Motor Cortex Plasticity and the Effect of Deep Intramuscular Needling Stimulation Therapy (DIMST) in Osteoarthritis Pain: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Motor Cortex Plasticity and the Effect of Deep Intramuscular Needling Stimulation Therapy (DIMST) in Osteoarthritis Pain (NCT01855958), a randomized na study. The primary outcome is Pain Pressure Threshold (PPT) After Intervention...

2. Clinical Question

The trial also examined cortical excitability in people with knee osteoarthritis and whether a DIMST session was followed by changes in pain intensity or measures of cortical activity. Its stated hypothesis was that cortical excitability is altered in this chronic pain condition and that DIMST could change pain and cortical excitability. Those statements describe the investigators’ rationale and hypothesis; they are not findings.

The primary measure was pain pressure threshold (PPT), recorded in kgf / cm2. Participants were instructed to report when they first perceived pain as pressure was applied with an electronic algometer. Measurements were taken at the knee and contralateral forearm, with the record describing averaged values from three successive readings. The registered timeframe was before and within one hour after intervention, while the posted primary outcome values are explicitly identified as after intervention.

The comparison therefore addresses a short-term, post-intervention difference between the two randomized groups. It does not, by itself, establish how either group changed from its own baseline, how long any observed difference lasted, or whether a difference mattered to participants in daily life. Those questions require information beyond the posted post-intervention group summaries.

3. Trial Design

The registry record describes a randomized, double-masked, parallel-group trial with an enrollment of 26. The study status is completed. It lists the phase as NA. The registered start was 2012-02, and the primary completion was 2012-06. The sponsor was Hospital de Clinicas de Porto Alegre.

The two procedures were DIMST and placebo-sham. The posted primary outcome groups each contain 13 participants. The DIMST description identifies acupuncture needles with guide tubes and an electroacupuncture device. The sham description says the same device was set to prevent current from passing through the electrodes. The available intervention descriptions are incomplete, so further procedural details are not reported in the registry record.

Randomization indicates that allocation was intended to be by chance, but the method used to generate the allocation sequence and conceal assignments is not reported in the registry record. The record identifies double masking, but it does not specify which people were masked or how masking was assessed. It also does not report whether participants were assigned in equal proportions by design, even though the posted group sizes are equal.

The primary outcome was PPT after intervention, with a stated timeframe of before and within one hour after intervention. Secondary outcomes listed in the record include intracortical inhibition (ICI), pain intensity, intracortical facilitation (ICF), and cortical silent period (CSP). The ICI, ICF, and pain-intensity results are posted; numerical CSP results are not reported in the registry record. The record lists seven outcome measures, but the populations’ demographic and clinical characteristics are not reported in the registry record.

The trial concerns a single intervention session, as stated in the study summary. Its outcome timing is consequently focused on a brief period around that session. The registry record does not report follow-up beyond the short timeframes attached to the outcomes, or details that would establish the study’s original sample-size rationale.

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: Eighty-five subjects were screened. Five refused to participate, fifty-four were not enrolled for the following reasons: Previous experience with acupuncture. Inability to walk a certain distance. Live distant of center. Twenty-six were recruited in the study and randomized further to active(n = 13) or placebo (n = 13)groups.

Overall Study

Reasons for not completing this period:

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 Pain Pressure Threshold (PPT) After Intervention.., measured over Before and within one hour after intervention..

Pain pressure threshold measures the amount of pressure applied before a participant reports pain. In general, it is a measure of pressure-evoked pain sensitivity: the endpoint is the pressure at the reported onset of pain, rather than a rating of ongoing pain intensity. A higher recorded threshold means more pressure was applied before pain onset was reported. This description explains the measure; it does not determine the clinical importance of a particular group difference.

The registry record says an electronic algometer with a 1-cm2 hard-rubber probe was applied over structures at the L1-L5 dermatome at the knee and at the contralateral forearm. Participants verbally reported the perception of pain onset. The outcome was the average of three successive readings taken at intervals of 3-5 min. Values are reported as means with standard deviations, in kgf / cm2.

The endpoint was chosen to assess pressure-evoked pain in the context of knee osteoarthritis and chronic pain. Its listed timeframe is before and within one hour after intervention, but the posted primary group summaries are labeled as after intervention. Those summaries support a comparison of post-intervention group means; they do not show the individual before-to-after changes or a baseline-adjusted estimate. The registry record does not report a threshold for what would count as an important difference to participants.

