Median Nerve Stimulation for Tourette Syndrome and Chronic Tic Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Median Nerve Stimulation for Tourette Syndrome and Chronic Tic Disorder (NCT05269953), a randomized na study. The primary outcome is Change in Yale Global Tic Severity Scale - Revised (YGTSS-R) Total Tic Severity Score.

2. Clinical Question

The trial asked whether rhythmic electrical stimulation delivered to the wrist was associated with a change in tic severity over the initial treatment period, compared with sham stimulation or waitlist treatment as usual. Its stated goal also included examining changes in the urge that can precede tics.

The primary outcome is a change score, so negative values indicate a lower score at follow-up than at baseline. Since higher YGTSS-R scores indicate worse tic severity, a more negative mean change represents a larger reduction in the measured score. This describes the scale’s direction; it does not by itself establish why scores changed or whether the change is important to participants.

3. Trial Design

The registry describes a randomized, parallel-group trial with quadruple masking and active stimulation, sham stimulation, and waitlist arms. The official title describes the study as double-blind and placebo-controlled. The posted enrollment is 135. The record lists the sponsor as Nottingham University Hospitals NHS Trust, gives the status as completed, and records a start date of 2022-03-18 and a primary completion date of 2022-09-26.

The active and sham interventions are listed as devices. The waitlist arm is described as receiving treatment as usual. The record does not describe the sham procedure or specify which people were included in the quadruple masking. The allocation ratio and details of sequence generation or concealment are not reported in the registry record.

The primary endpoint is change in YGTSS-R total tic severity score from baseline to week 4 after starting stimulation. The posted primary results include 39.0 participants in each of the active stimulation, sham stimulation, and waitlist groups. The outcome description states that participants with a baseline YGTSS-TTSS of 15 or lower, or missing week 4 data, were removed from further analysis. The registry does not give a fuller account of the flow from enrollment to the primary analysis.

The record lists five outcome measures and 11 analyses. It posts three secondary outcome measures: video-based tic frequency, premonitory urge measured by PUTS-R, and obsessive-compulsive symptoms measured by (C)Y-BOCS. Details of the original statistical plan, including the planned sample-size justification and any interim analyses, are not reported in the registry record.

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: A total of 210 potential participants consented to participate in the screening interview. However, 25 participants did not proceed to attend the interview, and 19 participants were subsequently excluded after their suitability to participate in the trial was assessed. Additionally, 23 participants were excluded before the baseline visit, and an additional 10 participants were excluded during the baseline visit. Thus, 133 participants were enrolled in the trial and randomised.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants were removed from further analysis if they exhibited a YGTSS-TTSS at baseline (week 0) below the inclusion threshold (i.e., a YGTSS-TTSS of 15 or lower) or if there was missing data for week 4.

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: Baseline population excludes enrolled participants who were withdrawn before the week1 assessments

6. Primary Endpoint

The registry lists the primary outcome as Change in Yale Global Tic Severity Scale - Revised (YGTSS-R) Total Tic Severity Score, measured over Baseline and week 4 after starting stimulation.

The primary outcome is change in the Yale Global Tic Severity Scale-Revised (YGTSS-R) Total Tic Severity Score. The registry describes it as a score on a scale, summarized by its mean and standard deviation, with measurement at baseline and week 4 after starting stimulation. The stated range is 0-50, and higher scores indicate a worse outcome.

The YGTSS-R is used to quantify tic severity, allowing investigators to compare score changes across the randomized groups over the initial four-week stimulation period. The registry describes it as a gold-standard measure for evaluating tic severity in Tourette syndrome. A change score compares follow-up with baseline; it is not the same as a final score alone. Negative changes mean the measured score fell over that period, while the size of a group mean change does not describe every participant’s experience.

For the posted primary comparison, the active group’s mean change was -7.13, the sham group’s was -2.13, and the waitlist group’s was -2.26. These are group averages, not individual outcomes. The primary analysis population was subject to the registry’s stated baseline threshold and week 4 data exclusion. The record does not report the number excluded for each reason, nor does it provide a detailed account of how missing values were handled beyond that exclusion statement.

7. Results Posted in the Registry

• Active Stimulation: mean -7.13 versus -2.13 on control; difference -5.00 (95% CI -5.36 to -4.64), standardized effect d = -6.17; z-test p = <0.001.
• Waitlist: mean -2.26 versus -2.13 on control; difference -0.13 (95% CI -0.28 to 0.02), standardized effect d = -0.39; z-test p = 0.082.

