EEG Changes With Guided Online Meditation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for EEG Changes With Guided Online Meditation (NCT03459690), a non-randomized na study. The primary outcome is Number of Participants With EEGs to Measure Changes in Wave Oscillations.

2. Clinical Question

The central statistical question is whether the study record reports how many participants had EEG data suitable for assessing the specified changes. It does not provide a numerical primary-outcome result or a reported analysis estimating a difference between the groups. The outcome description says that 13 participants enrolled, that 2 requested withdrawal and 1 was lost to follow-up, and that 7 novice and 3 experienced meditators completed the study. It then describes data cleaning for signal strength and intensity and ends after stating that only 7 participants… The registry record does not give the rest of that description or clarify how the final evaluable EEG count relates to the primary endpoint.

Because group assignment was non-randomized, any observed group contrast would also need to be interpreted in light of the groups’ differing prior meditation experience and any other differences not described in the registry record. The record does not report a comparative effect estimate or a statistical test. Accordingly, it does not answer whether the groups differed in EEG changes, nor does it establish that any change was caused by meditation.

3. Trial Design

This was a completed, parallel-group study with non-randomized allocation and no masking. The registry lists the phase as not applicable. Beth Israel Deaconess Medical Center is named as the sponsor. The study began on 2018-05-29, had a primary completion date of 2019-04-30, and is listed as completed. These registry entries describe the study record; they do not supply a fuller protocol or explain why the design choices were made.

The registry reports enrollment of 13 participants. The group descriptions distinguish experienced meditators from novice meditators according to their meditation histories. Among the participants described as completing the study, there were 7 novice meditators and 3 experienced meditators. The outcome description also reports 2 withdrawal requests and 1 participant lost to follow-up. These completion details should not be confused with the group denominators recorded for adverse events, or with the number of participants whose EEG data were suitable for the primary outcome.

The study lists meditation as a behavioral intervention and an Enobio 32 EEG machine as a device. Its stated focus is EEG changes with guided online meditation. The registry describes the primary outcome as the number of participants with evaluable EEGs for measuring changes in wave oscillations, with a timeframe of 6 weeks. It also lists outcomes related to wave amplitude and latency.

Non-randomized allocation means that the groups were not formed by random assignment, so the comparison is observational rather than a randomized treatment contrast. The study is also unmasked. The registry does not report whether EEG processing or outcome assessment was performed without knowledge of group membership. It does not report a protocol-level rationale for the allocation method, the planned analysis, or a sample-size justification. In particular, the record does not establish that the enrolled number was selected to provide a specified precision or power for the primary outcome.

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: Of the 13 participants enrolled in the study 2 participants requested withdrawal and 1 was lost to follow up, resulting in 7 novice meditators and 3 experienced meditators who completed the study. Following data cleaning for signal strength \& intensity among these 10 participants, only 7 participants (3 Experienced \& 4 Novice) had usable data for 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.

Population: Of the 13 participants enrolled in the study 2 participants requested withdrawal and 1 was lost to follow up, resulting in 7 novice meditators and 3 experienced meditators who completed the study.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With EEGs to Measure Changes in Wave Oscillations, measured over 6 weeks.

The primary endpoint is a count: the number of participants with EEG recordings considered evaluable for measuring changes in wave oscillations. The registry gives a 6-week timeframe. The outcome description says the recordings were intended to measure qualitative changes in wave oscillations, but the registry does not provide a numerical count for the primary endpoint or a complete description of the criteria used to classify an EEG as evaluable.

An evaluability count can describe whether usable measurement data were obtained. It is not, by itself, a measure of the size or direction of an EEG change. A count of participants with evaluable recordings therefore answers a data-availability question, not necessarily the scientific question of whether wave oscillations changed or whether change differed between groups. To interpret a change in measurements, readers would also need the measurement results and a defined comparison or summary. Those results are not reported in the registry record.

The endpoint is relevant to the study’s measurement process because EEG-based analyses depend on recordings that can be assessed. The outcome description mentions data cleaning for signal strength and intensity, indicating that data quality was considered. However, the record’s description ends mid-sentence after referring to only 7 participants, and it does not say what specific evaluability rule was applied, how many participants met it for the primary outcome, or whether the final count represented the full study or a particular group.

