BCI-FES Therapy for Stroke Rehabilitation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for BCI-FES Therapy for Stroke Rehabilitation (NCT04279067), a randomized na study. The primary outcome is Gait Velocity.

2. Clinical Question

3. Trial Design

This is a randomized, parallel-group trial with single masking. The registry lists an enrollment of 62 and identifies the trial as completed. The sponsor is the University of California, Irvine. The recorded start date is 2020-05-15, and the primary completion date is 2024-09-05. The phase is listed as not applicable.

The conditions are ischemic stroke and hemorrhagic stroke. The named study arms are BCI-FES dorsiflexion therapy with physiotherapy and dose-and-intensity-matched physiotherapy. The registry also lists BCI-FES dorsiflexion therapy, physiotherapy one hour, and physiotherapy two hours among the interventions. It does not report how those intervention listings map onto the treatment arms, so the precise treatment schedule should not be inferred from their names alone.

The BCI-FES description refers to EEG recording during attempted foot dorsiflexion on the paretic side and use of a custom BCI system. The comparator description refers to conventional physical therapy activities, including range-of-motion exercises and lower-extremity strengthening. The complete arm procedures are not reported in the registry record.

Random allocation is intended to support a fair comparison by reducing systematic differences between groups at assignment. A parallel design means the assigned groups are compared over the study period rather than participants crossing between treatments. The record identifies single masking but does not state who was masked or how masking was maintained. The allocation procedure, concealment details, and exact treatment exposure are not reported in the registry 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: Difference due to dropouts.

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 Gait Velocity, measured over Baseline to End of Therapy (4 weeks after initiation of therapy).

The primary endpoint is gait velocity, measured in meters per second. The assessment uses the time needed to traverse the middle 6 m of a 10-m walkway, with 5 repetitions at each assessment. The registry states that higher scores indicate better function. The primary timeframe is change from baseline to the end of therapy, described as four weeks after initiation of therapy.

Walking speed is a continuous measure: it can take values across a range rather than placing each participant into a small set of categories. It provides a way to quantify walking performance and to compare average change between treatment groups. Repeated traversals are part of the stated assessment procedure; how the repetitions are combined into a participant-level value is not reported in the registry record.

The registry describes the primary measure as a mean with standard deviation as its dispersion summary. A mean describes the central value across observations, while a standard deviation describes how spread out those observations are around the mean. These summaries can help characterize both the typical measured gait velocity and variation among participants. The posted record does not provide the endpoint values, changes, or a between-group estimate, so the size and precision of the primary comparison cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary endpoint as a continuous measure summarized by a mean and standard deviation. General statistical explanation: a continuous outcome retains information about the measured value, rather than reducing observations to categories such as improved or not improved. A mean summarizes the center of the observed values, while a standard deviation describes variability. These summaries do not, on their own, establish whether groups differ; interpretation also depends on the estimated contrast, its uncertainty, and the analysis method.

What does randomization contribute?

In general, random allocation aims to make treatment groups comparable at the time of assignment, including with respect to factors that are measured and factors that are not measured. It does not guarantee that every characteristic will be balanced in a particular trial. The registry identifies the design as randomized and parallel, but does not report the sequence-generation or allocation-concealment procedures. It also does not report baseline outcome summaries that could be used to describe observed group balance.

In a parallel-group analysis, the main comparison would ordinarily concern the outcome under each assigned strategy over the stated follow-up period. For this trial, the registry defines the primary timeframe as baseline to the end of therapy, four weeks after initiation. It does not report whether the intended analysis compares endpoint values, changes from baseline, or another model-based contrast. The exact statistical model and covariate adjustment plan are not reported in the registry record.

How should a confidence interval be understood?

General statistical explanation: a confidence interval expresses uncertainty around an estimated quantity under a specified procedure and its assumptions. A narrower interval indicates greater statistical precision, while a wider interval indicates less precision. The interval is not a measure of the probability that a particular fixed effect lies within the calculated bounds. Because no primary estimate or interval is reported, the precision of the gait-velocity comparison cannot be evaluated for this trial.

What can a significance test establish?

General statistical explanation: a significance test evaluates how compatible the observed data are with a null hypothesis under an analysis model. A small p-value is not a measure of treatment benefit, nor does it describe the magnitude of an effect. A non-small p-value does not establish that groups are equivalent. Effect estimates and their uncertainty are important for interpreting a comparison. The registry record does not report a primary test or p-value, and its analysis count is 0.

What does the planning illustration represent?