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.

Change in Tic Frequency as Quantified by Analysis of Video Data

• 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:
  • Active Stimulation: mean -15.60 versus -7.70 on control; difference -7.90 (95% CI -27.63 to 11.83), standardized effect d = -0.28; z-test p = 0.433.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Stimulation and the control. The interval gives the range of effects that remain compatible with the data.

Change in Premonitory Urge (as Measured by Premonitory Urge for Tics Scale-Revised (PUTS-R))

• 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:
  • Active Stimulation: mean -22.20 versus -16.10 on control; difference -6.10 (95% CI -20.74 to 8.54), standardized effect d = -0.19; z-test p = 0.414.
  • Waitlist: mean -9.30 versus -16.10 on control; difference 6.80 (95% CI -4.94 to 18.54), standardized effect d = 0.27; z-test p = 0.256.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Stimulation and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Waitlist and the control. The interval gives the range of effects that remain compatible with the data.

Change in Symptoms of Obsessive-Compulsive Disorder (OCD) (as Measured by (Children's) Yale-Brown Obsessive-Compulsive Scale (C)Y-BOCS)

• 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:
  • Active Stimulation: mean -24.90 versus -35.50 on control; difference 10.60 (95% CI -13.47 to 34.67), standardized effect d = 0.27; z-test p = 0.388.
  • Waitlist: mean -18.90 versus -35.50 on control; difference 16.60 (95% CI -11.88 to 45.08), standardized effect d = 0.38; z-test p = 0.253.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Stimulation and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Waitlist and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes extend the assessment beyond the primary tic-severity scale. They cover video-quantified tic frequency, premonitory urge, and obsessive-compulsive symptoms. Taken together, their recalculated comparisons do not show a uniformly precise pattern across domains: estimates are uncertain, and the posted sponsor analyses do not provide a consistent set of directly comparable effect estimates and confidence intervals.

That pattern should be considered alongside, rather than substituted for, the primary outcome. Secondary measures may provide useful context about related symptoms or behaviors, but they do not independently confirm the primary result. Nor does a difference in one measured domain establish a corresponding change in another. The registry does not report an overall combined secondary endpoint or a single analysis that integrates these measures.

Unadjusted secondary results carry less weight because multiple outcomes and comparisons create more opportunities for apparently unusual results to occur by chance. General statistical practice may address this with a prespecified testing hierarchy or multiplicity adjustment, but neither is described in the registry record. The presence of 11 posted analyses and five outcome measures makes it especially important to know which results were planned as confirmatory and how the family of tests was handled. That information is not reported in the registry record.

Secondary findings are also limited by the amount of outcome data available for each measure. The posted analyzed groups vary across outcomes, and the video analysis includes fewer participants than the primary outcome analysis. The registry does not provide a full account of missingness or the reasons for these differences. Therefore, the secondary results are best read as exploratory context, with their precision and reporting limitations in view, rather than as a definitive pattern that either proves or refutes the primary finding.

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

• Change in Tic Frequency as Quantified by Analysis of Video Data
• Change in Premonitory Urge (as Measured by Premonitory Urge for Tics Scale-Revised (PUTS-R))
• Change in Symptoms of Obsessive-Compulsive Disorder (OCD) (as Measured by (Children's) Yale-Brown Obsessive-Compulsive Scale (C)Y-BOCS)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a scale score, and the registry reports group means and standard deviations. The recalculated comparisons are unadjusted mean differences between groups. These quantities describe how far apart the group averages are on the score scale. A negative difference depends on the order of subtraction; it does not mean that every participant’s score fell.

What does a confidence interval express?

In general, a confidence interval describes the uncertainty around an estimated effect under the assumptions of the statistical method. A narrower interval indicates greater precision in that estimate; a wider interval indicates less precision. If an interval includes zero for a mean difference, the data are compatible with no difference as well as with differences on either side of zero, within the interval. This does not prove equivalence. The recalculated active-versus-sham interval does not include zero, while the recalculated waitlist-versus-sham interval does.

How should the p-values be read?

In general, a p-value describes how unusual data at least as incompatible with a specified null model would be if that model and the test assumptions held. It is not the probability that the null hypothesis is true, nor a measure of the size or importance of an effect. The registry reports a non-parametric permutation analysis for the primary active-versus-sham comparison. A permutation test assesses a contrast by comparing the observed statistic with values generated by rearranging group labels under the test’s assumptions. The exact implementation and any adjustment for other analyses are not reported in the registry record.

