is not stimulation versus no rehabilitation, but active tDCS plus CIMT versus sham tDCS plus CIMT. Clear interpretation depends on keeping that contrast distinct from the additional healthy-participant experiments listed in the record.

The outcome is a continuous, timed measure. Reporting group means and standard errors gives readers information about the recorded averages and their uncertainty as estimates. Yet descriptive summaries are not a substitute for a treatment-effect estimate with uncertainty. The absence of a posted inferential analysis makes this record a useful example of why outcome values alone may not answer a trial’s comparative question.

The record also illustrates how trial registrations can contain multiple experiments and intervention descriptions while the primary outcome applies to only one part of the study. The outcome description explicitly limits the Jebsen Taylor Hand Function Test to the stroke study. Interpreting the posted means in that scope avoids mixing results across different populations or stimulation procedures.

Finally, the record separates completion status from the completeness of results reporting. The study is marked completed, but the registry record does not include a posted analysis for the primary endpoint, secondary outcome results, or a statistical analysis plan. For clinical researchers, that distinction matters: a completed study can have outcome summaries in the record while still lacking the information needed to evaluate an effect’s precision, analysis assumptions, and robustness.

15. 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 main limitation for statistical interpretation is that the registry record reports primary outcome group means and standard errors but no inferential analysis. It does not provide a treatment-effect estimate, confidence interval, p-value, or the statistical model used. As a result, the precision and statistical compatibility of the between-group contrast cannot be assessed from the record.

The posted outcome groups each contain 7 participants. The record does not report baseline endpoint values or participant-level results, so it is not possible to assess individual variation, baseline balance on the outcome, or changes over time. It also does not explain how the enrollment of 44 relates to the outcome groups and the several study descriptions.

The record does not report a statistical analysis plan, sample-size justification, missing-data approach, or analysis-population definition. The absence of these details prevents assessment of whether the posted summaries follow a prespecified plan or how missing measurements and exclusions were handled. The planning assumptions described in the record are illustrations based on an observed effect, not a report of the trial’s own design justification.

The primary outcome is limited to a timed test of the non-constrained hand, with summed task time used for analysis. The record does not report the clinical importance threshold for this measure or additional information needed to interpret whether a difference would matter to patients. The timeframe is stated as 2 weeks, but further timing details are not reported in the registry record.

Descriptions of healthy-participant tDCS and tACS experiments add complexity to the registry record, while the primary endpoint applies only to the stroke study. The record does not fully explain how its total enrollment relates to all described groups. Masking is recorded as double, but the masked parties and procedures are not specified. These gaps limit evaluation of trial conduct and the scope of conclusions.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Use of Transcranial Direct Current Stimulation (tDCS) Coupled With Constraint Induced Movement Therapy in Stroke Patient — NCT01143649.
• Registry record last updated 2020-04-24; status last verified 2020-04.
• Results first posted 2017-03-06.
• 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.

19. Record Summary

The registry record identifies NCT01143649 as a completed randomized, double-masked, parallel study sponsored by Spaulding Rehabilitation Hospital. It lists enrollment of 44, a phase designation of NA, a start of 2010-04, and primary completion of 2011-04.

The primary outcome was the Jebsen Taylor Hand Function Test, measured in seconds at 2 weeks, and was performed only in the stroke study. The posted means are 68.0 seconds for tDCS + CIMT and 80.0 seconds for Sham tDCS + CIMT; each group is reported with 7 participants. The corresponding standard errors are 34.0 and 42.0.

The registry record does not report an inferential analysis for the primary outcome, secondary outcome results, a statistical analysis plan, or details of missing-data handling. The adverse-event listings report 0 serious and 0 other adverse events in the listed groups; deaths are not reported in the registry record.