Clinical Evaluation of the Nucleus 5 Cochlear Implant (CI) System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of the Nucleus 5 Cochlear Implant (CI) System (NCT01072409), a na na study. The primary outcome is CNC Monosyllabic Word Performance - Treated Ear.

2. Clinical Question

The stated purpose was to evaluate the performance of the Nucleus 5 Cochlear Implant System. The primary measure is open-set word recognition: participants hear speech and respond with words that are scored for correctness. The registry describes testing with speech at 0º azimuth in quiet. This specifies a listening condition for the assessment, not a comparison against another treatment or a claim about performance in other settings.

The clinical question is therefore descriptive within the implanted group. Without a concurrent control group, the record cannot answer how the measured performance would compare with an alternative intervention or with no implantation. Further details about the enrolled population, the intended analysis population, and the observed endpoint result are not reported in the registry record.

3. Trial Design

The registry record describes a completed, single-group evaluation of the Nucleus 5 Cochlear Implant System. The listed enrollment is 49, and the condition is hearing loss. The study is identified as a device evaluation; its phase is listed as not applicable. Allocation is also listed as not applicable, and masking is listed as none. These features indicate that the record does not describe a randomized, masked comparison between treatment groups.

The listed interventions are the Nucleus 5 Cochlear implant and cochlear implantation. The arm description is “Single arm design.” Since the record identifies no concurrent comparator, the design is suited to describing outcomes among the participants in the implanted group, but it does not provide a controlled estimate of a difference between treatment strategies.

The study start is recorded as 2010-03, primary completion as 2012-11, and status as completed. The registry record does not provide further detail about the study procedures, eligibility criteria, recruitment, follow-up completeness, or the timing of assessments beyond the primary endpoint’s stated 12-month timeframe. A protocol description and sample-size justification are not reported in the registry record.

The record lists one outcome measure and no analyses. It names the primary endpoint as mean CNC Monosyllabic Word Performance in the treated ear, measured in percent correct at 12 months. However, it does not report an outcome value, a measure of precision, or an inferential analysis. The design details can therefore establish what was intended to be studied, but not what the observed endpoint result was or how it was analyzed.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as CNC Monosyllabic Word Performance - Treated Ear, measured over 12 months.

The primary endpoint is CNC Monosyllabic Word Performance in the treated ear at 12 months, expressed as percent correct. The record specifies that the outcome is a mean and that its dispersion measure is the standard error. It describes the CNC Word Test as a validated test of open-set word recognition. Participants are presented with monosyllabic words and their responses are scored for words and phonemes correct in the correct sequence.

The registry describes the test as consisting of 10 lists, with 50 monosyllabic words in each list. Testing is specified with speech presented at 0º azimuth in quiet. This makes the outcome a measure of word recognition under a stated test condition. It is not, by itself, a broad assessment of every aspect of hearing, communication, or functioning in everyday environments.

A mean can describe the group’s average performance, while the standard error describes the precision of that estimated mean. These concepts are general statistical interpretations of the stated measure; the registry record does not report the actual mean or standard error. It also does not report individual scores, a baseline value, or a comparison value. As a result, the endpoint’s definition is available, but its observed magnitude and precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary outcome as a mean of a continuous measure and names the standard error as its dispersion measure. It does not report the numerical estimate or an analysis. The statistical concepts below are general explanations of how such measures are commonly interpreted, not descriptions of unreported study procedures.

What does a mean describe?

A mean summarizes the average value across the observations included in an analysis. For this endpoint, the value would represent average CNC word performance in the treated ear, expressed as percent correct. It is a group summary: it does not show the range of individual scores or how many participants had any particular score. Individual results can vary around the mean, and the mean alone does not describe that variation fully.

The record states that performance is scored for words and phonemes correct in the correct sequence. It also specifies speech presentation at 0º azimuth in quiet. These details define the assessment context and scoring approach. They do not establish that the same average would apply under different listening conditions or to other dimensions of hearing or communication.

What does the standard error mean?

In general, a standard error describes the statistical precision of an estimated quantity, such as a sample mean. A smaller standard error indicates a more precise estimate under the assumptions of the analysis; a larger standard error indicates less precision. It is not the same as the spread of individual participant scores. The standard error for this study’s endpoint is not reported in the registry record, so the precision of the estimated mean cannot be evaluated from the posted results.

