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 Combined CBIT and rTMS to Improve Tourette's Syndrome (NCT04795908), a na na study. The primary outcome is Tic Severity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04795908 |
| Phase | NA |
| Condition | Tourette Syndrome |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Florida |
| Results posted | Yes |
2. Clinical Question
The study asks whether a treatment sequence combining repetitive transcranial magnetic stimulation (rTMS) and Comprehensive Behavioral Intervention for Tics (CBIT) can be evaluated for changes in tic severity among adults with Tourette syndrome. The registry identifies clinical improvement in tic severity as the primary outcome, measured with the Yale Global Tic Severity Scale (YGTSS). It describes the treatment sequence, but the primary outcome values and a statistical comparison of outcomes are not reported in the registry record.
Population
Adults with Tourette syndrome. The registry reports enrollment of 3 participants. It does not report further participant characteristics in the record.
Intervention
Participants were to receive 16 sessions of rTMS over 4 consecutive days, followed by 8 sessions of CBIT over 10 weeks via telemedicine. The study description identifies tic severity as the principal clinical outcome.
Comparator
There is no separate control group in the registry design. The study is listed as single-group, and allocation is listed as NA. Comparisons across measurement times, if performed, would not be randomized comparisons between treatment groups.
Primary question
The primary question concerns tic severity through study completion, with the timeframe described as an average of 3 months. The record does not report the measured YGTSS values or an estimated change over time.
3. Trial Design
The STOP-TIC study is registered as a completed, single-group study sponsored by the University of Florida. The registry reports enrollment of 3 participants and identifies Tourette syndrome as the condition. It lists masking as none and allocation as NA. The record gives a start date of 2021-12-17 and a primary completion date of 2023-01-18.
The intervention sequence in the brief description begins with 16 rTMS sessions over 4 consecutive days. Participants were then to receive 8 CBIT sessions over 10 weeks through telemedicine. The registry lists transcranial magnetic stimulation as a device intervention and comprehensive behavioral intervention as a behavioral intervention. It also describes assessment of physiological outcomes using functional magnetic resonance imaging, high-density electroencephalography, and TMS.
A single-group design can describe participants' outcomes during a study, but without a separate comparison group it cannot isolate the effect of the intervention sequence from other explanations for change. These may include natural fluctuation, measurement variability, or changes associated with study participation. This is a general limitation of uncontrolled designs, not a claim about what occurred in these participants.
The record lists several secondary measures, including tic ratings, mood and anxiety scales, obsessive-compulsive symptoms, attention symptoms, quality of life, and high-density EEG. The record does not report detailed statistical analysis methods, participant flow, or the primary outcome results. Further protocol detail beyond the registry descriptions is 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.
Overall Study
| Stage | Active rTMS Group |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 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 | Active rTMS Group |
|---|---|---|
| Participants analysed | 3 | |
| Age, Categorical: <=18 years | Participants | 1 |
| Age, Categorical: Between 18 and 65 years | Participants | 2 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 24.67 (18 to 30) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 2 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Tic Severity, measured over Through study completion, an average of 3 months.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | score on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is tic severity measured with the YGTSS through study completion, with the timeframe described as an average of 3 months. The registry describes the YGTSS as a clinician-rated scale assessing tic severity. It includes a checklist of motor and vocal tics and ratings of their number, frequency, intensity, complexity, and interference. The combined Total Tic Severity Score ranges from 0 to 50; motor and phonic scores are each described as ranging from 0 to 25. A separate impairment dimension is scored from 0 to 50. Higher scores indicate greater tic frequency and severity.
A structured clinician rating gives researchers a defined outcome to measure and can capture different aspects of tic presentation. Repeated scores can be used to describe how severity changes over the study period, if the measurements and analysis are reported. In general, the endpoint's scale and direction help readers understand what a score represents and how to interpret a change.
The registry record does not report the observed YGTSS scores, an estimate of change, or uncertainty around an estimate. It therefore does not establish the size or precision of any change in tic severity. The scale description explains what the outcome measures; it is not itself evidence of a result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record reports enrollment of 3 participants in a single-group study. It identifies tic severity as the primary outcome and describes measurement with the YGTSS, but the primary outcome results are not reported in the registry record. No participant scores, average scores, changes from baseline, or estimates of uncertainty for tic severity are reported. Consequently, the clinical outcome cannot be quantified from this record.
