Effects of Heart Rate Oscillations During Meditation on Plasma Biomarkers of Alzheimer's Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Heart Rate Oscillations During Meditation on Plasma Biomarkers of Alzheimer's Disease (NCT06210035), a randomized na study. The primary outcome is Change in Plasma Amyloid Beta (Aβ) Levels.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group behavioral trial sponsored by the University of Southern California. The registry record lists an enrollment of 94 and describes three conditions: belly-focus concentration meditation, belly-focus concentration meditation with slow breathing, and a no-intervention control task. Participants in each group were asked to record heart rate during the daily activity or quiet rest. The record does not state the allocation ratio or describe any masking; masking is listed as none.

The intervention period was one week. Participants were also asked to visit the laboratory twice, before and after the intervention, for blood draws and assessments that included emotion questionnaires and a memory test. The registry record lists the trial as completed, with a start date of 2024-01-29 and a primary completion date of 2024-05-03. It does not report the number who completed the intervention or the number included in each outcome analysis.

The primary outcome was change in plasma amyloid beta levels. Secondary outcomes listed in the record were change in the plasma pTau-181/Tau ratio and change in emotional well-being. The record also describes episodic memory assessment in the study summary. It lists five outcome measures and four analyses, but does not explain how every measure maps to every analysis. The phase is listed as NA. No protocol details beyond those described in the registry record, including a fuller account of allocation procedures or the statistical analysis plan, are reported there.

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: Out of the 94 participants enrolled, 2 dropped before condition assignment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Population analyzed is composed by all randomization subjects who completed pre- and post-intervention blood draw and whose data quality was sufficient for data analysis.

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 Change in Plasma Amyloid Beta (Aβ) Levels, measured over Measured from blood draws before and after a one-week intervention.

The primary endpoint was change in plasma amyloid beta (Aβ) levels, expressed as an aggregate Z-score based on plasma Aβ40 and Aβ42 levels measured in pg/mL. Blood draws were taken before and after the one-week intervention. The record states that a Z-score of 0 represents the sample mean; higher values indicate a greater level of plasma Aβ. Thus, the endpoint is a standardized measure of the combined biomarker information, not a direct concentration in pg/mL.

The investigators selected this biomarker because the registry description notes that, in cognitively normal individuals, higher plasma Aβ has been found to be associated with a higher risk of converting to Alzheimer's disease, citing Song et al., 2011. That rationale describes an association; it does not establish that a change in this trial's biomarker represents a change in disease risk or clinical status. The study population is described as healthy adults aged 18-35, and the record does not say that participants had Alzheimer's disease.

The stated statistical question concerns whether change over time differed by condition. The registry describes a 2 (time: pre, post) × 3 (condition) ANOVA to test the time-by-condition interaction. The endpoint description gives the measure and planned comparison, but a single numerical estimate of that interaction or its uncertainty is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary-outcome description specifies a 2 (time: pre, post) × 3 (condition) ANOVA. In general, analysis of variance compares mean outcomes across groups or combinations of factors. Here, the time factor represents the two measurement occasions, and condition represents the three randomized groups. The interaction asks whether the pattern of change from pre to post differs by condition. It is the part of this analysis most directly aligned with the stated question about differences in change.

An interaction is not the same as a main effect. A time main effect would address average change across conditions, while a condition main effect would address average differences among conditions when averaging across time. Neither alone answers whether the groups changed differently. The registry record describes an interaction test, but does not report the test statistic, degrees of freedom, p-value, or a numerical estimate with uncertainty. The exact model details and any adjustments beyond the stated ANOVA are not reported in the registry record.

The outcome is an aggregate Z-score based on plasma Aβ40 and Aβ42. In general, standardization expresses a measure relative to a reference mean and scale. The record defines 0 as the sample mean and says that higher values correspond to greater plasma Aβ. It does not report the standardization procedure in greater detail, including the reference distribution or whether the same reference was used across measurements. Those details should not be inferred from the word “Z-score.”

The endpoint description states that the investigators used the mean as the parameter and standard error as the dispersion measure. In general, a mean describes the central value of a continuous outcome, while a standard error describes the uncertainty in an estimated mean. A standard error is not the same as the spread of individual participant values. Confidence intervals are often used to communicate a range of values compatible with an estimate under a statistical model; no primary-outcome confidence interval is reported in the registry record.