The registry describes a sample-size planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. The illustration is planning information, not evidence about the actual precision or success of this trial; it is not observed power. No planning estimates are reported in the registry record. The record’s stated convention is that non-time-to-event planning quantities refer to participants per arm. No new sample-size values can be interpreted without the missing estimates.

General statistical explanation: planning calculations depend on assumptions about the effect to detect, variability, allocation, and the analysis method. They describe a design scenario, not a probability that a completed trial has found a true effect. A calculation based on an observed effect is especially dependent on the stability of that estimate. Here, the registry record does not provide the outcome effect or variability needed to assess the illustration’s numerical implications.

Why does variability matter?

General statistical explanation: greater variability in a continuous outcome can make a group contrast less precise, because measurements are more dispersed around their group summaries. If observations are more variable than a simple model allows, over-dispersion can make uncertainty estimates too small unless the analysis accounts for it. The registry names standard deviation as the dispersion measure but does not report its value, nor does it describe any model for over-dispersion. No claim about the amount of variability or the adequacy of a model is possible.

What is not available about the analysis?

The registry does not report the primary analysis model, a prespecified estimand, adjustment variables, confidence intervals, test statistics, or analysis population. The record also flags that several outcome categories or time points were not reduced to one comparison. These gaps prevent reconstruction or appraisal of the primary statistical analysis. The available design description should therefore be kept separate from any conclusion about treatment effects.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists secondary outcomes of dorsiflexion range of motion, gait endurance measured by the Six Minute Walk Test, fall frequency, and an EEG map. It also identifies 5 outcome measures, but the relationship between that count and the listed measures is not explained. The primary outcome is noted as having several categories or time points and is not reduced to one comparison. The complete set of planned comparisons and the selection of any primary time point are not reported in the registry record.

When many outcomes, time points, or subgroup comparisons are examined, the chance of obtaining at least one apparently unusual result can increase. General statistical practice may address this through prespecified outcome hierarchies or multiplicity adjustments, but the registry does not report whether such an approach was planned or used. There are no posted analyses from which to determine how multiple comparisons were handled.

The primary outcome population description reads “Difference due to dropouts.” This does not specify which participants were included in an analysis or how missing measurements were handled. The number with missing gait-velocity observations, reasons for missingness, imputation procedures, and sensitivity analyses are not reported in the registry record. Missing data can affect both the estimate and its uncertainty, particularly if missingness is related to health status or treatment experience.

The record does not identify an intention-to-treat or per-protocol analysis population. It also does not report whether participants were analyzed according to random assignment, whether adherence was considered, or how withdrawals were incorporated. These are important features of an analysis plan, not details that can be inferred from randomization alone. With no reported endpoint results or analysis methods, neither multiplicity control nor missing-data assumptions can be evaluated.

11. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cardiac events (9.4%), severe adverse events (unrelated to study procedures) (6.7%), falls with injury (unrelated to study procedures) (6.2%), orthopedic injuries (3.1%).

The registry reports serious adverse event counts for the two named groups. For BCI-FES dorsiflexion therapy with physiotherapy, 7 serious events are reported among 32 at risk. For dose-and-intensity-matched physiotherapy, 3 serious events are reported among 30 at risk. The record also reports other adverse event counts: 3 among 32 at risk in the BCI-FES group and 2 among 30 at risk in the physiotherapy group. Deaths are reported as 0 in each group.

These are descriptive counts. The registry does not report event-level detail, timing, severity grading beyond the serious/other distinction, or a statistical comparison between groups. It does not clarify whether participants could experience more than one event or how events were attributed. The counts therefore should not be treated as numbers of affected participants unless that definition is confirmed in the registry.

The record lists cardiac events at 9.4%, severe adverse events unrelated to study procedures at 6.7%, falls with injury unrelated to study procedures at 6.2%, and orthopedic injuries at 3.1% among the top serious terms. The denominator and arm-specific attribution for these percentages are not reported in the registry record. They cannot be directly compared with the group counts without those details. Safety counts alone do not establish a causal relationship to either intervention.

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

The registry record establishes that a randomized, parallel-group stroke-rehabilitation trial was completed and identifies gait velocity as its primary outcome. It describes a comparison between BCI-FES dorsiflexion therapy with physiotherapy and dose-and-intensity-matched physiotherapy. It also reports adverse-event counts. These details explain the study question and some features of the available record.

They do not establish whether gait velocity changed, whether changes differed between groups, or how precise any difference might be. The registry does not report the primary outcome values, an effect estimate, a confidence interval, or a test result. Completion status is not evidence of a favorable, unfavorable, or null result. The trial’s rationale describes a hypothesis about BCI-FES, but a hypothesis is not an outcome finding.