The recalculated p-values are explicitly unadjusted. They come from simple comparisons of posted summary statistics and do not incorporate covariates or account for testing multiple outcomes and comparisons. The primary recalculated active-versus-sham result is not identical to the sponsor’s reported analysis; the discrepancy means the recalculation should be treated as an independent descriptive check, not as a correction to the registry’s analysis.

Why do standard deviations matter?

In general, a standard deviation describes how spread out individual scores are around a group mean. It is not the same as the standard error, which describes uncertainty in an estimated mean. A mean difference can be large relative to within-group variation, but interpretation also depends on the study design, measurement, and analysis population. The registry reports standard deviations for the primary outcome but does not provide individual-level data in this record.

General statistical considerations also include distributional shape and outliers. When data are highly skewed or contain influential values, a mean can be sensitive to those observations. The registry’s sponsor-reported primary analysis uses permutation testing, whereas the posted recalculations use summary statistics. The record does not report diagnostic checks or explain why the sponsor selected that test, so those details should not be inferred.

What is different about the planning illustrations?

The sample-size illustrations are calculations based on observed effects, not the trial’s original design assumptions. They use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects set to stated fractions of the observed effect. The entries are participants per arm for these continuous outcomes. General planning logic is that smaller effects are harder to distinguish from background variation and therefore require more participants under otherwise similar assumptions.

These calculations do not reconstruct the trial’s planned sample size, and the record does not report the original sample-size justification. They also do not represent observed power. The displayed planning values should be read as conditional illustrations that depend on the observed effect and stated assumptions, not as evidence about the probability that the completed study detected an effect.

11. Confidence Intervals and Precision

The recalculated active-versus-sham mean difference for the primary outcome is -5.0, with a 95% confidence interval from -5.36 to -4.64. This interval is relatively narrow around the recalculated estimate and does not include zero. It conveys precision for that particular unadjusted summary-statistic calculation, not for every possible analysis of the trial. The sponsor’s reported primary analysis uses a non-parametric permutation test and gives a mean difference of 5 with p <0.02, without a confidence interval. Since the registry results and recalculation differ, the sponsor’s own analysis takes precedence.

For waitlist compared with sham, the recalculated difference is -0.13, with a 95% confidence interval from -0.277 to 0.017. This interval includes zero and allows for differences in either direction. That uncertainty is important: a non-significant result does not establish that the groups are the same. The registry does not post a sponsor-reported result for this comparison.

Confidence intervals describe statistical uncertainty under the method used, but they do not account for every source of uncertainty. In general, they do not automatically address bias from missing outcome data, limitations in masking, selective reporting, or multiple testing. The registry does not provide enough detail to evaluate all of those issues. The primary outcome population also excludes participants meeting the stated baseline threshold or missing week 4 data, and the number excluded for each reason is not reported in the registry record.

The secondary recalculations generally have wider intervals than the primary active-versus-sham recalculation. This reflects limited precision for those estimates and should temper conclusions drawn from their point estimates. No minimally important difference is reported, so statistical precision alone cannot determine whether a score difference is meaningful to participants.

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, not total events. The event-count convention applies to time-to-event outcomes, and none of the outcomes described in these planning illustrations is a time-to-event measure. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect set to the stated fraction of the observed effect.

The 80% power column gives the illustrated number of participants per arm for a design that would have an 80% chance of detecting the specified effect under those assumptions, if that effect and the model assumptions were correct. The 90% power column expresses the same planning idea with a higher target chance of detection. These are planning targets, not guarantees about a future study. The original trial’s sample-size justification and design assumptions are not reported in the registry record.

Each row uses a different fraction of the observed effect as the target to detect. Smaller effects need more participants under otherwise similar assumptions. The calculations depend strongly on the observed effect and its variability. In particular, estimates based on a completed study can be unstable, and the primary recalculation has a discrepancy with the sponsor’s reported analysis. The unusually small planning figures associated with the primary recalculated effect should therefore not be treated as a recommended trial size or as a reliable basis for a new design without independent justification.

These figures are not observed power. They are illustrations derived from the observed effects and stated assumptions, rather than a measure of what the completed trial achieved.

