Effects of Robotic Versus Manually-Assisted Locomotor Training for Individuals With Incomplete Spinal Cord Injury: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Robotic Versus Manually-Assisted Locomotor Training for Individuals With Incomplete Spinal Cord Injury (NCT00127439), a randomized na study. The primary outcome is Self Selected Velocity on Treadmill.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized, parallel-group trial comparing robotic with manually assisted locomotor training. Masking is listed as none. The record reports enrollment of 19 participants and a completed study. It gives a start date of 2005-06 and a primary completion date of 2009-04. The phase is listed as NA.

In a parallel-group design, participants are assigned to one of the study arms and the groups receive their respective approaches. Random allocation is intended to reduce systematic differences in how participants enter each arm. It does not guarantee that the groups will be similar in every respect, particularly in a small study. The registry record does not describe the randomization procedure, allocation concealment, or whether any procedures were used to check baseline comparability.

The robotic arm combined a stepping device, body weight support, and a treadmill, with assistance from a physical therapist and trainers. The manual arm also used body weight support and a treadmill, with therapists and trainers assisting practice. These descriptions establish the broad contrast being studied, but the intervention text is incomplete. Detailed information about training intensity, progression, session schedules, adherence, and treatment fidelity is not reported in the registry record.

The primary outcome was self-selected treadmill velocity at 12 weeks. The registry lists nine outcome measures and ten analyses, but does not identify the statistical methods used for each analysis. The record also does not state how participants were handled if they did not complete training or outcome assessment. Although the trial is marked completed, completion status alone does not provide the results or establish how closely the study followed its planned procedures.

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: No significant events relative to enrollment.

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.

Population: 19 subjects were enrolled; 2 subjects (1:Manual; 1: Robotic) did not complete as intervening medical issues would not permit them to meet the study protocol's requirement for training intensity; and 2 subjects' (Manual) data was insufficient for data analysis and thus eliminated from analysis.

6. Primary Endpoint

The registry lists the primary outcome as Self Selected Velocity on Treadmill, measured over 12 weeks.

The primary endpoint was self-selected velocity on a treadmill, measured in m/s at 12 weeks. The registry describes participants walking on a treadmill with overhead safety support while wearing a harness. Treadmill speed was adjusted to be lower than overground walking speed and adjusted until the participant reached a comfortable speed.

Walking velocity is a continuous measure: it can take a range of values rather than placing each participant into a small set of categories. A mean can describe the group’s average measured velocity, while a standard deviation can describe how dispersed individual measurements are around that mean. The registry identifies the endpoint parameter as a mean and its dispersion as a standard deviation. These summaries would help readers understand both the average treadmill pace and the variability among participants.

A self-selected speed captures a participant’s chosen pace under the stated treadmill assessment conditions. It is not, by itself, a complete description of walking ability or of performance in other settings. The harness, treadmill, and speed-adjustment procedure are part of the measurement context and should be kept in mind when interpreting the endpoint.

The registry record does not report the endpoint’s group means or standard deviations, nor does it give an estimated comparison or uncertainty interval. Consequently, the amount or direction of any observed difference in treadmill velocity is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, parallel-group comparison with no masking. It identifies self-selected treadmill velocity at 12 weeks as the primary outcome, with the mean as the parameter and the standard deviation as the dispersion measure. It does not report the statistical test, model, covariate adjustment, or other analysis details used to compare the arms. Any explanation of these statistical concepts should therefore be read as general, rather than as a description of methods confirmed for this trial.

What does a mean describe?

General: a mean is the arithmetic average of the observed values in a group. For a continuous outcome such as treadmill velocity, it provides a concise description of the group’s central value. A comparison of group means can describe the average contrast between two assigned approaches, but the mean alone does not show how much participants vary or how uncertain the comparison is.

The registry specifies a standard deviation as the measure of dispersion. General: a standard deviation describes the spread of individual observations around the group mean. A larger spread indicates that measurements are more dispersed, while a smaller spread indicates that they are more closely clustered. The standard deviation is not the same as the uncertainty in the estimated mean or in a between-group contrast. The registry record does not report the actual means or standard deviations for the primary outcome.

Why does randomization matter?

General: random assignment is designed to make allocation to study groups independent of participants’ measured and unmeasured characteristics, on average across repeated assignments. This can help support a fair comparison. It does not ensure that a particular trial’s arms are identical at baseline, and chance differences can remain. The registry record identifies the allocation as randomized but does not describe the sequence-generation or concealment procedures, or report baseline outcome summaries in the information.

General: masking refers to whether participants, investigators, assessors, or other people involved in the study are kept unaware of assigned treatment. The record lists masking as none. It does not specify which roles were unmasked or whether outcome assessment was conducted independently. Since treadmill speed involves an assessment procedure, details about assessor training and consistency would help readers understand measurement conditions; such details are not reported in the registry record.

What would an effect estimate and confidence interval add?

