Measurement and Modification of Threat Interpretation Bias in Neurodegenerative Movement Disorders (Aims 2 & 3): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Measurement and Modification of Threat Interpretation Bias in Neurodegenerative Movement Disorders (Aims 2 & 3) (NCT05126862), a na na study. The primary outcome is Proportion of Participants Completing at Least 50% of the MindTrails Sessions.

2. Clinical Question

3. Trial Design

This is a completed, open pilot study registered as NCT05126862. The registry lists the University of Virginia as sponsor and gives the study status as completed. The recorded start date is 2021-12-10, and the primary completion date is 2023-07-09. The phase and allocation are listed as NA.

The study tests a web-based behavioral intervention called MindTrails in people with Parkinson disease and people with Huntington disease. Its brief summary describes the work as a pilot open trial intended to reduce anxiety symptoms. The intervention description specifies five online training sessions lasting 20 minutes each, delivered over five weeks. The record describes separate pilot groups for Parkinson disease and Huntington disease; it does not describe random assignment or a control condition.

The study is classified as a single-group model, and masking is listed as none. These design features matter when interpreting findings: observations from participants receiving the intervention can describe participation and changes over time if such results are reported, but they do not by themselves separate intervention effects from other explanations. A comparison between the two disease groups would also not function as a randomized control comparison.

The registry lists an enrollment of 43. It describes the primary outcome timeframe as between baseline and week 5, with assessments at baseline, week 3, and week 5 informing the completion definition. Further details about eligibility, recruitment, how participants were followed, and the protocol’s statistical plan are not reported in the registry record. The record lists two outcome measures but zero analyses; it does not provide numerical results for the primary endpoint.

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

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 Proportion of Participants Completing at Least 50% of the MindTrails Sessions, measured over Between baseline and week 5.

The primary endpoint is titled “Proportion of Participants Completing at Least 50% of the MindTrails Sessions.” It is listed as a count of participants, and its timeframe is between baseline and week 5. The accompanying definition describes completion as having outcome assessments for at least 2 of the 3 intervention timepoints: baseline, week 3, and week 5.

This endpoint is intended to describe whether participants remained engaged enough to complete a minimum portion of the study’s assessment schedule. In a pilot, such information can help characterize feasibility and participant follow-through. It is distinct from an endpoint that measures whether anxiety symptoms changed: completion indicates participation under the stated definition, not the direction or size of a clinical outcome.

There is a wording distinction worth keeping in mind. The title describes completing at least 50% of training sessions, while the operational definition uses completion of outcome assessments at specified timepoints. The registry record does not clarify whether training-session completion was separately measured for this endpoint. Nor does it report the observed number or proportion meeting the stated criterion. Consequently, the endpoint’s definition can be described, but its observed completion result cannot be interpreted from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with the distinction between a study design and an analysis result. The registry describes an open, single-group pilot, but a design description does not establish what the observed outcomes were. In this record, the primary endpoint is defined, yet no result for it is reported. Without a numerator, denominator, or estimated proportion, there is no endpoint estimate to assess for magnitude or precision.

What does a completion proportion describe?

In general, a proportion represents the share of an analyzed group meeting a specified condition. To interpret one, readers need to know both the condition and the group used as its denominator. Here, the stated condition is unusual in that the endpoint title refers to completing at least 50% of sessions, while the definition counts participants with outcome assessments at at least 2 of the 3 timepoints. The record does not report a result or clarify this difference. It is therefore not possible to reconstruct a proportion from the endpoint description alone.

The primary measure is listed as a count of participants, while its title uses the language of a proportion. These descriptions can be compatible if a count is used to form a proportion with a defined denominator, but that denominator and the observed count are not reported as endpoint results. No calculation should be inferred from the enrollment figures or the disease-group descriptions.

What does the single-group design allow?

Generally, a single-group study can describe outcomes observed among participants who receive an intervention. Without a control group, it cannot directly estimate how those outcomes compare with outcomes under an alternative condition. Changes over time may reflect the intervention, but may also reflect other influences, including the passage of time, measurement, or participant circumstances. The registry record does not specify an analysis designed to address these alternative explanations.

The record identifies Parkinson disease and Huntington disease groups, but it does not describe them as randomized or like-for-like comparison groups. Comparing them would mix differences associated with the conditions and participant groups with any differences in outcomes. The posted record also lists zero analyses, so it does not document a statistical comparison between these groups.

How should uncertainty be assessed?

