This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for EYE-TRAC Advance: Technology Verification (ETA-TV) Cohort 2 (NCT02877732), a non-randomized na study. The primary outcome is Changes in the Measurement of EYE-SYNC Data Immediately After Concussive Event, 2 Days, 7 Days and 14 Days Post Concussive Event..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02877732 |
| Phase | NA |
| Condition | Eye-tracking |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Stanford University |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes concussed subjects and control subjects in a prospective, multi-center feasibility and exploratory study. It lists enrollment as 12, but also states that the study was cancelled by the funder before collection of any outcome data and that only screening procedures were performed. The record does not report further details about participant characteristics or the number in each group.
Intervention
Both registered groups were to complete EYE-SYNC eye tracking and the listed assessments: Level of Alertness, SCAT-3 subtests, the Simple Reaction Time subtest of ANAM-SRT, and DEM. The concussed group description also says investigators would collect medical history and demographics from each subject. The record does not report that these assessments were completed as outcome procedures.
Comparator
The registered groups are Concussed Subject and Control Subject. Allocation is non-randomized, and the registry explicitly cautions that the arms are not a like-for-like control comparison. The record does not report how subjects were assigned to groups or provide participant-level information that would establish comparability.
Primary question
The planned primary question concerned changes in EYE-SYNC measurements immediately after a concussive event and at 2 days, 7 days, and 14 days post impact. The registry also lists planned comparisons between EYE-SYNC scores and SCAT-3, ANAM-SRT, and DEM test results. Because no outcome data were collected, these questions have no reported results in the registry record.
As registered, the study was intended to explore whether eye-movement measurements captured by EYE-SYNC changed over the stated post-impact time course and how those measurements related to other assessments. The study was described as a feasibility and exploratory cohort, rather than a randomized trial designed to estimate a treatment effect. No treatment assignment or treatment contrast is described. The registry record therefore supports describing the intended measurement questions, but not drawing conclusions about the performance of the device or the relationship between its scores and other tests.
3. Trial Design
This was a prospective, multi-center cohort feasibility and exploratory study sponsored by Stanford University. The registry lists a parallel model, non-randomized allocation, and no masking. Its phase is listed as NA. Enrollment is listed as 12. The study started in 2016-07, had a primary completion date of 2017-04, and is marked terminated. The registry attributes cancellation to the funder and says that no outcome data were collected; only screening procedures were performed.
The registered groups were Concussed Subject and Control Subject. Both descriptions specify EYE-SYNC eye tracking, Level of Alertness, SCAT-3 subtests for symptoms, immediate memory, balance, and orientation, the Simple Reaction Time subtest of ANAM-SRT, and DEM. The concussed group description also refers to collecting medical history and demographics. These are descriptions of the intended procedures, not evidence that the assessments were completed. The registry does not report group-specific enrollment, participant characteristics, or completed assessments.
Non-randomized allocation means the registry does not describe random assignment to the groups. The registry also cautions that the arms are not a like-for-like control comparison. Without reported participant characteristics or outcome data, the extent to which groups differed at entry cannot be assessed. No masking was planned according to the record. The record does not report further details about recruitment, operational procedures, or a statistical analysis plan. The listed assessments and scheduled post-impact measurements define the intended study framework, but the termination before outcome collection prevents an evaluation of the planned longitudinal or cross-assessment questions.
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
| Stage | Concussed Subject | Control Subject |
|---|---|---|
| STARTED | 6 | 6 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 6 | 6 |
Analysis population for the primary outcome, as defined in the registry: Study was cancelled by the funder prior to collection of any outcome data; only screening procedures were performed.
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.
| Characteristic | Unit | Concussed Subject | Control Subject | Total |
|---|---|---|---|---|
| Participants analysed | 6 | 6 | 12 | |
| Age, Continuous | years | 20 (18 to 23) | 20 (18 to 23) | 20 (18 to 23) |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 5 | 5 | 10 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Changes in the Measurement of EYE-SYNC Data Immediately After Concussive Event, 2 Days, 7 Days and 14 Days Post Concussive Event., measured over Immediate post impact, 2 days, 7 days and 14 days post impact..
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was framed as changes in EYE-SYNC data measured immediately after a concussive event and at 2 days, 7 days, and 14 days post impact. The description says that EYE-SYNC would track eye movement and that data would be recorded in a surface tablet connected to the device. No unit, summary measure, or parameter for the primary endpoint is reported in the registry record. The endpoint is therefore described by its intended measurement process and timing, rather than by a fully specified numerical outcome.
