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 Cochlear Implantation After Labyrinthectomy or a Translabyrinthine Surgical Approach (NCT02309099), a na na study. The primary outcome is Change in Consonant-Nucleus-Consonant (CNC) Words Scores Over Time.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02309099 |
| Phase | NA |
| Condition | Unilateral Acoustic Neuroma, Meniere's Disease |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of North Carolina, Chapel Hill |
| Results posted | Yes |
2. Clinical Question
Population
People with unilateral acoustic neuroma, described in the study summary as vestibular schwannoma, or Meniere's disease who had undergone labyrinthectomy or a translabyrinthine surgical approach. The registry lists enrollment of 10; it does not give detailed participant characteristics in the record.
Intervention
Cochlear implantation of the affected ear. The study sought to assess auditory performance during cochlear implant use after the surgical treatment. The registry describes speech-perception and localization tasks as areas of interest.
Comparator
For the primary CNC outcome, testing used the cochlear implant alone, with the contralateral ear plugged or masked. The secondary outcomes describe comparisons of the implant on with the contralateral ear open versus the implant off with the contralateral ear alone.
Primary question
How did CNC word scores change over intervals within the first 12 months of device use? The registry defines the score as the percentage of words correct, with higher scores better. It does not report the observed scores, change estimates, or uncertainty for this primary outcome.
The study rationale concerns whether cochlear implantation can support speech understanding and sound localization after these procedures. The summary notes that effective transmission through the auditory nerve could allow electric information from the affected ear to be combined with acoustic information from the non-affected ear. That is the motivation for examining performance, not a reported finding. The registry record does not establish whether participants experienced a particular degree or direction of change.
3. Trial Design
This was a completed, single-group device study sponsored by the University of North Carolina, Chapel Hill. The intervention was cochlear implantation of the affected ear. The registry lists enrollment of 10 and the conditions Unilateral Acoustic Neuroma and Meniere's Disease. Its summary describes participants as having undergone labyrinthectomy or a translabyrinthine surgical approach as treatment for vestibular schwannoma or Meniere's disease.
The registry records allocation as not applicable and masking as none. It therefore does not describe a randomized comparison between treatment arms. The primary outcome was assessed during cochlear implant use, with the contralateral ear plugged or masked. Secondary outcomes were framed as comparisons between implant-on listening with the contralateral ear open and implant-off listening with the contralateral ear alone. These are within-participant listening conditions, not evidence of a randomized parallel control group.
The primary outcome was change in Consonant-Nucleus-Consonant (CNC) word scores over time. The timeframe is intervals within the first 12 months of device use. The registry describes 21 outcome measures and 0 analyses. The record lists speech-in-quiet, speech-in-noise, and localization measures among the secondary outcomes, but does not give numerical results for them.
The study started in 2014-11, had primary completion on 2017-11-08, and is marked completed. Phase is recorded as not applicable. The registry record does not report the protocol details needed to reconstruct visit schedules, device-fitting procedures, eligibility criteria, or the rationale for the enrollment target. Allocation being not applicable should not be interpreted as evidence of a particular design feature beyond the record's single-group classification.
Planning calculations associated with the posted results use a hypothetical two-arm, equal-allocation framework and a normal approximation. Those assumptions do not describe the study's actual single-group design. Such calculations are illustrations for planning, not observed power, and the registry record does not report the study's own sample-size justification.
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: Groups were based on the participants' diagnosis (vestibular schwannoma or Meniere's disease) and subsequent surgery. Participants were initially consented into their specific group.
Overall Study
| Stage | Vestibular Schwannoma | Meniere's Disease |
|---|---|---|
| STARTED | 7 | 3 |
| Cochlear Implantation | 7 | 3 |
| Initial Activation | 7 | 3 |
| Cochlear Implant Use/Follow-Up | 5 | 3 |
| COMPLETED | 5 | 3 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | Vestibular Schwannoma | Meniere's Disease |
|---|---|---|
| Adverse Event | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: Cochlear Implant Use/Follow-Up One participant in the Meniere's disease group did not complete the 12-month follow-up interval (protocol deviation) and is excluded from that 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.
| Characteristic | Unit | Vestibular Schwannoma | Meniere's Disease | Total |
|---|---|---|---|---|
| Participants analysed | 7 | 3 | 10 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 5 | 1 | 6 |
| Age, Categorical: >=65 years | Participants | 2 | 2 | 4 |
| Sex: Female, Male: Female | Participants | 4 | 2 | 6 |
| Sex: Female, Male: Male | Participants | 3 | 1 | 4 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | Participants | 7 | 3 | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Consonant-Nucleus-Consonant (CNC) Words Scores Over Time, measured over Intervals within the first 12 months of device use.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | Percentage of words correct |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in Consonant-Nucleus-Consonant (CNC) word scores over time. Participants listened to recorded CNC word lists using the cochlear implant alone, while the contralateral ear was plugged or masked. The score is the percentage of words correct, and the registry states that a higher score is better. The timeframe is intervals within the first 12 months of device use.
