Dual-task Augmented Reality for PD DBS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dual-task Augmented Reality for PD DBS (NCT06418152), a na na study. The primary outcome is Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III: Motor Examination Score.

2. Clinical Question

3. Trial Design

The record identifies NCT06418152 as a completed study titled “Dual-task Augmented Reality for PD DBS.” Its official title is “Dual-task Augmented Reality Treatment (DART) for Parkinson's Disease and Deep Brain Stimulation.” The listed sponsor is Jay Alberts. The record lists the phase as NA, allocation as NA, masking as NONE, and model as SINGLE GROUP. These entries describe a behavioral intervention study without a listed randomized control arm or masking.

The study focuses on DART for postural instability and gait dysfunction in people with Parkinson's disease who already have a deep brain stimulator. The intervention is labeled “Multi-modal treatment.” The arm description says that five to ten individuals with PD and DBS will receive the intervention, with 16 sessions over an 8-week period but not more than 10-weeks. Sessions are described as approximately 30-minutes of dual-task activity scheduled over a 1 hour period. The description is truncated after “A physic,” so further details are not reported in the registry record.

Enrollment is listed as 7, and the record status is COMPLETED. The recorded study start is 2024-05-21 and primary completion is 2025-01-30. The primary endpoint timeframe is baseline and through study completion, averaging 8 weeks. These design and timing details describe the registered plan and status; they do not establish that every participant received every intended session or completed every assessment. Participant flow and treatment exposure are not reported in the registry record.

A Two Minute Walk Test is listed as a secondary outcome. The record lists 2 outcome measures and 0 analyses. The primary result, secondary outcome results, and analysis details are not reported in the registry record. A completed status indicates the registry's study status, but by itself does not supply outcome estimates or establish how complete the outcome data were.

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: All participants were in the same arm of this pilot study.

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 Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III: Motor Examination Score, measured over Baseline and through study completion, average 8 weeks.

The primary endpoint is the change in the MDS-UPDRS III motor examination score from baseline through study completion. The score is measured off medication. The record describes a range from 0 to 132 and states that lower scores indicate better motor function. It reports the mean as the measure of central tendency and the standard deviation as the measure of dispersion.

The MDS-UPDRS III is used to assess motor signs in Parkinson's disease. In a study focused on postural instability and gait dysfunction, a motor examination score offers a structured way to quantify motor status before and after the intervention period. A change score is intended to describe how the measured score differs over time within the study group. It is not, by itself, a treatment-versus-control effect when no separate control group is listed.

The timeframe is baseline through completion, averaging 8 weeks. Because lower scores indicate better motor function, interpretation of a reported change would depend on its direction, size, uncertainty, and the completeness of the measurements. Those values, including the baseline and completion means, standard deviations, and estimated change, are not reported in the registry record. The endpoint definition therefore describes what was intended to be measured, not what the study found.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical interpretation begins with the design. In a single-group study, participants receive the intervention and measurements may be compared over time. This differs from a randomized comparison, where treatment groups can be contrasted under an allocation process intended to reduce systematic differences between groups. Here, allocation is listed as NA and the model as SINGLE GROUP. The registry does not describe a concurrent control arm. A within-person or group-level change can document what happened during the study period, but it does not by itself identify what would have happened without the intervention.

What does a mean change describe?

The primary measure is continuous: the MDS-UPDRS III motor examination score. A mean summarizes the arithmetic center of a set of scores. A mean change would summarize the average difference between measurements over the specified period, if those measurements and an analysis were reported. The record names the mean and standard deviation as the outcome summary measures, but does not report numerical outcome summaries. No mean change can therefore be interpreted from the registry record.

The standard deviation describes how spread out individual measurements are around the group mean. It is not the same as the uncertainty in the mean. A confidence interval is a range of values compatible with the data and the statistical procedure used; it conveys uncertainty about an estimate. Its width depends on the variability of the observations and the amount of usable information. The record does not report a confidence interval or enough outcome data to assess one.

Why does the comparison matter?

With a control group, a treatment effect is often expressed as a difference in outcomes between the assigned groups. With a single-group pre-post design, an observed change is not the same estimand: it is change during the study period in the group that received DART. General influences such as measurement variability, regression toward typical values after an unusually high or low baseline measurement, concurrent care, or time trends may contribute to a pre-post difference. These are general limitations of uncontrolled comparisons; the registry does not report whether they affected this study.

The endpoint is measured off medication, which is part of its specified measurement condition. Consistency in measurement conditions can matter because measurement context may influence scores. The record does not provide operational details about how that condition was standardized, how assessments were conducted, or whether assessors were trained or blinded. Masking is listed as NONE, so no masking is indicated in the registry record.

What does a planning illustration mean?

