Revitalize Cognition: Near Infrared Stimulation in Older Adults: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Revitalize Cognition: Near Infrared Stimulation in Older Adults (NCT02582593), a randomized na study. The primary outcome is NIH Examiner Battery, Executive Composite Changes From Baseline to Post-testing.

2. Clinical Question

The study also addressed mood and other cognitive outcomes. The registry describes the work as a proof-of-concept randomized sham-controlled trial in older adults, motivated by the possibility that NIR stimulation might affect cognition and mood. Its primary outcome was specifically a change score for executive functioning, rather than a general measure of all cognitive or emotional effects.

The record identifies an older-adult NIR arm and an older-adult sham arm. It describes cognitively normal participants in both. The primary comparison therefore concerns the recorded outcomes in these trial groups; it does not, by itself, answer questions about other age groups, people with cognitive impairment, or other stimulation procedures. The registry notes that a Parkinson-specific aim is registered separately under NCT06688357.

3. Trial Design

The registry describes a randomized, triple-masked, parallel-group study. Participants were assigned to an active near-infrared stimulation group or a sham group. The registry labels the masking as triple but does not identify which roles were masked in the posted record. It lists the study phase as NA and the status as completed.

The active intervention used the MedX 1116 Rehab Console. The arm description says cognitively normal participants attended 6 treatment sessions over a two week period, with LED cluster stimulation for 60 minutes per session. The sham arm was described as having the same screening, baseline testing and LED cluster placement procedures, while the console was not turned on during the NIR session. The posted arm description is truncated after the active-arm description begins to explain the LED clusters, so further device-placement details are not reported in the registry record.

The registry records enrollment of 16. For the primary outcome, it reports a mean and standard deviation for 8 participants in the NIR group and 5 in the sham group. These are the outcome-specific group counts in the posted results; the registry record does not explain the difference between the enrollment figure and the outcome counts.

The recorded start date is 2015-12-18, and the primary completion date is 2023-11-17. The primary endpoint timeframe is change from baseline to approximately week 3. Three secondary outcomes are listed: an ARENA learning-retention composite and two NIH Toolbox Emotion scales, for psychological wellbeing and negative affect. The registry lists 4 outcome measures and 4 analyses overall. Details about the study’s recruitment flow, protocol deviations and reasons for missing outcome data are not reported in the registry record.

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: Three participants dropped out prior to beginning the sham intervention due study demands and family health issues.

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.

Population: 3 participants from the Sham Group opted not to undergo the intervention after passing screeing due to time demands and family health reasons.

6. Primary Endpoint

The registry lists the primary outcome as NIH Examiner Battery, Executive Composite Changes From Baseline to Post-testing, measured over Change in baseline to approximately week 3.

The primary endpoint is change in the NIH Examiner Battery Executive Composite from baseline to post-testing, with the timeframe described as approximately week 3. The battery is computer-based and combines executive-function tests into a composite intended to represent global executive functioning. Its reported unit is a z-score, and the registry describes a score range from -3.0 to 3.0. Higher scores correspond to better executive functioning; negative scores indicate impairment.

The change score is defined as the post-test score minus the baseline score. A change measure focuses the comparison on how scores shifted over the stated interval, rather than only on the final score. Comparing the groups’ mean changes is a way to assess whether the average recorded change differed between active stimulation and sham in this study.

The composite is used because executive functioning involves multiple related abilities, and the battery combines tests into a single summary measure. A composite can provide a broad outcome for a trial, but it does not show which individual executive skills account for a group result. Nor does a change in the composite, by itself, establish how meaningful that change is to participants in daily life. The registry record does not report a threshold for a clinically important difference or a separate interpretation of the size of score changes for individual participants.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a two-sided t-test for the comparison of mean change in the primary endpoint between the NIR and sham groups. The t-test is a method for comparing group means while accounting for the observed variation within groups. A two-sided test considers departures in either direction, rather than testing only whether one specified group has a higher mean. The reported test is an unadjusted group comparison as described in the registry; further details about covariate adjustment or the precise implementation are not reported in the registry record.

