Influence of Yogic Breathwork on CSF Circulation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Influence of Yogic Breathwork on CSF Circulation (NCT03858309), a randomized na study. The primary outcome is CSF Flow Velocities.

2. Clinical Question

The central contrast is between two breathing programs, rather than between a breathing program and no intervention. The registry describes randomized allocation and a parallel design. Group 1's practices are described generally as a set of breathing practices, while Group 2 is specifically described as slow breathing. Further details that would allow readers to characterize the exact difference between the practice protocols are not reported in the registry record.

3. Trial Design

This completed study, NCT03858309, is titled “Influence of Yogic Breathwork on CSF Circulation.” Oregon Health and Science University is listed as the sponsor. The registry identifies the trial as randomized, single-masked, and parallel, with an enrollment of 26. The identity of the people or procedures covered by masking is not reported in the registry record. The listed phase is NA.

Participants were assigned to Breathing Group 1 or Breathing Group 2. Both programs lasted 8 weeks and included 60-minute weekly group on-site sessions and 20-minute daily home sessions on 6 days/week between group sessions. The first arm received a set of breathing practices; the second received slow breathing practices. The record does not report additional details about how the two practice programs were standardized, whether adherence was monitored beyond the listed home-practice measures, or how allocation was generated or concealed.

The primary outcome was CSF Flow Velocities, measured in cm/s. Measurements were collected during breathing practices while participants were inside an MRI scanner, with flow quantified at the Foramen Magnum. The stated time points were baseline (pre-intervention) and post-intervention (after 8 weeks). The reported primary-outcome population consisted of participants with both MRI visits and analyzable CSF data: n=14, Group 1=7, and Group 2=7.

The registry lists secondary outcomes of systolic and diastolic blood pressure, body mass index, daily home practice frequency, and daily home practice duration. It also describes quality of life, sleep quality, and stress in the study summary. Numerical results for these outcomes are not reported in the registry record. The study started on 2019-07-10, had primary completion on 2019-11-25, and is listed as completed.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analysis population included participants who completed both MRI visits and had analyzable CSF flow data (n=14; Group 1=7, Group 2=7). Pre- and post-intervention peak CSF velocities (maximum cranially directed and minimum caudally directed) during breathing practices were summarized in absolute units (cm/s) as mean and standard deviation.

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.

Population: The baseline analysis population included all 21 participants who completed enrollment and provided pre-intervention data (Active n=11, Control n=10). These participants are represented in the baseline characteristics table.

6. Primary Endpoint

The registry lists the primary outcome as CSF Flow Velocities, measured over Baseline (pre-intervention) and post-intervention (after 8 weeks)..

The primary endpoint is CSF flow velocity, a continuous measure expressed in cm/s. The record says MRI-based flow was measured at the Foramen Magnum during breathing practices. Processing produced velocity waveforms describing CSF motion, from which peak velocities were summarized. Positive velocity represents cranially directed, or upward, fluid motion; negative velocity represents caudally directed, or downward, motion.

The registry describes maximum cranially directed and minimum caudally directed peak velocities at baseline and after the 8-week intervention. These directional summaries retain information about movement in both directions; a single signed average could obscure this distinction. The endpoint is relevant to the study's stated aim because it quantifies the movement of CSF during the breathing conditions being investigated. The registry record does not establish that a change in these velocities is a validated measure of broader health, nor does it report a threshold for interpreting a change as meaningful.

The posted outcome description specifies means and standard deviations as descriptive summaries. It does not include inferential tests or change-score analyses. Numerical outcome values are not stated in the record information presented, so the size, direction, and precision of any pre- to post-intervention pattern cannot be evaluated from those summaries alone. A mean describes the central value in a group; a standard deviation describes the spread of observations around that mean. Neither summary, by itself, establishes whether groups differ beyond what might arise from sampling variability.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the study as randomized, single-masked, and parallel. Randomization is a method for assigning participants to study groups by chance. In general, it is intended to reduce systematic differences in prognostic characteristics between groups, though it cannot guarantee balance in every realized trial. The record does not report how the random sequence was generated, how assignment was concealed, or who was masked. Those methodological details are not reported in the registry record.

