Neurofeedback-enhanced Mindfulness Meditation in Traumatic Brain Injury: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Neurofeedback-enhanced Mindfulness Meditation in Traumatic Brain Injury (NCT02615535), a randomized na study. The primary outcome is Change in Neurobehavioral Symptom Inventory.

2. Clinical Question

3. Trial Design

The registry record identifies this as a randomized, single-masked, parallel-group study, with Spaulding Rehabilitation Hospital as sponsor. Its status is completed. The recorded start is 2015-12, and primary completion is recorded as 2017-12. Enrollment is listed as 25. The record does not specify how the random sequence was generated, how allocation was concealed, or which people were masked. The meaning and practical implementation of single masking are therefore not reported in the registry record.

Participants were assigned to EEG neurofeedback-assisted meditation or non-EEG feedback-assisted meditation. In the EEG group, the MUSE device provided EEG neurofeedback and auditory feedback during meditation. In the comparison group, the MUSE device provided auditory instruction without EEG neurofeedback. This arrangement makes the presence of EEG feedback the main described distinction between the interventions, but the record does not establish whether other features, including contact time or session procedures, were identical.

The primary outcome was change in the Neurobehavioral Symptom Inventory, assessed from baseline to six weeks. The record also lists changes in cognitive, anxiety, depression, mindfulness, and EEG measures as secondary outcomes. It reports eight outcome measures, but does not provide a single primary comparison in the results available for this analysis. The specific analysis population, handling of participants who did not complete follow-up, and details of outcome assessment are not reported in the registry record.

The study is described as a device intervention and has phase listed as NA. That designation does not supply additional information about the study’s statistical design. The record does not report a sample-size justification, a target effect used in planning, an interim-analysis plan, or a detailed statistical analysis plan. Those elements should not be inferred from the randomized design or from the fact that the study is marked 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

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 Neurobehavioral Symptom Inventory, measured over baseline and six weeks.

The primary endpoint was change in the Neurobehavioral Symptom Inventory from baseline to six weeks. The registry describes this measure as covering common symptoms after head injury. It consists of 22 items, each scored from 0-4, with a total score ranging from 0 to 88. Higher scores indicate greater symptom severity. The planned summary was a mean, with standard error specified as the measure of dispersion.

A symptom scale can provide a structured way to describe participants’ reported difficulties and compare their average scores over time. Change from baseline focuses attention on how scores move during the study period, while a comparison between randomized groups is needed to distinguish the groups’ observed changes. The registry record does not state a threshold for a clinically important change or explain how item-level responses were combined beyond the total-scale description.

The record’s endpoint description does not include observed means, changes, or an estimate of the between-group contrast. It also does not report a confidence interval or test result for the primary question. Consequently, the scale’s range and direction can be explained, but the magnitude, precision, and statistical uncertainty of the study’s primary outcome cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a randomized, parallel-group comparison and identifies a continuous primary outcome summarized as a mean. It specifies standard error as the dispersion measure. These labels describe the study structure and intended summary, but they do not supply the missing numerical results. The statistical concepts below are general explanations of how such information is usually read; they are not claims about unreported procedures in this study.

What does randomization contribute?

In general, randomization assigns participants to groups using a chance-based process. Its purpose is to reduce systematic differences in prognostic characteristics between groups at the point of assignment. It does not guarantee that all characteristics will be balanced in a particular study, especially when the study is small, and it does not address differences that arise after assignment, such as unequal follow-up or adherence. The registry record says the allocation was randomized but does not report the sequence-generation or concealment procedures. The details needed to evaluate how assignment was implemented are therefore not reported in the registry record.

The parallel-group structure means that the two intervention groups are compared over the same general study period rather than crossing participants between interventions. Here, the described contrast is EEG neurofeedback-assisted meditation versus non-EEG feedback-assisted meditation. General interpretation of a parallel-group randomized study relies on knowing which participants were analyzed in each group and how outcomes were handled. The analysis population and those handling rules are not reported in the registry record.

What does a mean change represent?

In general, a mean is an average that summarizes the values in a group. For a change outcome, the interpretation depends on how change is defined, such as whether it is follow-up minus baseline or baseline minus follow-up. The registry identifies change from baseline to six weeks as the primary outcome, but the direction used to calculate change is not reported in the registry record. The score itself has a known direction: higher Neurobehavioral Symptom Inventory scores indicate greater symptom severity. A numerical change would be needed to connect that direction to the observed course of symptoms.

A between-group estimate is generally the key quantity for a randomized comparison. It describes the contrast between groups, rather than treating a change within one group as evidence that the intervention caused that change. In this study, no single primary between-group estimate is reported. Separate group averages, even if they were available, would not by themselves supply the precision or statistical test for the contrast.

How should standard error be read?

In general, a standard error describes the statistical precision of an estimated quantity, such as a sample mean. It is not the same as the spread of individual participants’ scores. A small standard error can indicate that a mean is estimated with greater precision, while a larger standard error indicates more uncertainty in that estimate. Interpretation depends on the estimate, the sample information, and the analysis that produced it. The registry record specifies standard error for the primary measure’s dispersion, but does not report a mean or standard error value.