Randomization is intended, in general, to make assigned groups comparable on average at the start of a trial, including on factors that were not measured. It does not guarantee identical groups in a particular trial, and it does not by itself resolve missing outcome data or measurement problems. The record identifies the study as randomized and parallel-group but does not report the randomization sequence method, concealment procedures, or allocation ratio. Masking is listed as none. The registry record does not report whether outcome assessors or analysts were masked.

The record defines the primary-outcome population as randomized participants who completed both blood draws and had data quality sufficient for analysis. This is not necessarily the same as every person enrolled or randomized. In general, restricting an analysis to participants with complete measurements can affect interpretation if completion or data quality is related to group assignment or outcome values. The record does not report the number excluded, reasons for missing or unusable measurements, or analyses addressing missing data.

For planning illustrations, the record states assumptions of a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. In general, such calculations describe the sample size that would be needed under specified assumptions; they are not observed power and do not establish what the trial was designed to detect. The record does not report the trial's own sample-size justification. The primary question involves three conditions and repeated measurements, so the stated two-arm planning assumptions should not be mistaken for the primary analysis specification.

Over-dispersion is a general issue for count outcomes when variability exceeds what a simple count model assumes. It is not a stated feature of this continuous primary endpoint, and the registry record does not identify an over-dispersion model. More broadly, the details needed to evaluate model assumptions, data distributions, and robustness are not reported in the registry record. Without those details and without the primary outcome estimates, the statistical description supports understanding the planned question but not independently assessing the analysis result.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures and four analyses. It identifies the primary endpoint as change in plasma amyloid beta levels and lists change in the plasma pTau-181/Tau ratio and change in emotional well-being among secondary outcomes. The study summary also describes emotion questionnaires and a memory test. The record does not explain the complete relationship between each outcome measure and each analysis, or how the several outcomes were ordered for interpretation.

When multiple outcomes, time points, or comparisons are examined, the chance of finding a nominally unusual result can increase. General methods for addressing multiplicity include defining a hierarchy of outcomes, adjusting inferential thresholds, or treating secondary analyses as exploratory. The registry record does not report whether any multiplicity procedure was planned or applied. It also does not report a full statistical analysis plan, so no approach should be assumed.

The primary-outcome analysis population required a pre-intervention and post-intervention blood draw and data of sufficient quality. The number of participants meeting those criteria, the amount and pattern of missing data, and the reasons for incomplete or unusable measurements are not reported in the registry record. Missing-data methods, sensitivity analyses, and the handling of participants who did not complete the intervention are also not reported there.

These gaps limit assessment of how representative the analyzed population was of all randomized participants and how robust the findings might be to alternative assumptions. They also prevent a complete appraisal of how selective reporting or multiple testing may affect interpretation. The registry record does not report whether an intention-to-treat analysis was performed.

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.

Most frequent non-serious adverse event terms

The registry record reports serious adverse events for the three groups separately. In the belly-focus concentration meditation group, 0 of 30 participants at risk were affected by a serious adverse event; in the belly-focus concentration meditation with slow breathing group, 0 of 32 were affected; and in the no-intervention control group, 0 of 30 were affected. No deaths are reported in any group.

For other adverse events, the record reports 3 of 30 participants affected in the belly-focus concentration meditation group, 0 of 32 in the slow-breathing group, and 0 of 30 in the control group. These are counts of participants affected, not descriptions of the events. The record does not report the event terms, timing, severity beyond the serious/other categories, or whether investigators considered events related to an intervention.

Zero reported serious events means none were recorded in the listed groups; it does not establish that an event is impossible or that the groups have identical safety profiles. The small number of reported events and the absence of event details do not support a comparative safety conclusion. No statistical comparison or uncertainty estimate for these counts is reported in the registry record.

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

The trial's stated purpose was to examine how two concentration meditation practices affect plasma biomarkers of Alzheimer's disease, and to examine emotional well-being and episodic memory. The randomized, parallel-group design compares belly-focus meditation, the same practice with slow breathing, and a quiet-rest control over one week. These design features describe the question and comparison; they do not, by themselves, establish an outcome.