7. Results Posted in the Registry

• DIMST, Deep Intramuscular Stimulation Therapy: mean 8.82 versus 6.66 on control; difference 2.16 (95% CI 0.29 to 4.03), standardized effect d = 0.89; z-test p = 0.023.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Intracortical Inhibition (ICI) After Intervention.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • DIMST, Deep Intramuscular Stimulation Therapy: mean 0.75 versus 0.57 on control; difference 0.18 (95% CI -0.24 to 0.60), standardized effect d = 0.33; z-test p = 0.405.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between DIMST, Deep Intramuscular Stimulation Therapy and the control. The interval gives the range of effects that remain compatible with the data.

Pain Intensity After Intervention.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • DIMST, Deep Intramuscular Stimulation Therapy: mean 0.88 versus 3.36 on control; difference -2.48 (95% CI -4.48 to -0.48), standardized effect d = -0.95; z-test p = 0.015.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for DIMST, Deep Intramuscular Stimulation Therapy than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Intracortical Facilitation (ICF) After Intervention.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • DIMST, Deep Intramuscular Stimulation Therapy: mean 1.20 versus 0.78 on control; difference 0.42 (95% CI -0.20 to 1.04), standardized effect d = 0.52; z-test p = 0.182.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between DIMST, Deep Intramuscular Stimulation Therapy and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes extend the primary PPT question by including pain intensity and measures of cortical excitability. Across the posted numerical comparisons, the ICI and ICF estimates are positive, while the pain-intensity estimate is negative. These directions describe the contrasts as calculated, but the measures have different meanings and scales; their signs should not be treated as directly comparable evidence of one common effect.

The intervals for the posted secondary comparisons vary in how clearly they distinguish a nonzero contrast. The ICI and ICF intervals include zero, whereas the pain-intensity interval does not. These are unadjusted comparisons, and the registry record does not report an approach for accounting for multiple outcomes. The secondary results should therefore be interpreted as exploratory context rather than as independent confirmation of the primary result.

The cortical measures are related to the study’s stated interest in excitability, while pain intensity assesses a reported pain experience. A difference in one does not automatically establish a corresponding difference in the other. The primary endpoint concerns pressure-evoked pain, so it also addresses a distinct aspect of pain measurement. Agreement or disagreement across these measures may be informative descriptively, but the record does not report a prespecified model that combines them.

CSP is among the listed secondary outcomes, but numerical CSP results are not reported in the registry record. The record also lists seven outcome measures, while only four secondary outcomes are identified in the posted secondary list. Results for other outcomes are not reported in the registry record. This incomplete reporting makes it difficult to assess the full pattern of secondary findings or determine whether all planned outcomes are represented.

Because secondary results involve multiple opportunities to observe a contrast, an unadjusted result has less weight than a primary result chosen in advance and interpreted under a prespecified analysis plan. That plan, including any outcome hierarchy or multiplicity adjustment, is not reported in the registry record. The secondary comparisons can describe the posted data, but they cannot independently establish broad effects across pain and cortical outcomes.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Intracortical Inhibition (ICI) After Intervention.
• Pain Intensity After Intervention.
• Intracortical Facilitation (ICF) After Intervention.
• Cortical Silent Period (CSP) After Intervention.

9. Statistical Interpretation

10. Statistical Methods Explained

What does a mean difference describe?

A mean is the arithmetic average of the observed values in a group. A mean difference compares two such averages. For the primary outcome, the contrast is defined as the DIMST mean minus the placebo-sham mean. A positive estimate therefore means the posted mean was higher in the DIMST group; a negative estimate would mean it was lower. This sign convention describes the direction of the contrast, not whether a difference is beneficial or important.

The outcome summaries also include standard deviations. In general, a standard deviation describes how dispersed individual observations are around their group mean. It is not the range of observed values, and it is not a confidence interval for a treatment contrast. Two groups can have similar means but different spreads, or similar spreads but different means. Considering both helps readers distinguish the location of group averages from the variability among observations.

How should the interval be read?

A confidence interval gives a range of values compatible with the observed data and the statistical model used to calculate it. In general, a narrower interval indicates greater precision, while a wider interval indicates greater uncertainty about the contrast. The endpoints are not guaranteed limits on the true effect. They are estimates of uncertainty that depend on assumptions, including the way the comparison was calculated.