In general, a confidence interval describes a range of values compatible with the observed data under the assumptions of an analysis. It communicates precision as well as the direction and scale of an estimate. No confidence interval or primary endpoint estimate is reported in the registry record, so the precision of a completion result cannot be evaluated. A p-value would address a specified statistical test, not the size or practical importance of an effect; no primary endpoint test result is reported either.

For event counts, the amount of information depends on how many events are observed and how they are distributed across the groups being analyzed. In general, sparse event data can make estimates imprecise. The safety record reports zero serious adverse events and zero other adverse events in each listed group, but does not provide comparative estimates or inferential analyses. Those counts should be read descriptively, not as a test of equivalence or proof of no risk.

What do the planning assumptions mean?

The sample-size planning description is an illustration based on an observed effect, not the trial’s own design justification. It specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of the observed effect. These are assumptions for planning illustrations; they are not evidence that this pilot used that allocation or that analysis. The actual study is recorded as a single-group model with no allocation.

Planning sample sizes are hypothetical design calculations, not observed outcomes and not “observed power.” The registry record does not report a protocol sample-size justification, the effect estimate used in the illustrations, or a statistical plan for the pilot. The planning assumptions therefore should not be treated as evidence about the trial’s execution or about the strength of its findings.

Finally, the registry lists two outcome measures and zero analyses. It does not report how outcomes were analyzed, whether estimates were adjusted, how missing observations were handled, or which analysis population was used. In the absence of those details and of numerical endpoint results, statistical interpretation must remain descriptive and bounded by the registered definitions.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Experimental: MindTrails Pilot in Parkinson's Dise", "Experimental: MindTrails Pilot in Huntington's Dis")
n      <- c(22, 21)
events <- c(14, 14)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Experimental: MindTrails Pilot in Parkinson's Dise  22  14  63.6  40.7  82.8  43.0  80.3  42.7  80.3
ARM  Experimental: MindTrails Pilot in Huntington's Dis  21  14  66.7  43.0  85.4  45.4  82.8  45.1  82.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and zero analyses. It does not identify which outcome measures were designated primary or secondary beyond the primary endpoint description, nor does it report statistical tests or a plan for handling multiple comparisons. Whether multiplicity adjustments were planned or used is not reported in the registry record. With no analyses or inferential results listed, there is no reported set of p-values to interpret in relation to multiple testing.

Missing-data handling is also not described. The primary definition depends on having assessments at specified timepoints, but the record does not explain how participants without assessments were classified, whether any imputation was used, or how missing observations affected the denominator. The completion criterion itself is based on observed assessment availability; it should not be mistaken for a general missing-data method.

The record does not describe analysis populations, such as whether all enrolled participants or only participants with particular follow-up data were included in an analysis. It also does not report exclusions from an analysis or reasons for missing data. These details matter because estimates can depend on who is included and how incomplete follow-up is treated.

Accordingly, neither the handling of multiplicity nor the handling of missing data can be evaluated from the posted record. The absence of these details does not show that no methods were used; it means they are not reported in the registry record.

12. 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 0% reporting threshold.

The registry reports adverse-event counts separately for the MindTrails pilot group in Parkinson disease and the MindTrails pilot group in Huntington disease. In each group, the number at risk for serious adverse events matches the number at risk for other adverse events as recorded. The serious adverse-event count is 0 in each group, the other adverse-event count is 0 in each group, and deaths are recorded as 0 in each group. No serious adverse-event terms are listed.

These are descriptive registry counts. They indicate that the record lists no serious or other adverse events and no deaths for the groups during the reported safety accounting. They do not establish that the intervention carries no risk. A zero count in a pilot record does not rule out events that were not captured, events too rare to appear in the study, or risks that would require other evidence to characterize.

The registry record does not describe the adverse-event collection procedures, follow-up duration for safety, or attribution of events to the intervention. The counts therefore should not be read as proof that MindTrails caused or prevented any event. They are limited to what was recorded for this study.

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

The record supports a description of a completed, open pilot of a web-based intervention in people with Parkinson disease and Huntington disease. It gives the intervention schedule, identifies the intended focus on anxiety symptoms, and defines a primary completion endpoint. It also records zero serious adverse events, zero other adverse events, and zero deaths in each of the two listed groups.

It does not report the observed primary endpoint result. Readers cannot tell from the registry record how many participants met the completion criterion, what proportion did so, or how precise such an estimate might be. The discrepancy between the endpoint title’s reference to session completion and its assessment-based definition adds uncertainty about exactly what completion represents.

