This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Trial of Scrambler Therapy or Sham Treatment for Low Back Pain (NCT01896687), a randomized na study. The primary outcome is Worst Low Back Pain Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01896687 |
| Phase | NA |
| Condition | Low Back Pain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Virginia Commonwealth University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people with persistent nonspecific low back pain. The registry lists low back pain as the condition and does not give further eligibility details or a more specific description of the analysed population.
Intervention
The active arm received Scrambler therapy applied to the region of low back pain for 30 minutes x 10 days. The study was a pilot evaluation of the treatment in relation to pain, pain sensitivity and mRNA expression of candidate genes.
Comparator
The comparator was sham Scrambler treatment. It was applied above the low-back-pain region at a nontherapeutic dose for 30 minutes x 10 days. This is the registry’s description of the sham procedure; further details about its delivery are not reported in the registry record.
Primary question
The listed primary measure is worst low back pain score on the Brief Pain Inventory, assessed from baseline to 3 weeks post-treatment. The registry record does not report the arm-level results or a numerical comparison, so it does not establish the observed difference in this outcome.
3. Trial Design
This was a randomized, double-masked, parallel-group pilot trial comparing Scrambler therapy with sham treatment for persistent nonspecific low back pain. The registry lists an enrollment of 30 and identifies Virginia Commonwealth University as the sponsor. The record lists the phase as not applicable and the status as completed.
The intervention description specifies Scrambler therapy applied to the region of low back pain for 30 minutes x 10 days. The sham treatment was applied to a region above the low-back-pain site at a nontherapeutic dose, also for 30 minutes x 10 days. The registry identifies the intervention as a device. It does not explain which study roles were masked, how masking was maintained, or whether masking was assessed.
The record gives a start date of 2013-03 and a primary completion date of 2013-08. It describes the trial as a pilot study intended to evaluate pain levels, pain sensitivity and mRNA expression of pain-sensitivity candidate genes. However, the registered primary outcome is worst low back pain score, and the record lists one outcome measure and one analysis. The available outcome description does not provide a numerical comparison between treatment arms.
Random allocation can help reduce systematic differences between groups at the point of assignment, but the registry does not report the sequence-generation or allocation-concealment methods. Nor does it report protocol details such as eligibility criteria or treatment adherence. The trial’s pilot designation describes its stated role, but the registry record does not give a sample-size justification or explain whether the study was designed to test a specific efficacy hypothesis.
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
| Stage | Scrambler Therapy | Sham Scrambler Treatment |
|---|---|---|
| STARTED | 15 | 15 |
| COMPLETED | 15 | 15 |
| NOT COMPLETED | 0 | 0 |
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.
| Characteristic | Unit | Scrambler Therapy | Sham Scrambler Treatment | Total |
|---|---|---|---|---|
| Participants analysed | 15 | 15 | 30 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 15 | 15 | 30 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 8 | 11 | 19 |
| Sex: Female, Male: Male | Participants | 7 | 4 | 11 |
| Region of Enrollment: United States | participants | 15 | 15 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Worst Low Back Pain Score, measured over baseline to 3 weeks post-treatment.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The listed primary endpoint is worst low back pain score measured with the Brief Pain Inventory (BPI), over baseline to 3 weeks post-treatment. The BPI assesses pain severity and location, pain medications, pain relief over the past 24 hours and past week, and the effect of pain on daily functions. For this study, the worst-pain score is the measure selected for analysis.
The score ranges from 0, meaning no pain, to 10, meaning pain as bad as you can imagine. It is a continuous measure, and the registry specifies that the parameter is the mean and the dispersion measure is the standard deviation. A mean describes the group’s average score; a standard deviation describes how spread out individual scores are around that average.
Worst pain is used to focus the analysis on the highest pain rating captured by the instrument rather than combining all of the BPI’s separate pain and function questions into one value. The baseline-to-follow-up timeframe also makes the planned measure a change-oriented assessment across treatment. However, the registry record does not report the observed means, standard deviations, change scores, or a between-arm estimate. It therefore does not show the magnitude or precision of any difference in the primary measure.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a randomized comparison of Scrambler therapy and sham treatment, but it does not report numerical results for the primary outcome. In particular, no group-level worst-pain means or standard deviations, between-arm effect estimate, confidence interval, or p-value are reported in the registry record. The listed outcome and its timeframe explain what the trial planned to assess; they do not reveal what the assessment found.
