Physiological Augmentation of Mindfulness Meditation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Physiological Augmentation of Mindfulness Meditation (NCT02754557), a randomized na study. The primary outcome is Multiscale Dissociation Inventory (MDI) Score.

2. Clinical Question

The registry also describes interest in meditative engagement and attentional control, as well as PTSD symptoms. The primary outcome named in the record, however, is the MDI score. The available record does not give a numerical estimate of the difference between arms, a confidence interval, or a statistical test for this primary outcome. It therefore does not establish how the groups’ MDI scores changed or whether any observed change differed between them.

3. Trial Design

The trial is recorded as randomized, with a parallel-group model and no masking. One group received breath-focused meditation; the other received breath-focused meditation plus physiological feedback. The feedback was a vibration on the wrist, delivered by a device placed on the participant’s arm, and the vibration was described as proportional to breathing. The registry lists Emory University as the sponsor.

The study enrolled 65 participants. The registry gives a start date of 2016-03, a primary completion date of 2021-09-21, and a status of completed. The phase is recorded as NA. The arm descriptions specify women with PTSD in both groups. Allocation proportions, the numbers randomized to each arm, and the numbers completing each visit are not reported in the registry record.

The primary outcome was assessed at baseline, Week 4 (post-treatment), and Week 8 (one month post-treatment). This is a repeated-time-point outcome: the clinical question can concern change over time within each group, a difference between groups at a particular visit, or a difference in how groups change across visits. These are distinct statistical questions and should not be treated as interchangeable. The record does not identify one numerical contrast as the sole reported comparison.

The trial’s design details do not disclose the planned allocation ratio, randomization procedure, concealment process, or treatment schedule beyond the intervention descriptions. The registry record does not report a sample-size justification for the trial or whether the study included interim analyses. The listed sample-size assumptions describe a planning illustration based on an observed effect, rather than establishing the original design rationale.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: This analysis includes participants who attended the indicated study visit. One participant in the Breath-Focused Meditation Plus Physiological Feedback group attended the one month post-treatment visit but did not complete the MDI.

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 Multiscale Dissociation Inventory (MDI) Score, measured over Baseline, Week 4 (post-treatment), Week 8 (one month post-treatment).

The primary endpoint is the Multiscale Dissociation Inventory (MDI) score, a self-report measure of dissociative symptoms. The registry describes it as a 30-item test measuring different forms of dissociative response. The listed scales include disengagement, depersonalization, derealization, emotional constriction or numbing, memory disturbance, identity dissociation, and total dissociation. Items are scored from 1 to 5, where 1 means never and 5 means very often. Total scores range from 30 to 150; higher scores indicate greater symptoms of dissociation.

The MDI is relevant to the stated study question because the trial aims to compare changes in dissociative symptoms between meditation alone and meditation with physiological feedback. A continuous score retains information across its scale rather than reducing participants to a yes-or-no category. The registry specifies a mean as the summary measure and standard deviation as the measure of dispersion. In general, a mean describes the group’s average score, while a standard deviation describes how spread out scores are around that average.

Scores were scheduled at baseline, Week 4 (post-treatment), and Week 8 (one month post-treatment). Repeated assessments can describe the course of scores over time, but the relevant comparison depends on the analysis question. Numerical MDI means, standard deviations, and between-group estimates are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary outcome as continuous and specifies a mean with standard deviation. A continuous outcome can take values across a scale, in this case the MDI total-score scale. The mean is a summary of the group’s scores; the standard deviation describes variation among participants. Neither statistic alone gives the comparative effect of the intervention. To address the randomized comparison, an analysis would ordinarily report a between-group contrast, with an uncertainty measure, at a clearly defined time point or for a clearly defined change over time. Such numerical analyses are not reported in the registry record.

What does a mean difference tell the reader?

As a general statistical concept, a mean difference expresses the distance between two group averages in the scale’s units. Its interpretation depends on which groups are contrasted and when scores are measured. A difference at Week 4 is not the same quantity as a difference in change from baseline to Week 4. For repeated measurements, an analysis can also address whether the pattern over visits differs by group. The registry gives the planned measurement visits, but does not report a numerical contrast or identify a reported model for the repeated measurements.

How should uncertainty be understood?

A confidence interval is a range of estimates that conveys statistical uncertainty around an estimated effect. It helps readers judge both the range of effects compatible with the data and the precision of the estimate. A p-value, in general, measures how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the test assumptions were true. It does not measure the probability that the null hypothesis is true, and it does not describe the size or importance of an effect. No confidence interval or p-value for the primary outcome is reported in the registry record, so these interpretations cannot be applied to a trial estimate.

