Non-invasive Cervical Electrical Stimulation for SCI: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Non-invasive Cervical Electrical Stimulation for SCI (NCT03414424), a na na study. The primary outcome is Electromyographic Responses (Active).

2. Clinical Question

The study’s stated purpose was to improve understanding of how CES interacts with spinal and brain circuits and to examine stimulation combined with active movement. Its longer-term rationale was to investigate whether stimulation might help engage spared nerve circuits after spinal cord injury. That rationale is not itself evidence of a clinical benefit. The posted primary outcome is a measurement of muscle activity, not a reported measure of regained hand function or a patient-reported outcome. The registry record does not report an analyzable result establishing whether CES changed active muscle responses.

3. Trial Design

This was a completed, single-group study of cervical electrical stimulation for spinal cord injury, sponsored by Bronx VA Medical Center. The registry lists phase as NA, allocation as NA, and masking as none. Enrollment is recorded as 30. The study began on 2017-08-22, and primary completion is recorded as 2021-04-30.

The intervention descriptions identify CES at rest and CES plus active hand or wrist movements. The registry states that all subjects underwent the same full protocol, including both conditions. This is not a randomized comparison of separate arms. The record does not establish that the able-bodied and spinal cord injury groups were intended as randomized, matched, or otherwise exchangeable control groups; the posted safety figures list them separately, but they should not be interpreted as a like-for-like treatment comparison.

The study description says that its work included examining how stimulation interacts with other circuits and testing combinations of CES with active hand and wrist movements. The primary outcome is tied to concurrent active movement and has a timeframe of up to one day. Additional details about the sequence of procedures, visit structure, dose or intensity of stimulation, and how the planned aims were allocated across participants are not reported in the registry record.

The registry lists two outcome measures, but only the primary outcome is described in the record. It lists zero analyses. The primary outcome entry explains that technical problems affected data collection: the relative timing of stimulation and active effort was irregular, grant funding expired, and the data collected for this aim could not be analyzed. Thus, completion status does not mean that the primary endpoint produced an interpretable treatment-effect estimate.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Data collection for this outcome was plagued with technical problems. The relative timing of cervical stimulation relative to active effort was irregularly applied. Grant funding expired. It is not possible to analyze the data collected for this aim.

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 Electromyographic Responses (Active), measured over up to one day.

The primary endpoint, titled Electromyographic Responses (Active), concerns muscle activity while participants make active finger or wrist movements. The registry says that the effect of cervical electrical stimulation on concurrent movement would be measured using the root-mean-square of ongoing muscle activity in various hand and forearm muscles. The stated timeframe is up to one day.

Electromyography records electrical activity associated with muscle activation. The root-mean-square is a way to represent the magnitude of a varying signal over a defined period. In general, such a measure can describe the size of muscle activity during a task; by itself it does not establish that a movement is more useful, coordinated, or meaningful to a participant. Those interpretations would require suitable outcome definitions and analyzable data.

The record explains why the primary endpoint is not available for interpretation: the relative timing of cervical stimulation and active effort was irregularly applied, and the investigators state that the collected data for this aim could not be analyzed. No endpoint values, variability estimates, confidence intervals, or statistical test results are reported for this outcome. Consequently, the registry does not permit an estimate of the direction, magnitude, or precision of CES-associated changes in active muscle activity. The measurement was intended to study a physiological response; it is not a reported result about functional recovery.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record identifies a single-group study, no allocation, and no masking. Its primary outcome could not be analyzed, so there is no inferential result from that endpoint to explain. The concepts below are general statistical context for understanding what different analyses would mean; they do not imply that the registry reports those analyses for this trial.

What does a single-group design allow?

In general, a single-group design can describe measurements collected under different conditions or at different times in the same study. Whether a within-participant contrast is possible depends on the actual measurement schedule, the outcome data, and a prespecified analysis. The registry says everyone underwent CES at rest and CES with active movement, but it does not report an analyzable primary endpoint or a statistical comparison between those conditions. It also does not describe a randomized sequence or report how order and timing were handled.

A control group can help distinguish an intervention-associated change from other explanations, but only when the comparison is appropriate to the question and design. Here, the registry does not describe a randomized control arm. The able-bodied and spinal cord injury labels in the safety record do not create a randomized treatment comparison. Differences between groups could reflect characteristics other than stimulation, and the posted record does not present an analysis that addresses such differences.

Why does timing matter for a signal outcome?

For a measurement intended to capture muscle activity during concurrent stimulation and effort, the timing defines which observations represent the condition of interest. In general, irregular timing can make measurements less comparable: a signal recorded at one phase of an effort may not represent the same response as a signal recorded at another phase. This is a measurement and design issue, not merely a question of which statistical test to use. The registry specifically says that relative timing was irregularly applied and that the data for the aim could not be analyzed.

