Muscle Vibration in MS to Improve Walking: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Muscle Vibration in MS to Improve Walking (NCT03403413), a na na study. The primary outcome is 10MWT.

2. Clinical Question

The study's stated rationale links muscle vibration to improved coordination of hip, knee, and ankle flexion, with walking speed as the measured endpoint. This is a feasibility-oriented question in a small, single-group study, rather than a randomized comparison of treatment and control. The outcome description says repeated measurements were collected and averaged, and that testing took place with and without vibration. It also describes the assessment time as after twelve 1 hour sessions over four weeks. That differs from the arm description's planned schedule of 1 hour, 3 times per week for 12 weeks; the registry record does not explain the difference. With no reported primary outcome results, the record cannot establish how walking speed changed during the study or how precisely any change was estimated.

3. Trial Design

This was a single-group device study of muscle vibration during walking in people with multiple sclerosis. Allocation is recorded as NA, and masking is listed as NONE. The registry identifies enrollment as 5 and the study status as TERMINATED. It lists the VA Office of Research and Development as sponsor. The phase is recorded as NA. The study start is listed as 2017-01-01 and primary completion as 2018-12-31.

The arm description specifies bilateral vibration of the tibialis anterior, rectus femoris, short head of biceps, and tensor fasciae latae during walking. It describes sessions lasting 1 hour, 3 times per week for 12 weeks. The stated aim was to test feasibility and improve walking speed through better coordination of hip, knee, and ankle flexion. The primary outcome timeframe, however, describes assessment after twelve 1 hour sessions in four weeks of gait training with muscle vibration. These are two different schedule descriptions in the registry record, and no explanation for the difference is reported.

The study has no parallel control arm or randomized allocation. The primary outcome description includes testing both with and without vibration, but it does not turn those measurement conditions into randomized groups. Repeated measurements were collected and averaged, according to the outcome description. Details of the ordering of those conditions, measurement visits, or the method used to combine observations are not reported in the registry record.

The registry lists four outcome measures and zero analyses. The primary outcome is the 10MWT, expressed as speed in m/s and summarized as a mean with standard deviation. Primary outcome results are not reported in the registry record. The record does not state why the study was terminated, whether enrollment reached a recruitment target, or whether feasibility criteria were met. It also does not report a sample-size justification or a statistical analysis plan. The design therefore supports a description of the intended pilot and the outcomes registered, but not an assessment of comparative efficacy.

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.

Before assignment: 3

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Multiple sclerosis

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 10MWT, measured over baseline and after twelve 1 hour sessions in four weeks of gait training with muscle vibration. Outcome measures were tested both with and without muscle vibration and repeated measures were collected and averaged..

The primary endpoint is the 10MWT, recorded as walking speed in m/s. A timed walking test is used to quantify walking performance as a continuous measure: higher or lower recorded speeds represent different observed levels of performance, though the registry record does not report the observed values for this study. The outcome is identified as a mean, with standard deviation as its dispersion measure.

Walking speed is relevant to the stated study question because the intervention aimed to improve walking in people with multiple sclerosis and gait deficits. The arm description proposes that muscle vibration could affect coordination of hip, knee, and ankle flexion, while the primary endpoint focuses on the resulting walking speed rather than directly measuring coordination. That makes the 10MWT a functional outcome aligned with the walking goal, but it cannot by itself explain the mechanism behind any change.

The registry describes the measurement timeframe as baseline and after twelve 1 hour sessions in four weeks of gait training with muscle vibration. It also says testing occurred both with and without vibration, with repeated measurements collected and averaged. The arm description gives a different treatment schedule: 1 hour, 3 times per week for 12 weeks. The registry record does not clarify this discrepancy or give details of the averaging procedure. The primary endpoint values, their standard deviation, and any change estimate are not reported in the registry record. As a result, the endpoint's intended role is clear, but the study's observed walking-speed findings cannot be assessed from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical interpretation begins with the type of endpoint. The 10MWT outcome is continuous and is recorded in m/s. The registry identifies the summary as a mean and the dispersion as a standard deviation. A mean describes the central value of a set of measurements. A standard deviation describes how spread out individual measurements are around that mean; it is not the same as the uncertainty in the estimated mean. The registry record does not report either summary for the primary endpoint.