CNC testing measures open-set word understanding: the listener must identify spoken words rather than choose among a fixed set of answers. This makes the task a direct measure of speech recognition under the specified listening condition. As a general statistical point, repeated measurement over time can describe how a measured outcome changes during follow-up; it does not by itself identify why that change occurred. In a single-group study, changes may reflect several influences, and the design does not isolate an implant effect through a randomized control comparison.
The registry specifies the mean as the summary parameter and the full range as the dispersion measure. A mean describes the group’s average score, while a full range describes the spread from the lowest to the highest observed value. These summaries would help characterize both typical performance and variability, but the registry record does not report the actual CNC scores, means, ranges, or change estimates. It therefore does not allow a reader to assess the size, direction, or precision of the primary outcome change.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a clinical question and an outcome definition, but it does not report the primary endpoint measurements or a statistical analysis of those measurements. In particular, it gives no observed CNC score values, changes over time, confidence intervals, or p-values. Consequently, the posted record does not establish the direction or magnitude of change in word recognition, or how precisely any change was estimated.
The stated endpoint is clinically interpretable as a percentage of words correct under a specific listening condition: cochlear implant alone, with the contralateral ear plugged or masked. It is not the same question as whether a person performs better with both ears available, nor is it a comparison against a separate untreated group. The secondary outcomes address other listening conditions, including implant-on listening with the contralateral ear open and implant-off listening with the contralateral ear alone. Those comparisons are listed as outcomes, but their numerical results are not reported in the registry record.
The study is classified as single-group, with allocation not applicable and no masking. Without a randomized comparator, change during follow-up cannot by itself distinguish a device-associated change from other influences, such as familiarity with testing or changes over time. This is a general limitation of interpreting change in an uncontrolled study, not evidence that any particular influence occurred in this study. The registry record does not report enough information to assess how those influences were handled.
The listed enrollment is 10, and the primary outcome description notes that one participant in the Meniere's disease group did not complete the 12-month follow-up interval and was excluded from that analysis. That statement identifies a specific analysis-population issue, but it does not supply the primary outcome results or establish how other outcomes handled missing observations. A missing follow-up can affect interpretation if the participants with and without measurements differ in relevant ways; whether that occurred is not reported in the registry record.
The record lists 21 outcome measures and 0 analyses. The number of listed outcomes makes it important to distinguish an outcome being named in a registry from an outcome having a reported estimate. The record does not state whether a multiplicity adjustment or a prespecified hierarchy was used, so the risk of selective emphasis across outcomes cannot be evaluated from the registry information.
Overall, the registry supports a description of the study question, design, and measurement plan, as well as limited safety counts. It does not support a quantitative conclusion about CNC performance or the other listening outcomes. A planning calculation based on an observed effect, if presented alongside posted results, should not be read as evidence of observed power; no such power can be inferred from a planning illustration.
9. Statistical Methods Explained
The registry describes a mean CNC score, full-range dispersion, and change over time. It does not report the inferential methods used to analyze the primary outcome. The explanations below describe general statistical ideas relevant to this design; they do not claim that a particular method was used in this study.
What does a mean score describe?
A mean is an average across the observations included in an analysis. For a percentage-correct word score, it gives a group-level summary of performance under the specified listening condition. A mean can be useful for comparing measurements over time, but it can conceal differences among participants. The registry identifies the mean as the parameter of interest and the full range as the measure of dispersion. The full range gives the lowest and highest observed scores, but it does not show how observations are distributed between those endpoints. Neither summary can be reconstructed without the underlying scores or reported results.
When measurements are collected repeatedly from the same participants, the observations are related rather than independent. A method that accounts for this within-participant structure can represent the fact that repeated scores from one person tend to be more alike than scores from different people. The registry record does not report whether the analysis used a repeated-measures model, a paired comparison, or another approach. It also does not report model assumptions, covariates, or how observations at different intervals were combined.