The registry also lists outcomes concerning evaluable EEGs for wave amplitude and wave latency. It does not report numerical results for those outcomes either. Without endpoint counts and measurement summaries, the registry record does not establish how much information was available to evaluate the intended EEG changes.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a number of participants with evaluable EEGs. For a count outcome, the direct result would ordinarily be a count accompanied by a clear account of which participants were eligible to contribute data. A comparison might additionally describe counts by group or use a model appropriate to the outcome and study design. The registry record does not report such results or an analysis method. The following concepts are general explanations, not descriptions of analyses documented for this study.

What does an evaluability count describe?

An evaluability count concerns whether the collected measurement data meet criteria for analysis. For EEG data, signal quality can affect whether a recording can be interpreted for a stated purpose. The registry outcome description mentions cleaning for signal strength and intensity, but the precise quality thresholds, review process, and rules for excluding recordings are not reported in the registry record. Without those definitions, the count cannot be independently interpreted as a reproducible measure of data quality.

A count also needs a denominator. Readers need to know which participants were expected to contribute, how missing recordings were treated, and whether the count refers to all enrolled participants, those who completed the study, or another analysis population. The record provides enrollment and completion information but does not state the final denominator or a complete endpoint count. The general principle is that a count without its population definition can be difficult to compare or interpret.

What would a group comparison require?

In general, a comparison between groups requires a clearly defined outcome, a stated analysis population, and a method suited to the outcome and design. For a simple binary outcome such as whether a participant has an evaluable EEG, group summaries could report the number meeting the criterion and the number assessed in each group. An inferential comparison would also need an effect measure and a description of uncertainty. Those choices are not reported in the registry record, and no group estimates or statistical tests are posted.

Randomization is relevant because it can help make groups comparable on average at the start of a study. This study was non-randomized, and group membership reflected prior meditation history. General statistical adjustment can address measured differences under stated assumptions, but it cannot automatically remove bias from unmeasured differences. The registry does not report an adjusted analysis, covariates, or a causal method. A raw group contrast, if available, would therefore need cautious interpretation and would not alone show that meditation caused a change.

How should uncertainty be understood?

In general, a confidence interval is a range of values compatible with the observed data and a statistical model, and it communicates precision as well as an estimate’s uncertainty. A narrow interval typically indicates greater precision than a wide interval, while neither interval width nor a point estimate resolves design bias. No confidence interval is reported for the primary outcome in the registry record. Because there is no posted primary estimate, the record also does not allow a reader to assess its precision.

For counts or binary participant outcomes, methods may need to account for the scale and distribution of the data. General methods can differ in how they handle small groups, sparse events, or unequal denominators. The registry record does not report a model, test, or uncertainty method for the EEG outcomes, so it is not possible to determine which, if any, was used.

What does over-dispersion mean?

As a general statistical concept, over-dispersion occurs when observed variability is greater than a model assumes. If a count model assumes less variability than the data contain, its uncertainty estimates can be too small, making results appear more precise than warranted. This concept is relevant to some count-data analyses, but the primary endpoint is described as a participant count and no count model or analysis is reported. The registry therefore offers no basis for determining whether over-dispersion was assessed or relevant to an actual fitted model.

What do the planning assumptions mean?

A planning illustration is not the same as a design justification or an observed result. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the target effect is described as a stated fraction of the observed effect. The record does not report the trial’s own sample-size justification or establish that these assumptions guided enrollment. Such an illustration is conditional on its assumptions and is not observed power. Sample-size illustrations describe hypothetical planning needs under specified conditions; they do not change what the study observed or make an unreported outcome available.

In general, a two-sided significance level defines how a test treats departures in either direction under its null model. Equal allocation is a planning assumption about how participants would be divided between groups. A normal approximation uses a normal distribution as an approximation for a sampling distribution. The suitability of any such assumptions depends on the design and data. Because the registry reports no primary analysis, these general ideas should not be mistaken for a documented analysis plan for this study.

