Comparison of Hearing Aid Fitting Outcomes Between Self-fit and Professional Fit for MDHearing Smart Hearing Aids: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of Hearing Aid Fitting Outcomes Between Self-fit and Professional Fit for MDHearing Smart Hearing Aids (NCT05165121), a randomized na study. The primary outcome is Number of Participants With Improvement at 1 Month as Measured by the Abbreviated Profile of Hearing Aid Benefit (APHAB) and Speech Spatial Qualities 12 (SSQ 12) Scale..

2. Clinical Question

3. Trial Design

The study is registered as a randomized, parallel-group trial with no masking. It is marked completed. The registry lists an enrollment of 91 and gives a start date of 2020-09-21 and a primary completion date of 2021-08-30. Those registry-level details do not establish how many participants contributed data to each endpoint; the posted endpoint counts are reported separately by measure and fitting group.

The study description identifies three components: a human factors study, a self-fit study, and a professional-fit study. The human factors component was intended to assess the feasibility of self-fitting among listeners with mild to moderate sensorineural hearing loss. The clinical study compared fitting outcomes for self-fit and professional-fit groups. The available arm descriptions do not supply a complete account of the procedures, and the allocation method, concealment, and operational details are not reported in the registry record.

The primary outcome is described as the number of participants with improvement at 1 month, assessed using APHAB and SSQ 12. The posted results list each measure and fitting group separately. The registry identifies the device as MDHearing Smart hearing aids and describes use of the MDHearing app for adjusting the aids. Detailed eligibility criteria, site information, and how the study components related to one another 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.

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 Number of Participants With Improvement at 1 Month as Measured by the Abbreviated Profile of Hearing Aid Benefit (APHAB) and Speech Spatial Qualities 12 (SSQ 12) Scale., measured over 1 month.

The primary endpoint counts participants recorded as having improvement at 1 month, measured using the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech Spatial Qualities 12 (SSQ 12) scale. The registry posts separate counts for APHAB, SSQ 12, and SSQ 12 Part B in the self-fit and professional-fit groups. It reports 32 participants with improvement in each listed measure-group entry.

The registry description gives the score interpretation for the measures. APHAB scores range from 1% to 99%, with a higher score indicating improvement. SSQ scores range from 0 to 10, with a higher score indicating hearing perfectly in that situation. SSQ Part B scores range from -5 to +5, with a higher score indicating improved hearing in that situation. These scales capture reported aided benefit, which is the outcome the study aimed to compare between fitting approaches.

The record does not explain the threshold or rule used to classify an individual as having improvement, nor does it post the underlying scores or change from baseline. Therefore, the count endpoint supports interpretation of the recorded improvement classifications, but not of the magnitude or distribution of score changes.

7. Results Posted in the Registry

• APHAB - Professional Fit Group: 100.0% (32/32) versus 100.0% (32/32) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.
• SSQ 12 - Self Fit Group: 100.0% (32/32) versus 100.0% (32/32) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.
• SSQ 12 - Professional Fit Group: 100.0% (32/32) versus 100.0% (32/32) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.
• SSQ 12 Part B - Self Fit Group: 100.0% (32/32) versus 100.0% (32/32) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary result is a binary outcome: whether a participant was classified as having improvement. For a binary endpoint, a group proportion describes the share of the endpoint denominator with the event, and the risk difference subtracts one group proportion from the other. A risk difference of 0.0 means the posted proportions are the same. Here the registry posts identical event counts and denominators for the listed self-fit and professional-fit entries, and the posted risk-difference estimates are 0.0.

A confidence interval expresses uncertainty around an estimated effect under the assumptions of the statistical method used. It is intended to show a range of effect values compatible with the data and method, rather than to certify that the true effect lies within a particular range. The registry posts limits of 0.0 and 0.0 for the listed comparisons. Because every recorded participant in each endpoint entry is classified as improved, the binary data have no observed non-event variation. The posted interval should be understood in that context; it does not capture uncertainty about how improvement was defined, unrecorded data, or the scales' underlying score changes.

Random allocation, when implemented as intended, can help balance factors that influence outcomes between groups. The record identifies the study as randomized, but does not describe the sequence-generation process, allocation concealment, or the details of implementation. No masking was used. For subjective questionnaire outcomes, knowledge of fitting assignment could potentially affect reporting or assessment; the registry does not describe steps taken to address that possibility.

Several questions about the statistical analysis cannot be resolved from the record. It does not report a full analysis plan, the statistical test used, a confidence-interval method, a prespecified improvement threshold, or how incomplete questionnaire responses were handled. No adjusted analysis is posted. There are no posted analyses listed in the registry record. The displayed risk differences are therefore best treated as summaries of the recorded group counts, rather than as a complete account of a prespecified inferential analysis.

