Single-Sided Deafness in the Medicare Population: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Single-Sided Deafness in the Medicare Population (NCT05250414), a na na study. The primary outcome is Performance of the Cochlear Implant System Will be Assessed Through Speech Perception Testing in Noise Completed Through One Year (12 Months) Post Activation..

2. Clinical Question

3. Trial Design

The registry record describes a completed, single-group study sponsored by Med-El Corporation. It lists an enrollment of 18 and the MED-EL Cochlear Implant System as the device intervention. The study's stated purpose is to evaluate safety and effectiveness in adults 65 years of age and older. The condition is unilateral hearing loss.

The study is not randomized and has no like-for-like control arm. Consequently, its principal effectiveness comparison is before and after implantation in the same participants, rather than a comparison between independently assigned groups. The primary endpoint description specifies a pre-operative best-aided assessment using a CROS hearing aid and comparison with cochlear-implant scores at follow-up. The registry lists the primary assessment timeframe as one year (12 months) post activation, while the endpoint description also refers to a 6-month score.

The record lists the study as completed. It does not report a phase or allocation method beyond indicating that allocation is not applicable. Masking is listed as none. The registry lists secondary outcomes concerning speech perception in noise, speech perception in quiet, and subjective benefit through one year post implantation. The brief outcome descriptions do not give their observed results.

The registry record does not report a detailed protocol, eligibility criteria, participant characteristics, or a sample-size justification. It lists one analysis, but the analysis model and its implementation are not reported in the registry record. These omissions limit assessment of how the study was conducted and how its results were intended to be interpreted.

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: Two participants enrolled and elected not to go through with cochlear implantation under the study. One participant enrolled and surgery was attempted, but ossification of the cochlea precluded the ability to surgically place the electrode, so the participant was withdrawn from the study. Due to the withdrawal of these three subjects prior to implantation, their enrollment slots were reallocated. This resulted in a total enrollment of 18 subjects, however, only 15 subjects were implanted.

Overall Study

Reasons for not completing this period:

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 Performance of the Cochlear Implant System Will be Assessed Through Speech Perception Testing in Noise Completed Through One Year (12 Months) Post Activation., measured over One year (12 months) post activation.

The primary endpoint is change in speech perception in noise, expressed in percentage points. The described test uses AzBio sentences, with speech presented from the front and noise presented to the acoustic-hearing (contralateral) ear. Testing is described at 60 dB SPL and a signal-to-noise ratio of 0 dB SNR. Scores represent the percentage of words correctly repeated from the test list; higher scores indicate better performance on this measure.

Before implantation, sentence testing is described with a CROS hearing aid. The pre-operative best-aided score is to be compared with scores after cochlear-implant activation, including the 6-month and 12-month assessments. This repeated assessment can describe how a participant's measured performance changes over time. The registry defines improvement as a change of at least 10 percentage points.

Speech-in-noise testing is used to measure performance under listening conditions that include competing sound, which is the specific ability targeted by this endpoint. It is a test outcome, not a direct measure of every aspect of hearing or daily communication. The registry also lists speech perception in quiet and subjective benefit as secondary outcomes, but does not report their results. Neither the average primary-endpoint change, its variability, nor the number of participants meeting the improvement definition is reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change describe?

General: For a continuous outcome, a mean summarizes the average measured value across participants. In a before-and-after study, the mean change summarizes the average within-participant difference between assessments, if the analysis is based on paired observations. The mean alone does not show how much participants vary from one another. The registry identifies the primary outcome as a mean and its dispersion as a standard deviation, but it does not report the actual estimates.

For this endpoint, the measured score is a percentage of words repeated correctly, while the change is expressed in percentage points. General: a mean change can be easier to interpret when the measurement scale and direction are clear. Here, higher AzBio scores are described as better performance, and improvement is defined in the registry as at least 10 percentage points. No observed mean change is reported, so the direction and size of the result cannot be stated.

What does a standard deviation tell the reader?

General: A standard deviation describes spread among observed values around their mean. It is not the same as a confidence interval and does not by itself establish how precisely the mean has been estimated. A small standard deviation indicates that observations are clustered more closely around the average, while a larger one indicates more spread. The registry names standard deviation as the dispersion measure but does not report its value for the primary endpoint.

How would a confidence interval help?

General: A confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. It helps readers judge precision: a narrower interval indicates greater precision than a wider interval. It does not guarantee that the true value lies in the interval, and it does not address biases arising from the study design or data collection. No confidence interval for the primary endpoint is reported in the registry record.

What can a p-value establish?