In general, repeated measurements can be used to describe how a measure changes over time within a participant. For an exploratory feasibility study, such measurements may also help assess whether the planned data collection can be carried out and whether the measure is suitable for further study. Those are general purposes of repeated measurement; the registry does not report a particular analysis method or decision criterion for this endpoint.
The registry says the study was cancelled before any outcome data were collected and that only screening procedures were performed. Consequently, no EYE-SYNC measurements or changes between the planned assessment times are reported. The stated endpoint indicates what the investigators intended to measure, but it does not establish that the measure was obtained or that any change occurred.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry record reports no outcome data. Although the primary outcome description specifies EYE-SYNC measurements at the immediate post-impact assessment and at 2 days, 7 days, and 14 days post impact, the population description says the funder cancelled the study before outcome collection and that only screening procedures were performed. The planned measurement schedule must therefore be distinguished from measurements actually observed. No numerical estimate of change, uncertainty interval, or test of a hypothesis is reported in the registry record.
The record lists 6 outcome measures and 0 analyses. It also names planned secondary comparisons between EYE-SYNC scores and SCAT-3, ANAM-SRT, and DEM results. These are planned questions, not reported associations. Without observed scores, readers cannot assess whether EYE-SYNC data varied over the specified time course, whether they were associated with the other assessments, or how precise any such relationship might have been. The registry record does not report a completed analysis or a result that answers these questions.
The non-randomized design and the registry caution that the two groups are not a like-for-like control comparison are relevant to the intended comparison. In general, non-randomized groups may differ for reasons other than the characteristic being studied, so a difference between groups would not automatically be attributable to the study condition. In this record, however, there are no outcome results to compare and no reported participant characteristics with which to evaluate group comparability. The design caution is important context, but it cannot substitute for unavailable data.
The registry lists zero adverse events in its group fields. Given the statement that only screening procedures were performed and no outcome data were collected, those entries should not be read as a comprehensive assessment of safety during the planned study procedures. They describe what is recorded, not evidence about the frequency of events under a completed assessment schedule.
The record includes a planning note describing sample-size illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. A planning illustration is not an observed result or observed power. Because the same registry record says no outcomes were collected, it does not report an empirical effect from this study that can be interpreted as an observed change. Any planning values must be understood as assumptions-based illustrations, not as evidence that the intended measurement question was answered. Overall, the record documents a planned exploratory study and its termination, not findings about EYE-SYNC performance or clinical outcomes.
9. Statistical Methods Explained
The registry record describes intended study procedures and design features, but does not report a statistical analysis plan. It lists 6 outcome measures and 0 analyses. In addition, it states that the study ended before outcome data were collected. The explanations below describe general statistical ideas relevant to the planned questions; they should not be mistaken for methods that the investigators are reported to have used.
What would a change over time represent?
In general, a longitudinal measurement question asks how values from the same participant vary across scheduled assessments. A change estimate needs a defined outcome scale and a clear rule for which measurements are compared. The registry identifies EYE-SYNC eye-movement tracking and the intended assessment times, but does not report the primary measure's unit, summary parameter, or calculation rule. It is therefore not possible to tell from the record whether the planned analysis would have focused on a single score, several movement characteristics, or another summary of the recorded data.
Repeated observations from the same participant are usually related rather than independent. General statistical methods for longitudinal data account for that within-participant relationship when estimating average changes or describing variation. The registry does not specify whether such a method was planned. It also does not report a baseline definition, a primary contrast between assessment times, or how measurements from participants with incomplete follow-up would have been handled. The planned assessment schedule alone does not identify those choices.
What would a comparison with the other tests mean?
The secondary outcomes name comparisons between SCAT-3 and EYE-SYNC scores, ANAM-SRT and EYE-SYNC scores, and DEM and EYE-SYNC scores. In general, an association analysis describes whether measurements tend to vary together. Its interpretation depends on how each assessment is scored, whether higher values have a consistent meaning, what participants contribute data, and which association measure is chosen. The registry record does not report those details or the intended statistical technique. Even if an association were observed, it would not by itself show that one measurement causes a change in another or that the measures can be used interchangeably.
Agreement is a separate concept from association. Two measures can be related while still differing in scale or in the values they assign to an individual. General methods for evaluating agreement examine how closely paired measurements correspond, rather than only whether their values move together. The registry describes the planned comparisons as comparisons of scores; it does not report an agreement objective or a method for assessing agreement. Thus the record does not establish whether the investigators intended to test correlation, agreement, or another form of relationship.