What does a mean and standard deviation describe?

For a continuous endpoint, a mean can summarize measured walking speeds across participants or repeated observations, depending on the analysis definition. The standard deviation describes variation in the measurements being summarized. To interpret those statistics fully, readers need to know which measurement occasions and conditions contributed to the summary. Here, the outcome description states that repeated measures were collected and averaged and that testing occurred both with and without vibration. It does not specify whether the reported mean would be a participant-level average, an average of all measurements, or a summary for each testing condition. Nor does it report separate values. This distinction matters because repeated readings from the same person are related rather than independent observations.

How should within-person measurements be understood?

Repeated measurements can help describe a person's performance across more than one observation, but they require analysis that respects the connection among observations from the same person. Treating correlated readings as though they came from unrelated people can misstate the amount of information in the data. Averaging repeated measures can produce a simpler summary, but the averaging method determines what that summary represents and may conceal variation between sessions or testing conditions. The registry record does not report the number or ordering of repeat measurements, the averaging rule, or a model for repeated observations. It therefore does not permit evaluation of how within-person correlation was handled.

In general, an estimate of change can be accompanied by a confidence interval, which gives a range of values compatible with the observed data and the assumptions used to calculate the interval. A narrow interval indicates more precision than a wide interval, while neither width nor statistical significance alone establishes clinical importance. A p-value, if reported, would describe how compatible the observed data are with a specified null model; it would not measure the probability that an intervention works. No change estimate, confidence interval, or p-value for the primary outcome is reported in the registry record.

What can a single-group design estimate?

In a single-group design, measurements may describe the participants before and after an intervention, or under different measurement conditions. Such comparisons can document observed change, but they do not provide the same counterfactual comparison as a concurrent control group. In general, a control group helps distinguish intervention-associated change from changes that might occur over time or from measurement and study participation effects. This study is recorded as SINGLE GROUP, with allocation NA; therefore, it is not a randomized two-arm comparison. The registry record does not report a separate control group or a randomized assignment.

The outcome description mentions tests with and without muscle vibration. This is not equivalent to assigning participants to independent intervention and control arms. The conditions appear within the outcome measurement description, but the record does not explain their order, whether they were paired at the same visits, or whether the analysis compared them. Those details would be necessary to interpret a contrast between the conditions and to account for possible order or carryover effects. No such contrast or analysis is reported.

What do the planning illustrations represent?

Sample-size planning uses assumptions about the effect a future study aims to detect, the variability of the endpoint, the statistical test, and the allocation structure. The record's planning assumptions specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They define the effect to detect as a stated fraction of the observed effect. These are planning assumptions, not features of this single-group study's allocation. A planning calculation does not show that a study had a particular probability of finding a result, and it should not be described as observed power.

The record says the planning illustration is computed from the observed effect, but the primary outcome effect is not reported in the registry record. Without that estimate and its underlying variability, the planning calculation cannot be evaluated from the registry information. The stated assumptions also use a two-arm framework, which differs from the registered single-group design. Any such illustration is best read as a hypothetical design exercise under its stated assumptions, not as evidence about the study's outcome or its design adequacy.

What analysis details are missing?

The registry lists zero analyses. That does not provide a statistical method for interpreting the endpoint, and the analysis plan is not reported in the registry record. It does not state whether a change score, a repeated-measures model, or another approach was intended. The analysis population, handling of missing outcomes, treatment of measurements taken with and without vibration, and any adjustment for multiple outcomes are also not reported in the registry record. These omissions limit reproducibility: a reader cannot determine which observations would contribute to an estimate, how uncertainty would be calculated, or how the primary question would be tested.