How should change over time be understood?
Change over time can be described by comparing scores across follow-up intervals. As a general statistical concept, an estimate of change describes the direction and size of a measured difference, while its uncertainty describes how much the estimate might vary because of sampling variability. A confidence interval is one way to express that uncertainty: it gives a range of values compatible with the data under the method’s assumptions. A narrow interval indicates greater precision than a wide interval. The registry record does not report a change estimate or confidence interval for CNC scores, so the precision of the primary outcome is not available.
Time itself may be represented in different ways, such as treating visits as separate categories or modeling a trend. Those choices answer different questions and can rely on different assumptions. The registry says that the endpoint concerns intervals within the first 12 months of device use, but does not give the analytic specification for time. It is therefore not possible to tell whether the reported endpoint was intended to estimate a change between selected visits, an overall trend, or another summary across follow-up.
What does the absence of a randomized comparator imply?
In a randomized comparison, random assignment helps make groups comparable on average, supporting causal interpretation of a between-group contrast. This study is recorded as single-group, with allocation not applicable. Its primary outcome concerns performance during implant use over time, rather than a randomized contrast between an implant group and a control group. As a general matter, observed change in a single group can be described, but it does not alone identify what would have happened to the same participants without the intervention. The registry does not report a method intended to address that counterfactual question.
The secondary outcomes describe listening-condition contrasts: cochlear implant on with the contralateral ear open versus implant off with the contralateral ear alone. Comparing conditions within a participant can control for characteristics that remain stable during testing, but it does not automatically remove order effects, learning, or other differences between test conditions. The registry record does not report the order of condition presentation or whether it was randomized, so those design details cannot be assessed.
Why can over-dispersion matter?
As a general statistical concept, over-dispersion occurs when the observed variability is greater than a model assumes. If a model understates variability, standard errors can be too small and intervals or tests can appear more conclusive than the data warrant. Whether over-dispersion is relevant depends on the outcome and the chosen model. CNC scores are bounded percentages, and the registry identifies a mean and full range, but it does not report a model or evidence about its distribution. No claim about over-dispersion in this study can therefore be made.
What do planning calculations represent?
Sample-size planning estimates address how many participants a future study might need under stated assumptions. The planning description associated with the posted results specifies a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It also describes effects to detect as fractions of an observed effect. These are planning assumptions, not a description of the single-group trial’s actual allocation, and the associated calculations are not observed power.
For time-to-event outcomes, the planning description refers to a total number of events; other planning results are expressed as participants per arm for 80% power or another stated power level. These quantities depend on assumptions about the effect and design. They should not be interpreted as participants enrolled or as evidence that the completed study had a particular probability of detecting an effect. The registry record does not report the trial’s own sample-size justification. Since it does not report the observed CNC effect in the registry record for this analysis, a reader cannot assess the basis or relevance of an effect-based planning illustration.
Which inferential details are unavailable?
The registry record does not report the primary analysis model, a hypothesis test, a confidence interval, a p-value, adjustments for repeated testing, or a prespecified analysis hierarchy. It also does not report whether the analysis was adjusted for baseline scores or other participant characteristics. These details matter because model choice and analysis decisions affect how an estimate and its uncertainty should be interpreted. Without them and without outcome measurements, statistical significance and precision cannot be evaluated from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 21 outcome measures and 0 analyses. The listed outcomes include CNC word scores, AzBio sentence scores in quiet and noise, BKB-SIN scores in noise, and localization RMS error. Several outcomes are specified under different listening conditions. Naming multiple outcomes does not show that each was analyzed or reported, and the registry record does not provide results for the primary endpoint or the secondary outcomes in the registry record.
When a study examines many outcomes or comparisons, the chance of obtaining at least one apparently unusual result by chance can increase. Statistical approaches can address this issue through an adjustment, a prespecified primary outcome hierarchy, or careful emphasis on estimation and uncertainty. The registry record does not report a multiplicity strategy, so it is not possible to determine whether or how multiplicity was handled. This absence should not be treated as evidence that no adjustment was made; the method is not reported in the registry record.
The primary outcome description identifies a missing 12-month follow-up for one participant in the Meniere's disease group and says that participant was excluded from that analysis. This is the only specific missing-data detail reported in the record. It does not state whether earlier measurements were available, how other outcome analyses treated missing observations, or whether any imputation or sensitivity analysis was performed. Those methods are not reported in the registry record.
