Virtual Reality Biofeedback for Postpartum Anxiety and Depression: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Virtual Reality Biofeedback for Postpartum Anxiety and Depression (NCT04925765), a na na study. The primary outcome is Intervention Feasibility.

2. Clinical Question

The clinical question is about the participant experience of using the session, rather than a comparison of treatment outcomes between groups. The registry record also names depression and State-Trait Anxiety Inventory outcomes assessed from baseline to post-intervention. These are secondary outcomes; numerical results for them are not reported in the registry record.

This design can describe what participants reported after taking part, but it does not establish how those reports compare with usual care, no intervention, or another program. With no control group, changes over time cannot be separated from other influences on participants' experiences or symptoms. The registry record identifies feasibility and acceptability as the study purpose, so the primary question should be read as an assessment of the session's practicality from participants' perspective, not as a test of comparative clinical efficacy.

3. Trial Design

The registry record identifies NCT04925765 as a completed study with a single-group model and six participants enrolled. It lists no allocation scheme and no masking. The record names one intervention, the Virtual Reality Biofeedback Session, and says all participants complete a one-hour virtual reality session. The study start date is 2021-09-01, and the primary completion date is 2021-09-30.

The stated purpose is to test patient feasibility and acceptability of a virtual reality biofeedback program in postpartum women for anxiety and depression outcomes. The primary outcome is intervention feasibility, collected immediately after the session. The record also names depression and State-Trait Anxiety Inventory outcomes from baseline to post-intervention. It lists four outcome measures, but numerical results for the primary and secondary outcomes are not reported in the registry record.

A single-group design means the study has no concurrent control group against which to compare participants' experiences or symptom measurements. The record does not report a randomization procedure, and none is indicated by the recorded single-group design. Masking is listed as none. These features are relevant when interpreting the findings: participant ratings can describe the experience among those enrolled, but they cannot by themselves estimate a comparative effect attributable to the session.

The registry record does not report a sample-size justification, detailed eligibility criteria, recruitment methods, session delivery procedures beyond the one-hour duration, or a statistical analysis plan. It also does not report whether the session was completed by every enrolled participant or how outcome data were handled if missing. Such information is important for assessing how closely the recorded experience reflects the intended study population and process. The status is completed, but completion alone does not establish that results were posted or that all planned analyses were performed.

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 women who were willing to participate received the same treatment arm, VR biofeedback session.

Overall Study

Analysis population for the primary outcome, as defined in the registry: postpartum women

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 Intervention Feasibility, measured over Completed immediately after the VR session..

The primary endpoint is intervention feasibility, expressed as a mean score with a standard deviation. Participants were asked whether they were able to complete the session without difficulty, using a Likert scale from 1 to 5. The scale description assigns 1 to great difficulty and 5 to no difficulty. The assessment was to be completed immediately after the virtual reality session.

This measure is used to capture participants' direct appraisal of whether the session could be completed without difficulty. Such an endpoint addresses a practical aspect of an intervention: whether participants experience the activity as manageable. It is distinct from a measure of anxiety or depression symptoms, and it does not on its own establish whether a program changes those symptoms.

The registry record specifies that the outcome is presented as an average score and standard deviation among participating patients. However, neither the mean nor the standard deviation is reported in the registry record. Therefore, the direction and distribution of the participants' feasibility ratings cannot be evaluated from the numerical outcome information available. The scale anchors explain how a rating should be interpreted, but without the observed score they do not reveal how participants actually responded.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a single-group study and a continuous primary outcome summarized as a mean and standard deviation. It lists no analyses. The numerical outcome estimates, confidence intervals, p-values, and detailed analysis methods are not reported in the registry record. The explanations below describe general statistical concepts relevant to this design; they are not claims about methods used in this study.

What does a mean and standard deviation describe?