What would an effect estimate and confidence interval convey?

In general, an effect estimate quantifies the observed contrast on the outcome’s measurement scale. A confidence interval conveys uncertainty around that estimate under the assumptions of the analysis. A narrow interval can indicate greater precision than a wide interval, but neither the estimate nor an interval can repair systematic measurement problems or an unsuitable comparison. No primary effect estimate or confidence interval is reported in the registry record, so there is no basis for interpreting the size or precision of a primary treatment contrast.

What is the role of a significance test?

In general, a significance test assesses how compatible data are with a specified null model under the analysis assumptions. A p-value does not measure the probability that a treatment works, and it does not describe the size or clinical importance of an effect. The registry lists zero analyses and provides no primary test result. It would therefore be inappropriate to infer statistical significance or lack of significance from the fact that no analyzable outcome is posted.

How should planning illustrations be read?

In general, a sample-size calculation is a planning exercise based on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. It is not an observed result and does not show that a study had a particular probability of detecting an effect after data collection. The registry’s planning description states a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it also says the effect to detect is a stated fraction of the observed effect. It distinguishes event totals for time-to-event calculations from participants per arm for other calculations.

Those planning assumptions should not be confused with this study’s design description. The registry lists a single group and does not describe a randomized two-arm allocation. The primary outcome was not analyzable, and the record does not report a primary observed effect estimate from which readers could assess a realized effect. Any planning illustration is not observed power, not a substitute for an outcome analysis, and not evidence that an effect was detected. The registry does not report a trial-specific sample-size justification or the basis for a confirmatory statistical plan.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variation is greater than a model assumes. If a model underestimates variability, standard errors can be too small and intervals or tests can appear more decisive than warranted. The appropriate model depends on the outcome distribution and design. The registry record does not report an analysis model for the primary endpoint, so there is no basis to say whether over-dispersion was assessed or relevant to an analysis of these data. For this study, the reported barrier is that the primary data could not be analyzed because of irregular timing and funding expiry, not a reported model-fit problem.

These methods concepts clarify what statistical results could ordinarily describe, but they cannot fill the gap left by the unavailable primary analysis. The record provides no primary contrast, uncertainty estimate, or test result to which those interpretations could be applied.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and zero analyses. The primary outcome is described as active electromyographic responses, but the record does not describe the second outcome measure. It does not report a hierarchy of outcomes, an adjustment for multiple testing, or a strategy for controlling the chance of false-positive findings across analyses. Such details are not reported in the registry record.

In general, multiplicity arises when a study evaluates several outcomes, time points, subgroups, or statistical contrasts. If many tests are considered, interpreting each test in isolation can overstate the strength of evidence. A prespecified hierarchy or adjustment can help clarify which results are confirmatory and how uncertainty should be understood. No such plan should be inferred from the number of outcomes alone.

Missing-data handling is also not reported. The registry states that technical problems affected data collection for the primary aim and that the data collected for that aim could not be analyzed. It does not report how many primary measurements were missing or unusable, why individual observations were unavailable, or whether any imputation or sensitivity analysis was conducted. Since the endpoint itself is reported as not analyzable, there is no posted analysis population or missing-data method to evaluate.

The record does not state whether analyses were planned by intention to treat, per protocol, or another population definition. The registry enrollment figure does not establish how many participants contributed usable data to any particular outcome. Without outcome-specific denominators and analysis details, readers cannot assess the representativeness of the observations or the effect of missingness on an estimate. No inference about the direction of bias is justified from the information recorded.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists safety figures separately for Able-bodied and Spinal Cord Injury groups. In each listed group, 15 participants are recorded as at risk for serious adverse events, with 0 affected; deaths are also listed as 0. For other adverse events, each group lists 7 affected among 15 at risk. The record does not list any serious adverse event terms, and it does not give the terms for the other adverse events in the information.

These counts are descriptive. They do not show that the two groups are comparable, and they should not be read as a randomized comparison. The study is described as single group, with no allocation, and the record cautions that the arms are not a like-for-like control comparison. The safety categories also do not provide detail about event severity beyond the serious-versus-other distinction, timing, recurrence, or attribution to stimulation.

Zero recorded serious events and zero deaths do not establish that the risk of such events is zero. In general, an absence of recorded events in a study does not rule out uncommon events, and interpretation depends on the amount and duration of observation and the completeness of reporting. The registry does not provide further safety follow-up details. These counts therefore describe what the record reports, not a comprehensive assessment of safety or a comparison of risk between populations.

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

The result that can be stated is about the availability of evidence: the registry says the primary active electromyographic data could not be analyzed. It does not report an estimated effect of CES on muscle activity during active finger or wrist movements. As a result, the record does not establish either a benefit or an absence of effect for that primary physiological outcome.