The record does not define a broader analysis population, such as an intention-to-treat or per-protocol population. The primary outcome population note identifies the exclusion for that analysis, but does not describe a general rule for inclusion across outcomes. The registry record also does not report whether analysis decisions were prespecified in a protocol or statistical analysis plan. These gaps limit assessment of whether the analysis population and outcome reporting followed a plan established before results were known.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Vestibular Schwannoma | 2 | 7 | 28.6% |
| Meniere's Disease | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Vestibular Schwannoma | 0 of 7 |
| Meniere's Disease | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Vestibular Schwannoma | 4 of 7 |
| Meniere's Disease | 2 of 3 |
Most frequent serious adverse event terms
| Event term | Organ system | Vestibular Schwannoma | Meniere's Disease |
|---|---|---|---|
| Unsuccessful Initial Activation | Ear and labyrinth disorders | 2 of 7 | 0 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Vestibular Schwannoma | Meniere's Disease |
|---|---|---|---|
| Facial nerve weakness | Nervous system disorders | 3 of 7 | 0 of 3 |
| Metallic taste on tongue on implanted side | Nervous system disorders | 1 of 7 | 0 of 3 |
| Fever and congestion | General disorders | 0 of 7 | 1 of 3 |
| "Unsettling feelings" reported | Psychiatric disorders | 0 of 7 | 1 of 3 |
| Nasal drainage and itching in noise | Immune system disorders | 0 of 7 | 1 of 3 |
| Migration of receiver/stimulator portion of cochlear implant | Product Issues | 1 of 7 | 0 of 3 |
| Dizziness | Ear and labyrinth disorders | 1 of 7 | 0 of 3 |
| Aural pressure | Ear and labyrinth disorders | 1 of 7 | 0 of 3 |
Serious events with the highest arm-level rate: unsuccessful initial activation (28.6%).
The registry reports serious adverse event counts separately for the Vestibular Schwannoma and Meniere's Disease groups. In the Vestibular Schwannoma group, 2 of 7 participants at risk had a serious adverse event; in the Meniere's Disease group, 0 of 3 participants at risk had a serious adverse event. For other adverse events, the record reports 4 of 7 at risk in the Vestibular Schwannoma group and 2 of 3 at risk in the Meniere's Disease group. Deaths are reported as 0 in each group.
The record also identifies “Unsuccessful Initial Activation” as the top serious-event term, with 28.6%. It does not specify in the registry record which group that percentage refers to, or provide further context for the term. It should not be assigned to a group or interpreted as a causal assessment based on the information reported.
These are descriptive registry counts. They do not establish that the cochlear implant caused an event, and the record does not provide a separate comparator group for interpreting event rates. The group counts are small, so a count alone cannot characterize the range of possible underlying risk with precision. The registry record does not give event timing, severity details beyond the serious-event classification, relatedness assessments, or follow-up exposure information. Absence of reported deaths is not evidence that every other safety outcome was absent.
12. What the Result Does, and Does Not, Mean
The registry record documents a study designed to examine cochlear implantation after labyrinthectomy or a translabyrinthine surgical approach in people with vestibular schwannoma or Meniere's disease. It defines a primary measure of open-set word understanding and lists additional speech-perception and localization outcomes. The record also provides limited adverse-event counts. These details establish what the study intended to investigate and some features of its design.
They do not establish the results of the primary question. No CNC score measurements, changes, confidence intervals, or p-values are reported in the registry record. The numerical results for the listed secondary outcomes are also not reported in the registry record. A reader therefore cannot determine the observed direction or size of performance changes, the variation between participants, or the precision of any estimate.
The study’s single-group design is important to interpretation. Even if change measurements were available, a within-group change over time would not, by itself, be equivalent to a randomized comparison. Changes could reflect the intervention, but could also reflect other influences associated with time, testing, or participant experience. This is a general interpretive limitation, not evidence that any specific alternative explanation occurred in this study.
The study summary states that combining electric information in the affected ear with acoustic information in the non-affected ear might support speech perception in noise and localization if the auditory nerve transmits the signal effectively. That statement is the study rationale. It is not a report that those outcomes improved. The listed secondary contrasts are relevant to the rationale, but their measurements are not available in the registry record.