General: A p-value describes how unusual data at least as extreme as the observed data would be under a specified null hypothesis and statistical model. It is not the probability that the null hypothesis is true, and it does not measure the magnitude or clinical importance of an effect. Interpretation also depends on the analysis plan and study design. The registry record does not report a primary-endpoint p-value or enough analysis detail to determine the testing procedure.

Why does the single-group design matter?

General: Repeated measurements on the same participants can account for the fact that each participant serves as their own reference over time. They do not create a randomized control group. Changes may also be influenced by time, measurement conditions, participant expectations, or other factors. Without a concurrent comparison group, it is harder to separate an intervention-associated change from these possible influences. This is a design consideration, not evidence that any particular alternative explanation occurred in this study.

The endpoint description sets out pre-operative testing with a CROS hearing aid and follow-up testing after activation. It refers to a 6-month and a 12-month CI score, while the primary timeframe is listed as one year (12 months) post activation. The registry record does not explain the planned statistical handling of the repeated assessments or specify which visits contribute to the primary analysis.

Why can over-dispersion matter?

General: Over-dispersion occurs when variation in the data is greater than a statistical model assumes. If a model does not account for that extra variation, standard errors may be too small and confidence intervals may be too narrow. This concept is especially relevant to count outcomes, but the primary endpoint is continuous. The registry identifies a mean and standard deviation for the primary outcome and does not report a model that would permit assessment of over-dispersion.

What is known about the analysis plan?

The registry lists one analysis, but does not report its model, covariates, estimation method, hypothesis test, or approach to repeated measurements. It also does not report whether the primary analysis was adjusted or unadjusted. These details matter because different valid methods can yield different estimates or uncertainty measures, particularly when observations are incomplete or measurements are repeated. No analysis should be inferred from the endpoint description alone.

The record does not report a sample-size justification or the assumptions used when planning enrollment. A planning calculation based on an observed effect, if considered separately, is not evidence of the study's original design assumptions or of observed power. The record's lack of a reported justification means the adequacy of the planned enrollment cannot be assessed from this information.

For safety, the registry presents participant counts in an intent-to-treat group and an intervention group. General: safety counts are descriptive unless a defined comparison and analysis support a comparative inference. Because the trial is not randomized and no safety analysis method is reported, the counts should be read as event reporting within listed groups rather than as evidence of comparative risk.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and one analysis. It identifies the primary endpoint as speech perception in noise and lists secondary outcomes relating to speech perception in noise, speech perception in quiet, and subjective benefit. The registry record does not report a multiplicity plan, such as whether any adjustment was used when assessing more than one outcome or time point. Without that information, the handling of multiple statistical questions cannot be assessed.

The primary endpoint description includes a pre-operative score and follow-up scores at 6 months and 12 months, while the listed primary timeframe is one year (12 months) post activation. The registry does not specify whether each follow-up time was analyzed separately, how repeated measurements were modeled, or which assessment was designated for formal inference. Those choices can affect interpretation, especially when several outcomes or visits are examined.

Missing-data methods and the number of participants with evaluable primary-endpoint measurements are not reported in the registry record. The record does not state how incomplete follow-up, unavailable tests, or withdrawals were handled in the effectiveness analysis. It also does not give a detailed definition of the analysis population for the primary endpoint. Although an intent-to-treat group is named in the safety information, that does not establish which participants or measurements were included in the primary effectiveness analysis.

These omissions leave uncertainty about whether the reported analysis, if available elsewhere, would represent all enrolled participants or only those with observed follow-up measurements. The registry record does not provide enough detail to evaluate missingness, attrition, or sensitivity analyses.

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.

Most frequent non-serious adverse event terms

The registry lists an intent-to-treat group with 18 participants at risk for serious adverse events and 0 affected, and 18 at risk for other adverse events with 3 affected. It also lists an intervention group with 15 participants at risk for serious adverse events and 0 affected, and 15 at risk for other adverse events with 2 affected. Deaths are listed as 0 in both groups.

These are descriptive counts. The registry does not report serious adverse-event terms, and its list of top serious terms is empty. It also does not identify the non-serious event types, their timing, severity, or relationship to the device. The counts therefore cannot describe which events occurred or how they were assessed.

The intent-to-treat and intervention groups are not randomized comparison arms. The record does not explain the relationship between these two listed safety populations, so their counts should not be added together or interpreted as independent groups. In particular, the counts do not establish a comparative safety effect. The record indicates no reported serious events or deaths in the listed groups, while the available event detail remains limited.

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

The registry record establishes that the study evaluated cochlear implantation in adults 65 years of age and older with unilateral hearing loss, and it defines a speech-in-noise endpoint based on AzBio sentence testing. It also describes a pre-operative best-aided assessment and follow-up after activation. These details explain what the investigators intended to measure, but they do not reveal the measured effectiveness result.