Nor does the absence of a reported comparison establish that the treatments have the same effect. Similarity, benefit, or harm cannot be determined without outcome estimates and their uncertainty. The safety counts are also not a substitute for the primary endpoint and do not, by themselves, show that an event was caused by an intervention.

In general, a treatment-effect estimate describes the observed contrast for the participants and setting studied. Its interpretation depends on the trial conduct, outcome measurement, missing data, analysis population, and statistical model. The registry does not report enough information to assess these features fully. Further, the relationship between the intervention listings and the named arms is not clear in the record.

The appropriate interpretation is therefore limited: the registry identifies the clinical question, design, endpoint, and selected safety information, but does not post primary results. No conclusion about comparative effectiveness, clinical importance, or treatment equivalence can be drawn from the available outcome information.

13. Why This Trial Matters Statistically

This trial is statistically notable because it asks a comparative question using a continuous functional outcome. Gait velocity is measured in meters per second, and the registry describes an assessment based on repeated traversals of a walkway. Such a measure can represent graded differences in performance, but interpretation requires the actual group summaries and a clearly defined comparison.

The randomized parallel design is relevant because it is intended to support a comparison between assigned treatment strategies. Yet design labels do not replace analysis results. To understand the evidence, readers need the estimated between-group contrast, a measure of uncertainty, and details of the analysis population and missing-data handling. These are not reported in the registry record.

The record also illustrates why outcome definitions and time points matter. The primary timeframe is baseline to end of therapy, while the record notes that the primary outcome has several categories or time points and was not reduced to one comparison. Without a clearly reported primary contrast, readers cannot identify which result would answer the main question or assess the implications of multiple comparisons.

Planning calculations have a different role from outcome analysis. The registry describes assumptions for a sample-size illustration based on the observed effect, but such planning information is not observed power and does not demonstrate that a result is precise. Since the numerical illustration and primary outcome estimates are not reported, the record cannot be used to judge whether the trial’s results meet a particular precision goal.

Finally, the safety counts emphasize the importance of distinguishing descriptive reporting from causal comparison. Counts require clear definitions and denominators, and the listed serious-event terms lack reported arm attribution. Statistical interpretation depends not only on calculations but also on transparent reporting of what was measured, who was analyzed, and how uncertainty was handled.

14. 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 interpretation is that the registry record does not report primary gait-velocity results or a statistical analysis. Without group summaries, an effect estimate, and uncertainty measures, the comparative outcome cannot be evaluated. The record reports an analysis count of 0 and notes that the primary outcome involves several categories or time points that were not reduced to one comparison.

Important trial details are also incomplete. The registry does not report eligibility criteria, participant characteristics, the allocation procedure, who was masked, or the full treatment procedures. Although it names two study arms, it also lists physiotherapy one hour and physiotherapy two hours as interventions without explaining their relationship to those arms. This limits how specifically treatment exposure can be characterized.

The handling of missing data is unclear. The primary outcome population description refers to a difference due to dropouts, but the record does not report how many endpoint measurements were missing, why they were missing, which participants were analyzed, or whether sensitivity analyses were performed. It also does not describe the primary statistical model, adjustment strategy, or approach to multiple outcomes and time points.

Safety information is limited to counts and selected serious-event terms. Definitions, event timing, participant-level event status, and arm attribution for the listed percentages are not reported. No causal interpretation can be made from these summaries alone. The registry’s completed status and enrollment listing do not resolve these reporting gaps or establish that outcome data were available for every enrolled participant.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: BCI-FES Therapy for Stroke Rehabilitation — NCT04279067.
• Registry record last updated 2026-02-10; status last verified 2025-12.
• Results first posted 2026-02-10.
• 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.

18. Record Summary

NCT04279067 is a completed, randomized, parallel-group trial sponsored by the University of California, Irvine. It lists single masking and an enrollment of 62. The study concerns ischemic and hemorrhagic stroke and compares BCI-FES dorsiflexion therapy with physiotherapy against dose-and-intensity-matched physiotherapy.

The primary outcome is mean gait velocity in meters per second, assessed from baseline to the end of therapy, four weeks after initiation. Higher scores indicate better function. Secondary outcomes include dorsiflexion range of motion, gait endurance, fall frequency, and an EEG map.

The registry reports selected adverse-event counts but does not report primary outcome results, an effect estimate, confidence interval, or statistical test. Analysis methods, missing-data handling, and analysis populations are also not reported in the registry record. The posted information therefore describes the trial question and selected design and safety details, but does not permit an assessment of the primary comparative outcome.