The record reports zero analyses. It does not report a prespecified statistical model, a confidence-interval method, an adjustment strategy, or an interim-analysis plan. These elements should be treated as not reported in the registry record rather than inferred from the outcomes or planning illustration.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Experienced Meditators", "Novice Meditators")
n      <- c(3, 7)
events <- c(3, 4)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Experienced Meditators  3  3  100.0  29.2  100.0  43.9  100.0  39.8  99.4
ARM  Novice Meditators  7  4  57.1  18.4  90.1  25.0  84.2  24.5  84.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures: the primary outcome concerning participants with evaluable EEGs for wave oscillations, and secondary outcomes concerning evaluable EEGs for wave amplitude and latency. Multiple outcomes can create a multiplicity issue when several hypotheses are tested. In general, conducting multiple tests can increase the chance of at least one apparently notable result under a setting where all null hypotheses hold. Statistical plans may address this through a prespecified hierarchy or adjustment, but no multiplicity procedure is reported in the registry record.

The record reports zero analyses and no numerical results for the listed outcomes. It does not state whether a testing hierarchy, adjustment, or distinction between confirmatory and exploratory analyses was planned. Therefore, there are no reported inferential results for which the effect of multiplicity control can be assessed. The number of listed outcomes alone does not show that all were tested.

Missing data also affect interpretation. The record says 13 participants enrolled, 2 requested withdrawal, and 1 was lost to follow-up. It reports that 7 novice and 3 experienced meditators completed the study. The primary-outcome description then mentions cleaning EEG data for signal strength and intensity and ends after stating that only 7 participants… The record does not provide the remainder of the description, the final evaluable count, or a complete explanation of which missing or unusable recordings were excluded.

The registry does not report imputation, a sensitivity analysis, or a rule for including participants with incomplete follow-up or non-evaluable EEGs. It also does not define analysis populations such as all enrolled participants or participants with usable recordings. These details are important because the participants with evaluable data may differ from those without it. Without a stated analysis population and missing-data approach, the potential effect of incomplete follow-up and data cleaning cannot be quantified.

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 adverse-event record lists experienced meditators and novice meditators separately. For experienced meditators, the number at risk for serious adverse events is 4 and the number affected is 0; the corresponding figures for other adverse events are 4 at risk and 0 affected. For novice meditators, the serious-event figures are 9 at risk and 0 affected, and the other-event figures are 9 at risk and 0 affected. Deaths are recorded as 0 in both groups. No serious adverse-event terms are listed.

These are descriptive registry counts. A recorded zero means that the registry reports no affected participants in that category; it does not establish that an event was impossible or that all events would necessarily have been detected and entered. The record does not describe adverse-event definitions, monitoring procedures, assessment windows, or how relatedness to meditation or the EEG device was judged. Those details are not reported in the registry record.

The adverse-event denominators should not be treated as the number completing the EEG outcome. The registry separately reports completion counts and an incomplete description of EEG data cleaning. Nor do the two non-randomized groups form a like-for-like safety comparison: they were defined by different meditation histories, and the registry does not report a comparative safety analysis. The figures describe what was recorded, not a causal estimate of safety or a general assurance about risk.

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

The registry record establishes that a completed study enrolled 13 participants and examined EEG measurements in experienced and novice meditators during a study of guided online meditation. It describes a primary outcome based on the number of participants with evaluable EEGs for wave oscillations over 6 weeks. It also reports group completion information and mentions that data cleaning was performed for signal strength and intensity.

Those details do not amount to a reported finding about EEG change. The registry does not provide the numerical primary outcome, group-specific EEG results, or an estimate of the size or direction of any change. It reports zero analyses. The description of the endpoint ends mid-sentence after saying that only 7 participants…, so the final evaluability information cannot be recovered from the record. The secondary outcomes related to amplitude and latency also lack reported numerical results.

The study design further limits what any group contrast could establish. Participants were not randomly allocated, and experienced and novice groups were defined by different meditation histories. Even a reported difference would not, by itself, demonstrate that guided meditation caused that difference. Other differences between participants may contribute, and the registry does not report an adjusted analysis intended to address them.

The absence of a numerical result is not evidence that EEG measures did not change, that no group difference existed, or that the study collected no usable recordings. It indicates that the registry record does not provide enough information to answer those questions. Similarly, adverse-event counts recorded as zero are registry observations, not proof that no unrecorded or undetected events occurred.