What does the p-value describe?

In general, a p-value measures how compatible the observed result, or a more extreme result, is with a specified null hypothesis under the assumptions of the statistical model. The reported p-value is .575. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. A result that does not meet a conventional significance threshold does not prove that the groups are the same. To assess precision and the range of plausible effects, a confidence interval is useful; no confidence interval is reported for this comparison in the registry record.

What does Cohen’s D describe?

The registry reports Cohen’s D of 0.27. In general, Cohen’s D expresses a difference between group means relative to a measure of within-group variation. It is a standardized effect-size measure, distinct from the original endpoint’s z-score unit. Its interpretation depends on the context, including measurement properties and variability; a label such as small or large cannot substitute for clinical interpretation. The registry does not report a confidence interval for Cohen’s D, leaving its precision unclear.

Why do the standard deviations matter?

The reported standard deviations describe variation in individual change scores around each group mean. The NIR group’s standard deviation is 0.5 and the sham group’s is 0.1. In general, variability affects the precision of estimated means and the comparison between groups. When variability differs between groups, the choice and assumptions of a test can matter. The registry names a two-sided t-test but does not report whether it used a pooled-variance or unequal-variance version, or provide diagnostic checks. Those details are not reported in the registry record.

Means and standard deviations are summaries, not complete descriptions of the observations. In general, small groups can make summary estimates especially sensitive to individual values, and distributional features such as skewness or outliers are difficult to assess from these summaries alone. The posted results do not include individual data or a distributional plot in the registry record. The comparison therefore needs to be interpreted with attention to limited information about the underlying outcome values.

How should the planning illustrations be read?

In general, sample-size calculations estimate how many participants per arm might be needed to detect a specified effect under stated assumptions. Such calculations are planning illustrations, not evidence about the chance that this completed trial detected an effect. The registry’s planning assumptions specify a two-sided significance level of 0.05, equal allocation between arms and a normal approximation, with the effect expressed as a fraction of the observed effect. The calculation is described as based on the observed effect, not the trial’s own design. The registry record does not report the trial’s sample-size justification or protocol-based target. Any planning illustration should therefore be understood as conditional on its assumptions, not as observed power or confirmation that the trial was adequately sized.

Power is a design concept: in general, it is the probability that a planned test will reject its null hypothesis when a particular effect is true and the model assumptions hold. Calculating power after seeing the observed result does not provide an independent measure of evidence. The observed effect itself is uncertain, especially in a small study, so planning calculations based on it also inherit that uncertainty. The registry does not report interim analyses or a prespecified statistical analysis plan, so those aspects cannot be evaluated from the posted record.

For continuous outcomes, assumptions about the distribution of errors and the independence of observations are relevant to a t-test. In general, over-dispersion means that the data vary more than a model assumes; if present, it can make standard errors and test results unreliable unless the analysis accounts for it. The registry record does not report an assessment of over-dispersion or other model diagnostics. The endpoint is summarized as a mean and standard deviation and analyzed by a t-test, but the posted details do not permit independent verification of the underlying assumptions.

The registry reports 4 analyses and 4 outcome measures, while 3 secondary outcomes are listed. Multiple outcomes or analyses can raise the possibility of chance findings when each is tested separately. In general, multiplicity procedures can adjust interpretation or testing to address that issue. Whether an adjustment was planned or applied is not reported in the registry record. The primary result should be kept distinct from any secondary outcome result, and the record does not provide enough detail to reconstruct a complete multiplicity strategy.

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("Older Adult Group NIR", "Older Adult Group - Sham")
n   <- c(8, 5)
m   <- c(0.33, 0.22)
sp  <- c(0.5, 0.1)
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  Older Adult Group NIR  8  0.330  0.500  -0.088  0.748
CARM  Older Adult Group - Sham  5  0.220  0.100  0.096  0.344

11. Analyses Reported by the Sponsor

The registry reports the sponsor’s two-sided t-test for the primary comparison as Cohen’s D of 0.27 and p = .575. The listed group means and standard deviations describe change scores in the NIR and sham arms. The sponsor’s analysis is the inferential result reported in the registry; a recalculation from posted summary statistics, where available, would be an unadjusted reconstruction and would not replace the sponsor’s own analysis. The registry record does not report a discrepancy between the reported analysis and a recalculation.