The planned primary measure is the mean worst low back pain score on the BPI from baseline to 3 weeks post-treatment. A treatment comparison would need to make clear how the baseline and follow-up observations were used, what the comparison scale represents, and how uncertainty around the estimate was quantified. Those analysis details and numerical results are not reported in the registry record. The record’s note that the primary outcome has several categories or time points and was not reduced to one comparison further limits interpretation of a single primary contrast.
Without an effect estimate and its uncertainty, the size and direction of any observed difference cannot be assessed. Without a reported test result, there is no basis to describe statistical evidence for a between-arm difference. Even if a p-value were available, it would not by itself describe the size or practical importance of an effect; an estimate and confidence interval would be needed to understand the range of effects compatible with the data.
The study is labelled a pilot trial, and the registry lists enrollment of 30. That context does not substitute for reported outcome data. Nor can the planning assumptions for a sample-size illustration be read as evidence about the trial’s observed effect or as observed power. The registry says that the illustration uses the observed effect, a two-sided significance level of 0.05, equal allocation, a normal approximation, and a stated fraction of the observed effect. It does not report numerical illustration results in the record.
The safety figures are also limited to the reported event counts. In each arm, 0 participants are listed as affected by serious adverse events among 15 at risk, and 0 are listed as affected by other adverse events among 15 at risk. Those counts describe the registry entries; they do not establish that no event occurred outside the recorded categories or that rare harms are excluded. Death counts are not reported in the registry record.
9. Statistical Methods Explained
The methods described in the registry record are limited. It identifies a randomized, double-masked, parallel design and a continuous primary outcome parameterized as a mean with standard deviation. It does not describe the statistical model, the precise comparison estimand, the handling of baseline values, or the method used to account for repeated measurements or multiple outcome time points. These omissions matter because the choice of analysis determines what effect is estimated and how its uncertainty is calculated.
What does a mean represent?
For a continuous score, the mean is the arithmetic average across the observations included in an analysis. In this trial, the selected score is worst pain on the BPI. A mean can convey the typical level in a group, but it does not describe every participant’s experience. The distribution of the scores and the spread around the mean also matter. The registry specifies standard deviation as the measure of dispersion, but does not report group-level standard deviations or means.
A treatment contrast could be expressed in different ways, such as a difference in follow-up scores or a difference in change from baseline. These are not interchangeable descriptions in every analysis, particularly when baseline scores vary or when repeated measurements are modelled. The record gives a baseline-to-3-weeks-post-treatment timeframe but does not say which contrast or model was used. Therefore, a reader cannot infer the exact estimand from the outcome description alone.
What would a confidence interval add?
A confidence interval is a statistical way to show the uncertainty around an estimated effect. Its width reflects how precisely the effect has been estimated under the chosen model and assumptions. A narrow interval indicates greater precision than a wide interval, while the values it spans indicate which effect sizes are compatible with the data under that method. The registry record does not report a confidence interval for the primary comparison, so the precision of any treatment estimate cannot be judged.
A p-value, if reported, would address how compatible the observed data are with a specified null hypothesis under the analysis assumptions. It would not indicate the probability that the null hypothesis is true, and it would not measure the clinical importance of an effect. A p-value should be considered alongside the estimated effect and its confidence interval. No primary-comparison p-value is reported in the registry record.
Why can over-dispersion matter?
Over-dispersion is a general issue for count outcomes: it occurs when the observed variability is greater than a model expects. It can make standard errors too small if a model assumes less variation than the data contain, leading to overly narrow intervals or misleading test results. The primary outcome in this trial is a continuous pain score, not a count outcome, and the registry does not report a model or an over-dispersion assessment. This general concept should not be mistaken for a feature documented in this trial’s analysis.
How should sample-size illustrations be understood?