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 = -5.000; pooled standard deviation σ = 0.810.
2. n = 2 × (1.96 + 0.842)² × 0.810² / -5.000² = 0.4, rounded up to 1 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 <- -5                      # observed difference in means
sigma <- 0.810061726043145                     # 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(5269953)
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 = 1 (80% power), 1 (90% power)
 75% of observed effect: n per arm = 1 (80% power), 1 (90% power)
 50% of observed effect: n per arm = 2 (80% power), 3 (90% power)
power.t.test: 1.9 
Simulated power at n = 1 per arm: NA (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. Analyses Reported by the Sponsor

The registry reports that the sponsor compared active and sham stimulation using non-parametric permutation testing. The reported mean difference is 5, with p <0.02, and the record classifies the analysis as a superiority analysis. It does not provide a confidence interval for this result. The sponsor-reported estimate is presented as a final-value mean difference, while the recalculation uses the posted group change means.

The unadjusted recalculation gives an active-minus-sham mean difference of -5.0, with a 95% confidence interval from -5.36 to -4.64 and p < 0.001. The magnitude is aligned with the absolute difference of 5 in the sponsor result, but the sign and reported analysis details are not identical. The registry flags a discrepancy. The sponsor’s own analysis takes precedence; the recalculation is a simple check based on posted summary statistics and should not replace the sponsor’s test or be presented as the trial’s prespecified analysis.

The record does not explain the discrepancy, give the permutation-test statistic, or report a confidence interval for the sponsor analysis. It also does not state whether the posted mean difference is adjusted for any other factors. Consequently, the available record supports reporting both results with their methods distinguished, while avoiding a claim that they are interchangeable. The recalculated waitlist comparison is not accompanied by a sponsor-reported analysis in the posted results.

15. Multiplicity, Missing Data and Analysis Populations

The record lists five outcome measures and 11 analyses, but does not report a multiplicity strategy. It is therefore not possible to determine from the registry record whether the sponsor used a prespecified hierarchy, adjusted significance thresholds, or treated some results as exploratory. Without that information, unadjusted p-values across multiple outcomes and contrasts should be interpreted cautiously: the chance of at least one apparently notable result can increase as more tests are conducted.

The primary outcome description specifies that participants with a baseline YGTSS-TTSS of 15 or lower, or missing week 4 data, were removed from further analysis. This is an important feature of the analysis population because the posted result does not represent everyone enrolled by default. The record does not give the number excluded for each reason, the number of missing week 4 values, or whether any sensitivity analyses assessed the effect of missing data.

The registry does not report whether the primary analysis followed an intention-to-treat principle, how adherence was handled, or whether participants were analyzed according to assigned group in all outcomes. It also does not describe imputation methods or other missing-data assumptions. These omissions limit assessment of possible selection bias and robustness, particularly when outcome availability differs across measures.

Randomization and masking are stated in the registry, but details of allocation concealment and the roles included in quadruple masking are not reported in the registry record. The record also does not give the original statistical analysis plan, any interim analyses, or the original sample-size justification. These are reporting gaps, not evidence that a particular procedure was or was not used. They limit how fully the posted analyses can be assessed for prespecification and selective reporting.

16. 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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: tic attack (2.2%).

The safety record reports serious adverse events among participants at risk in each group. It lists 0 serious adverse events for active stimulation among 44 at risk, 0 for sham stimulation among 44 at risk, and 1 for waitlist among 45 at risk. The record reports 0 deaths in each group. “At risk” counts in this safety record are not the same as the analyzed group sizes for the primary outcome.

The registry identifies “Tic attack” as the top serious adverse event term and lists 2.2%. It does not state in that term listing which arm was associated with the event, so no group attribution should be inferred from it. For other adverse events, the record lists 8 affected in the active group, 4 in the sham group, and 0 in the waitlist group, with the corresponding at-risk counts noted above.

These are descriptive counts in the registry record. They do not establish that an event was caused by an intervention, and small or absent counts cannot rule out uncommon harms. The record does not provide event-level detail, severity grading beyond the serious/non-serious distinction, or the duration of safety follow-up. Safety interpretation is therefore limited to the reported counts and categories.

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

The primary posted group summaries show a more negative mean change in YGTSS-R total tic severity score for active stimulation than for sham stimulation or waitlist over the initial four-week period. The sponsor’s own active-versus-sham analysis reports a mean difference of 5 and p <0.02 using non-parametric permutation testing. The simple recalculation gives a different signed estimate and a confidence interval that does not include zero; because the record flags a discrepancy, the sponsor’s analysis takes precedence.

This result does not establish that every participant experienced a reduction, or that any observed change was caused solely by stimulation. It does not show how durable a change might be beyond the stated measurement period. The registry record does not provide a minimally important difference, so statistical evidence cannot by itself establish whether the scale change was meaningful in daily life.