A confidence interval is a general way to express uncertainty around an estimate. Its interpretation depends on the method used and the assumptions that support it. No confidence interval or interval construction method for the primary endpoint is reported in the registry record. There is therefore no basis for describing a range of plausible mean values from the posted endpoint information.

What can a single-group design estimate?

A single-group study can describe outcomes observed among participants who receive the intervention. A comparator is needed to estimate a between-group contrast. Without such a group, changes over time, selection into the study, concurrent events, and other influences cannot be separated from the intervention using a randomized comparison. These are general limitations of interpretation for uncontrolled designs, not findings that a particular influence affected this study.

The registry record labels allocation as not applicable and describes a single-arm design. It does not identify a control arm or a randomized allocation procedure. Therefore, even a reported mean would be a description of the implanted group’s measured performance, not a randomized treatment-effect estimate. The record’s outcome value is itself not reported, so even that descriptive estimate cannot be interpreted numerically.

What analysis details are available?

The record lists one outcome measure and no analyses. It does not report a model, test statistic, p-value, confidence interval, adjustment strategy, or analysis population. It also does not report how missing endpoint observations were handled. These details are not reported in the registry record; their absence from the record should not be read as proof that they were not addressed elsewhere.

General statistical practice distinguishes a prespecified analysis from analyses selected after looking at the data, because analytic choices can affect interpretation. The registry record does not provide a statistical analysis plan or enough detail to assess whether the outcome analysis followed a prespecified plan. A sample-size justification is also not reported in the registry record. Any planning illustration based on an observed effect should not be mistaken for the trial’s original design justification or for observed power.

Over-dispersion is a general issue that arises when variability in data exceeds what a chosen statistical model assumes. It can make standard errors and tests unreliable if the model does not account for the extra variability. The registry describes a continuous mean endpoint and a standard error, but it does not report a model or indicate that over-dispersion was assessed. No conclusion about that issue can be drawn for this study from the registry record.

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("Implanted")
n   <- c(38)
m   <- c(56.8)
sp  <- c(3.9)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
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  Implanted  38  56.800  24.041  48.898  64.702

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure, identified as the primary endpoint. It does not report additional outcome measures or analyses in the posted results. A multiplicity strategy—such as an approach to controlling the chance of false-positive findings across multiple tests—is not reported in the registry record. With no analyses posted, the record does not permit assessment of how hypotheses were tested or whether any adjustment was made.

Missing-data methods are also not reported in the registry record. The entry does not state how many participants completed the 12-month assessment, how many contributed to the endpoint analysis, or how missing measurements were handled. It does not describe imputation, exclusions, or sensitivity analyses. Enrollment of 49 should not be taken to mean that all enrolled participants posted endpoint data.

The analysis population is not reported in the registry record. The record does not specify whether the endpoint was analyzed among all enrolled participants, those implanted, those with an available 12-month measurement, or another defined group. The adverse-event record separately lists 38 participants at risk in the implanted group, but does not identify that count as the endpoint analysis denominator.

These reporting gaps limit assessment of the primary result and of its susceptibility to missing data or selective analysis. They do not establish that multiplicity or missing-data procedures were not considered in the full study; only that the registry record does not report them.

12. Safety Results

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

Other (non-serious) adverse events

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

The implanted group’s safety listing reports 38 participants at risk, with 0 participants affected by serious adverse events and 0 affected by other adverse events. These are the posted counts for the categories shown in the registry record. The record does not list serious adverse-event terms, and the number of deaths is not reported in the registry record.

Counts should be read alongside their stated group and denominator. The 38 participants at risk are not the same as the overall enrollment figure of 49, and the registry record does not explain the difference or state how the safety group relates to endpoint follow-up. The posted counts therefore do not establish complete safety follow-up for all enrolled participants.

Zero reported events in these categories means that no affected participants are entered in the registry record for the listed group. It does not, by itself, demonstrate that no events occurred outside the reported categories, that all events were captured, or that safety is comparable with another intervention. No concurrent comparator is identified. These figures describe the safety reporting in the registry record and should not be extended beyond that record.

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

The registry record establishes that the study was completed and that its primary endpoint was mean CNC Monosyllabic Word Performance in the treated ear at 12 months. It also gives the measurement unit, percent correct, and describes the test and listening condition. These registry entries explain what the study set out to measure, but the numerical endpoint result is not reported in the registry record.