The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. It describes planning for a stated fraction of the observed effect and distinguishes participants per arm for non-time-to-event outcomes from total events for time-to-event outcomes. These are assumptions for a planning exercise, not a description of the trial’s original design justification. No numerical planning results are reported in the registry record.
A planning calculation asks how much information a future study might need under specified assumptions. It does not show what this trial observed, and it is not observed power. When an observed effect is used as the planning basis, the illustration depends on that estimate and on the assumed target fraction. The registry record does not provide a sample-size justification for this pilot trial, and no numerical calculation should be inferred from the listed assumptions alone.
Randomization, masking, and the parallel structure describe important design features, but they do not identify the statistical analysis in full. The record does not report the randomization method, analysis model, standard-error method, adjustment variables, or treatment of repeated assessments. Those details are necessary to reproduce or fully evaluate an estimate. Since no numerical primary outcome comparison is reported, recalculation from summary statistics is also not possible from this record.
10. Multiplicity, Missing Data and Analysis Populations
The registry describes the study as evaluating pain levels, pain sensitivity, and mRNA expression of pain-sensitivity candidate genes. It lists one outcome measure and one analysis, but the primary outcome description indicates multiple categories or time points and notes that these were not reduced to one comparison. Thus, the registry record does not identify a single numerical primary contrast that can be interpreted as the definitive result.
Multiplicity arises when multiple outcomes, time points, or comparisons are tested. Considering many tests can increase the chance of observing at least one apparently notable result by chance. Statistical approaches can account for this, or investigators can define a primary comparison in advance and treat other analyses as secondary or exploratory. The registry record does not report a multiplicity adjustment, a hierarchy of tests, or which comparisons were designated primary for analysis. No specific correction should be assumed.
Missing-data handling is not reported in the registry record. It does not give the number of participants with an observed primary outcome at each time point, the reasons for missing measurements, or whether an analysis used imputation, complete cases, or another approach. Missingness can affect estimates if the availability of measurements is related to participant characteristics or outcomes, so the analysis population and assumptions are relevant to interpretation.
The analysis population is not reported in the registry record. It is therefore unclear whether the listed analysis included all randomized participants, only those who received treatment, or another defined group. The record also does not report interim analyses or a statistical analysis plan. These are unknowns, not evidence that such procedures were or were not used.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Scrambler Therapy | 0 | 15 | 0.0% |
| Sham Scrambler Treatment | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Scrambler Therapy | 0 of 15 |
| Sham Scrambler Treatment | 0 of 15 |
The registry lists 0 participants with serious adverse events among 15 at risk in the Scrambler Therapy arm, and 0 among 15 at risk in the Sham Scrambler Treatment arm. It also lists 0 participants with other adverse events among 15 at risk in each arm. No serious adverse-event terms are listed.
These entries should be read as recorded counts for the registry’s reported categories. They do not establish that no adverse event of any kind occurred, that all events were captured, or that treatment cannot cause a rare event. The record does not provide event definitions, surveillance procedures, follow-up details for safety, or a description of how events were attributed to treatment. Those details are not reported in the registry record.
Death counts are not reported in the registry record. The death fields are not populated with a count, so they should not be interpreted as a confirmed zero. The at-risk counts describe the numbers reported for the adverse-event entries; they should not be used to infer the number with complete primary-outcome data. Overall, these safety figures are limited registry counts and do not support broader conclusions about comparative safety.
12. What the Result Does, and Does Not, Mean
The registry establishes that a completed pilot randomized trial was designed to compare Scrambler therapy with sham treatment for persistent nonspecific low back pain. It identifies the treatment schedules, the double-masked parallel design, and worst low back pain score on the BPI as the listed primary measure. It also records an enrollment of 30 and a baseline-to-3-weeks-post-treatment timeframe.
Those design details do not reveal the trial’s numerical primary result. The registry record does not report the arm-level scores, the estimated treatment contrast, the uncertainty around that estimate, or a test result. Consequently, it is not possible to describe the direction, magnitude, or precision of the primary outcome comparison from the registry record. The absence of a reported comparison is not evidence that the treatments produced identical outcomes, nor does it establish that one treatment performed better.
