Effects of Combined rTMS and Treadmill Training in People With Parkinson's Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Combined rTMS and Treadmill Training in People With Parkinson's Disease (NCT02701647), a randomized na study. The primary outcome is Fastest Walking Speed.

2. Clinical Question

3. Trial Design

The registry record identifies this study as a randomized, double-masked, parallel-group trial. It lists enrollment of 51 and a status of completed. The recorded start was 2016-10 and primary completion was 2018-12. The phase is listed as NA. The sponsor is The Hong Kong Polytechnic University. These details describe the registered design and timeline; they do not provide numerical evidence about the primary outcome.

Three groups are described: 25-Hz rTMS with treadmill training, 1-Hz rTMS with treadmill training, and sham rTMS with treadmill training. For the active regimens, the record describes 1200 pulses in total, delivered at an intensity of 80% resting motor threshold, before 30 minutes of treadmill training. The 25-Hz regimen is described as 600 pulses in 6 minutes for each hemisphere, and the 1-Hz regimen as 600 pulses in 10 minutes for each hemisphere. The sham description includes a disconnected cable at the stimulation site and a second coil positioned posterior to the neck, but the registered description does not fully specify that procedure.

Random allocation is intended, in general, to reduce systematic differences between groups at the point of assignment. A parallel design means the comparison is between groups assigned to their respective conditions, rather than a crossover in which participants receive each condition in sequence. The registry labels masking as double, but does not report which roles were masked or how masking was assessed. The randomization procedure, allocation concealment details, and any planned stratification are not reported in the registry record.

The record lists secondary measures including Timed-Up-and-Go Test (iTUG), the Motor Section of Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS III), walking distance in a 2-Minute Walk Test, Mini Balance Evaluation Systems Test Scores, and Dual-task Timed-Up-and-Go Test (DT-TUG). It reports 9 outcome measures overall, but does not list numerical results for the primary endpoint.

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

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 Fastest Walking Speed, measured over Baseline, 1 day post-intervention, 1 month post-intervention, 3 month post-intervention.

The primary endpoint is fastest walking speed, recorded in centimeters per second. The registry describes a walking task in which each participant is instructed to walk 14 meters at their fastest speed for three trials. The time for the middle 10 meter is recorded, and the average of the three trials is used for analysis. Measurements are scheduled at baseline, 1 day post-intervention, 1 month post-intervention, and 3 month post-intervention.

In general, walking speed is a continuous measure: it can take a range of values rather than placing each participant into a category. A speed measure is used to quantify gait performance directly, and repeated measurements can describe how that performance changes over time. Averaging trial measurements, as specified in the registry, is a way of producing a participant-level measurement from repeated task attempts. The registry identifies the outcome as a mean with standard deviation as its dispersion measure.

The outcome definition does not itself show whether walking speed changed, how the groups compared, or how precisely any group difference was estimated. Numerical group summaries and inferential results for fastest walking speed are not reported in the registry record. Nor does the registry provide a threshold for interpreting a change as important to participants. The outcome should therefore be read as the trial’s planned measure of gait speed, not as a reported finding.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a mean of a continuous measurement, with standard deviation as the stated measure of dispersion. General statistical interpretation separates the estimated group outcome from its variability and from uncertainty about a comparison. A mean describes the average measurement in a group; a standard deviation describes how spread out individual measurements are around that group average. Neither quantity, by itself, establishes whether groups differ or whether an estimated difference is precise.

What would a group comparison estimate?

In general, a randomized trial can estimate a contrast between outcomes in groups assigned to different conditions. For a continuous endpoint, that contrast might be expressed using group means, but the appropriate comparison depends on the prespecified analysis. The registry does not report a numerical estimate for fastest walking speed or specify the exact contrast used for inference. It therefore does not support reconstructing a treatment comparison from the endpoint description alone.

A confidence interval, in general, gives a range of values compatible with the data and the analysis assumptions at a stated confidence level. Its width communicates precision: a narrower interval indicates less statistical uncertainty than a wider interval, under the same method. A confidence interval does not establish clinical importance by itself. The registry record does not report a confidence interval for the primary endpoint, so neither the range of plausible effects nor the precision of an estimate can be evaluated.

What do significance tests tell readers?

In general, a p-value measures how incompatible the observed data are with a specified null model, assuming that model and the test’s assumptions. It is not the probability that the null hypothesis is true, nor does it quantify the size or importance of an effect. The registry does not report a p-value or a statistical test for the primary outcome. No conclusion about statistical significance can be drawn from the outcome definition or the adverse-event counts.

The record specifies measurements at baseline, 1 day post-intervention, 1 month post-intervention, and 3 month post-intervention. Repeated measurements on the same participant are related, so a suitable analysis generally needs to account for that dependence rather than treating every measurement as unrelated. A model may also distinguish the group effect, the time pattern, and whether changes over time differ between groups. The registry does not state which model or comparison was used, whether baseline adjustment was planned, or how within-participant correlation was handled.