General statistical context is useful when interpreting a binary endpoint with no observed non-events. Estimates from data with variation can reflect both the direction and precision of a group contrast. When every recorded response falls into the same event category, the observed data do not reveal how the groups might differ in a broader population. A degenerate interval can result from the way a calculation represents the observed counts; it should not be mistaken for proof that uncertainty is literally absent.

The scales themselves retain information that is lost when converted to a yes-or-no improvement classification. A score difference can vary in size even when all participants meet a threshold for improvement. Without baseline and follow-up score summaries, participant-level results, or the classification rule, the posted count cannot quantify that variation. The record also does not state whether a participant needed to improve on both measures, either measure, or a particular subscale to be counted as improved.

The planning illustration assumptions described for the page use a two-sided significance level of 0.05, equal allocation, and a normal approximation, with target effects defined as fractions of the observed effect. Such calculations are planning illustrations, not observed power or evidence about the trial's original design. The registry does not report its own sample-size justification or statistical planning assumptions. In particular, no trial-specific rationale for the enrolled number is reported in the registry record.

10. Confidence Intervals and Precision

The posted comparisons report risk differences of 0.0 and confidence limits of 0.0 and 0.0. On their face, these values indicate identical observed binary proportions and no interval width in the displayed calculation. The underlying posted counts also show every endpoint denominator classified as improved in both fitting groups.

That apparent exactness should not be confused with broad certainty about the treatment contrast. The interval is tied to the binary outcome and the calculation represented in the registry; it does not express uncertainty about the improvement definition, measurement properties, missing responses, or unobserved score variation. The record does not identify the confidence level or interval method, so those details are not reported in the registry record.

Because no non-improvement outcome is recorded in any listed group entry, the data provide little information about how often improvement might fail to occur in a wider population. The same counts are compatible with very different distributions of underlying scale changes, since the record provides no score-level results. Precision about the binary count must therefore be separated from precision about the magnitude of hearing-related benefit.

The study's enrollment figure and the endpoint denominators refer to different registry summaries. They should not be conflated: the posted outcome entries report their own group denominators, while the record does not explain the flow from enrollment to each endpoint result. Reasons for any difference, missing outcome handling, and the confidence-interval construction are not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome description covering APHAB and SSQ 12, with separate posted entries for APHAB, SSQ 12, and SSQ 12 Part B in each fitting group. It reports no secondary outcomes and no posted analyses. It does not explain whether the measures or subscale entries were treated as separate hypotheses, how a primary result was selected among them, or whether any adjustment for multiple comparisons was planned. A multiplicity strategy is not reported in the registry record.

The record does not describe how missing questionnaire data were handled, whether all randomized participants were included in the endpoint analysis, or which analysis population was used. It also does not report participant flow, reasons for missingness, or whether the posted denominators reflect all participants assigned to the fitting groups. The registry outcome entries list 32 for each measure-group denominator, but do not explain how those denominators were derived.

These omissions matter because the number and handling of measurements can affect interpretation. If multiple measures or subscales are assessed, selecting or emphasizing results after seeing the data can change the strength of statistical evidence. Missing outcomes can also alter the analyzed population or the apparent event rate, depending on their frequency and reasons. Without a prespecified analysis plan and details of missing-data handling, these aspects cannot be evaluated from the registry record.

The posted counts can still be described directly: the reported improvement count equals the reported denominator for each listed entry. That descriptive statement does not resolve whether the analysis followed a prespecified plan or whether all relevant participants and outcomes are represented.

12. 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.

The registry reports adverse-event information for three groups: Human Factors, Clinical Study - Self-fit Group, and Clinical Study - Professional-fit Group. For each group, the listed number at risk is 20, 36, and 35, respectively, and the counts for serious adverse events, other adverse events, and deaths are all 0. These are the registry's reported counts for the groups and categories shown.

A zero count means no event in that category was recorded in the listed group data; it does not prove that the risk is absent. The record does not provide event descriptions, follow-up duration for safety reporting, ascertainment procedures, or details about whether adverse events were actively solicited. It also does not list serious adverse-event terms.

Safety counts should be read separately from the hearing-benefit endpoint. They do not establish that the device or fitting approach is risk-free, and they do not indicate whether the study was designed to detect uncommon events. The registry's safety summary is limited to the reported groups, at-risk counts, and event counts.

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

The registry result supports a limited descriptive statement: in the posted primary-outcome entries, the self-fit and professional-fit groups have the same reported number of participants classified as improved for APHAB, SSQ 12, and SSQ 12 Part B. The posted risk differences are 0.0 with limits of 0.0 and 0.0. This is the pattern in the recorded binary results.

