PC-Based Rehabilitation of Auditory Function: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PC-Based Rehabilitation of Auditory Function (NCT00724347), a na na study. The primary outcome is .Speech Discrimination Ability.

2. Clinical Question

The scientific rationale in the record concerns difficulty understanding speech in noisy environments among older people. It describes hearing-related changes and age-related changes in neural processing as possible contributors, and proposes perceptual training as a way to improve discrimination of speech sounds. These statements motivate the study; they are not findings from the registered outcome data.

The brief summary calls the project a randomized trial, but the design fields identify a single-group study and give allocation as not applicable. The registry record therefore does not establish a randomized comparison. It also does not report outcome-analysis results, so the clinical question cannot be answered from posted results in this record.

3. Trial Design

The registry lists the study as completed, with enrollment of 18 and a single-group model. Allocation is recorded as not applicable, and masking is recorded as none. The sponsor is the US Department of Veterans Affairs. The study start is listed as 2008-07 and primary completion as 2013-03.

The registered intervention is behavioral: consonant identification training. The arm description specifies hearing-impaired listeners using hearing aids who undertook two months of training in their homes. The stated assessment schedule is testing before and after two months of PC training, with speech tests conducted in the laboratory.

The record’s brief summary uses the phrase “randomized trial,” while its design fields say single group and allocation not applicable. The registered arm information does not describe a randomized allocation or a like-for-like control arm. The summary also refers to comparison with baseline performance and with other older hearing-impaired people who used hearing aids without training. The record does not give enough design information to establish how that external comparison was assembled or analyzed.

Although enrollment is listed as 18, the serious-adverse-event group reports 16 participants at risk. The registry does not explain the difference, and the adverse-event denominator should not be treated as a reported analysis population for the efficacy outcome. The record lists one outcome measure and no analyses. A detailed statistical analysis plan, sample-size justification, interim-analysis plan, and defined analysis populations are not reported in the registry record.

4. Participant Flow and Accounting

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

Before assignment: Most listeners with hearing loss were tested with and without their hearing aids prior to beginning 8 weeks of at-home PC training.

Overall Study

Analysis population for the primary outcome, as defined in the registry: older hearing impaired listeners with hearing aids.

5. Baseline Characteristics

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

Population: Hearing impaired with hearing aids

6. Primary Endpoint

The registry lists the primary outcome as .Speech Discrimination Ability, measured over Subjects will receive two months of PC training and be tested before and after 2-months of training with speech tests in the laboratory...

The primary outcome is titled “Speech Discrimination Ability.” Its listed unit is signal-to-noise ratio in dB SNR, and the outcome type is a mean. The description specifies a mean consonant-identification threshold improvement measure in z-scores relative to normal-hearing subjects, based on consonant and sentence discrimination tests. Testing was planned before and after two months of PC training, using laboratory speech tests.

The registry wording therefore includes two measurement descriptions: a signal-to-noise ratio unit and an improvement measure expressed in z-scores. It does not explain how these are connected, or specify which value is the primary reported scale. That measurement detail is not reported in the registry record and should not be resolved by assuming a conversion or preferred interpretation.

In general, speech discrimination measures can quantify how well a listener distinguishes speech sounds under specified listening conditions. A signal-to-noise ratio expresses the relative level of speech and background noise at a test condition; a change in a threshold can characterize how challenging a condition is when performance reaches a defined criterion. A z-score expresses a result relative to a reference distribution. These are general descriptions, not additional details about the trial’s scoring procedure.

The record also mentions computerized tests of auditory short-term verbal memory and auditory pattern discrimination. These are described as additional assessments, not as the named primary outcome. No numerical outcome estimate, variability estimate, or analysis result is reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What the registered outcome represents. The primary outcome is described as a mean, which is a summary of measurements across participants. The registry names speech-discrimination ability and gives signal-to-noise ratio in dB SNR as its unit. Its description also refers to a mean threshold improvement measure in z-scores relative to normal-hearing subjects. These terms describe different scales, and the record does not explain their relationship. No outcome values or variability estimates are reported, so the scale ambiguity cannot be resolved from posted results.

How a mean and standard deviation are generally read. In general, a mean gives a central summary of observed values, while a standard deviation describes how spread out individual observations are around that mean. The registry identifies standard deviation as the dispersion measure for the continuous outcome, but does not post a standard deviation or an outcome mean. A standard deviation describes participant-to-participant variation; it is not the same as uncertainty in an estimated mean.

What a confidence interval would add. In general, a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. No confidence interval is reported for the primary outcome in the registry record. Without one, the precision of a change estimate cannot be assessed from this record.