Why does variability matter?

In general, standard deviations describe variation among participant measurements, while standard errors and confidence intervals describe uncertainty in an estimated quantity. Those are different concepts. Greater variability can make a group contrast less precise, while sample size, the analysis method, and the structure of repeated measurements also affect precision. The record says the primary endpoint is reported as a mean with standard deviation, but it does not give those numerical summaries. There is therefore no basis for assessing outcome variability or precision from the registry record.

General statistical methods also require assumptions. A normal approximation, for example, is an assumption used by some methods for estimating or testing a mean difference; it is not established simply because the endpoint is continuous. The registry does not report the model, diagnostic checks, transformation choices, or robustness analyses used for the primary outcome. These details are not reported in the registry record.

How should planning illustrations be read?

The registry’s stated planning approach uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning illustrations for detecting a stated fraction of the observed effect. Such calculations are planning aids: they describe the number of participants per arm that a hypothetical study might require under those assumptions. They are not observed power, and they do not show how much power this completed trial had after its data were collected. The registry record does not report the underlying primary-outcome effect estimate needed to assess those planning assumptions against the posted results.

A planning calculation depends on its target effect and assumptions about variability and analysis. If the target is defined as a fraction of an observed effect, that is a hypothetical design choice, not a guarantee that the effect will recur in another study. Planning estimates are especially difficult to interpret without the effect estimate and its uncertainty. The registry record does not report a statistical sample-size justification, nor does it report an actual primary-outcome estimate from which to judge the planning illustration.

The registry reports 0 analyses. This absence means the registry record does not identify an analysis plan or report model-based results. It does not establish which procedures may have been used outside the information recorded. Details such as the analysis population, handling of missing outcome measurements, prespecified contrasts, covariate adjustment, and any sensitivity analyses are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is measured at baseline, 1 day post-intervention, 1 month post-intervention, and 3 month post-intervention. The record also lists 9 outcome measures overall, including measures of timed mobility, walking distance, balance, and motor symptoms. Whenever analyses examine several outcomes or follow-up times, the chance of obtaining at least one apparently notable result can increase if each comparison is treated as an independent test. In general, multiplicity methods can address that issue, but the choice depends on which outcomes and comparisons were planned.

The registry does not report a statistical analysis plan, identify a primary follow-up contrast, or state whether an adjustment for multiple comparisons was used. The record reports 0 analyses. It is therefore not possible to determine from the registry record which comparisons were tested or how their results should be interpreted in relation to one another. The absence of reported multiplicity procedures is not evidence that no procedure was used; it means the registry does not report one.

Missing-data handling is also not reported in the registry record. The outcome description does not say whether participants with incomplete follow-up measurements were included in any analysis, how missing measurements were addressed, or whether sensitivity analyses were conducted. The analysis population is not specified. Without participant flow and the number of observations contributing to each endpoint and time point, the completeness of the outcome data cannot be evaluated.

These gaps matter because the interpretation of repeated measurements depends on both the comparison selected and the data available for that comparison. They also limit assessment of whether analyses followed a prespecified plan. The registry record supports identifying the outcome schedule and the broader set of measures, but not reconstructing the multiplicity strategy, missing-data approach, or analysis population.

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 reports serious adverse events, other adverse effects, and deaths separately for the three groups. For the 25-Hz rTMS group, each reported count is zero among 17 participants at risk. For the 1-Hz rTMS group, each count is zero among 17 participants at risk. For the sham rTMS group, each count is zero among 16 participants at risk. The registry lists no serious adverse-event terms.

These figures mean that the registry record reports no events in the listed categories for the groups and participants at risk. They should not be read as proof that no adverse events occurred outside the categories or collection period captured by the registry. The record does not report the event definitions, surveillance procedures, duration of safety follow-up, or whether events were collected systematically at each visit. It also does not provide detailed event narratives or severity information beyond the separate serious and other adverse-effect counts.

In general, a zero count in a study does not establish that an event is impossible or that two interventions have identical safety profiles. The amount of information a zero count provides depends on the population observed, the duration and completeness of monitoring, and the event definition. The registry’s reported counts are descriptive and should be interpreted within those limits.

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

The registry record identifies a clear statistical question: whether high- or low-frequency rTMS, when followed by treadmill training, is associated with different fastest-walking-speed outcomes than sham rTMS followed by treadmill training. It also describes a repeated walking-speed measurement schedule and lists secondary measures. Those design features help readers understand what the investigators intended to compare.

However, the registry does not report numerical results for fastest walking speed. Without group summaries or a between-group estimate, the direction and size of any observed difference are unknown from the record. Without a confidence interval, its precision cannot be judged. Without a reported inferential analysis, the statistical compatibility of the data with different possible effects cannot be assessed. These omissions do not establish that there was no effect; they mean the posted registry record does not provide the numerical evidence needed to characterize one.