The primary endpoint's mean change, standard deviation, confidence interval, and p-value are not reported in the registry record. Nor does the record state how many participants met the defined improvement threshold. Therefore, the posted information does not establish the magnitude, direction, or precision of change in speech-in-noise scores. Missing numerical results should not be interpreted as either a positive result or a null result.

The study's single-group design also limits what can be concluded causally. General: an observed change over time in an uncontrolled study cannot, on its own, isolate the effect of an intervention from other influences that may change or differ across assessments. The registry record does not report a randomized control comparison.

The safety entries report zero serious adverse events and zero deaths in the listed groups, alongside counts of other adverse events. They do not provide the event descriptions needed to characterize those non-serious events. These counts should be understood as the registry's recorded safety data, not as proof that an intervention is free of risk.

In short, the record documents the study question and some design and safety information, but does not report the primary effectiveness findings. It cannot support a quantitative estimate of benefit or a conclusion about clinical importance.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why outcome definitions and outcome results need to be distinguished. The registry gives a detailed description of the primary speech-in-noise measure, including the testing conditions, scoring direction, follow-up timeframe, and improvement threshold. Yet it does not report the observed endpoint result. A defined measurement plan is useful, but without the estimate and its uncertainty, readers cannot assess the result's size or precision.

The study also illustrates the interpretive limits of a single-group design. A pre-operative score can provide a within-participant reference, but it is not equivalent to a randomized concurrent control. General: changes over time can be described statistically without establishing that the intervention alone caused them. That distinction is especially important when considering effectiveness claims.

The record's safety counts offer another lesson: simple event counts can be useful for describing what was recorded, but sparse detail restricts their meaning. Without event terms, timing, and analysis context, readers cannot evaluate the character of non-serious adverse events or make a sound comparison between listed populations.

Finally, the record identifies outcomes and an analysis count without reporting enough information about the statistical plan, missing data, or multiplicity. Those details affect interpretation of estimates and their uncertainty. The study therefore matters statistically not because its results can be quantified from the registry record, but because it shows how much an endpoint definition can tell readers—and how much remains unresolved when outcome estimates and analysis details are not reported.

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 effectiveness is that the registry record does not report numerical results for the primary endpoint or the secondary outcomes. It gives no mean change, standard deviation, confidence interval, p-value, or participant-level response count for the stated improvement threshold. Effect size and precision therefore cannot be assessed.

The study is single-group and not randomized. Its pre-operative-to-follow-up structure can describe change over time but does not supply a concurrent control for separating intervention-associated change from other influences. The registry record does not give enough detail to evaluate the comparability of testing conditions across visits.

Although the endpoint description refers to a 6-month and 12-month CI score, the primary timeframe is listed as one year (12 months) post activation. The record does not clarify how both time points relate to the primary analysis. It also does not report a detailed statistical plan, missing-data approach, or the number of participants with evaluable endpoint measurements.

The registry does not report the sample-size justification, detailed eligibility criteria, or participant characteristics beyond the stated population of adults aged 65 years and older with unilateral hearing loss. Consequently, the basis for enrollment and the representativeness of participants cannot be assessed from the record.

Safety information is limited to counts, with no serious adverse-event terms and no descriptions of the other adverse events. The relationship between the listed safety populations is not explained. These limitations constrain interpretation of both effectiveness and safety without implying that unreported information had any particular value.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Single-Sided Deafness in the Medicare Population — NCT05250414.
• Registry record last updated 2026-08-31; status last verified 2026-08.
• Results first posted 2026-08-31.
• 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

NCT05250414 is a completed, single-group study sponsored by Med-El Corporation. Its stated purpose is to evaluate safety and effectiveness of cochlear implantation in adults 65 years of age and older. The intervention is the MED-EL Cochlear Implant System, and the condition is unilateral hearing loss. The registry lists enrollment of 18 and no masking.

The primary endpoint is change in AzBio speech perception in noise, reported as percentage-point change, with a primary timeframe of one year (12 months) post activation. The description references pre-operative best-aided testing and 6-month and 12-month CI scores, and defines improvement as at least 10 percentage points. Secondary outcomes concern speech perception in noise, speech perception in quiet, and subjective benefit.

The registry record does not report the primary or secondary outcome results, detailed statistical methods, missing-data handling, or a sample-size justification. Safety listings report 0 serious adverse events and 0 deaths in both listed groups, with other adverse events recorded for 3 participants in the intent-to-treat group and 2 in the intervention group.