Within-person and between-group analyses. A before-and-after design can be analyzed by examining each participant’s change, or by comparing group summaries at the two time points. In general, a paired analysis uses the fact that the two measurements come from the same participant. A randomized between-group analysis instead compares outcomes across assigned groups and can support a causal interpretation when its design and analysis are appropriately conducted. The registry describes before-and-after testing in one arm, but does not report the method used to analyze repeated measurements. It also does not report an analyzed randomized comparison. The specific statistical method is not reported in the registry record.

Why a control comparison matters. General statistical interpretation distinguishes change over time from a difference attributable to an intervention. In a single group, an observed change may reflect the intervention, but a before-and-after result alone does not establish that the intervention caused the change. Repeated exposure to a test, natural variation, or other time-related factors can also affect measured outcomes. A control group can help address these alternatives when it is designed and analyzed comparably. The registry summary mentions other hearing-aid users who did not train, but details of their selection, comparability, and analysis are not reported in the registry record.

Multiplicity and several assessments. In general, testing multiple outcomes or multiple contrasts increases the chance that at least one result appears noteworthy by chance if no adjustment or prespecified hierarchy is used. The registry lists one outcome measure, while its description mentions consonant and sentence discrimination tests and additional computerized tests of auditory short-term verbal memory and auditory pattern discrimination. It does not state how these measures were prioritized, whether multiple comparisons were planned, or whether an adjustment was used. Those details are not reported in the registry record.

Over-dispersion. Over-dispersion is a general concern for count outcomes when observed variability exceeds what a chosen count model expects. The registered primary outcome is continuous, not a count, so count-model over-dispersion is not the central issue for interpreting this endpoint. For continuous measurements, the relevant questions include the distribution of values, the adequacy of model assumptions, and whether the analysis accounts for repeated measurements. The registry does not report diagnostic checks or model details.

Planning calculations. The registry’s planning description says that illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with effects expressed as a stated fraction of the observed effect. It also distinguishes total event counts for time-to-event illustrations from participants per arm for other outcomes. These assumptions describe planning illustrations, not the design actually documented for this single-group study. The numeric planning counts and the observed effect used for those illustrations are not reported in the registry record. Such counts, when available, are planning estimates and not observed power. They do not establish that the study had a particular probability of detecting an effect after the data were collected.

Analysis reporting. The record lists no analyses and gives no test statistic, model estimate, standard error, p-value, or confidence interval. The statistical analysis plan, handling of repeated measures, covariate adjustment, and treatment of outliers are not reported in the registry record. General statistical concepts can clarify what those quantities would mean, but cannot substitute for trial-specific results.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, but its description includes consonant and sentence discrimination tests and additional computerized assessments of auditory short-term verbal memory and auditory pattern discrimination. The record does not specify a hierarchy among these measures, identify which comparisons were confirmatory, or report a multiplicity adjustment. Whether the study used any prespecified strategy for multiple outcomes or tests is not reported in the registry record.

No outcome analyses are listed. The record does not report the number of participants with primary-outcome observations at baseline or after training, the number excluded from an analysis, or the reasons for any exclusions. Although enrollment is listed as 18, the safety group’s at-risk count is 16; that count does not establish the efficacy analysis population. The reason for the difference is not reported.

Missing-data methods are not described. It is not reported whether missing measurements were left unanalyzed, imputed, or addressed through a model that could use incomplete repeated observations. The record does not define an intention-to-treat, per-protocol, or other analysis population. It also does not report sensitivity analyses addressing missing outcomes.

These omissions limit assessment of whether the available observations represent all enrolled participants and how robust an estimate would be to missing data or multiple testing. No conclusion about those practices can be drawn from the registry record.

11. 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 serious-adverse-event record lists Arm 1 with 16 participants at risk and 0 participants affected by a serious adverse event. It also lists 16 at risk and 0 affected for other adverse events. These are the posted counts for this group; they do not provide a comparative safety estimate because the registered design is single group.

Deaths are recorded as null, which means the registry record does not provide a count. Serious adverse-event terms are not listed. The record therefore does not give details about specific events or establish whether any events were assessed as related to training.

The enrollment figure is 18, whereas the adverse-event group lists 16 at risk. The reason for the difference is not reported in the registry record. The at-risk count is specific to the adverse-event reporting and should not be assumed to represent the number with outcome measurements or the number completing the study.

In general, a zero count in a registry entry means no affected participants were recorded in that category for the stated group; it does not by itself establish that no event could occur or that the intervention is free of risk. The registry record does not provide further detail about safety monitoring or event collection.