The distinction between no effect and no analyzable estimate is important. A study can produce an estimate near zero, with uncertainty around it; this record instead says that the data for the primary aim cannot be analyzed. Without a valid estimate and an account of its uncertainty, readers cannot determine the direction or size of any underlying response from the posted primary outcome information.

The study’s motivation refers to possible ways of engaging spared nerve circuits and to the longer-term goal of strengthening residual circuits to hand muscles. Those statements describe the scientific rationale and future aims. They are not results demonstrating improved function. The endpoint described in the registry is a muscle-activity measure during movement, and no functional recovery result is reported for the primary aim.

The safety figures provide descriptive counts in the two listed groups, including no serious adverse events or deaths recorded and 7 participants with other adverse events in each group. They do not establish comparative safety, since the study is not a randomized comparison and the groups are not identified as like-for-like controls. Event details and further follow-up information are not reported in the registry record.

Completion status and the enrollment figure do not change these limits. A completed study can have an endpoint that cannot be analyzed, as the registry explicitly reports for this aim. The appropriate conclusion is narrow: the study record documents an investigation of CES and active movement, but it leaves the primary physiological question unanswered in the posted results. It cannot support a conclusion about clinical effectiveness, nor can it establish that CES has no effect.

13. Why This Trial Matters Statistically

This study illustrates why the quality and consistency of measurement are central to statistical interpretation. The primary endpoint depended on relating cervical stimulation to active effort. The registry reports irregular application of their relative timing and states that the data for the aim could not be analyzed. Even a clearly defined physiological measurement cannot answer its intended question if the observations do not support a consistent analysis.

It also illustrates the difference between a study’s scientific rationale and its reported evidence. The motivation concerns residual circuits and possible future approaches to hand function after spinal cord injury. The primary endpoint, however, is electromyographic activity during movement. A physiological signal may be relevant to a research question, but it does not by itself demonstrate a functional improvement. Keeping these levels of inference separate prevents an intended long-term application from being mistaken for an observed result.

The single-group structure is another important statistical feature. Without a randomized control comparison, changes or differences cannot automatically be attributed to CES. The fact that all subjects underwent the same protocol, and that the safety record distinguishes able-bodied and spinal cord injury groups, does not establish a causal comparison between treatments or populations.

Finally, the record demonstrates why non-results should be described precisely. The primary data are reported as not analyzable; that is different from a negative test or a small estimated effect. The distinction matters for future readers assessing what question was asked, what outcome was intended, and whether the posted evidence answers it. Here, the registry conveys the intended measurement and the reason it could not yield an interpretable primary result, while leaving the effect itself unknown.

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 principal limitation is explicit in the registry: technical problems affected data collection for the primary outcome, the relative timing of cervical stimulation and active effort was irregularly applied, and the data collected for this aim could not be analyzed. No primary effect estimate or uncertainty measure is available to evaluate.

The record describes a single-group protocol in which all subjects underwent CES at rest and with active hand or wrist movements. Allocation is NA and masking is none. It does not provide a randomized control comparison, so the design as recorded does not support attributing an observed difference to CES through a randomized contrast. The record also cautions that the listed groups are not a like-for-like control comparison.

Details needed to assess the endpoint and its analysis are not reported in the registry record. These include the number of usable primary measurements, outcome-specific analysis populations, the signal-processing procedure beyond the root-mean-square description, handling of repeated measurements, and any statistical model. The record does not report a statistical analysis plan, a sample-size justification for the trial, or methods for addressing multiplicity and missing data.

The registry lists two outcome measures but does not describe the second in the information. The safety figures do not include the terms for other adverse events or detailed follow-up information. Participant characteristics, eligibility details, and the precise distribution of study procedures are also not reported in the registry record.

These limitations restrict interpretation to the study’s stated aims, design, and posted safety counts. They do not establish that a treatment effect is absent; they mean that the primary effect cannot be evaluated from the reported analysis.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Non-invasive Cervical Electrical Stimulation for SCI — NCT03414424.
• Registry record last updated 2023-11-29; status last verified 2023-11.
• Results first posted 2023-11-29.
• 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

NCT03414424 is a completed single-group study titled Non-invasive Cervical Electrical Stimulation for SCI, sponsored by Bronx VA Medical Center. The registry lists enrollment of 30, no allocation, no masking, and phase NA. The study began on 2017-08-22, with primary completion on 2021-04-30.

Participants underwent CES at rest and CES alongside active hand or wrist movements. The primary outcome was electromyographic activity during active finger or wrist movement, measured as the root-mean-square of ongoing muscle activity in hand and forearm muscles, with a timeframe of up to one day. The registry states that irregular timing and technical problems prevented analysis of data for this aim.

The safety record lists 0 serious adverse events and 0 deaths in each listed group, and 7 participants with other adverse events among 15 at risk in each group. The record does not provide an analyzable primary effect estimate, so it does not resolve whether CES changed active muscle responses.