For the primary contrast, the interval is from 0.294 to 4.026 kgf / cm2. Because both endpoints are above zero, the interval is consistent with a positive mean difference under the calculation used. It still covers a range of possible magnitudes, and the record does not say which magnitudes would be clinically important. Statistical compatibility with a nonzero difference is not the same as evidence that the difference is important to patients.

What does a p value contribute?

A p value describes how unusual the data, or data more extreme, would be under a specified null model. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of a result. The primary unadjusted p value is 0.023. It should be read alongside the estimated difference and its interval, rather than as a stand-alone verdict.

These p values are identified as unadjusted. That matters because multiple outcomes and comparisons can create more opportunities for apparently notable findings. Unless a multiplicity approach is specified, unadjusted p values do not account for that broader testing context. The registry record does not report a multiplicity plan or a prespecified hierarchy for interpreting the secondary endpoints.

Why can unequal variability matter?

In general, comparisons of means rely on assumptions about how observations behave and how their variability is represented. If the spread differs substantially between groups, a method that assumes equal variances may give an inaccurate estimate of uncertainty. In settings with count data, over-dispersion means that observations vary more than a simple count model expects; accounting for it can prevent uncertainty from being understated. The outcomes in this trial are continuous, so the count-data concept of over-dispersion is not the issue being assessed.

The posted comparison calculations include a pooled standard deviation. Pooling summarizes the within-group spread for a standardized comparison, under assumptions about the groups’ variability. The registry record does not report the investigators’ chosen statistical method or checks of those assumptions. The comparisons are therefore best understood as unadjusted calculations from the posted group summaries, not as a complete account of the original analysis.

What can and cannot be inferred from summary data?

Group means and standard deviations are compact summaries. They do not show individual observations, the shape of each group’s distribution, or whether unusual values influenced a mean. They also do not show how each participant’s measurement changed from before to after intervention. Although the primary outcome timeframe includes measurements before and after, the posted primary values are explicitly described as after intervention. The registry record does not report a paired change analysis or a baseline-adjusted comparison.

The posted group sizes are 13.0 in each arm for the primary outcome. A group size gives context for the amount of information available, but it does not by itself determine the precision of a result; variability also matters. With a small study, estimates can be sensitive to the observations included. This is a general consideration, not a claim that any particular observation affected these results.

The registry record lists zero reported analyses. It does not explain whether this means no analysis details were entered, whether analyses were not submitted, or whether another process was used. The statistical plan, missing-data approach, analysis population, and treatment of protocol deviations are not reported in the registry record. Readers therefore cannot verify prespecification or reproduce the investigators’ full analysis from the registry entry alone.

11. Confidence Intervals and Precision

The primary mean-difference estimate is 2.16 kgf / cm2, with an interval from 0.294 to 4.026. The interval lies on the positive side of zero, but it spans a range of magnitudes. It conveys both the direction suggested by the data and the uncertainty around how large the group difference may be. It does not identify a single exact effect.

Precision depends on the variability of measurements and the amount of information in the comparison. The posted standard deviations differ between the DIMST and placebo-sham groups, and the primary outcome summaries show 13.0 participants in each group. The interval is more informative about uncertainty in the contrast than either group’s standard deviation alone. The registry record does not report additional information about missing measurements or the exact analysis population used.

In general, a confidence interval is not a range that contains the true value with certainty, and its interpretation depends on the statistical model and procedure used. The registry record does not specify the confidence level or the full method used for the posted interval. It also does not state a threshold for clinical importance. Consequently, the interval can be used to describe statistical precision, but not to decide whether its values would represent a meaningful change for participants.

The unadjusted p value of 0.023 addresses compatibility with a null comparison under the calculation used; it does not remove uncertainty about effect size. Consideration of the interval, the short measurement timeframe, and the record’s unreported analysis details is important when judging how much confidence to place in the estimate.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm for 80% power and participants per arm for 90% power. They are not total events: this is a continuous-outcome comparison, and the planning illustration assumes equal allocation between two arms. In general, 80% power means that a study designed under the stated assumptions would have an 80% chance of detecting the specified effect at the chosen significance level if that effect were the true one. The 90% column describes the corresponding design with a higher chance of detection under those assumptions.