A confidence interval is a range of values compatible with the data and the statistical model at a stated confidence level. It conveys uncertainty around an estimate and helps distinguish a precise estimate from one that remains compatible with a wide range of effects. A confidence interval is not reported for the primary comparison. Without one, the precision of the treatment contrast cannot be assessed. A p-value, if reported, would address compatibility with a specified null hypothesis under an analysis model, but it would not describe the size or practical importance of an effect. No primary p-value is reported in the registry record.

Why can outcome distributions matter?

General statistical methods for continuous outcomes often use a model that summarizes group averages and their uncertainty. Such methods may rely on assumptions about the outcome distribution, the relation between measurements, and the consistency of variability. If data are strongly skewed, contain influential observations, or violate model assumptions, a mean-based model may not fully describe the data. Over-dispersion, in general, means that observed variability exceeds what a chosen model expects; this can make standard errors too small if the model does not account for it. The registry record does not report distribution checks, model diagnostics, or any adjustments for unusual variability.

Repeated measurements also require attention to the relationship between baseline and follow-up values. General approaches can analyze follow-up scores while accounting for baseline, or model change scores, among other options. These choices can affect estimates and precision. The registry record identifies a change outcome and its assessment times, but the specific statistical model, covariates, and method for handling repeated observations are not reported in the registry record.

What can be concluded from the posted results?

The record does not provide the primary comparison needed to apply these concepts to the study’s outcome. The completion status and enrollment entry do not reveal the observed mean change or uncertainty. The absence of a reported estimate should not be replaced with an assumption that no difference occurred. It also does not show that a difference was present. The appropriate statistical reading is that the primary outcome’s numerical result and inferential precision are not reported in the registry record.

The record lists several secondary outcome domains. In general, examining many outcomes raises a multiplicity question: when many hypotheses are tested, the chance of at least one apparently unusual result can increase. Analysts may use a prespecified hierarchy, adjustment procedure, or other interpretation plan, but no such plan is reported in the registry record. It would be inappropriate to assume a correction was or was not used. Likewise, the record does not report an interim-analysis plan or explain whether the outcome analyses were prespecified in a detailed statistical analysis plan.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists the Neurobehavioral Symptom Inventory as the primary outcome and identifies several secondary outcome domains, including cognitive tests, anxiety, depression, mindfulness, and EEG activity. It reports eight outcome measures. When a study considers multiple outcomes, general statistical interpretation must account for the possibility that some results may appear notable by chance. A prespecified strategy can help define which comparisons are confirmatory and how secondary findings should be interpreted. A multiplicity plan is not reported in the registry record.

The record does not give a single primary-outcome comparison, and it lists zero analyses in the posted analysis information. It therefore does not provide a basis for assessing the outcome estimates, tests, or any multiplicity adjustment. The record also does not say whether outcomes were analyzed according to a hierarchy, whether any adjustments were made, or whether all listed outcomes were measured and analyzed as planned. Those details are not reported in the registry record.

Missing-data handling is also not described. The record does not report how missing baseline or follow-up measurements were treated, whether any imputation or model-based method was used, or how withdrawal from the study affected inclusion in analyses. The analysis population is not reported in the registry record. Without these details, it is not possible to determine whether the outcome results, if available elsewhere, represent all randomized participants or a subset with observed follow-up data.

General statistical practice distinguishes the population assigned to groups from the population included in a particular analysis. The handling of participants after randomization can affect the interpretation of a treatment contrast. The registry record does not state whether the primary analysis followed assignment regardless of adherence, whether participants were excluded, or how protocol deviations were handled. These are unanswered reporting questions, not evidence that any particular method was used.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry record lists zero serious adverse events and zero other adverse events in the EEG Neurofeedback-assisted Meditation group, with 10 participants at risk for each category. It lists the same counts in the Non-EEG Feedback-assisted Meditation group: zero serious adverse events and zero other adverse events, with 10 participants at risk for each category. Deaths are listed as zero in both groups.

These entries describe the recorded counts. They do not explain how adverse events were solicited, the period during which they were monitored, how seriousness was defined, or how relatedness to an intervention was judged. Those details are not reported in the registry record. The record also does not provide event descriptions or explain whether the risk populations correspond to all participants assigned to each group.

Zero recorded events should be read as zero in the registry fields, not as proof that no event could occur or that the interventions were free of risk. The posted counts alone cannot establish how completely events were captured or how precise a safety comparison would be. The registry record reports no top serious adverse-event terms.

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

The registry record establishes the study’s stated question and design: a randomized comparison of EEG neurofeedback-assisted meditation with non-EEG feedback-assisted meditation for people with traumatic brain injury. It identifies change in the Neurobehavioral Symptom Inventory from baseline to six weeks as the primary outcome and describes how the scale is scored. It also gives selected adverse-event counts. These details show what the study was intended to assess and provide some context for reading its outcome measure.