Without the mean and its standard error, the observed group performance and its precision cannot be assessed. Without a reported analysis, there is no posted estimate or test to interpret. The record therefore does not support a numerical conclusion about the primary endpoint. This is a limitation of the registry information available for statistical interpretation, not evidence about what the full study may have found.

The design is single-group, with no concurrent comparator identified. A result from such a design could describe the implanted participants, but it would not by itself estimate a comparative effect against another treatment or a no-intervention group. The record also does not provide enough detail to assess endpoint completion, missing-data handling, or the defined analysis population.

The safety listing reports zero serious and zero other adverse events among 38 participants at risk in the implanted group. Those counts are limited to the categories and denominator recorded. Deaths are not reported in the registry record, and comparative safety cannot be evaluated from a record with no comparator.

In short, the registry record provides a study description, a defined primary outcome, and limited adverse-event counts, but not the primary outcome result or its statistical analysis. It should not be used to claim that the device did or did not produce a particular level of performance, or that it is more or less effective or safe than another option.

14. Why This Trial Matters Statistically

This trial is statistically notable for the contrast between a clearly named measurement and the absence of a posted outcome estimate. The registry describes a specific continuous endpoint: mean treated-ear CNC word performance at 12 months, in percent correct, with standard error as the stated dispersion measure. That information helps identify what a result would represent. It does not substitute for the result itself.

The single-group design also matters for the kinds of conclusions the study can support. A single-arm evaluation can describe measurements among participants in that group, whereas a comparative effect requires a suitable comparator. The registry record does not identify a concurrent control group or randomized allocation. This is an important distinction when interpreting a device evaluation: a measured group outcome and a controlled estimate of treatment difference are different statistical quantities.

Reporting the analysis population, missing-data approach, and uncertainty would also be important for interpreting a continuous endpoint. The registry record lists enrollment of 49 but does not state how many participants contributed to the 12-month endpoint. It does not report an analysis, a mean, or a standard error. Readers therefore cannot assess the endpoint’s magnitude, precision, or completeness from the posted information.

The adverse-event counts add a limited description of safety reporting, but they do not resolve the missing endpoint information or provide a comparison. Overall, the record illustrates why design, outcome definition, denominator, analysis, and results all matter: each contributes a different piece of the evidence, and one cannot replace the others.

15. 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 trial is that the registry record does not report the numerical result for its primary endpoint. Although the outcome, unit, timeframe, and intended summary are identified, neither the mean nor its standard error is posted. The registry also lists no analyses, leaving no reported inferential result or interval estimate to evaluate.

The study is recorded as single-group, with no comparator identified and masking listed as none. This restricts interpretation to a potential description of the implanted group rather than a controlled comparison. The registry record does not provide enough detail to assess eligibility criteria, participant characteristics, or the representativeness of the enrolled group beyond identifying hearing loss as the condition.

Enrollment is listed as 49, while the implanted safety group lists 38 participants at risk. The record does not explain this difference. It also does not report the number contributing to the 12-month endpoint, the analysis population, follow-up completeness, or missing-data handling. These omissions prevent assessment of whether the endpoint summary, if available elsewhere, would represent all enrolled participants or a subset.

The statistical analysis plan, sample-size justification, and any multiplicity procedures are not reported in the registry record. The assessment is specified in quiet at 0º azimuth, so the registry’s endpoint definition is tied to that test condition; the record does not establish how performance relates to other settings. Finally, the death count is not reported in the registry record, and the adverse-event counts lack a comparator. These limitations constrain interpretation of both performance and safety without establishing what unreported study materials may contain.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Evaluation of the Nucleus 5 Cochlear Implant (CI) System — NCT01072409.
• Registry record last updated 2016-10-27; status last verified 2014-09.
• Results first posted 2014-09-25.
• 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.

19. Record Summary

This completed registry record describes a single-group evaluation of the Nucleus 5 Cochlear Implant System for hearing loss. Enrollment is listed as 49. The study start is 2010-03, primary completion is 2012-11, allocation is not applicable, and masking is none.

The primary endpoint is mean CNC Monosyllabic Word Performance in the treated ear at 12 months, measured in percent correct. The record describes the test but does not report the endpoint result, standard error, or an analysis. It lists one outcome measure and no analyses.

For the implanted safety group, 38 participants are listed at risk, with 0 serious and 0 other adverse events reported. Deaths are not reported in the registry record. No concurrent comparator is identified, and details about the endpoint analysis population and missing data are not reported in the registry record.