General: A mean is an average that gives a compact description of the center of a set of scores. For this endpoint, the mean would summarize participants' responses on the 1-to-5 feasibility scale. A standard deviation describes how spread out the scores are around that average. A small spread indicates that individual scores are relatively similar to one another, while a larger spread indicates more variation. Neither statistic is reported for this endpoint in the registry record, so the group average and score variability cannot be assessed.

The outcome is a Likert-scale rating with ordered response categories. The registry record specifies a mean and standard deviation as the summary. General: Such summaries treat the numerical steps between scale values as if they can be represented by an average distance. The scale anchors provide an intuitive direction for interpretation, but a mean alone would not show the distribution of responses. A response pattern with different clusters of ratings can sometimes yield the same average as a more uniform pattern. Individual counts or a distribution would help describe that structure, but those results are not reported in the registry record.

What would a confidence interval contribute?

General: A confidence interval describes uncertainty around an estimated quantity under a specified statistical method and its assumptions. For a mean, it can show a range of values compatible with the observed data and method. It is not a range containing a stated proportion of individual participants' scores, and it does not correct for systematic limitations such as selection into the study or the lack of a comparator group. No confidence interval for the primary outcome is reported in the registry record.

With only six participants enrolled, any estimate based on the group would be informed by a small number of observations. General: Smaller samples usually provide less precise estimates than larger samples, all else equal, and individual observations can have substantial influence on a mean. The registry record does not report the endpoint values, so the degree of precision cannot be quantified. Enrollment is not necessarily the same as the number with complete outcome data; the number assessed for the primary endpoint is not reported in the registry record.

How does the single-group design affect analysis?

General: A single-group study can describe outcomes observed among enrolled participants. If measurements are collected before and after an intervention, a within-participant analysis may describe change over time. That change is not equivalent to a randomized between-group treatment effect. Without a concurrent comparator, other changes over time, co-occurring care, measurement variation, or regression toward typical values can contribute to observed changes. The record names baseline-to-post-intervention symptom outcomes but does not report numerical results or analyses for them.

The primary feasibility rating is recorded immediately after the session, rather than as a comparison between randomized groups. It is therefore naturally interpreted as a description of participants' post-session reports. The registry record does not state whether a particular inferential test or confidence interval was planned for the mean. It does not report a prespecified threshold for deciding that the session met a feasibility criterion. These details should not be inferred from the fact that the outcome has a numerical scale.

What can and cannot be inferred from p-values?

General: A p-value, when used, measures how incompatible the observed data are with a specified statistical model and null hypothesis, assuming the model and hypothesis. It is not the probability that the null hypothesis is true, nor does it measure the magnitude or practical importance of an outcome. A p-value also does not replace an estimate and an interval describing uncertainty. No p-value or hypothesis test is reported in the registry record, and the record lists no analyses.

Statistical significance would not answer the feasibility question by itself. For a participant-rated feasibility outcome, the score's magnitude, its distribution, the scale's interpretation, and a prespecified criterion would all matter to a fuller assessment. The registry record provides the scale anchors but no observed ratings or decision criterion. Therefore, no conclusion about meeting a feasibility target can be drawn from the available record.

What does the sample-size illustration mean?

General: A planning illustration based on an observed effect is a hypothetical calculation of how many participants might be needed for a later comparison under specified assumptions. It is not the number actually analyzed, and it is not observed power. The registry record describes general assumptions for such planning illustrations, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions do not describe this single-group study's design. The record does not report the trial's own sample-size justification, and the outcome values needed to assess an observed-effect-based illustration are not reported in the registry record.

Planning calculations are conditional on their assumptions and on the effect size chosen for the calculation. General: A calculation using a fraction of an observed effect illustrates a smaller target effect under the chosen model; it does not guarantee that a future study will achieve a particular result. Such numbers should not be interpreted as evidence that the current study had a particular power. In this record, no numerical outcome estimate or analysis is available to evaluate as the basis for a trial-specific effect calculation.

Why does variability matter?