Sample-size planning asks how many observations a future design might need under chosen assumptions. The registry describes an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustration is based on the observed effect and considers an effect to detect that is a stated fraction of that effect. These assumptions describe the illustration, not the registered trial design: this study is listed as single-group, and allocation is NA. The numeric sample-size outputs, observed effect estimate, and details needed to assess the illustration are not reported in the registry record.

Power is a design-stage probability of detecting an effect of a specified size under stated assumptions. A planning calculation is not the probability that a completed study's finding is true, and it does not indicate the probability that the study has demonstrated an effect. The described sample-size figures are planning illustrations, never observed power. Since no numeric planning outputs or primary effect estimate are reported in the registry record, no particular planning value can be interpreted.

Why can over-dispersion matter?

For outcomes modeled as counts, over-dispersion means that variation is greater than a model assumes. If ignored, standard errors can be too small and confidence intervals too narrow. This is a general principle for count-data analyses. The primary endpoint in this study is a continuous score, and the registry record does not report a count-outcome analysis or a statistical model. It would therefore be inappropriate to claim that over-dispersion was present or that a particular correction was used.

For continuous outcomes, analysts may consider the distribution of measurements, the scale of the outcome, and whether the chosen summary and model represent the data adequately. A mean and standard deviation are listed as the intended summaries, but the record does not describe a model, adjustment variables, treatment of repeated observations, or diagnostic checks. No method beyond what is stated in the registry record should be attributed to the investigators.

What can be inferred when results are absent?

The registry lists 0 analyses and does not report the primary outcome values. This limits interpretation to the design and endpoint definitions rather than efficacy estimates. It is not possible to reconstruct a result from the enrollment, scale range, or intended timeframe. The same principle applies to secondary outcomes: naming the Two Minute Walk Test does not provide its observed result. Statistical interpretation requires the estimate and information about its variability, not only the measure's name.

In general, the analysis population should be defined so readers know which participants contribute to each estimate. Missing observations can affect both precision and potential bias, depending on why they are missing and how they are handled. The registry does not report an analysis population, amount of missing outcome data, or a missing-data method. These omissions prevent an assessment of whether the analyzed observations represent all enrolled participants.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Interventional Arm")
n   <- c(4)
m   <- c(3.25)
sp  <- c(3.27)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Interventional Arm  4  3.250  3.270  -1.953  8.453

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 2 outcome measures: the primary MDS-UPDRS III motor examination score and the secondary Two Minute Walk Test. When several outcomes or several analyses are considered, the chance of at least one apparently notable result can increase if each is tested separately. General approaches to multiplicity include identifying a primary outcome in advance, setting a testing hierarchy, or adjusting inference across tests. The registry identifies a primary endpoint, but a multiplicity procedure or testing hierarchy is not reported in the registry record.

The record lists 0 analyses. It does not report a statistical analysis plan, the number or timing of outcome assessments actually analyzed, or whether any additional comparisons were conducted. It is therefore not possible to assess how multiplicity was handled or whether reported findings, if any, were selected from several analyses. No outcome estimates are reported in the registry record.

Missing-data handling is also not reported in the registry record. The record does not state how many participants had primary or secondary endpoint measurements at each time, whether any measurements were missing, why they might be missing, or whether imputation or another method was used. Missingness matters because a complete-case mean can describe only participants with observed data and may not represent the original group if data availability is related to outcome or participant characteristics. This is a general concern, not a claim that missing values occurred in this study.

The analysis population is not reported in the registry record. It is therefore unclear which participants would contribute to an efficacy analysis and whether the intended analysis included everyone enrolled or only participants meeting a specified measurement or treatment criterion. The stated enrollment of 7 does not establish the number included in any outcome analysis. Without the analysis population and missing-data details, precision and representativeness cannot be evaluated.

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.

Most frequent non-serious adverse event terms

The registry reports safety counts for the Interventional Arm, with 7 at risk for serious adverse events and 0 affected. For other adverse events, 7 were at risk and 2 were affected. The reported deaths count is 0. These are counts in the registry record, not estimates of comparative risk: the study has a single-group model and no separate control group is listed.

The distinction between “serious” and “other” adverse events is important. The serious-event count is reported separately from the count for other adverse events. The record lists no top serious-event terms. That absence of terms does not add detail about the two other adverse events, whose descriptions are not reported in the registry record. The record also does not provide event-level narratives, timing, duration, severity, relatedness to the intervention, or whether an affected participant had more than one event.

These figures describe the recorded safety counts, but they do not establish that every possible harm was captured or that the intervention caused an event. With no comparator, the counts cannot show how event occurrence differed from what would have happened without DART. The safety information should be read as a limited descriptive account rather than a comparative safety estimate.

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

The registry record establishes that a completed, single-group study was registered to evaluate DART for people with Parkinson's disease and previously implanted DBS, with postural instability and gait dysfunction as the focus. The intended primary measure was change in the MDS-UPDRS III motor examination score from baseline to study completion, measured off medication. The record also identifies the Two Minute Walk Test as a secondary outcome and provides adverse-event counts.