The listed planning assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. The entries for 100% of the observed effect use the full observed contrast as the planning target; the entries for 75% and 50% use smaller targets. Smaller effects generally require more participants to detect, which is why the planning figures increase as the assumed fraction of the observed effect decreases.

These values are planning illustrations based on the observed effect, not a reconstruction of the trial’s original design. The trial’s own sample-size assumptions and justification are not reported in the registry record. The figures also do not tell how many participants were actually enrolled; the registry lists an enrollment of 26 and the posted primary summaries contain 13.0 participants in each group. These calculations are not observed power. They describe hypothetical design requirements under the stated assumptions, not the probability that the completed trial has established a result.

A curve, if considered alongside the entries, represents the same general relationship between assumed effect size and required enrollment. It should be read as a planning aid whose values depend on the stated model and assumptions, not as a forecast of the trial’s results or as evidence that a particular effect is true.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 2.160; pooled standard deviation σ = 2.428.
2. n = 2 × (1.96 + 0.842)² × 2.428² / 2.160² = 19.8, rounded up to 20 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 2.16                      # observed difference in means
sigma <- 2.42784884208222                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1855958)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 20 (80% power), 27 (90% power)
 75% of observed effect: n per arm = 36 (80% power), 48 (90% power)
 50% of observed effect: n per arm = 80 (80% power), 107 (90% power)
power.t.test: 20.8 
Simulated power at n = 20 per arm: 0.779 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several outcomes, timepoints, or comparisons are examined. Even when each individual test uses a conventional significance threshold, considering many tests increases the chance that at least one will appear notable by chance. Researchers may address this by specifying a primary outcome, defining a testing hierarchy, or using an adjustment method. These are general approaches; the registry record does not report which, if any, were planned for this trial.

The registry lists seven outcome measures and identifies a primary endpoint as well as secondary outcomes. Four secondary outcomes are posted in the secondary list, and numerical results are available for ICI, pain intensity, and ICF. CSP is listed but its numerical result is not reported in the registry record. The record does not say whether the outcomes were all prespecified in this form, whether all were analyzed, or how any multiplicity was considered.

The posted p values are unadjusted. They describe individual comparisons without accounting for the broader set of outcomes. This does not make the results unusable, but it means the secondary p values should not be read as if they were the sole planned test. The registry record does not report a family-wise error strategy, a false-discovery approach, or another multiplicity procedure.

Missing-data handling is also not reported in the registry record. There is no description of how absent outcome values were treated, whether any participants were excluded from an outcome analysis, or whether sensitivity analyses were performed. The record does not identify an intention-to-treat, per-protocol, or other analysis population. It is therefore not possible to determine from the registry entry whether all randomized participants were included in each analysis or how deviations from assigned procedures were handled.

These gaps limit assessment of the analysis’s prespecification and robustness. They do not establish that the investigators failed to conduct those procedures; they indicate that the procedures are not reported in the registry record.

15. 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.

The adverse-event record reports zero serious adverse events among the 13 participants at risk in the DIMST group and zero among the 13 at risk in the placebo-sham group. It also reports zero other adverse events among the 13 participants at risk in each group. These entries describe the recorded counts for the groups and the listed risk denominators.

Zero reported events in a small study does not establish that an event cannot occur, nor does it provide a precise estimate of uncommon risks. It is also important to distinguish a recorded zero from information that was not reported. The deaths fields are null, so deaths are not reported in the registry record. No serious-event terms are listed.

The record does not provide additional details about how adverse events were collected, their observation window, or whether there were events not captured in the posted categories. These figures should therefore be read as the registry’s adverse-event reporting, not as a complete assessment of safety or proof of absence of risk.

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

The posted primary result is a positive post-intervention mean difference in PPT between DIMST and placebo-sham, with an unadjusted interval that does not include zero and an unadjusted p value of 0.023. This describes a statistical contrast in a pressure-evoked pain measure within one hour of a single session. It is not, by itself, evidence about longer-term outcomes or a broader measure of pain and function.

The registry record does not establish how clinically important the contrast is. It does not report a threshold for a meaningful PPT difference, participants’ assessments of benefit, or the duration of any observed difference. A statistically distinguishable group average is not automatically a meaningful change for an individual, and group means do not describe every participant’s experience.