The primary endpoint is a biomarker measure, not a diagnosis or a clinical outcome. The registry description says that higher plasma Aβ is associated with higher risk of converting to Alzheimer's disease in cognitively normal individuals. That association does not mean that a short-term change in the biomarker necessarily predicts a corresponding change in an individual's future risk. Nor does it establish that the study participants had Alzheimer's disease; the study summary describes healthy adults aged 18-35.

The registry record does not report a single primary-outcome comparison or its numerical estimate, precision, or statistical test result. Accordingly, it is not possible from the reported primary-outcome information to determine the direction or magnitude of a difference in change among the groups. The record also does not report numerical results for the listed secondary outcomes. The absence of those results from the registry record should not be converted into a claim that there was no effect.

The safety counts describe the events recorded in each group, but do not establish causation or comparative risk. The study's enrollment and one-week intervention period also define the scope of the trial; the record does not describe longer follow-up. No conclusion about clinical benefit, disease prevention, or treatment should be drawn from the endpoint definition or study rationale alone.

13. Why This Trial Matters Statistically

This trial raises a statistical question about change over time, not simply a comparison of final measurements. Measuring participants before and after an intervention allows investigators to examine whether the pattern of change differs among randomized conditions. The stated time-by-condition interaction aligns with that question, while a single pre-to-post change in one group would not by itself establish a difference between groups.

The endpoint also illustrates the distinction between a biomarker and a clinical outcome. A standardized aggregate based on plasma Aβ40 and Aβ42 can be used to represent a biological measurement, but its interpretation depends on how it is constructed and on the uncertainty around estimated group differences. The record defines the direction of the score and its rationale, while leaving the primary comparison unreported. That makes clear why an endpoint description and an outcome result are different kinds of information.

Completeness of follow-up is another important issue for repeated measurements. The primary-outcome population required both blood draws and sufficient data quality. Without counts of excluded participants, reasons for missing data, and methods for addressing missingness, readers cannot assess how the analyzed population relates to all randomized participants.

Finally, several outcomes and analyses are listed, but the record does not report a multiplicity approach or the numerical primary and secondary results. Clear outcome hierarchy, transparent handling of missing data, and reporting of estimates with uncertainty are important for interpreting a randomized trial. This record offers useful design and endpoint details, while leaving those result-level questions unresolved.

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 registry record does not report a numerical primary-outcome result for the time-by-condition analysis. It therefore does not provide an effect estimate, confidence interval, or p-value for the stated primary question. A single primary comparison was not produced from the outcome's multiple categories or time points.

The analysis population required completed pre- and post-intervention blood draws and data quality sufficient for analysis. The number of randomized participants who met these requirements, the reasons for missing or unusable data, and the handling of such data are not reported in the registry record. The enrollment figure alone does not identify the number contributing to the primary analysis.

The record describes healthy adults aged 18-35, while listing Alzheimer disease as a condition. It does not report additional participant characteristics or the analyzed sample's composition. Generalizability beyond the described population cannot be assessed from the registry information alone. The intervention and measurement period lasted one week; longer-term outcomes are not described in the record.

Other limitations of the reported information include no stated allocation ratio, no description of the randomization method, and no detailed account of assessor or analyst masking. The record lists several outcome measures and analyses but does not report how multiplicity was handled. It also does not report the trial's own sample-size justification, model diagnostics, or sensitivity analyses. These omissions restrict evaluation of both precision and robustness.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Heart Rate Oscillations During Meditation on Plasma Biomarkers of Alzheimer's Disease — NCT06210035.
• Registry record last updated 2026-01-05; status last verified 2025-12.
• Results first posted 2026-01-05.
• 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

NCT06210035 is a completed randomized, parallel-group behavioral trial sponsored by the University of Southern California, with an enrollment of 94. It compared one week of belly-focus concentration meditation, the same practice with slow breathing, and quiet rest. Participants were asked to record heart rate and attend laboratory visits before and after the intervention.

The primary outcome was change in an aggregate plasma Aβ Z-score, analyzed as a time-by-condition question. The registry record describes the endpoint and analysis but does not report a single numerical primary-outcome comparison. It lists secondary outcomes involving the plasma pTau-181/Tau ratio and emotional well-being, and describes memory assessment in the study summary.

No serious adverse events or deaths are reported in the three groups. Three participants in the belly-focus concentration meditation group were affected by other adverse events; none were reported in the other groups. Event details and comparative safety analyses are not reported in the registry record.