The record does not report a single primary-outcome comparison, a confidence interval, or a primary test result. It therefore does not establish the direction, size, or precision of a difference between the intervention groups. It cannot support a conclusion that the groups differed, and it cannot support a conclusion that they were equivalent. Lack of a reported comparison is an information gap, not a numerical result.

The same caution applies to the listed secondary outcomes. Their inclusion does not tell the reader whether cognitive, emotional, mindfulness, or EEG measures changed, or whether results favored either group. The record does not provide those results or a plan for interpreting multiple outcomes. Likewise, zero adverse-event counts in the listed fields should not be treated as a complete guarantee about safety, because event-collection and follow-up details are not reported.

More complete interpretation would require reported outcome estimates for each group and their between-group contrast, together with measures of uncertainty and a clear account of the analysis population and missing data. Details of randomization, masking, adherence, and analysis procedures would also help readers assess the credibility of the comparison. Until those results and methods are reported, the defensible conclusion is limited to the study’s design and the information recorded about its outcomes, not the effectiveness of either approach.

13. Why This Trial Matters Statistically

This study presents a useful statistical question because its comparison separates EEG neurofeedback from a meditation approach that also includes auditory instruction. That contrast is more specific than a comparison against no intervention: the described groups both involve device-based auditory guidance, while only one includes EEG neurofeedback. A well-reported comparison could therefore help readers understand the contribution of the EEG feedback component, subject to how closely the groups’ other procedures were matched. Whether those procedures were otherwise equivalent is not reported in the registry record.

The primary outcome also illustrates why a defined measure and timeframe matter. The Neurobehavioral Symptom Inventory is described as assessing common symptoms after head injury, with a specified score range and direction. The baseline-to-six-week change provides a stated period for evaluating the measure. But those design details cannot substitute for an estimate of the difference between groups and its uncertainty. Clear outcome reporting is necessary for readers to judge the size and precision of a result.

Statistically, a completed randomized study can still be difficult to interpret when its primary comparison and analysis details are absent from the registry record. Reporting the estimate, uncertainty, analysis population, and missing-data approach would allow readers to assess both the result and its limitations. A stated approach to multiple outcomes would also clarify how secondary findings should be weighed. In this record, these elements are not reported, leaving the study question visible but the primary statistical answer unavailable.

The record is also a reminder that safety counts require context. Zero recorded events are meaningful as entries in the registry, but interpretation depends on how events were collected and which participants were monitored. Those details are not reported. The statistical importance of the study therefore lies not in an outcome conclusion that the record does not provide, but in the need to distinguish a clearly described design from an interpretable result.

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.

Several study-specific details needed to judge the design and results are not reported in the registry record. Although allocation is identified as randomized, the method used to generate the sequence and conceal assignments is not described. Masking is labeled single, but the record does not identify who was masked or how masking was maintained. These omissions limit assessment of the procedures that can protect a randomized comparison from avoidable bias.

The registry record gives an enrollment entry of 25, while the adverse-event fields list 10 participants at risk in each group. It does not explain the relationship between those entries or identify the analysis populations. No conclusion about allocation, completion, or follow-up should be inferred from these figures alone. The number of participants with primary-outcome data at baseline or six weeks is not reported in the registry record.

Intervention delivery is described at a broad level, but the record does not report session frequency, session duration, adherence, fidelity, or treatment exposure. It also does not give detailed eligibility criteria or participant characteristics. These omissions make it difficult to assess how the interventions were implemented and to whom the study’s findings might apply, even if outcome results were available.

The primary endpoint is identified, but its observed values and the between-group result are not reported. The statistical model, handling of missing data, analysis population, and multiplicity strategy are also not reported in the registry record. The record does not state a sample-size justification or interim-analysis plan. Without these details and the actual outcome estimates, neither the precision of the primary comparison nor the robustness of its analysis can be assessed.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Neurofeedback-enhanced Mindfulness Meditation in Traumatic Brain Injury — NCT02615535.
• Registry record last updated 2020-03-30; status last verified 2020-03.
• Results first posted 2019-12-06.
• 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

NCT02615535 is a completed randomized, single-masked, parallel-group device study sponsored by Spaulding Rehabilitation Hospital. It lists enrollment as 25 and concerns traumatic brain injury. The comparison was EEG neurofeedback-assisted meditation using MUSE with auditory feedback versus non-EEG feedback-assisted meditation with auditory instruction but no EEG neurofeedback.

The primary outcome was change in the Neurobehavioral Symptom Inventory from baseline to six weeks. The registry describes its 22 items, 0-4 item scoring, total range of 0 to 88, and the interpretation that higher scores indicate greater symptom severity. The posted record does not report a single primary comparison or its statistical results. It also lists zero serious adverse events, zero other adverse events, and zero deaths in each group, with 10 at risk per group for serious and other adverse events. Analysis procedures, missing-data handling, and a multiplicity plan are not reported in the registry record.