What does a descriptive mean show?

The primary outcome is continuous, and the registry states that means and standard deviations were used. A mean gives a measure of the center of observed values. A standard deviation describes how dispersed those values are around the mean. Together, they can communicate the approximate level and variability of a measurement in a group. They do not indicate whether a difference is statistically distinguishable from chance, and they do not by themselves estimate the uncertainty around a difference between groups.

For this endpoint, direction is important. The registry defines positive CSF velocities as cranial, or upward, movement and negative velocities as caudal, or downward, movement. It describes maximum cranially directed and minimum caudally directed peak velocities. Reporting these directional peaks separately can preserve information about motion that a single overall average might conceal. The outcome description states the unit as cm/s.

Why distinguish baseline from follow-up?

Measurements were planned at baseline before intervention and after the 8-week intervention. In general, a post-intervention comparison asks whether the groups differ at follow-up, while a change-score comparison asks how measurements shifted from baseline within each group and whether those shifts differ between groups. These are related but not identical estimands. Baseline values can be useful for understanding the starting measurements and for improving precision in a prespecified analysis. The registry submission reports descriptive statistics and does not include change-score analyses or an inferential comparison adjusting for baseline.

A confidence interval, in general, conveys uncertainty around an estimated effect under specified statistical assumptions. A p-value, in general, assesses compatibility between data and a particular null hypothesis under a statistical model; it does not measure the probability that a hypothesis is true. Neither a confidence interval nor a p-value for the primary outcome is reported in the registry record. Without an effect estimate and its uncertainty, the precision of any difference cannot be assessed from the posted descriptive statements.

What can randomization support?

Randomization can support a causal interpretation of a between-group contrast when allocation, follow-up, measurement, and analysis are appropriately conducted. It does not automatically resolve missing outcome data, departures from assigned interventions, or selective outcome reporting. In this study, the primary outcome summaries concern participants who completed both MRI visits and had analyzable CSF data. The record does not report an inferential analysis of all randomized participants or a method for handling missing MRI outcomes. Therefore, the descriptive analysis population should not be treated as equivalent to an analysis of every enrolled participant.

General statistical practice distinguishes an intention-to-treat analysis, which retains participants in their randomized groups, from analyses limited to participants with observed or usable outcome data. The registry identifies the MRI analysis population but does not name an intention-to-treat analysis or describe how missingness was handled. The reasons that participants are not in the MRI analysis population are not reported in the registry record.

Why does multiplicity matter?

When a study considers multiple outcomes, time points, directions of effect, or comparisons, the chance of obtaining an apparently unusual result can increase if each is tested separately without an appropriate plan. This is the general problem of multiplicity. A statistical plan may specify a primary comparison, a hierarchy of outcomes, or an adjustment for multiple testing. The registry provides a primary outcome title and lists additional outcomes, but a multiplicity strategy is not reported in the registry record. Since the posted primary results are descriptive and contain no inferential tests, there are no reported multiplicity-adjusted or unadjusted p-values to interpret.

The sample-size assumptions described for planning illustrations use a two-sided significance level of 0.05, equal allocation, a normal approximation, and a stated fraction of an observed effect. Such calculations, in general, illustrate the number of participants per arm needed under those assumptions to detect a chosen effect size. They are not observed power and do not establish that the completed study had a particular probability of detecting an effect. The record does not report a trial-specific sample-size justification, and no numerical planning results are stated in the record information presented.

These methods distinctions are important because descriptive summaries, inferential tests, and planning calculations answer different questions. Descriptive statistics characterize observed measurements; inferential analyses estimate and test contrasts; planning calculations explore design requirements under assumptions. The registry's primary outcome submission is descriptive, so it supports characterization of the recorded measurements but does not report a tested comparative effect.