The reported p-value does not establish equivalence or show that there is no effect. The effect estimate and p-value should be read together with the small outcome groups and the absence of a reported confidence interval. A recalculation from summary data cannot recover details that are not posted, such as individual observations, analysis-population decisions, or any adjustments not described in the registry. The sponsor’s stated analysis therefore remains the relevant reported test, while the posted summaries allow only a limited check of its context and precision.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures and 4 analyses, including the primary executive-composite change and secondary outcomes for learning-retention, psychological wellbeing and negative affect. Testing several outcomes can increase the chance that at least one result appears notable by chance. In general, multiplicity is addressed by prespecifying a hierarchy, adjusting significance thresholds, or otherwise defining how results will be interpreted across outcomes. Whether any such approach was planned or used is not reported in the registry record. The reported primary p-value should not be treated as evidence about every secondary outcome, and no secondary-outcome results are included in the registry record described for this analysis.

The primary outcome summaries are reported for 8 participants in the NIR group and 5 in the sham group, while the registry records enrollment of 16. The registry does not explain why the outcome counts differ from enrollment. It does not report reasons for missing data, whether participants discontinued, how missing observations were handled, or whether any imputation was used. Those omissions limit assessment of potential bias from missing outcomes.

The analysis population is also not described in enough detail to identify whether results are based on all randomized participants, only those with observed post-testing, or another defined group. The randomized design is recorded, but the registry does not report an intention-to-treat definition or a per-protocol analysis for this endpoint. These details matter because excluding participants after randomization can affect comparability between groups. Without the analysis-population definition and missing-data methods, the posted estimate cannot be interpreted as a fully documented analysis of all randomized participants.

The registry lists a primary endpoint timeframe of change from baseline to approximately week 3. It does not report additional assessment timing details or how deviations from the planned timing were handled. The availability of the outcome summaries permits a description of the recorded comparison, but not a complete audit of outcome ascertainment or analysis decisions.

13. 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 reports no serious adverse events in the NIR group among 8 participants at risk and no serious adverse events in the sham group among 5 participants at risk. It also reports no other adverse events in either group and no deaths. These are counts in the posted adverse-event record for the stated groups.

A count of zero observed events is not proof that an event cannot occur or that the intervention is free of risk. In general, safety estimates depend on the number of participants observed, how long they were followed, how events were defined and how completely they were collected. The registry record does not report the safety follow-up duration, event-collection procedures, or a detailed list of serious adverse-event terms; no top serious-event terms are listed. The posted figures therefore describe what was recorded, not a comprehensive guarantee about safety.

The serious-event figures are separate from the primary cognitive endpoint. They do not establish whether the intervention changed executive-function scores, and the primary efficacy comparison does not determine safety. Because the registry records small at-risk groups and provides limited event-collection detail, these counts should be interpreted as a concise report of observed events in this study rather than a precise estimate of risk in a broader population.

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

The posted primary results show positive mean change scores in both groups, with a numerically higher mean in the NIR group. The registry’s two-sided t-test reports p = .575, and Cohen’s D is 0.27. Taken together, these figures describe the observed group summaries and the sponsor’s test; they do not provide strong precision about the magnitude of a possible group difference. No confidence interval is reported, and the outcome groups are small.

The result does not demonstrate that active stimulation and sham are equivalent. Equivalence requires a prespecified margin and an analysis designed to assess whether the effect lies within that margin. Such a margin and analysis are not reported in the registry record. Nor does a non-significant result prove that there is no effect. The data are compatible with uncertainty that cannot be adequately characterized from the posted summaries alone.