The record’s pilot designation is relevant context, but it does not itself determine the strength of evidence. A pilot trial may be used to evaluate procedures or obtain information for later research, but the registry does not state a specific design purpose beyond evaluating pain-related measures and candidate-gene expression. The record also does not provide a sample-size justification or numerical planning illustration results. Planning assumptions should not be treated as observed findings or as observed power.
The reported adverse-event counts are limited to the categories and at-risk entries recorded. They do not show that all potential harms have been ruled out, and death counts are not reported in the registry record. In short, the record informs readers about the trial’s structure and intended assessment, but does not provide enough numerical outcome information to determine what the primary comparison showed.
13. Why This Trial Matters Statistically
This trial is statistically notable as a randomized, double-masked, parallel-group pilot comparison of a device-based intervention with a sham procedure. A sham comparator can help distinguish effects associated with the active procedure from changes that may accompany treatment context or repeated assessment. The registry’s description makes clear that the sham was delivered at a nontherapeutic dose and at a site above the area of low back pain; further procedural detail is not reported in the registry record.
The primary measure is a patient-reported pain score, and the registry specifies a mean and standard deviation. That choice makes the target outcome understandable, but interpretation still depends on the analysis contrast, the handling of baseline and follow-up values, the amount of missing information, and the uncertainty around the estimate. Those details and the numerical comparison are not reported in the registry record.
The study also illustrates the distinction between a trial’s design and its results. Randomization and masking describe methods intended to strengthen a comparison; they do not replace outcome estimates. Likewise, a planning illustration based on an observed effect is not evidence about the precision or power actually achieved in the pilot. The registry record supplies assumptions for such an illustration but no numerical results or original sample-size justification.
For biostatistical interpretation, the central lesson is to separate what the record documents from what remains unavailable. Here, the design, outcome definition, timing, and selected safety counts are described, while the primary treatment estimate and its precision are not. That gap limits conclusions about the comparative outcome, regardless of how the trial was structured.
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.
Several trial-specific limitations follow from the registry information. The study is described as a pilot and lists enrollment of 30, but the registry record does not report a sample-size justification or specify the precision expected for the primary outcome. Without an estimate and its uncertainty, the adequacy of the available information for the planned comparison cannot be evaluated from the record.
The primary outcome description identifies a baseline-to-3-weeks-post-treatment period, yet the registry notes multiple categories or time points and does not reduce them to one comparison. It does not report which time-point contrast was used or the statistical model. This makes the intended primary estimand unclear and prevents assessment of whether the analysis matched the stated outcome timeframe.
Other relevant analysis information is also not reported in the registry record: group-level outcome summaries, missing-data handling, analysis population, randomization procedures, masking roles, and a detailed statistical analysis plan. The record does not explain adherence to the 30 minutes x 10 days schedule or report how deviations were handled. These are limits of what can be assessed from the record, not assertions about what investigators did.
The registry describes the study as assessing pain sensitivity and mRNA expression of candidate genes in addition to pain levels, but the presented primary outcome information does not provide results for these aims. The record also gives limited safety detail beyond the reported counts, with death counts not reported. Taken together, these omissions constrain interpretation of both the primary comparison and the completeness of the clinical picture.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Trial of Scrambler Therapy or Sham Treatment for Low Back Pain — NCT01896687.
- Registry record last updated 2017-06-14; status last verified 2017-06.
- Results first posted 2014-09-15.
- 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.
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18. Record Summary
The registry record describes NCT01896687, a completed pilot randomized, double-masked, parallel trial sponsored by Virginia Commonwealth University. It compared Scrambler therapy with sham Scrambler treatment for persistent nonspecific low back pain. Enrollment was 30; the record lists a start date of 2013-03 and primary completion in 2013-08.
The primary measure was worst low back pain score on the BPI, assessed from baseline to 3 weeks post-treatment. Scrambler therapy and sham treatment were each scheduled for 30 minutes x 10 days, with the sham applied above the pain region at a nontherapeutic dose. Numerical primary-outcome results and a treatment-effect estimate are not reported in the registry record.
The record lists 0 serious and 0 other adverse-event participants among 15 at risk in each arm. Death counts are not reported in the registry record. Analysis-population details, missing-data methods, and the statistical model are also not reported.