The study’s design also limits what can be concluded about intervention effects. There is no randomized comparator, no allocation, and no masking. The disease-specific groups are not control groups. Consequently, the record does not provide a controlled estimate of whether MindTrails changed anxiety symptoms or whether any changes were caused by the intervention.

The brief summary describes reducing anxiety as the study purpose, but the primary endpoint described in the record concerns completion. The registry lists two outcome measures and zero analyses, and reports no numerical anxiety outcome. It is therefore not possible to judge symptom effects, statistical significance, or clinical importance from the posted information.

In short, the record describes a pilot design and a participation-oriented endpoint, but does not report results needed to assess completion or anxiety outcomes. The safety counts are reassuring only in the narrow sense that no events are listed in the record; they do not establish absence of risk. Conclusions should remain limited to these documented details.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of why endpoint wording and endpoint definition both matter. The title describes completing at least 50% of training sessions, whereas the operational definition is based on assessments at baseline, week 3, and week 5. Those are related but not necessarily identical measures of engagement. Clear alignment between a title, an operational definition, and a reported result is essential for readers to know what was counted.

The distinction between feasibility outcomes and clinical outcomes is also important. A completion measure can describe whether participants contributed follow-up information under a specified rule. It does not, by itself, measure anxiety improvement. Because the study’s stated purpose concerns anxiety while its primary endpoint concerns completion, the two questions should not be treated as interchangeable.

The single-group, open design makes the study suitable for describing a pilot experience, but limits causal interpretation. Without a control comparison, observed changes cannot be separated from other possible explanations. The Parkinson disease and Huntington disease groups are distinct clinical populations, not substitutes for randomized controls. The record’s classification and lack of reported analyses reinforce the need to avoid comparative conclusions.

Finally, registry completeness affects interpretability. The record lists outcome measures but no analyses, and gives no numerical primary endpoint or anxiety result. It also does not describe missing-data handling or analysis populations. Those omissions leave readers unable to evaluate the size, precision, or robustness of outcome estimates. The statistical value of a pilot depends not only on its design, but also on transparent definitions and results.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations specific to this record constrain interpretation. First, the primary endpoint’s title and definition do not align precisely: the title refers to completing at least 50% of MindTrails sessions, while the definition uses outcome assessments at at least 2 of the 3 specified timepoints. The record does not explain whether session completion was separately captured or how the wording difference should be resolved.

Second, no numerical primary outcome result is reported. There is no count of participants meeting the completion criterion, no reported proportion, and no interval describing precision. The registry’s enrollment and group descriptions cannot fill this gap. The record also lists zero analyses, so no statistical findings can be evaluated.

Third, the design is open and has no control group or allocation. The separate disease groups are not a randomized comparison, and the record does not report an analysis comparing them. This limits causal interpretation of any changes that might have been observed, although the record does not provide numerical anxiety results in the first place.

Further limitations include the absence of reported participant characteristics, eligibility details, analysis populations, missing-data procedures, and a statistical analysis plan. The record does not clarify how the two outcome measures relate to one another or how multiplicity was considered. It also does not report safety collection procedures or event attribution. These are reporting gaps in the registry record; they should not be taken as proof that the study team did not consider or collect the information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Measurement and Modification of Threat Interpretation Bias in Neurodegenerative Movement Disorders (Aims 2 & 3) — NCT05126862.
• Registry record last updated 2024-12-20; status last verified 2024-12.
• Results first posted 2024-12-20.
• 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.

19. Record Summary

NCT05126862 is a completed, open pilot sponsored by the University of Virginia. It evaluates MindTrails, a web-based behavioral cognitive bias modification intervention, in people with Parkinson disease and Huntington disease. The intervention description specifies five 20-minute online sessions over five weeks. The study is classified as a single-group model, with no allocation and no masking.

The primary endpoint concerns completion between baseline and week 5. Its title refers to completing at least 50% of sessions, while its definition uses outcome assessments at at least 2 of the 3 timepoints: baseline, week 3, and week 5. The registry lists two outcome measures and zero analyses, but reports no numerical result for the primary endpoint or anxiety outcomes.

The safety record lists zero serious adverse events, zero other adverse events, and zero deaths in each disease-specific group. These counts are descriptive and do not establish absence of risk. Results needed to evaluate endpoint magnitude, precision, or intervention effects are not reported in the registry record.