10. Multiplicity, Missing Data and Analysis Populations

The registry names CSF Flow Velocities as the primary outcome and lists multiple secondary outcomes, including blood pressure, body mass index, and daily home practice frequency and duration. The study summary also identifies quality of life, sleep quality, and stress as areas of interest. Numerical results for the secondary outcomes and these additional areas are not reported in the registry record.

The primary outcome itself encompasses cranially and caudally directed peak velocities, measurements during breathing practices, and baseline and post-intervention time points. When multiple outcomes or comparisons are tested, multiplicity can make isolated nominal findings harder to interpret. A prespecified testing hierarchy or multiplicity adjustment can help control the interpretation of a family of tests. Such a plan is not reported in the registry record. The posted primary results are descriptive and include no inferential tests, so no multiplicity-adjusted or unadjusted testing results are available to assess.

The primary outcome analysis population is described as participants who completed both MRI visits and had analyzable CSF data: n=14, Group 1=7, and Group 2=7. The trial enrollment was 26. The record does not report the reasons for the difference between enrollment and the stated primary-outcome population, the number with missing MRI data by reason, or any method for imputing or otherwise handling missing measurements. It also does not describe whether outcome availability differed according to group or participant characteristics.

In general, complete-case summaries describe only participants with usable observations. If outcome availability is related to measurements or group assignment, those summaries may not represent all randomized participants. This is a general concern, not a claim about what occurred in this trial. The registry does not provide the missing-data information needed to evaluate it. It also does not report a prespecified analysis population beyond the stated requirement for completed MRI visits and analyzable 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 adverse-event record lists zero serious adverse events and zero other adverse events in each breathing group. It reports 11 participants at risk in Breathing Group 1 and 10 in Breathing Group 2 for both serious and other adverse events. Deaths are reported as zero in each group, and no top serious event terms are listed.

These figures describe what was recorded for the groups and the stated at-risk counts. They do not establish that no adverse events could occur, nor do they quantify the risk of an event beyond the registry's reporting. With no reported events, the record does not provide an event rate estimate that can be compared statistically between the groups. The at-risk counts in the adverse-event record also differ from the stated primary MRI analysis population; those populations refer to different reporting contexts and should not be conflated.

The registry does not report additional details about how adverse events were solicited, monitored, classified, or attributed to an intervention. The listed zero counts therefore should be read as registry-reported event counts, not as proof of absence of risk or as a comprehensive assessment of safety.

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

The record documents a randomized comparison of two breathing programs, with CSF flow velocity as the primary outcome. It describes MRI measurements at baseline and after an 8-week intervention and specifies the direction represented by positive and negative velocities. For the primary outcome, the registry identifies an analysis population with completed MRI visits and analyzable CSF data, and describes its results as means and standard deviations.

That information establishes what was measured and how the posted primary summaries were characterized. It does not establish whether either breathing program changed CSF velocity, whether the groups differed, or whether any observed pattern was attributable to the intervention. The registry explicitly reports no inferential tests or change-score analyses. Numerical effect estimates and uncertainty measures needed to assess the magnitude and precision of differences are not reported in the registry record.

The result also should not be extended beyond the measured endpoint. CSF velocity during breathing practices is the stated primary measurement; the record does not establish that it is interchangeable with broader clinical outcomes. Although the study summary mentions quality of life, sleep quality, and stress, their results are not reported in the registry record. The record likewise lists secondary outcomes, but does not report their numerical findings.

Randomized assignment is a design feature, not a substitute for outcome data or an inferential analysis. The stated MRI analysis population is smaller than the enrollment, and the reasons and handling of unavailable or unanalyzable measurements are not reported. Consequently, the descriptive summaries cannot automatically be read as representing everyone enrolled or as an estimate of the effect in a broader population.