General: Variability affects how precisely a group mean can be estimated and how readily differences can be distinguished from random variation in a comparison. A mean without a standard deviation or another uncertainty measure gives an incomplete picture of the observed scores. In this study, both the mean and standard deviation are specified as the intended form of the primary outcome, but neither numerical value is reported in the registry record. No estimate of variability, precision, or statistical evidence should therefore be inferred.

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("Virtual Reality Session")
n   <- c(6)
m   <- c(4.83)
sp  <- c(0.41)
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  Virtual Reality Session  6  4.830  0.410  4.400  5.260

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary feasibility outcome and secondary outcomes concerning depression and State-Trait Anxiety Inventory scores from baseline to post-intervention. It also records four outcome measures, but numerical results for these outcomes are not reported in the registry record. No analyses are listed. The record does not describe a multiplicity adjustment or explain how conclusions across multiple outcomes would be controlled.

General: When several outcomes are examined, the chance of obtaining an apparently noteworthy result by chance can increase, depending on the testing strategy. A prespecified hierarchy, adjustment method, or clear distinction between primary and exploratory analyses can help readers understand how multiple findings should be interpreted. The registry record identifies the primary outcome and names secondary outcomes, but a detailed statistical plan for handling multiple comparisons is not reported in the registry record. No claim about adjustment or unadjusted testing can be made.

The number of participants with observed data at each assessment is not reported in the registry record. Although six participants were enrolled and the adverse-event summary lists six at risk, those details do not establish that all six provided every outcome measurement. The record does not describe missing-data frequency, reasons for missingness, imputation, or sensitivity analyses. General: Missing data can affect both the population represented by an analysis and the validity of estimates, particularly if missingness relates to participants' outcomes or experience.

The analysis population is also not described. The registry record does not report whether analyses were planned for all enrolled participants, only those completing the session, or another group. It does not report exclusions from analyses or how protocol deviations were handled. Those details are relevant to understanding which participants contributed to any result, but there are no numerical outcome analyses in the record to interpret. The absence of such information should be treated as unreported detail, not as evidence that there were no missing observations or exclusions.

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 record reports 0 serious adverse events among 6 participants at risk in the virtual reality session group. It also reports 0 other adverse events among 6 participants at risk and 0 deaths. These are the recorded counts for the group; they are not rates calculated.

General: An adverse-event count describes events recorded during the study under its monitoring and reporting procedures. A zero count means no events of that category were recorded in the reported group; it does not prove that the risk is absent. Small studies are limited in their ability to characterize uncommon events, and the observed count depends on how events are defined, monitored, and reported.

The registry record does not report event definitions, detailed monitoring procedures, timing, severity criteria for non-serious events, or participant-level follow-up. It also does not provide a comparison group. The safety figures therefore describe the counts recorded among the participants at risk and should not be treated as a comparative estimate or a guarantee about safety in other settings or populations.

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

The record establishes that a completed, single-group study enrolled six postpartum women to assess a one-hour virtual reality biofeedback session. The primary outcome was a participant rating of whether completing the session was difficult, measured immediately afterward on a scale from 1 to 5. The scale anchors indicate that higher scores represent less difficulty. These details clarify what the study set out to measure.

However, the numerical primary outcome is not reported in the registry record. The mean and standard deviation needed to characterize the group rating are absent. The secondary outcomes are named, but numerical results for depression and State-Trait Anxiety Inventory scores are also not reported in the registry record. As a result, the available information does not establish how participants rated feasibility or whether symptom scores changed.

The study's single-group design also means it has no randomized comparator. General: Even if a before-and-after change were reported, the design alone would not show that the session caused that change. Other influences over time could contribute, and without a control group those influences cannot be separated from the intervention's possible contribution.

The safety summary records 0 serious adverse events, 0 other adverse events, and 0 deaths among 6 participants at risk. Those counts are useful as a description of what the registry reports for this group, but the small enrollment and lack of detailed monitoring information limit broader interpretation.