Why does uncertainty matter?
In general, a confidence interval expresses the range of estimates compatible with the data and the statistical assumptions used. A narrower interval indicates greater precision for the estimate, while a wider interval indicates more uncertainty. A point estimate alone does not show that uncertainty. Here, no outcome estimates or confidence intervals are reported because the record says outcome data were not collected. It is consequently impossible to assess the precision of a change estimate or an association estimate from the posted results.
Over-dispersion is a general issue that arises when observed variability is larger than a statistical model assumes. If a method assumes less variability than is present, standard errors and uncertainty intervals may be too small. Choosing a distribution or variance structure that reflects the data can matter in analyses of counts or repeated measurements. The registry does not identify a model, outcome distribution, or observed variability, so there is no basis for saying that over-dispersion arose in this study or that any particular adjustment was used. This is general methodological context only.
How should the planning assumptions be read?
The registry's planning note describes illustrations using a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect, and distinguishes participant-per-arm calculations from total-event calculations for time-to-event settings. These are planning assumptions, not a report of the study's actual allocation or an analysis of observed outcomes. The registry describes a non-randomized study and does not report a time-to-event primary endpoint.
In general, sample-size calculations estimate how much information a future study might need under specified assumptions about the effect, variability, allocation, and statistical method. Changing assumptions can change the resulting planning estimate. A calculated sample size does not show that a study achieved a particular probability of detecting an effect, and it is not a substitute for an outcome estimate with uncertainty. The registry record does not report a sample-size justification as part of the study's own design. Since it also reports no outcome data, a planning illustration based on an observed effect cannot be treated as an effect established by the completed study. The planning values should be interpreted as scenarios under stated assumptions, not as evidence of effectiveness, measurement performance, or observed power.
Overall, the record leaves the analysis methods unresolved. It does not report a model for repeated measurements, a test for the secondary comparisons, a handling rule for missing values, or an inferential framework. These are not details that can be recovered from the list of endpoints. The absence of reported results is particularly important: statistical methods require data, and no method can yield a study-specific estimate from measurements that the registry says were never collected.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 6 outcome measures and 0 analyses. It identifies one primary outcome description and three secondary comparisons involving EYE-SYNC and SCAT-3, ANAM-SRT, and DEM. The record does not report how the outcomes were prioritized for analysis, whether any comparisons were planned as confirmatory, or whether a method to account for multiple comparisons was specified. In general, when several outcomes or hypotheses are examined, the chance of at least one apparently notable result can increase. A multiplicity strategy may define which comparisons are primary or adjust the interpretation of multiple tests. No such strategy is reported, and the absence of collected outcomes means the issue cannot be assessed through actual results.
The record does not report a missing-data plan, an analysis population, or a rule for including participants in each analysis. In general, missing-data methods address incomplete measurements and rely on assumptions about why data are missing. Those assumptions can affect estimates, especially when follow-up measurements are part of the question. In this study, the registry states that outcome data were not collected and only screening procedures were performed. This is not simply a report of scattered missing follow-up values within a completed outcome dataset; the intended outcome dataset was not obtained. The record therefore offers no basis for applying or evaluating a missing-data method.
Because the record says there were no outcome data, it does not report an intention-to-treat, per-protocol, or other analysis population. Those labels should not be inferred from the registered design. Likewise, no multiplicity correction, imputation method, or sensitivity analysis should be attributed to the study. The relevant limitation is that the record does not document these statistical choices and contains no outcome analyses with which to evaluate their consequences.
11. What the Result Does, and Does Not, Mean
The registry record documents an intended exploratory evaluation of EYE-SYNC measurements following a concussive event, with assessments planned immediately after impact and at 2 days, 7 days, and 14 days post impact. It also documents planned comparisons with SCAT-3, ANAM-SRT, and DEM. These details describe the questions the study was meant to address. They do not constitute evidence that the measurements changed or that the assessments were related.
The record says the funder cancelled the study before collection of any outcome data and that only screening procedures were performed. Thus, no study-specific outcome estimate, effect size, confidence interval, or statistical significance result can be interpreted from the registry. No conclusion about the performance of EYE-SYNC, the accuracy of its measurements, or its relationship to the listed tests follows from the planned assessments alone. The listed enrollment of 12 does not change that distinction: an enrollment entry is not an outcome result.
The non-randomized design and the caution that the registered groups are not a like-for-like control comparison also limit what the intended group structure could establish. In general, comparisons between non-randomized groups may reflect differences between participants as well as differences related to the study condition. The record does not report enough participant information to assess comparability, and, more fundamentally, reports no outcome values to compare.