The absence of a control group is central to interpretation. A change observed over time in a single group would describe what happened among those participants during the study, but it would not by itself show that the intervention sequence caused the change. In general, a comparison group helps distinguish treatment-associated change from changes that might have occurred over time or through other influences. The registry lists no randomized allocation and no like-for-like control comparison.
Enrollment of 3 also means that the record concerns a very small participant group. Even if individual outcomes were reported, results from a group of this size would offer limited information about how variable responses may be across a wider population. Here, individual primary outcomes are not reported, so neither the pattern across participants nor the precision of a group estimate can be assessed.
The adverse-event record reports no serious adverse events at baseline, post-TMS, or post-CBIT, with 3 participants at risk at each listed time. It reports other adverse events affecting 3 participants post-TMS, and none at baseline or post-CBIT. These are descriptive counts at distinct timepoints. The registry does not identify the non-serious event terms in the information, and the counts do not establish when an event began, how long it lasted, or whether it was caused by a study intervention.
Overall, the record describes the design, treatment sequence, outcomes selected, and adverse-event counts, but does not provide the primary efficacy results or detailed statistical analyses. Its information supports a description of the study, not a conclusion about the magnitude, precision, or cause of changes in tic severity.
9. Statistical Methods Explained
The registry record identifies a mean as the primary outcome parameter and full range as its dispersion measure. It does not report a numerical mean or range for the YGTSS outcome. A mean is a way of describing the center of a set of observations. The full range describes the lowest and highest observed values. In general, a mean can be informative about the group average, while the range gives a sense of how far apart the most extreme observations are. With a small group, individual observations can strongly influence both summaries; a range also does not show how values are distributed between its endpoints.
The record does not report confidence intervals for the primary outcome. In general, a confidence interval expresses the uncertainty around an estimate under a specified statistical method and its assumptions. It is distinct from the range of individual observations: a range describes the observed values, while a confidence interval describes uncertainty about an estimated quantity. Without an outcome estimate and interval, readers cannot assess the reported precision of the primary result.
The study is listed as single-group, with masking none and allocation NA. These design features matter to analysis. A within-group description can summarize outcomes over time, but it is not equivalent to a randomized between-group contrast. In general, a difference between measurements in the same participants accounts for the pairing of those measurements, whereas a comparison of separate groups depends on group allocation and comparability. The record does not report a statistical method for repeated measurements, a model specification, covariate adjustment, or a planned contrast.
The registry's planning assumptions describe a hypothetical sample-size illustration: two-sided significance level 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect stated as a fraction of the observed effect. These are assumptions for a planning exercise, not a description of the actual single-group design. The registry record does not report a protocol sample-size justification, and sample-size planning figures are not observed power. In general, power is a design-stage probability under specified assumptions; it cannot be treated as evidence that an observed result is reliable. The record also does not report numerical outputs for planning scenarios in the information.
The assumptions of equal allocation and two arms do not match the listed single-group study design. They should therefore be read as part of the planning illustration, not as evidence that participants were assigned to two arms. The record does not explain how the planning illustration relates to the trial's design. It also does not report a prespecified effect size, a variance assumption, or the method used to obtain an observed effect. Those details are not reported in the registry record.
What does the design allow?
Because there is no control group, any analysis of measurements over time would be descriptive of the enrolled participants' trajectories. In general, an uncontrolled before-and-after analysis cannot separate treatment effects from time trends, regression to the mean, concurrent care, or measurement variability. This does not mean that any of these factors affected the study; their influence cannot be evaluated using a randomized control comparison that is absent from the design. The record does not report a specific within-person analysis or a treatment-effect estimate.
Why does uncertainty matter?
A statistical estimate is more informative when its uncertainty is also reported. For a small sample, uncertainty is especially important because observed values may vary substantially depending on the individuals enrolled. General methods for representing uncertainty include confidence intervals and model-based standard errors, but the registry record does not report either for the primary outcome. The uncertainty around the adverse-event proportions is also not reported. No alternative inferential statistic should be inferred from the descriptive counts alone.
What does over-dispersion mean?
In general, over-dispersion occurs when observed variation in data is greater than a statistical model assumes. It can make standard errors too small and inferential results too optimistic if the model does not account for the extra variability. The primary endpoint is a scale score, and the record does not report a model or a distributional assessment. There is no basis in the registry record to claim that over-dispersion was present or that a method was used to address it.