It does not establish that the two fitting approaches are equivalent or that either approach produces a particular magnitude of benefit. Equivalence requires a defined margin and an analysis designed to assess whether the difference is sufficiently small; neither is reported in the registry record. The posted counts also cannot show whether scale scores changed by a small or large amount, because score summaries and the improvement classification rule are not included.

The result should not be generalized beyond the measures, follow-up time, and participants represented by the registry entries. The primary endpoint concerns improvement at 1 month. Longer-term outcomes, detailed usability results, and other clinical outcomes are not posted in the registry record. The record also does not provide enough information to assess missing data, analysis populations, or the full statistical plan.

The safety summary records no serious adverse events, other adverse events, or deaths in the listed groups. This is a report of observed counts, not proof that such events cannot occur. Overall, the posted results describe a strikingly uniform binary endpoint, while leaving important questions about score-level effects, methods, and generalizability unresolved.

14. Why This Trial Matters Statistically

This trial raises an important statistical distinction between a recorded improvement classification and the size of improvement on a scale. The registry reports all participants in each listed endpoint entry as improved, leaving no observed non-improvement responses to differentiate the groups on this binary outcome. That pattern can look definitive when expressed as a zero risk difference and a zero-width interval, but it carries less information about the distribution of underlying outcomes than the display might suggest.

For clinical researchers, this illustrates why endpoint definitions matter. A count of improved participants depends on a rule that converts scale results into categories. Without the threshold and underlying APHAB and SSQ scores, readers cannot determine how much change was observed or whether modest and substantial changes were treated alike. A continuous score summary and a clearly prespecified meaningful-change definition would answer different questions from the binary count.

The record also illustrates the importance of transparent reporting of analysis populations, missing data, and statistical plans. The endpoint denominators are posted, but the participant flow and handling of incomplete outcomes are not described. The registry identifies randomization and lack of masking, while leaving implementation details unreported. These details shape how confidently a group comparison can be interpreted.

Finally, identical observed counts do not by themselves demonstrate equivalence. A valid equivalence interpretation requires an explicit margin and suitable analysis. The available result is useful as a straightforward description of the recorded outcome, while its methodological limits show why estimates should be read alongside endpoint definitions, score-level summaries, and prespecified analysis details.

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 main limitation is that the primary endpoint is presented as counts of participants with improvement, but the registry does not define the threshold or rule used to classify improvement. The underlying APHAB and SSQ scores, baseline values, changes over time, and measures of score variability are not posted. The count therefore cannot show the magnitude or distribution of reported benefit.

All listed endpoint entries show the same count as denominator, producing no recorded non-improvement variation. This limits what the binary data can say about differences between fitting groups, and the posted zero risk differences should not be read as evidence of equivalence. No equivalence margin or non-inferiority analysis is reported.

The record does not report the statistical analysis plan, confidence-interval method or level, p-values, missing-data procedures, or analysis populations. It does not explain participant flow from enrollment to the endpoint denominators, or whether the analysis followed intention-to-treat principles. Allocation concealment and randomization implementation are also not described. No masking was used, which is relevant to questionnaire-based outcomes, though the record does not discuss possible steps to reduce assessment or reporting effects.

The follow-up stated for the primary outcome is 1 month. Longer-term results are not reported in the registry record. Safety reporting gives event counts but lacks detailed ascertainment and follow-up information. The record also does not report secondary outcomes or posted analyses. These limitations restrict conclusions to the registry's displayed counts and its brief description of the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Comparison of Hearing Aid Fitting Outcomes Between Self-fit and Professional Fit for MDHearing Smart Hearing Aids — NCT05165121.
• Registry record last updated 2023-07-06; status last verified 2021-12.
• Results first posted 2023-07-06.
• 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

NCT05165121 is a completed, randomized, parallel-group study with no masking, comparing self-fit and professional-fit outcomes for MDHearing Smart hearing aids. The registry lists an enrollment of 91 and describes human factors, self-fit, and professional-fit components. The primary outcome is the number of participants with improvement at 1 month, measured using APHAB and SSQ 12.

For APHAB, SSQ 12, and SSQ 12 Part B, the posted outcome entries report 32 participants with improvement in each fitting group. The posted risk-difference estimates are 0.0, with limits of 0.0 and 0.0. The registry records zero serious adverse events, other adverse events, and deaths in each listed safety group.

The record does not report the improvement threshold, score-level results, full statistical plan, missing-data handling, or a formal equivalence analysis. The results therefore describe the posted binary counts, rather than establishing equivalence or quantifying the size of score changes.