Why do the multiple visits matter?

Baseline, Week 4, and Week 8 provide more than one possible time-based comparison. A pre-to-post change, an arm contrast at one follow-up, and a contrast in change across follow-ups answer different questions. If several outcomes or time points are tested, the chance of at least one apparently notable result can increase. This is the general reason multiplicity matters. The registry lists 20 outcome measures and indicates that the primary outcome has several categories or time points and was not reduced to one comparison. It does not report an analysis plan or multiplicity adjustment. The record therefore does not show which contrasts were prespecified as primary for inference or how multiple comparisons were handled.

What does the planning illustration mean?

The registry’s stated planning assumptions describe an illustration computed from an observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. The record’s note distinguishes participants per arm for non-time-to-event calculations from total events for time-to-event calculations. These are planning assumptions, not observed trial results and not evidence of the study’s original sample-size rationale. The numerical planning outputs and a trial-specific justification are not reported in the registry record. Sample-size calculations are not observed power; they cannot substitute for an effect estimate and its uncertainty.

What can randomization and lack of masking tell us?

Random allocation is intended, in general, to make assigned groups comparable at the start of a trial by distributing measured and unmeasured factors through chance. It does not guarantee identical groups, particularly in a finite sample, and assessment of baseline balance requires the relevant data. The registry records randomization but does not report the allocation procedure or baseline outcome values. It also records no masking. In general, lack of masking can matter when participants’ expectations or outcome reporting could be influenced by knowledge of the assigned condition. The MDI is described as self-report, but the record does not describe procedures to address this issue. These considerations identify potential interpretive issues; they do not establish that bias occurred.

What is known about the analysis population?

The primary-outcome description says the analysis includes participants who attended the indicated study visit. This is a visit-attendance description, not enough information to determine whether all randomized participants were included in each analysis, whether an intention-to-treat approach was used, or how missing observations were handled. Those analysis details are not reported in the registry record. The record notes one attendee in the physiological-feedback arm who did not complete the MDI at the one-month post-treatment visit. No other visit-specific missing-data counts or statistical handling of missingness are reported.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is scheduled at baseline, Week 4, and Week 8, and the registry notes that it has several categories or time points and was not reduced to one comparison. The record also lists 20 outcome measures. Multiple outcomes and time points can create multiple opportunities to test a hypothesis. In general, if many tests are interpreted together without an appropriate plan, the chance of a false-positive finding across the family of tests may increase. The registry does not report which comparisons were prespecified for confirmatory inference, whether a hierarchy was used, or whether any adjustment for multiplicity was applied.

The outcome-population description is based on attendance at the indicated visit. It specifically notes that one participant in the breath-focused meditation plus physiological-feedback group attended the one-month post-treatment visit but did not complete the MDI. This clarifies one instance of missing outcome data; it does not report the complete missingness pattern across arms and visits.

In general, missing-data methods rely on assumptions about why outcomes are unavailable. Different assumptions can lead to different estimates, so the analysis population and handling of missing observations are important. The registry record does not report whether missing values were imputed, whether analyses used all randomized participants, or whether sensitivity analyses assessed departures from the primary assumptions. The record also does not give visit-specific analysis counts. These omissions limit assessment of both the multiplicity of the reported comparisons and the influence of missing data.

11. 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 zero serious adverse events among 27 participants at risk in the breath-focused meditation group and zero among 38 participants at risk in the breath-focused meditation plus physiological-feedback group. It reports zero other adverse events among 27 participants at risk in the meditation group and zero among 38 at risk in the feedback group. Deaths are reported as zero in both groups, and no serious adverse-event terms are listed.

These are the posted event counts and at-risk group sizes. They do not establish that no symptoms or other unwanted experiences occurred outside the registry’s reported event categories, nor do they establish that an event could not occur. In general, an observed count of zero is a description of the recorded trial experience, not proof of zero underlying risk. The registry record does not provide further event descriptions or additional detail on adverse-event collection. These figures should therefore be read as the adverse-event information recorded for the trial, not as a complete characterization of safety.

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

The registry record establishes that a randomized, parallel-group study compared breath-focused meditation with the same practice plus breath-linked wrist vibration in women with PTSD. It identifies the MDI as the primary outcome and specifies assessments at baseline, Week 4, and Week 8. It also records enrollment of 65 and a completed status. These details describe the study question and conduct at a high level.