How should the summaries be read?
The YGTSS description supplies the score ranges and direction of interpretation, but not the observed scores. A score summary would need to be interpreted in light of the measurement schedule, the number of participants contributing data, and any missing observations. In general, specifying whether a summary uses all enrolled participants or only those with observed measurements is important. The registry record does not report the analysis population, missing-data method, or participant-level completion of outcome assessments.
Thus, the available methods information describes the endpoint and a separate planning illustration, while leaving the primary statistical analysis plan and efficacy estimates unreported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 8 outcome measures and 7 analyses. The record identifies tic severity as the primary outcome and lists secondary measures including the Modified Rush Videotape Tic Rating Scale, Beck Depression Inventory, Beck Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale, Adult ADHD Self-Report Scale, Gilles de la Tourette Syndrome - Quality of Life Scale, and high-density EEG. The presence of multiple outcomes and analyses raises a general multiplicity issue: when many statistical questions are tested, the chance of at least one apparently notable result can increase. Statistical plans sometimes address this by designating a primary endpoint, adjusting significance thresholds, or treating secondary analyses as exploratory.
The registry record does not report whether multiplicity adjustments were planned or used, how the 7 analyses map to the 8 outcome measures, or whether any secondary outcomes were designated as confirmatory. It does not report analysis-specific significance thresholds or a hierarchy among outcomes. No adjustment method or confirmatory interpretation should be assumed.
The record also does not report missing outcome data, the number of participants completing each assessment, or a missing-data approach. In general, missingness can affect interpretation if people with unavailable measurements differ from those whose measurements are observed. Common analytic strategies rely on assumptions about why data are missing; without information about the amount and pattern of missingness, readers cannot evaluate those assumptions. The record does not report imputation, complete-case analysis, or another approach.
Analysis populations are also not specified. The registry does not say whether outcomes were intended to include all enrolled participants, only participants who completed treatment, or another defined group. This information is important for judging whether estimates reflect the full enrolled group and for understanding how departures from the planned treatment sequence were handled. These analysis details are not reported in the registry record.
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 |
|---|---|---|---|
| Baseline | 0 | 3 | 0.0% |
| Post-TMS | 0 | 3 | 0.0% |
| Post-CBIT | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Baseline | 0 of 3 |
| Post-TMS | 0 of 3 |
| Post-CBIT | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Baseline | 0 of 3 |
| Post-TMS | 3 of 3 |
| Post-CBIT | 0 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Baseline | Post-TMS | Post-CBIT |
|---|---|---|---|---|
| Headache | Nervous system disorders | 0 of 3 | 3 of 3 | 0 of 3 |
The registry reports serious adverse-event counts at baseline, post-TMS, and post-CBIT. At each listed timepoint, 3 participants were at risk and 0 were recorded as having a serious adverse event. Deaths are listed as 0 at each timepoint. These are the recorded counts in the registry; they are not estimates of risk beyond the observed participants and reporting periods.
For other adverse events, the record lists 0 affected at baseline, 3 affected post-TMS, and 0 affected post-CBIT, with 3 at risk at each timepoint. The record does not list specific serious adverse-event terms, and the non-serious event descriptions are not reported in the information. The registry counts alone do not indicate event type, duration, severity beyond the serious/non-serious classification, or cause.
These rows refer to timepoints in the same single-group study, not to independent randomized groups. Counts at different timepoints should not be added to create a total number of distinct participants or events. In general, adverse-event counts are descriptive and should be interpreted alongside event definitions, observation periods, and participant-level details. Such details are not reported in the registry record. The small enrollment also limits how much these counts can establish about less common events.
12. What the Result Does, and Does Not, Mean
The record establishes that the completed STOP-TIC study enrolled 3 participants in a single-group study of rTMS followed by CBIT for adults with Tourette syndrome. It identifies the YGTSS measure of tic severity as the primary outcome and gives the intended treatment sequence and assessment timeframe. The record also provides adverse-event counts at baseline, post-TMS, and post-CBIT.
However, the primary outcome measurements and analyses are not reported in the registry record. It is therefore not possible to determine the observed tic-severity scores, the direction or size of any change, or the precision of an estimated change. The registry description of a scale and its scoring does not substitute for participant results. Similarly, the registry's designation of the study as completed does not itself provide evidence about the primary endpoint.