The adverse-event listing reports zero serious and zero other events in both groups, with deaths also recorded as zero. These registry figures are useful as a description of reported events, but they do not prove that risk is absent. In sum, the record describes the study question, intervention schedules, endpoint, analysis subset, and descriptive reporting approach. It does not report tested comparative results or enough information to make claims about efficacy, clinical importance, or broader consequences.

13. Why This Trial Matters Statistically

This study is statistically instructive because its stated scientific question and its posted analysis are not the same thing. The question concerns whether breathing programs influence CSF circulation, while the registry submission reports descriptive summaries without inferential tests or change analyses. Recognizing that distinction prevents descriptive measurements from being mistaken for evidence of a tested treatment contrast.

The outcome also illustrates how measurement definitions matter. CSF flow velocity has a direction, with positive values denoting cranial movement and negative values denoting caudal movement. The registry describes peak velocities in both directions rather than presenting the endpoint as a single generic quantity. Understanding the sign and the summary being analyzed is essential before interpreting any values.

The analysis population matters as well. The trial enrolled 26, while the primary outcome description applies to participants who completed both MRI visits and had analyzable CSF data, reported as n=14. Enrollment and outcome availability answer different questions. A reader needs the analysis population, the reasons data are unavailable, and the method for handling missing observations to judge how directly reported summaries reflect the randomized groups. Those missing-data details are not reported in the registry record.

Finally, the record highlights why design calculations, descriptive data, and evidence of an effect should not be conflated. Planning illustrations based on an observed effect are not observed power, and descriptive means and standard deviations are not inferential comparisons. The registry does not report a trial-specific sample-size justification or comparative uncertainty estimates. These distinctions are useful when evaluating any clinical trial record: the design describes the intended comparison, while the analysis and reporting determine what conclusions the posted data can support.

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 primary outcome reporting is restricted to participants who completed both MRI visits and had analyzable CSF data. The registry reports this group as n=14, with Group 1=7 and Group 2=7, compared with an enrollment of 26. Reasons for unavailable or unanalyzable measurements are not reported in the registry record. Without those details, the potential for bias from missing outcome data cannot be assessed.

The registry submission gives descriptive statistics only and includes no inferential tests or change-score analyses. It therefore does not provide a direct estimate of the comparative effect of the two programs, an uncertainty interval, or a statistical test. Numerical primary outcome values are not reported in the record information presented, limiting assessment of the magnitude, direction, and variability of the observed pattern.

The endpoint includes multiple directional summaries and time points. A single comparison is not reported, and a statistical plan explaining how multiple outcome features were prioritized or handled is not reported in the registry record. The record also does not report a trial-specific sample-size justification. Thus, readers cannot assess whether the planned enrollment was selected to provide a particular level of precision or power for a prespecified contrast.

Further limitations include the lack of reported details about sequence generation, allocation concealment, the identity of those masked, and the precise content of the breathing practices. The registry describes both intervention schedules but does not report enough protocol detail to establish how closely the programs differed beyond the descriptions given. The outcome results for secondary measures, quality of life, sleep, and stress are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Influence of Yogic Breathwork on CSF Circulation — NCT03858309.
• Registry record last updated 2025-10-29; status last verified 2025-10.
• Results first posted 2025-10-29.
• 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

NCT03858309 is a completed, randomized, single-masked, parallel study sponsored by Oregon Health and Science University. It enrolled 26 participants and compared two 8-week breathing programs. Both included 60-minute weekly on-site group sessions and 20-minute home sessions on 6 days/week.

The primary outcome was CSF flow velocity measured by MRI at the Foramen Magnum during breathing practices, at baseline and after intervention. The posted primary outcome description concerns participants with both MRI visits and analyzable CSF data: n=14, Group 1=7, and Group 2=7. It reports descriptive summaries only, with no inferential tests or change-score analyses.

Numerical comparative effects, uncertainty estimates, missing-data handling, and results for the listed secondary outcomes are not reported in the registry record. The adverse-event listing records zero serious events, zero other events, and zero deaths in both groups.