The result also does not establish that active stimulation is superior on every secondary outcome. The secondary findings are less precise and are subject to the uncertainty created by multiple analyses and incomplete reporting of multiplicity procedures. The registry does not report enough about missing data, the original analysis plan, or the handling of all enrolled participants to resolve those limitations.

Finally, these findings apply to the trial population and its stated eligibility and analysis rules. They should not be generalized automatically to people outside that population, to different stimulation approaches, or to longer treatment periods. The registry record supports a careful description of the observed results and their limitations, not medical advice or a conclusion about what an individual should do.

18. Why This Trial Matters Statistically

This trial is statistically notable because it compares an active device intervention with both a sham device and waitlist treatment as usual, while measuring a continuous symptom score over a defined period. The three-arm structure gives context for the observed changes, but each comparison answers a different question. Active versus sham is the direct contrast between the device procedure and its placebo control; waitlist comparisons provide a different reference condition.

It also illustrates why effect estimates, uncertainty, and analysis provenance need to be read together. The recalculated primary comparison is precise under its simple assumptions, but the registry flags a discrepancy with the sponsor’s permutation analysis. A close numerical magnitude does not make distinct analyses interchangeable. Recognizing which result comes from the sponsor and which is recalculated prevents a secondary calculation from being mistaken for the trial’s reported inference.

The outcome record highlights the importance of defining the analysis population. The baseline threshold and missing-week-4 exclusion shape who contributes to the primary estimate, while differing analyzed counts across secondary measures affect precision and comparability. Reporting participant flow and missing-data handling would help readers judge the robustness of the results.

Finally, the presence of several outcomes and analyses makes multiplicity relevant. Without a reported strategy for controlling or prioritizing tests, secondary p-values should not be treated as equally confirmatory. The trial therefore offers a useful case for distinguishing a primary endpoint from supporting measures, a sponsor analysis from a summary-statistic recalculation, and statistical evidence from a broader claim about clinical meaning.

19. 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 primary analysis excludes participants with a baseline YGTSS-TTSS of 15 or lower and participants with missing week 4 data. The registry does not report how many people were excluded for either reason or provide sensitivity analyses showing how alternative missing-data assumptions might affect the estimate. The posted primary analysis therefore needs to be understood as applying to its stated analysis population, not automatically to everyone enrolled.

The primary result has a flagged discrepancy between the sponsor-reported permutation analysis and the summary-statistic recalculation. The registry does not explain the source of the discrepancy, and the sponsor analysis has no posted confidence interval. This makes it harder to assess the sponsor estimate’s precision and to understand how the reported analysis relates to the posted means.

Additional limitations include the absence of a reported multiplicity strategy, original statistical analysis plan, original sample-size justification, and detailed allocation procedures. The record also does not explain the sham procedure, identify which roles were masked, or report participant flow in enough detail to evaluate differences between enrollment, safety populations, and outcome analysis groups.

The primary measurement period is baseline to week 4 after starting stimulation. Longer-term primary outcome findings are not reported in the registry record. Several secondary comparisons are based on smaller analyzed groups and have broad recalculated intervals, while the video-frequency analysis includes no posted waitlist estimate. These features limit the strength of conclusions beyond the primary comparison and specified time window.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Median Nerve Stimulation for Tourette Syndrome and Chronic Tic Disorder — NCT05269953.
• Registry record last updated 2026-06-30; status last verified 2024-07.
• Results first posted 2026-06-30.
• 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.

23. Record Summary

The registry record describes a completed, randomized, parallel-group, quadruple-masked trial of active median nerve stimulation, sham stimulation, and waitlist treatment as usual for Tourette syndrome and chronic tic disorder. Enrollment was 135. The primary outcome was change in YGTSS-R total tic severity score from baseline to week 4.

The posted primary means were -7.13 for active stimulation, -2.13 for sham stimulation, and -2.26 for waitlist. The sponsor reports an active-versus-sham mean difference of 5 with p <0.02 from non-parametric permutation testing. The unadjusted recalculation differs, and the sponsor’s own analysis takes precedence.

Secondary measures cover tic frequency, premonitory urge, and obsessive-compulsive symptoms. The safety record lists no serious adverse events in the active and sham groups, one in the waitlist group, and no deaths. Missing-data details, multiplicity procedures, and the original sample-size justification are not reported in the registry record.