Accordingly, the record supports a description of the study's purpose, structure, intended outcomes, and reported event counts. It does not support a conclusion about the magnitude or precision of feasibility ratings, symptom changes, or comparative effects. It also cannot establish whether the session would have similar participant experiences in a larger or different population. Missing numerical outcome results should not be interpreted as either favorable or unfavorable findings.

14. Why This Trial Matters Statistically

This study illustrates why a clearly defined feasibility outcome is distinct from a clinical symptom endpoint. The primary measure asks whether participants could complete a session without difficulty, while the secondary outcomes concern depression and anxiety measures over time. Keeping these questions separate helps prevent a usability or acceptability measure from being mistaken for evidence of symptom benefit.

It also demonstrates the value of reporting the actual endpoint summary, not only its scale and intended summary format. A mean and standard deviation would allow readers to describe the average rating and its variability. Without those numerical values, the outcome cannot be interpreted, even though the scale anchors and timing are specified. Transparent reporting of the number assessed and missing observations would further clarify how much information supports the estimate.

From a design perspective, a single-group study is suited to describing participants' experiences, but it does not provide a concurrent counterfactual comparison. General: Comparative causal questions need designs and analyses that address what might have happened to similar participants without the intervention. The registry record does not describe such a comparison, so any potential symptom trajectory should be distinguished from a treatment effect.

The record also highlights the importance of a statistical analysis plan for multiple outcomes, missing data, and analysis populations. The primary and secondary outcome labels identify their intended roles, but details about analysis choices are not reported. Without numerical results or these methods, readers cannot assess precision, multiplicity, or the robustness of findings. For biostatistical interpretation, the central lesson is to align claims with the design and the results actually reported: a completed record and event counts do not replace outcome estimates.

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 most consequential limitation for interpretation is that numerical results for the primary feasibility score are not reported in the registry record. The mean and standard deviation are specified as the outcome summary, but the values are absent. Numerical results for the named secondary depression and anxiety outcomes are also not reported. Thus, the available information cannot describe the observed feasibility ratings or symptom patterns.

The study enrolled six participants and used a single-group design. The record provides no comparator arm, allocation scheme, or masking. These features limit any assessment of comparative effects, and the small enrollment means that any group description would be based on few observations. The participant characteristics and eligibility criteria are not reported in the registry record, so the scope of generalization cannot be assessed from the available details.

The record does not report how many participants completed each assessment, whether any observations were missing, or how missing data were handled. It also does not describe the analysis population, statistical tests, confidence intervals, or prespecified decision criteria for feasibility. A detailed statistical analysis plan and sample-size justification are not reported in the registry record. These omissions prevent evaluation of the analysis choices and the precision intended for the study.

Safety information consists of recorded counts and lacks detail about event definitions and monitoring. The zero counts should therefore be read as descriptive registry entries, not as evidence that risks are absent. Finally, the stated dates and completed status describe the registry record's study timeline and status, but do not resolve the absence of posted numerical outcome estimates.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Virtual Reality Biofeedback for Postpartum Anxiety and Depression — NCT04925765.
• Registry record last updated 2024-04-17; status last verified 2024-04.
• Results first posted 2024-04-17.
• 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.

19. Record Summary

NCT04925765 is recorded as a completed, single-group study with six participants enrolled. The study assessed a one-hour virtual reality biofeedback session in postpartum women, with the stated purpose of evaluating feasibility and acceptability in relation to anxiety and depression outcomes.

The primary outcome was a post-session rating of difficulty completing the session, on a 1-to-5 scale, intended to be summarized as a mean and standard deviation. Depression and State-Trait Anxiety Inventory outcomes from baseline to post-intervention are also named. Numerical results for these outcomes are not reported in the registry record, and no analyses are listed.

The registry reports 0 serious adverse events, 0 other adverse events, and 0 deaths among 6 participants at risk. A sample-size justification, detailed statistical plan, missing-data handling, and analysis population are not reported in the registry record.