General: an effect estimate expresses the observed contrast between groups using a defined scale. For this continuous endpoint, a difference in means would be one possible way to express a group contrast, but the registry record does not state that this was the analysis used or report such an estimate. A confidence interval communicates uncertainty around an estimate under the assumptions of the calculation. It can show which values are reasonably compatible with the observed data and analysis method. No confidence interval for the primary outcome is reported in the registry record, so its precision cannot be evaluated.

A p-value, if reported, would address how compatible the data are with a specified statistical null model, given the test’s assumptions. It would not quantify the size or practical importance of an effect. No p-value for the primary outcome is reported in the registry record. No significance threshold or test specification is reported either, so it is not possible to reconstruct the inferential procedure from the record.

Why can small studies have limited precision?

General: when a study includes relatively few participants, estimates can be sensitive to the results of individual participants, and uncertainty may be substantial. The registry reports enrollment of 19. That count alone does not establish how much precision the trial achieved: precision also depends on the observed variability, the analysis, and how many participants contributed data to the endpoint. The outcome-specific analysis population and the observed variability are not reported in the registry record.

General: over-dispersion means that observed variability is greater than a statistical model assumes. If an analysis assumes less variation than is actually present, its uncertainty estimates can be too small. Appropriate modeling and uncertainty estimates depend on the data structure and analysis plan. The registry record does not report whether over-dispersion was assessed or whether any model requiring such an assessment was used; no claim about over-dispersion can be made for this trial.

What do the planning illustrations represent?

General: sample-size planning asks how many participants would be needed under chosen assumptions to detect a specified effect with a chosen error rate and power. A planning calculation based on an observed effect is illustrative; it is not evidence that the trial was designed using that effect, and it is not the same as observed power. The registry record states that its planning illustration uses a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect expressed as a fraction of an observed effect. It says that non-time-to-event planning values are participants per arm, while time-to-event values are total events. The numerical planning estimates and the trial’s own sample-size justification are not reported in the registry record.

These planning assumptions describe a calculation framework, not the trial’s analysis. The registry record does not report the original sample-size rationale, the target effect, or whether recruitment and analysis followed a prespecified plan. Planning values should therefore be interpreted as illustrations, not as observed results or proof that the trial had sufficient or insufficient power.

10. Multiplicity, Missing Data and Analysis Populations

The record lists nine outcome measures and ten analyses. Multiple outcomes or analyses can create multiplicity: when several statistical questions are examined, the chance of finding an apparently notable result by chance can increase if each is treated as an isolated test. General: approaches to multiplicity can include specifying a primary outcome in advance, controlling an error rate across tests, or interpreting secondary analyses as exploratory. The registry identifies a primary endpoint, but does not report whether or how multiplicity was addressed.

The record does not provide the analysis plan, identify all planned comparisons, or state which results were prespecified. It also does not report the results for the other outcome measures. The count of measures and analyses is not enough to determine which analyses were confirmatory, whether outcomes were measured at multiple time points, or whether any adjustment was used. Those details are not reported in the registry record.

Missing outcome data can affect both the analysis population and the interpretation of a group comparison. General: an analysis restricted to participants with observed outcomes may be biased if the chance of having an observed outcome is related to the outcome itself or to group assignment. Statistical methods for missing data rely on assumptions, which should be made explicit. The registry record does not report missing-data counts for the primary outcome, reasons for missingness, imputation methods, or sensitivity analyses.

The record reports enrollment of 19 but does not specify how many participants contributed to the primary endpoint analysis. It does not state whether participants were analyzed according to their randomized assignment, whether any participants withdrew, or how adherence and protocol deviations were handled. The analysis population and the handling of missing data are not reported in the registry record. Without those details, readers cannot assess whether the outcome comparison represents all randomized participants or a subset.

11. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: hospitalized (10.0%).

The registry reports serious adverse events for 0 of 9 participants in the robotic arm and 1 of 10 in the manually assisted arm. It reports other adverse events for 6 of 9 participants in the robotic arm and 7 of 10 in the manually assisted arm. These figures are participant counts with the arm denominators stated in the record. They should not be read as a complete account of the nature or timing of events.

The registry lists “Hospitalized” at 10.0% among the top serious terms. The information reported does not identify the arm associated with that term or provide further event-level detail. Death counts are not reported in the registry record. The record also does not report how adverse events were defined, the period over which they were collected, event severity beyond the serious classification, or whether investigators judged events to be related to training.

General: adverse event counts are descriptive safety information. They do not, on their own, establish that an intervention caused an event or that differences between arms are reliable. Interpretation depends on event definitions, follow-up, completeness of reporting, participant exposure, and the clinical context. The registry record does not provide enough detail to evaluate those factors or to make a causal comparison from the reported counts.

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

The registry record establishes that a randomized, parallel-group study compared robotic with manually assisted locomotor training for people with spinal cord injury. It identifies self-selected treadmill velocity at 12 weeks as the primary endpoint and reports enrollment of 19 participants. It also records adverse event counts for the two arms. These registry entries describe the scope and structure of the study.