The distinction between a study question and a study result is important. A randomized design can help support causal comparisons when allocation, follow-up, measurement, and analysis are carried out appropriately. The design label alone does not show that groups were similar in every relevant respect after randomization, that all measurements were complete, or that a particular difference was observed. The registry does not report enough information to evaluate those issues for the primary endpoint.

The listed adverse-event figures are also descriptive rather than a full safety analysis. The record reports zero serious events, other adverse effects, and deaths in each group, but does not specify the monitoring period or event-collection methods. Those counts should not be extended beyond the information recorded.

Accordingly, the defensible reading is limited: the trial was registered as a randomized, double-masked, parallel comparison of three stimulation conditions alongside treadmill training, with fastest walking speed as the primary endpoint. The record provides the measurement definition and group safety counts, but not numerical primary-outcome findings. It cannot establish whether active stimulation changed walking speed, how large any difference was, or how precisely such a difference was estimated.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why a registered design and an interpretable result are not the same thing. The record identifies random allocation, masking, parallel groups, a primary continuous outcome, and scheduled follow-up measurements. These features describe the intended framework for making a group comparison. Yet without numerical outcome estimates and their uncertainty, readers cannot assess the primary statistical result.

The study also illustrates the analytical choices created by repeated measurements and multiple outcomes. Fastest walking speed is recorded at baseline and at several post-intervention times, while other registered measures address mobility, balance, and motor symptoms. In general, investigators need to specify which comparisons are primary, how repeated observations are handled, and how findings across outcomes are interpreted. The registry record does not report those analysis details.

For biostatisticians and clinical researchers, the difference between a descriptive endpoint definition and a reported effect estimate is central. Knowing that the endpoint is a mean in centimeters per second does not reveal the average outcome in any group. Knowing the schedule does not reveal whether the trajectory differed. A usable interpretation ordinarily needs the estimates, variability or uncertainty, analysis method, and the number of observations contributing to each comparison.

The registry’s adverse-event counts likewise demonstrate why the context of data collection matters. Zero recorded events are relevant descriptive information, but their interpretation depends on definitions and follow-up that are not stated in the record. Clear reporting of outcome estimates, analysis populations, missing-data handling, multiplicity decisions, and safety monitoring would allow a more complete statistical appraisal.

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 for interpreting this trial from the registry record is the absence of numerical results for fastest walking speed. Although the record defines the outcome and its measurement times, it does not report group means, standard deviations, between-group estimates, confidence intervals, or p-values. The primary statistical finding therefore cannot be evaluated.

The record lists 9 outcome measures but does not provide results for the named secondary outcomes in the information available. It does not identify the primary follow-up comparison or report how repeated measurements and multiple outcomes were analyzed. The analysis plan, statistical model, analysis population, and missing-data procedures are not reported in the registry record. The registry reports 0 analyses, so the methods underlying any primary comparison cannot be assessed from this record.

Several design details are also missing. The randomization method, allocation concealment, the roles covered by double masking, and the success of masking are not reported. The sham-arm description does not fully specify its procedure. The record does not provide baseline group characteristics, participant flow, adherence information, or the number of observations available at each follow-up time.

The safety data are limited to aggregate counts for serious adverse events, other adverse effects, and deaths. Event definitions, monitoring procedures, and safety follow-up duration are not reported. These limitations restrict what can be inferred from the zero counts and prevent a broader assessment of safety reporting.

Finally, the registered planning assumptions do not replace a trial-specific statistical justification or a reported outcome analysis. The registry does not report the target effect used for the original design or a numerical primary outcome estimate. Consequently, readers cannot use the record alone to assess whether the study was designed around a clinically meaningful effect or whether the completed data estimate such an effect precisely.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Combined rTMS and Treadmill Training in People With Parkinson's Disease — NCT02701647.
• Registry record last updated 2019-11-22; status last verified 2018-06.
• Results first posted 2019-10-31.
• 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.

18. Record Summary

The registry record describes a completed randomized, double-masked, parallel-group trial of 25-Hz rTMS, 1-Hz rTMS, or sham rTMS, each followed by treadmill training, in people with Parkinson’s disease. Enrollment is listed as 51, with a start of 2016-10 and primary completion of 2018-12. The primary endpoint is fastest walking speed, measured at baseline, 1 day post-intervention, 1 month post-intervention, and 3 month post-intervention.

The record describes how walking speed was measured and lists secondary mobility, balance, and motor-symptom outcomes. It reports zero serious adverse events, other adverse effects, and deaths in each group. Numerical results for the primary endpoint, statistical comparisons, analysis populations, and missing-data methods are not reported in the registry record. The trial question and measurement plan can therefore be described, but the size, direction, and precision of the primary outcome comparison cannot be assessed from the posted record.