In general, statistical methods should follow the study's design and measurement structure. A model for repeated data should account for within-person dependence, and a comparison of conditions should make clear how the pairing and timing are handled. If several outcomes or contrasts are tested, multiplicity can increase the chance of at least one apparently unusual result; a prespecified hierarchy or adjustment may address that concern. These general principles cannot substitute for the methods actually used, which are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies four outcome measures and names the 10MWT as the primary outcome. It reports zero analyses. The other outcome measures and any analysis results are not reported in the registry record. Naming one primary endpoint can help distinguish the central question from additional outcomes, but the record does not state whether other outcomes were tested, how they were prioritized, or whether any multiplicity procedure was planned. A correction or testing hierarchy should not be assumed.

Multiplicity is a general concern when several outcomes, time points, or contrasts are examined. The more analyses considered, the greater the chance that at least one result may look unusual by chance alone. Prespecifying a primary outcome and analysis can reduce ambiguity, while adjustment methods may be used when appropriate. The registry record does not report an analysis plan, so it is not possible to determine how multiplicity was addressed or whether the primary outcome was analyzed according to a prespecified method.

Missing-data handling is also not reported in the registry record. There is no account of missing 10MWT measurements, reasons for any missingness, or methods used to address it. The analysis population is not reported in the registry record, so it is unclear which participants or observations would be included in an outcome analysis. Enrollment is recorded as 5, but this does not establish how many had usable baseline or follow-up measurements.

These gaps matter because missing observations and analysis choices can affect both the estimated mean and its uncertainty. In general, an analysis should make clear how observed data are used and whether assumptions about missingness are needed. No conclusions about completeness of follow-up, exclusions, or robustness to missing data can be drawn from the registry information.

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.

The registry's feasibility safety entries record 5 at risk for serious adverse events and 0 affected; for other adverse events, it also records 5 at risk and 0 affected. Deaths are recorded as 0, and no top serious adverse-event terms are listed. These figures describe what is entered in the registry record; they are not a comparison with an untreated group.

Zero recorded events should be read narrowly. It means that the registry reports no affected participants in these categories for the listed risk group. It does not establish that no events occurred outside the recorded categories, that all events were captured, or that the intervention has no risk. The record does not provide additional detail about adverse-event definitions, monitoring, event timing, or completeness of reporting. With a small enrollment entry and no comparator, the safety information is descriptive and has limited ability to characterize uncommon events or compare event rates.

The registry labels the group Feasibility. That context is consistent with a pilot focus, but the adverse-event entries alone do not establish whether the intervention was feasible or tolerated. The record does not report a broader feasibility assessment or the reason the study was terminated. The safety figures should therefore be interpreted as registry-reported counts, not as proof of safety or as evidence that a particular event risk is absent.

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

The record gives a clear outline of the intended pilot: muscle vibration during walking was studied in people with multiple sclerosis, and walking speed on the 10MWT was designated as the primary endpoint. It also records a single-group design, enrollment of 5, a terminated status, and the intervention's targeted lower-extremity muscles. Those details help readers understand the question and the design in which it was asked.

The central result needed to assess that question is not reported in the registry record. There are no primary endpoint values, no reported estimate of change, and no uncertainty interval or test result. As a result, the record does not show whether walking speed increased, decreased, or remained similar during the study, nor how precise an estimate would be. It cannot support a conclusion that muscle vibration did or did not improve walking.

Even if a before-and-after estimate were available, the single-group design would limit causal interpretation. A change over time could be associated with the intervention, but without a separate comparator it would not by itself distinguish the intervention from other explanations for change. The description of testing with and without vibration adds measurement conditions but does not create a randomized control arm. The details needed to interpret those repeated measurements are not reported.

The two schedule descriptions also leave uncertainty about the intended exposure and assessment timing: the arm description specifies 1 hour, 3 times per week for 12 weeks, while the primary outcome timeframe describes twelve 1 hour sessions in four weeks. The registry record does not explain this discrepancy. This limits a reader's ability to connect any hypothetical outcome measurement to a precise treatment schedule.