The planning note and any sample-size illustrations are not findings. Planning calculations rely on assumptions and describe hypothetical study requirements; they do not show that an effect was observed, that a planned study had adequate precision, or that a hypothesis was tested. The most direct conclusion is that this registry record describes an uncompleted exploratory study with no collected outcome data. It cannot be used to claim either a positive or a negative result for the planned measurement questions.
12. Why This Trial Matters Statistically
This study is statistically instructive because it separates a registered research question from an answer supported by outcome data. The record contains a defined schedule for EYE-SYNC measurements and names related assessments, but it also states that the study was cancelled before any outcome data were collected. A clearly stated endpoint and assessment schedule are necessary for an analysis, but they do not produce an estimate by themselves. Readers need to distinguish protocol-level intentions from reported results.
The record also illustrates why feasibility and exploratory aims need careful interpretation. A feasibility study can be designed to examine whether procedures and measurements can be carried out, while an exploratory study may investigate patterns that could motivate later research. In this case, the record does not report completed outcome assessments, so it does not provide evidence about feasibility of the outcome collection or exploratory patterns in the measurements. The intended purpose should not be mistaken for a demonstrated finding.
The non-randomized group structure reinforces the importance of design context. The registry itself warns that the arms are not a like-for-like control comparison. General statistical adjustment cannot automatically remove every difference between groups, and an analysis must be interpreted in light of how participants entered the groups. Since the record reports neither outcome data nor participant characteristics, a comparison cannot be evaluated.
Finally, the planning note shows why sample-size calculations should be separated from observed results. Planning assumptions can guide a future study, but they are not evidence that the current study detected an effect or achieved a particular precision. The cancellation makes this distinction especially clear: without collected outcomes, there is no study-specific estimate to support inference. For clinical researchers and biostatisticians, the record is a reminder that transparent reporting of termination and data availability is essential to prevent planned analyses from being mistaken for completed evidence.
13. 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 principal limitation is that the registry says the study was cancelled by the funder before collection of any outcome data; only screening procedures were performed. This prevents evaluation of the primary EYE-SYNC outcome and the planned secondary comparisons. No effect estimates, measures of uncertainty, or completed statistical analyses are reported. The registry status is terminated, and its listed primary completion date does not imply that the planned outcomes were measured.
The registry describes the study as prospective, multi-center, feasibility and exploratory, but does not report details about the participating centers, recruitment, screening, or participant characteristics. Enrollment is listed as 12, while group-specific numbers and the distribution of participants are not reported in the registry record. The record therefore does not establish who contributed to screening or whether any group comparisons could have been assessed.
Important measurement and analysis details are also absent. The primary outcome has no reported unit or parameter, and the record does not specify how eye-movement tracking data would be summarized. It does not report a statistical analysis plan, missing-data approach, analysis population, multiplicity strategy, or sample-size justification as part of the study's own design. These omissions preclude appraisal of the intended inferential methods beyond the broad endpoint description.
The non-randomized allocation and explicit warning that the groups are not a like-for-like control comparison limit the intended comparative interpretation. In addition, the registry's zero adverse-event entries should be interpreted in light of the fact that only screening procedures were performed, rather than as a comprehensive assessment during the planned outcome procedures. Together, these constraints mean the record is informative about the planned study and its termination, but not about the observed behavior of the device measurements or the planned clinical assessments.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: EYE-TRAC Advance: Technology Verification (ETA-TV) Cohort 2 — NCT02877732.
- Registry record last updated 2018-05-30; status last verified 2018-04.
- Results first posted 2018-04-30.
- 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.
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17. Record Summary
NCT02877732, titled EYE-TRAC Advance: Technology Verification (ETA-TV) Cohort 2, was a prospective, multi-center feasibility and exploratory cohort study sponsored by Stanford University. The registry lists non-randomized allocation, no masking, a parallel model, phase NA, and enrollment of 12. It records a start date of 2016-07, a primary completion date of 2017-04, and terminated status.
The planned primary outcome concerned EYE-SYNC eye-movement data immediately after a concussive event and at 2 days, 7 days, and 14 days post impact. Planned secondary comparisons involved SCAT-3, ANAM-SRT, and DEM. The record states that the funder cancelled the study before collection of any outcome data and that only screening procedures were performed. It lists 6 outcome measures and 0 analyses. Accordingly, the registry reports the study's intended questions and design, but no outcome findings.