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

The record describes a behavioral training study in which hearing-impaired listeners using hearing aids were to complete two months of home-based consonant identification training. It identifies laboratory speech testing before and after training as the primary assessment approach. The record also describes additional auditory assessments.

Those design details do not establish an outcome. No pre- or post-training estimates, changes, standard deviations, confidence intervals, or p-values are reported. It is therefore not possible to say from the registry record whether speech-discrimination performance changed, in what direction it changed, or how precisely it was estimated. The additional auditory measures likewise have no posted results in this record.

The single-group design is important to interpretation. Even if a before-and-after difference were reported, such a difference would not, on its own, establish that training caused the change. The registry summary mentions nontraining hearing-aid users as a comparison, but the design fields do not identify a randomized control arm, and comparative analysis details and results are not reported.

The record’s brief summary calls the study randomized, but the design information lists a single group and allocation as not applicable. The registry therefore does not document random allocation. Nor does it provide enough information to interpret the comparison mentioned in the summary as a controlled causal estimate.

The primary outcome wording presents an additional interpretive limitation: the unit is listed as dB SNR, while the description refers to an improvement measure in z-scores. No clarification or outcome values are reported. The record can establish what the investigators intended to assess, but not the observed result or its clinical meaning.

13. Why This Trial Matters Statistically

This study illustrates why design labels and outcome results need to be read together. The brief summary uses the phrase “randomized trial,” while the registered model is single group and allocation is not applicable. Those details do not support treating the record as a randomized comparison. A statistical interpretation should distinguish the study’s stated motivation from the design information and analyses actually documented.

It also shows why outcome definitions matter. The primary measure is named as speech-discrimination ability, with dB SNR listed as the unit, while the description refers to a z-score improvement measure. Without a clear link between these scales and without numerical estimates, readers cannot determine the size or precision of the outcome on a specific scale.

The record describes several auditory tasks, although it lists one outcome measure and no analyses. In general, multiple measures make prespecified outcome priorities and multiplicity methods relevant to interpretation. Those methods are not reported in the registry record, so the extent to which they were addressed cannot be evaluated.

Finally, the study is listed as completed, but outcome analyses are absent from the record. A completed status is not a substitute for posted results. This distinction is useful in clinical research: registration details can describe a research question and planned assessment, while only reported estimates and their uncertainty can show what the collected data indicate.

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 most direct limitation is that the registry record contains no outcome analyses. It does not report primary-outcome values, changes, variability, confidence intervals, or statistical tests. The record therefore cannot support an estimate of the magnitude or precision of a training-associated change.

The registered design is single group, with allocation listed as not applicable and masking listed as none. The record does not document randomized assignment or a concurrent randomized control arm. Although the brief summary refers to other older hearing-impaired hearing-aid users who did not train, information about their selection, comparability, and analysis is not reported in the registry record.

The outcome scale is not fully clear. The unit is listed as dB SNR, but the description refers to an improvement measure in z-scores relative to normal-hearing subjects. The record does not explain how these descriptions relate or provide results that could clarify the measurement.

Enrollment is listed as 18, while the safety group lists 16 participants at risk. The reason for that difference is not reported. The number with primary-outcome data, completion status by participant, and reasons for missing data are also not reported.

The record describes several auditory assessments but does not report an analysis plan, multiplicity strategy, or analysis populations. It gives no detailed information about the training dose beyond two months at home, nor does it report adherence. These limitations concern what the registry documents; they do not establish what procedures may or may not have occurred outside the record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: PC-Based Rehabilitation of Auditory Function — NCT00724347.
• Registry record last updated 2015-01-27; status last verified 2015-01.
• Results first posted 2015-01-13.
• 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

NCT00724347, “PC-Based Rehabilitation of Auditory Function,” is listed as completed. The registry describes a single-group behavioral study of home-based consonant identification training over two months among older hearing-impaired listeners using hearing aids. Enrollment is listed as 18; the sponsor is the US Department of Veterans Affairs.

The primary outcome is speech-discrimination ability, assessed with laboratory speech tests before and after training. The registry lists dB SNR as the unit and describes a z-score improvement measure. Additional computerized auditory assessments are mentioned. The design fields list allocation as not applicable and masking as none, although the brief summary calls the study randomized.

No outcome analyses are listed. Numerical efficacy results, missing-data methods, analysis populations, and detailed statistical methods are not reported in the registry record. The safety group lists 16 participants at risk and 0 affected for serious and other adverse events; deaths are not reported.