The endpoint is an executive-function composite measured from baseline to approximately week 3. It is not a direct measure of every cognitive domain, mood, daily functioning, or long-term outcome. The record lists additional outcomes, but their results are not part of the primary comparison. The posted primary score change also does not specify whether any observed change was meaningful to participants; a clinically important threshold is not reported in the registry record.

The trial is described as a proof-of-concept study in cognitively normal older adults. Its results should not be generalized automatically to other populations, different stimulation protocols, or other settings. Randomization and sham control are important design features for a comparative trial, but limited outcome counts, missing-data details, and absent information about the analysis population constrain interpretation. The record supports a description of the measured outcome and reported test, not a treatment recommendation or a definitive conclusion about effectiveness.

15. Why This Trial Matters Statistically

This study is statistically instructive because it pairs a randomized sham-controlled design with an outcome that is a change score on a continuous composite measure. The design gives a framework for comparing groups, while the outcome summaries make it possible to distinguish the observed mean changes from the variability of individual changes. Those are separate aspects of a result: the mean describes the group average, while the standard deviation describes spread around that average.

The outcome counts also illustrate why effect estimates need to be read with attention to precision. The registry reports results for 8 participants in the NIR group and 5 in the sham group. A numerical difference between group means is not, on its own, evidence of a robust effect. The reported p-value and standardized effect size add information, but the absence of a confidence interval leaves uncertainty about the range of effects consistent with the data. Small groups also limit how much can be learned about distributional patterns and the influence of individual observations.

The record highlights the distinction between a proof-of-concept result and a definitive assessment. A trial can be completed and still leave important questions unanswered about missing outcomes, the analysis population, multiplicity and the sample-size rationale. Reporting these details helps readers understand what was estimated, how the estimate was obtained and how much confidence to place in it. For this record, several of those details are not reported, so the sound statistical reading is deliberately bounded by the posted summaries and test result.

16. 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 outcome groups for the primary endpoint are small, and the registry does not provide a confidence interval for the reported effect. The means and standard deviations do not show individual results or the full distribution of change scores. The difference between the enrollment figure and the reported primary-outcome counts is not explained in the registry record.

The record does not report reasons for missing data, the method used to handle missing outcomes, or a defined analysis population. It is therefore not possible from the posted information to determine whether the primary comparison includes all randomized participants or to assess how missingness may have affected the result. The registry also does not report whether the t-test used a pooled-variance or unequal-variance method, nor does it describe checks of the test assumptions.

The endpoint is assessed from baseline to approximately week 3, and the record does not give a clinically important threshold or evidence about longer-term outcomes. The primary measure summarizes executive functioning and does not establish effects on other cognitive domains, mood or daily functioning. The study’s stated population is cognitively normal older adults, limiting the scope of conclusions to the population and procedures described.

The registry lists multiple outcomes and analyses but does not report a multiplicity strategy or the statistical analysis plan. It also does not report a protocol-based sample-size justification or interim analyses. The arm description for active treatment is truncated in the record, and further device details are not reported. Together, these gaps limit independent evaluation of the protocol, analysis decisions and generalizability of the findings.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Revitalize Cognition: Near Infrared Stimulation in Older Adults — NCT02582593.
• Registry record last updated 2025-02-19; status last verified 2025-01.
• Results first posted 2025-02-19.
• 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.

20. Record Summary

NCT02582593, titled Revitalize Cognition: Near Infrared Stimulation in Older Adults, is recorded as a completed randomized, triple-masked, parallel-group study sponsored by the University of Florida. The registry describes a sham-controlled proof-of-concept study in cognitively normal older adults and records enrollment of 16.

The primary endpoint was change in the NIH Examiner Battery Executive Composite from baseline to approximately week 3. The reported mean changes were 0.33 in the NIR group and 0.22 in the sham group. The registry reports a two-sided t-test, Cohen’s D of 0.27 and p = .575. Primary-outcome group counts were 8 and 5, respectively; no confidence interval is reported.

The registry lists three secondary outcomes and reports no serious or other adverse events and no deaths in the listed groups. Missing-data methods, analysis-population details, multiplicity procedures and the sample-size justification are not reported in the registry record.