It does not report the primary outcome values or an estimated change. It therefore does not show whether the motor score increased, decreased, or remained similar during the study period, or how precisely any change was estimated. The secondary outcome result is also not reported in the registry record. An endpoint definition and a completed status are not substitutes for outcome results.

Even if a pre-post change were reported, a single-group study would not by itself demonstrate that the intervention caused that change. Without a control group, other explanations for change over time cannot be separated from an intervention effect. This is a general limitation of the design, not evidence that any particular alternative explanation occurred.

The safety counts provide a descriptive record of serious and other adverse events, but no comparison group is listed. They do not determine causality or establish comparative safety. Similarly, the enrollment number alone does not show how many participants contributed to each outcome analysis; the analysis population is not reported in the registry record.

The appropriate interpretation is consequently bounded: the record describes the intended intervention, study design, endpoint definitions, status, and listed safety counts. It does not provide the efficacy estimates or analysis detail needed to judge the observed motor outcome, the secondary outcome, or the precision of either. No conclusion that DART does or does not improve motor function follows from the information reported.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between a registered question and a reported result. The record specifies a clinical target, a behavioral intervention, a primary motor examination score, and a within-group timeframe. Those details define what the study intended to examine. They do not, on their own, provide an estimate of the outcome.

The single-group design makes the interpretation of change especially important. A change from baseline can describe the trajectory observed among participants who receive the intervention, but a treatment effect requires a suitable counterfactual comparison: what would have happened to a comparable group without the intervention. Since no control group is listed, the design does not directly supply that contrast. This distinction is essential when describing early or preliminary studies.

The record also illustrates why precision and analysis details matter alongside the outcome direction. A mean change would need information about variability and uncertainty to show how tightly the data locate the estimate. The record does not report the primary estimate, dispersion results, confidence interval, analysis population, or missing-data approach. The enrollment of 7 cannot answer these questions.

Finally, the listed planning assumptions should not be conflated with the actual trial design or with observed evidence. The planning illustration uses assumptions involving two arms even though the study model is single-group. Understanding that separation helps prevent a sample-size exercise from being mistaken for a design description or a measure of completed-study power. The record is therefore useful for clarifying the registered question and the limits of what can be inferred from the posted information.

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.

The central limitation for interpreting efficacy is that outcome results are not reported in the registry record. The primary MDS-UPDRS III change, baseline and completion summaries, and uncertainty measures are absent. The secondary Two Minute Walk Test result is also not reported. Without these results, the magnitude, direction, and precision of outcome changes cannot be evaluated.

The single-group design does not include a listed control arm. A before-and-after observation in the treated group cannot separate intervention-associated change from other influences that may operate over time. This does not invalidate descriptive information, but it limits causal interpretation. Allocation is listed as NA and masking as NONE; further details about assessment conduct are not reported in the registry record.

The record lists enrollment as 7, but does not report participant flow, treatment adherence, session completion, withdrawals, or the analysis population. It is not possible to determine from the record how many participants completed the intervention or contributed data to each endpoint. The arm description is truncated, limiting detail about treatment delivery beyond the stated schedule.

There is no reported analysis plan, model, adjustment strategy, missing-data method, or multiplicity procedure. The record lists 0 analyses. Consequently, the analytic choices behind any outcome estimates cannot be reviewed, and no outcome estimates are reported to assess. The sample-size planning assumptions describe an illustration rather than the listed single-group design, and numeric planning outputs are not reported in the registry record.

The safety information is also limited to aggregate counts. Event descriptions, timing, severity details, and relatedness are not reported in the registry record. These limitations constrain both efficacy and safety interpretation; they do not establish that unreported procedures or events did or did not occur.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Dual-task Augmented Reality for PD DBS — NCT06418152.
• Registry record last updated 2025-09-30; status last verified 2025-09.
• Results first posted 2025-09-30.
• 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.

19. Record Summary

NCT06418152 is listed as COMPLETED and uses a SINGLE GROUP model. It evaluates the behavioral, multi-modal DART intervention for Parkinson's disease and previously implanted DBS, with postural instability and gait dysfunction as the focus. Enrollment is listed as 7. The primary endpoint is change in the off-medication MDS-UPDRS III motor examination score from baseline through completion, averaging 8 weeks; lower scores indicate better motor function. The Two Minute Walk Test is listed as a secondary outcome.

The primary and secondary outcome results, analysis population, analysis methods, and missing-data handling are not reported in the registry record. The safety counts list 0 affected by serious adverse events among 7 at risk, 2 affected by other adverse events among 7 at risk, and 0 deaths. The record therefore describes the study design and registered measures but does not provide efficacy estimates or their precision.