The record does not report the numerical primary-outcome results. It therefore cannot establish whether MDI scores changed, whether the groups differed, how large any difference was, or how precise an estimate might be. It also cannot support a conclusion about statistical significance. The trial’s completed status is not a substitute for outcome estimates, and the intervention description is not evidence of an effect.

Even if numerical results were available, interpretation would depend on the particular contrast, its uncertainty, the analysis population, and how repeated measurements and multiple outcomes were handled. Those details are not reported in the registry record. A comparison of changes over time would answer a different question from a comparison of group averages at one follow-up. Missing MDI data for one participant at the Week 8 visit are noted, but the overall missing-data pattern and its handling are not described.

The adverse-event entries report zero serious adverse events, zero other adverse events, and zero deaths in each group, with the listed at-risk counts. Those entries describe the recorded event counts; they do not prove that risk is absent. Overall, the record identifies a relevant comparative question and its planned primary measure, but does not provide enough outcome or analysis information to determine the observed comparative result.

13. Why This Trial Matters Statistically

This trial is statistically notable as a comparison of an intervention with an added physiological component against the same meditation practice without that component. That structure focuses the intended contrast on the addition of breath-linked feedback, rather than comparing meditation with no meditation. The registry describes the device’s feedback as wrist vibration proportional to breathing.

The primary outcome is continuous and repeated across baseline and two follow-up visits. That combination makes clear why specifying the estimand—the exact quantity the analysis is meant to estimate—is important. A group difference at a follow-up, a within-group change, and a difference in changes between groups are not equivalent. The registry record does not report a single numerical comparison that resolves these possibilities.

The record also illustrates why trial status and outcome reporting are separate matters. Although the study is listed as completed, the primary-outcome results and statistical analyses are not reported. Without estimates and uncertainty intervals, readers cannot assess the magnitude or precision of the comparison. Without analysis details, readers cannot assess how the visits, outcomes, or missing measurements were incorporated.

Finally, the MDI is self-reported and the trial is listed as having no masking. This makes the distinction between a carefully defined outcome and a fully documented analysis especially relevant. In general, outcome definition, analysis population, multiplicity handling, and missing-data assumptions all contribute to how a treatment contrast should be interpreted. The registry record supplies the question and measurement framework, but not the results needed for an evidence-based statistical reading of the comparative effect.

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 main limitation for interpreting the trial is that numerical results for the named primary endpoint are not reported in the registry record. No MDI means, standard deviations, effect estimates, confidence intervals, or p-values are given. The direction and precision of the comparison therefore cannot be assessed.

The registry identifies several outcome time points and lists 20 outcome measures, but does not report a statistical analysis plan or a multiplicity strategy. It is not possible to determine which contrasts were intended to be primary for inference or how repeated measures were analyzed. Although the record mentions a planning illustration based on an observed effect, the trial’s own sample-size justification is not reported.

The record states that the primary-outcome analysis includes participants attending each visit and notes one participant in the feedback group who attended the Week 8 visit but did not complete the MDI. It does not report the full attendance or missing-data pattern, the analysis population by visit, or the method used to address missing values. This limits assessment of potential effects of missing outcome data.

The trial is recorded as randomized but without masking. The allocation procedure and concealment details are not reported. The primary measure is a self-report scale, and the record does not describe additional steps related to assessment or reporting. These are interpretive considerations, not evidence that the results were biased. The enrollment count and completed status do not resolve these limitations, and the record does not support conclusions about the comparative outcome.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Physiological Augmentation of Mindfulness Meditation — NCT02754557.
• Registry record last updated 2022-10-17; status last verified 2022-09.
• Results first posted 2022-10-17.
• 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.

18. Record Summary

The registry record describes a completed randomized, parallel-group trial of breath-focused meditation alone versus breath-focused meditation with physiological feedback for women with PTSD. Enrollment was 65; the sponsor was Emory University. The record lists no masking and records the study phase as NA.

The primary outcome was MDI score, scheduled at baseline, Week 4 (post-treatment), and Week 8 (one month post-treatment). Higher total scores indicate greater dissociative symptoms. The registry lists 20 outcome measures and zero analyses. Numerical primary-outcome results and a trial-specific analysis plan are not reported in the registry record. The adverse-event entries report zero serious adverse events, zero other adverse events, and zero deaths in both groups.