The appropriate conclusion is therefore limited: the registry describes a completed, small, single-group study and its planned outcome domains, but the reported information is insufficient to quantify the primary or secondary outcome results. The safety counts should likewise be read as descriptive event reports rather than proof of cause or a complete safety profile. The record does not support a treatment recommendation or a definitive efficacy conclusion.
13. Why This Trial Matters Statistically
This study illustrates why a clearly stated outcome is not the same as a reported result. The registry defines CNC word recognition as a percentage correct, identifies the listening condition, specifies a mean and full range, and gives a follow-up timeframe within the first 12 months of device use. Those details help a reader understand what was intended to be measured. Without the observed scores and an estimate of change, however, the statistical question remains unanswered in the registry record.
It also demonstrates the distinction between describing within-group change and estimating a causal effect. The single-group classification and allocation marked not applicable mean that the primary endpoint is not presented as a randomized treatment-versus-control contrast. This matters because a change over time can be informative about observed performance while still leaving the counterfactual outcome unknown. Statistical interpretation should match the design rather than imply a stronger comparison than the record describes.
The study includes multiple outcome domains and listening conditions. That breadth can be useful for examining speech understanding and localization from different perspectives, but it also makes clear reporting of outcome hierarchy, analysis choices, and missing-data handling important. Those details are not reported in the registry record. Without them, readers cannot judge how planned outcomes were prioritized or how uncertainty and multiplicity were addressed.
Finally, the record is a reminder to separate planning assumptions from observed evidence. Planning illustrations based on an observed effect and hypothetical two-arm assumptions do not describe the completed single-group design, and they are not observed power. Enrollment, a completed status, and a defined endpoint do not substitute for outcome estimates. For biostatisticians and clinical researchers, that distinction is central to transparent reporting and appropriately bounded conclusions.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The primary limitation for interpreting this specific study from the registry record is the absence of reported primary outcome measurements and analyses. The record defines CNC testing and its timeframe, but provides no scores, estimates of change, uncertainty intervals, or hypothesis-test results. Numerical results for the listed secondary outcomes are also not reported in the registry record. Without those results, the magnitude and precision of observed performance cannot be assessed.
The single-group design limits causal interpretation. Allocation is recorded as not applicable and masking as none; the record does not describe a randomized control comparison. It therefore does not provide a between-group estimate that would separate change associated with the intervention from change over time or other influences. The registry also does not report the order of listening conditions for secondary comparisons, leaving potential condition-order considerations unresolved.
The enrollment is listed as 10. The primary outcome note states that one participant in the Meniere's disease group missed the 12-month follow-up interval and was excluded from that analysis. The record does not explain whether missingness affected earlier observations or other outcomes, and does not report imputation or sensitivity analyses. It does not provide enough information to assess the representativeness of the analysis population or whether missing follow-up could have influenced the observed results.
The registry lists multiple outcomes, but does not report a multiplicity strategy, analysis hierarchy, statistical analysis plan, or model specification. Detailed participant characteristics, eligibility criteria, visit schedule, and sample-size justification are not reported in the registry record. The listed safety counts also lack the event timing and relatedness details needed for a fuller interpretation. These limitations concern what can be concluded from the registry information; they do not establish that unreported procedures or analyses were not conducted.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Cochlear Implantation After Labyrinthectomy or a Translabyrinthine Surgical Approach — NCT02309099.
- Registry record last updated 2019-01-07; status last verified 2018-01.
- Results first posted 2018-12-10.
- 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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18. Record Summary
NCT02309099 is a completed, single-group device study sponsored by the University of North Carolina, Chapel Hill. It examined cochlear implantation of the affected ear after labyrinthectomy or a translabyrinthine surgical approach in the context of vestibular schwannoma or Meniere's disease. Enrollment is listed as 10. The study started in 2014-11 and reached primary completion on 2017-11-08.
The primary outcome is change in CNC word scores over intervals within the first 12 months of device use, measured as percentage of words correct while listening with the cochlear implant alone and the contralateral ear plugged or masked. The registry lists 21 outcome measures and 0 analyses. It does not report primary outcome estimates or numerical results for the secondary outcomes in the registry record.
The record reports serious and other adverse-event counts by condition group, and deaths of 0 in each group. One participant in the Meniere's disease group did not complete the 12-month follow-up interval and was excluded from that primary analysis. Allocation is not applicable, masking is none, and no randomized control comparison is described.