The design also limits what any observed change could establish. A single-group study has no concurrent control group, so a change over time would not by itself identify the intervention sequence as its cause. In general, uncontrolled observations can be useful for describing feasibility or generating questions for further study, but causal interpretation requires caution. The record does not report a randomized comparison.
The adverse-event counts are also limited to description. No serious adverse events or deaths are listed at the reported timepoints; other adverse events are recorded for all 3 participants post-TMS, with none listed at baseline or post-CBIT. Event details and causal assessments are not reported in the record. These counts cannot establish an overall safety profile.
Accordingly, the registry record documents a small completed study and the outcomes it intended to assess, but it does not establish whether tic severity changed, by how much, or whether any change was attributable to treatment. It also does not establish how results might generalize beyond the enrolled participants.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of how design and reporting determine what readers can conclude. Its single-group structure is explicit: there is no randomized control comparison, and allocation is listed as NA. That distinction matters because an outcome measured over time can describe the enrolled participants, but cannot by itself separate treatment-associated change from other possible explanations.
The study also illustrates the importance of reporting numerical endpoint results, not only naming an outcome instrument. The YGTSS description identifies what is assessed, its scoring structure, and the direction of the scale. Without the observed scores or an estimate of change, however, readers cannot assess the result's magnitude or precision. Clear outcome definitions and complete numerical reporting serve different purposes, and both are needed for interpretation.
Enrollment of 3 makes the limits of sparse data especially visible. With a very small group, individual observations can matter substantially to a group summary, and the findings cannot establish the range of outcomes that might occur in a wider population. This is a general issue in small studies and is not a claim about any unreported participant outcome.
Finally, the registry separates outcome measurement, adverse-event tracking, and planning assumptions. A planning illustration based on two arms does not alter the listed single-group design, and it should not be read as observed power. The record's reporting gaps—such as the absence of primary outcome estimates and details of missing-data and multiplicity methods—show why statistical transparency is essential alongside study completion status.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The principal limitation for interpreting this record is that the primary YGTSS results are not reported in the registry record. There are no numerical endpoint summaries, changes, or uncertainty estimates. As a result, the clinical outcome cannot be evaluated from the posted record, regardless of the scale's detailed description.
The design is single-group, with no randomized comparator and masking listed as none. This prevents a direct comparison against a control group and leaves any within-group change open to alternative explanations. The enrollment of 3 further limits precision and the ability to characterize variation among adults with Tourette syndrome.
The registry does not report participant characteristics beyond the condition and adult population in the brief description. It does not report how many participants completed each treatment component or each outcome assessment. Missing-data procedures, analysis populations, statistical models, and multiplicity handling are not reported in the registry record. These omissions prevent assessment of how incomplete observations or multiple analyses may have influenced interpretation.
The intervention description in the brief summary specifies the sequence and frequency of rTMS and CBIT, but does not give all implementation details. The record does not report the reasons for any protocol deviations or whether all participants received the intended sequence. The adverse-event listing provides counts but not event terms or detailed event characteristics in the information. Therefore, neither intervention adherence nor detailed safety interpretation can be assessed from these registry entries.
These limitations are specific to what the registry record reports and should not be mistaken for proof that a particular procedure or analysis was absent from the full study. Where a detail is unavailable, it is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Combined CBIT and rTMS to Improve Tourette's Syndrome — NCT04795908.
- Registry record last updated 2024-04-30; status last verified 2023-12.
- Results first posted 2024-01-12.
- 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
NCT04795908, titled “Combined CBIT and rTMS to Improve Tourette's Syndrome,” is a completed, single-group study sponsored by the University of Florida. The registry reports 3 participants with Tourette syndrome and a treatment sequence of rTMS followed by CBIT. The primary outcome is tic severity measured with the YGTSS through study completion, with a timeframe described as an average of 3 months.
The record lists secondary outcomes spanning tic ratings, mood, anxiety, obsessive-compulsive symptoms, attention symptoms, quality of life, and high-density EEG. No serious adverse events or deaths are listed at the reported timepoints; other adverse events are recorded for 3 participants post-TMS. Primary tic-severity results and detailed statistical analysis methods are not reported in the registry record.