The result also does not show the size of a before-to-after change within either group. Although the outcome timeframe includes measurements before and after intervention, the posted primary values are identified as after intervention. The record does not report a change-score analysis or baseline-adjusted estimate. Nor does the result establish that DIMST caused the observed difference; evaluation of causal claims depends on design implementation, complete outcome data, and analysis details that are not fully reported.

The trial’s limited enrollment and short outcome window constrain how far the estimates can be generalized. Participant characteristics beyond the condition are not reported, and the record does not report follow-up beyond the near-term outcome timeframes. The findings should be understood as applying to the recorded groups, procedure, measure, and assessment period rather than as evidence about all people with osteoarthritis or chronic pain.

Finally, the secondary outcomes do not provide a uniform, fully reported picture. Some results are imprecise, multiplicity handling is not reported, and numerical CSP results are absent from the registry record. The registry evidence can inform a statistical reading of the posted measurements, but it does not settle clinical value, persistence, or the full profile of outcomes.

17. Why This Trial Matters Statistically

This trial is statistically informative because it illustrates the difference between a group contrast and a within-person change. The primary result compares post-intervention group means. The registered timeframe mentions measurements before and after intervention, but the available primary summaries do not report a change analysis. Keeping those questions separate prevents the post-intervention contrast from being mistaken for a measured baseline-to-follow-up change.

It also shows why estimates, intervals, and p values should be read together. The mean difference conveys the estimated direction and scale, the interval expresses uncertainty about its magnitude, and the p value describes compatibility with a null model under the unadjusted calculation. None of these alone determines clinical importance. The registry record does not provide a threshold that would define an important PPT difference.

The study’s range of outcomes raises a further statistical issue: multiple testing. Pain pressure threshold, pain intensity, and cortical measures address related but distinct questions. Without a reported multiplicity strategy or analysis hierarchy, secondary findings are more appropriately treated as contextual than as a set of confirmatory claims. Incomplete numerical reporting for CSP also prevents a full account of the listed secondary outcomes.

Finally, the sample-size illustration makes clear that planning requirements depend on the effect size a study aims to detect. Planning from an observed effect is not the same as recovering the original design rationale, which is not reported in the registry record. Together, these issues make the record a useful example of how reporting detail, uncertainty, and outcome selection shape interpretation of a small randomized study.

18. 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 registry record gives an enrollment of 26 and the posted primary summaries show 13.0 participants in each arm. This is a limited amount of information for estimating between-group differences, particularly when individual measurements vary. The record does not report participant characteristics beyond knee osteoarthritis and chronic pain, so it is difficult to assess how well the enrolled group represents other populations.

The outcome window is brief: the primary timeframe is before and within one hour after intervention, and the study summary describes one session. The record does not report longer-term follow-up. It therefore cannot characterize persistence of the post-intervention measurements or outcomes over a longer period.

Several analysis details are not reported in the registry record, including the randomization method, allocation concealment, which parties were masked, the statistical analysis plan, the analysis population, and missing-data handling. The record also does not report a sample-size justification or multiplicity approach. These omissions limit assessment of prespecification, risk of bias, and robustness without establishing that any particular method was or was not used.

The posted summaries do not provide individual-level data or baseline-to-follow-up changes for the primary endpoint. Numerical CSP results are not reported, and the relationship between the seven listed outcome measures and the outcomes with posted results is not fully described. The sham intervention’s description is also incomplete. These trial-specific reporting limitations constrain interpretation beyond the comparative summaries that are available.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Motor Cortex Plasticity and the Effect of Deep Intramuscular Needling Stimulation Therapy (DIMST) in Osteoarthritis Pain — NCT01855958.
• Registry record last updated 2017-09-15; status last verified 2015-08.
• Results first posted 2015-09-22.
• 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.

22. Record Summary

The registry record describes a completed randomized, double-masked, parallel-group study of DIMST versus placebo-sham in knee osteoarthritis and chronic pain. It lists an enrollment of 26 and a primary endpoint of pain pressure threshold after intervention, measured in kgf / cm2. The posted mean difference was 2.16, with an interval from 0.294 to 4.026 and an unadjusted p value of 0.023.

Secondary outcomes include pain intensity and cortical measures. Some numerical results are posted, while CSP results are not reported in the registry record. The record does not report the statistical plan, missing-data approach, analysis population, or multiplicity handling. The findings concern short-term measurements around a single session and do not establish clinical importance or longer-term effects.