The most defensible interpretation is therefore descriptive and limited: the record documents the study’s purpose, design, enrollment and completion information, and intended outcomes, but it does not report the statistical results needed to assess EEG changes. Any quantitative planning illustration should be understood as hypothetical planning information rather than an observed clinical or EEG finding.

14. Why This Trial Matters Statistically

This study highlights a basic distinction in clinical and experimental research: collecting measurements, determining whether they are usable, and estimating a scientific effect are related but separate tasks. The primary outcome is a count of participants with evaluable EEGs. That can describe measurement availability, but it does not by itself quantify changes in wave oscillations. A clear account of data quality and endpoint results is needed to connect the study’s measurement process with its scientific question.

The record also illustrates why participant flow and analysis populations matter. Enrollment, follow-up, study completion, and EEG evaluability are not interchangeable. The registry reports 13 enrolled participants, withdrawal requests, loss to follow-up, completion counts by group, and data cleaning, but the final primary-outcome count and its denominator are not reported. Without that information, readers cannot judge how much of the enrolled group contributed to the endpoint or how missing and unusable measurements affected the result.

Design matters just as much as measurement. Experienced and novice meditators were not randomly assigned to groups; they were classified by their histories. A comparison between those groups could reflect differences beyond the study activity. Reporting a group contrast would not remove that limitation, but a transparent description of the design and analysis would help readers understand what the contrast could support.

Finally, the record shows why a named outcome is not the same as a reported result. Outcomes and timeframes identify what a study intended to assess. Estimates, uncertainty, analysis populations, missing-data methods, and a statistical plan are needed for a fuller evaluation. Here, those statistical results are not reported. The study is therefore a useful reminder that registry completeness and interpretability depend not only on recording a study’s aims, but also on reporting how its outcomes were obtained and analyzed.

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 main trial-specific limitation is that the primary outcome is not numerically reported. The registry defines it as a count of participants with evaluable EEGs but does not state the final count, the group-specific counts, or the denominator used. The accompanying description is truncated after referring to only 7 participants, leaving the relationship between data cleaning and the final endpoint unclear.

Participant flow is only partly described. The record reports enrollment of 13, 2 withdrawal requests, 1 participant lost to follow-up, and completion by 7 novice and 3 experienced meditators. It does not report a complete accounting of participant status for each outcome or explain how incomplete follow-up affected analysis. The count of participants with evaluable data should not be inferred from the completion figures.

The non-randomized design and the definition of groups by meditation history limit causal interpretation. Masking is listed as none, and the registry does not say whether EEG processing or outcome assessment was conducted without knowledge of group membership. The record does not describe a comparison method, adjustment for potential differences between groups, or a causal analysis.

Further limitations include the absence of reported statistical analyses, effect estimates, uncertainty intervals, outcome values, and a statistical analysis plan. The registry does not report the criteria for EEG evaluability, the details of signal-quality cleaning, a missing-data method, an analysis population, or a multiplicity approach for the listed outcomes. It also does not report the study’s own sample-size justification. These omissions prevent readers from assessing the precision, robustness, or completeness of any EEG finding.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: EEG Changes With Guided Online Meditation — NCT03459690.
• Registry record last updated 2024-03-28; status last verified 2023-09.
• Results first posted 2024-03-28.
• 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

NCT03459690 is a completed, non-randomized, unmasked parallel-group study sponsored by Beth Israel Deaconess Medical Center. The registry lists enrollment of 13 participants, a study start date of 2018-05-29, and a primary completion date of 2019-04-30. Participants were described as experienced or novice meditators, and the study concerned guided online meditation and EEG measurements.

The primary outcome was the number of participants with evaluable EEGs for measuring changes in wave oscillations over 6 weeks. Secondary outcomes concerned evaluable EEGs for wave amplitude and latency. The record reports 2 withdrawal requests, 1 participant lost to follow-up, and completion by 7 novice and 3 experienced meditators. Its primary-outcome description is incomplete and does not give a final evaluability count.

No numerical outcome results or statistical analyses are reported. The adverse-event record lists zero affected participants for serious and other adverse events in each group, and zero deaths. The registry does not report the statistical plan, a sample-size justification, analysis populations, or methods for missing data and multiplicity.