The registry record does not report the primary endpoint results. There are no group means, standard deviations, between-group estimate, confidence interval, or p-value for treadmill velocity. Therefore, the record does not establish the direction, size, or precision of the primary comparison. It cannot support a statistical conclusion about whether the groups differed on the registered primary outcome.

General: a study’s result should be interpreted in light of the estimate, its uncertainty, the design, and the completeness of the analysis. A finding can be uncertain even when a point estimate is available, and a statistical test does not by itself describe the magnitude or practical relevance of a difference. In this record, the key primary-outcome estimate and its uncertainty are unavailable, so those considerations cannot be applied to the trial’s outcome.

The adverse event counts are also limited in what they can establish. They describe the counts recorded by arm, but the registry does not give the event details or information needed to assess completeness, timing, or attribution. They should not be treated as proof of a causal safety difference.

The study’s completed status does not substitute for posted outcome results. Nor does the existence of multiple outcomes and analyses establish what was found or how the analyses were conducted. The registry record supports a description of the trial design, endpoint, and reported event counts; it does not supply enough results or methodological detail to draw a conclusion about comparative effectiveness or to reconstruct the statistical analysis.

13. Why This Trial Matters Statistically

This study is statistically notable as a randomized comparison of two approaches to locomotor training with a continuous, function-related endpoint. The contrast is clear at a broad level: robotic-assisted versus manually assisted practice, both involving treadmill and body weight support. A continuous endpoint such as treadmill velocity can capture gradations in measured performance rather than reducing the result to a yes-or-no category.

The record also illustrates why design information and results need to be read together. Random allocation and a defined primary endpoint help identify the question the study was organized to address. But enrollment of 19 participants and a completed status do not reveal the observed effect or its precision. Without the primary outcome summaries and comparison estimate, the central statistical question remains unanswered by the registry record.

The multiple listed outcomes and analyses make transparent reporting particularly important. Readers need to know which comparisons were planned, how missing data were handled, and whether any multiplicity strategy was used to distinguish the primary question from additional analyses. Those details are not reported in the registry record. Their absence limits the ability to evaluate the evidential status of any possible result.

The record’s planning-illustration description also highlights a general distinction: sample-size calculations based on an observed effect are planning exercises, not retrospective proof that a study was adequately powered. The trial’s own sample-size justification is not reported in the registry record. Taken together, the study provides a useful example of how a registered randomized design can define a focused statistical question while leaving key information needed for interpretation unreported.

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 most direct limitation of the available record is that it does not report results for the primary endpoint. Group means, standard deviations, an estimated contrast, confidence interval, and p-value are not reported in the registry record. The primary comparison’s direction, size, and precision therefore cannot be assessed.

The study enrolled 19 participants, but the number contributing data to the primary analysis is not reported in the registry record. The record does not describe missing outcome data, participant withdrawals, adherence, or how protocol deviations were handled. It also does not state the analysis population or whether participants were analyzed according to randomized assignment.

Although the record identifies random allocation and no masking, it does not describe the randomization procedure or which study roles were unmasked. Further details of the interventions are limited because the arm descriptions are truncated. Training schedules, intensity, progression, and fidelity are not reported in the registry record. These omissions make it difficult to assess how the assigned approaches were implemented and how the outcome assessment was conducted.

The record lists nine outcome measures and ten analyses but does not describe the statistical analysis plan, the methods used for the primary comparison, or how multiplicity was handled. It does not report baseline summaries, the original sample-size justification, or missing-data sensitivity analyses. These are reporting limitations; they do not establish that the trial lacked such procedures, only that they are not reported in the registry record.

Safety information is also limited to event counts and a listed serious-event term. Event descriptions, timing, follow-up, and attribution are not reported in the registry record. These gaps restrict interpretation of the safety counts as well as the primary endpoint.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Robotic Versus Manually-Assisted Locomotor Training for Individuals With Incomplete Spinal Cord Injury — NCT00127439.
• Registry record last updated 2018-01-24; status last verified 2018-01.
• Results first posted 2018-01-24.
• 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

NCT00127439 is a completed, randomized, parallel-group study comparing robotic and manually assisted locomotor training for people with spinal cord injury. The record reports enrollment of 19 participants, no masking, a start date of 2005-06, and a primary completion date of 2009-04. Self-selected treadmill velocity at 12 weeks is identified as the primary outcome, measured in m/s.

The record lists nine outcome measures and ten analyses. It reports serious adverse events for 0 of 9 participants in the robotic arm and 1 of 10 in the manually assisted arm, and other adverse events for 6 of 9 and 7 of 10, respectively. It lists “Hospitalized” at 10.0% among the top serious terms. Death counts are not reported in the registry record.

Primary outcome results, analysis methods, missing-data handling, and the study’s own sample-size justification are not reported in the registry record. The available information describes the trial question and design but does not permit assessment of the primary outcome comparison.