The safety entries report 0 serious adverse events, 0 other adverse events, and 0 deaths among the recorded risk groups. Those counts are descriptive and do not establish absence of risk. Overall, the registry is informative about the study's aims and broad design, but its missing efficacy results, analysis details, and explanation of termination prevent a fuller assessment of what the study found or why it ended.

13. Why This Trial Matters Statistically

This study illustrates why the design and the reported outcome data must be read together. The registered question concerns walking performance after muscle vibration, but the design is single-group rather than a randomized comparison. That distinction determines what an observed change could establish: a within-group pattern can describe what happened over time, while a causal contrast requires a suitable comparison and assumptions that support it. The measurement conditions of with and without vibration do not, on their own, provide a parallel control group.

The record also highlights the importance of reporting endpoint summaries and uncertainty. The primary outcome is specified as mean walking speed with standard deviation, yet its results are not reported in the registry record. Without the estimate and its variability, readers cannot assess the direction, magnitude, or precision of any change. The presence of a registered endpoint is not a substitute for reporting the observed data and analysis.

Repeated measurements create another important statistical issue. They can capture variation across assessments, but readings from the same person are related. The record says they were collected and averaged, without specifying how. Clear reporting of measurement conditions and aggregation is needed to understand what a summary represents and to judge whether the analysis reflects the data structure.

Finally, the planning assumptions describe equal allocation between two arms, although the study itself is recorded as single-group. This makes the distinction between a hypothetical planning illustration and the actual design especially important. Planning calculations are conditional on their assumptions and do not establish observed power or study findings. In this record, the missing outcome estimate further limits interpretation of an illustration based on an observed effect. These features make the study a useful example of how design, endpoint reporting, and analysis transparency jointly shape what can be learned from a pilot.

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 interpreting this specific study is that primary outcome results are not reported in the registry record. There is no 10MWT mean or standard deviation, and no estimate comparing baseline with follow-up or comparing testing conditions. The registry also lists zero analyses, leaving no reported statistical approach against which to evaluate an estimate.

The study's single-group design limits what any within-group change could establish. There is no separate control arm, and allocation is recorded as NA. Testing both with and without vibration is described, but the registry does not explain the order, timing, or analytic contrast between those conditions. It is therefore not possible to treat those measurements as a randomized comparison.

The intervention schedule is described differently in the arm and outcome entries. The arm description states 1 hour, 3 times per week for 12 weeks, whereas the primary outcome timeframe refers to twelve 1 hour sessions in four weeks. The registry does not resolve the inconsistency. It also does not describe adherence, actual exposure, or any departures from the intended regimen.

Additional limitations include the small enrollment entry of 5, the lack of reported analysis methods, and the absence of information on missing data and analysis populations. The record does not state why the study was terminated or whether termination affected outcome collection. It lists four outcome measures but does not report results for them or explain how multiple outcomes were handled. These omissions constrain both statistical reproducibility and interpretation of feasibility, effectiveness, and safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Muscle Vibration in MS to Improve Walking — NCT03403413.
• Registry record last updated 2020-05-08; status last verified 2020-04.
• Results first posted 2020-05-08.
• 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

NCT03403413, titled “Muscle Vibration in MS to Improve Walking,” is a terminated, single-group device study sponsored by the VA Office of Research and Development. The registry records enrollment of 5, a start date of 2017-01-01, and primary completion on 2018-12-31. Its aim was to explore the feasibility of cyclic muscle vibration during walking for people with multiple sclerosis and gait deficits.

The intervention description identifies bilateral vibration of four lower-extremity muscles. The primary endpoint is 10MWT walking speed in m/s, summarized as a mean with standard deviation. The record identifies four outcome measures and zero analyses. Primary outcome results, statistical analysis details, missing-data methods, and the reason for termination are not reported in the registry record. Safety entries record 0 serious adverse events, 0 other adverse events, and 0 deaths for the listed risk groups. The outcome timeframe and intervention arm descriptions give different schedules, with no explanation reported.