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 Smell, Voice and Nasal Swabs as Markers for Neuro-degenerative Disorders (NCT03299062), a non-randomized na study. The primary outcome is Alpha-synuclein Levels From Nasal Swabs.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03299062 |
| Phase | NA |
| Condition | Alzheimer Disease, Neurodegenerative Diseases |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 9 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Arkansas |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes groups of people undergoing evaluation of voice dysfunction by an ear, nose, and throat doctor. The arm descriptions include people with Parkinson’s disease, people with other neurodegenerative disorders, and people with voice dysfunction without evidence of those disorders. The registry reports an enrollment of 9 and says enrollment ended early, leaving too few samples for the planned outcome analysis.
Intervention
The listed diagnostic test is cytology and immunohistochemistry on nasal swab samples. The intended laboratory assessment concerned alpha-synuclein, Amyloid-beta (A-beta), and Phospho-tau (p-tau) staining.
Comparator
There is no randomized control comparison. The study is described as non-randomized and parallel, with no masking. Its groups represent different clinical categories rather than a randomized treatment-versus-control contrast.
Primary question
The primary outcome asks whether nasal swabs can provide an adequate sample for cytology and immunohistochemistry evaluation of the named markers. The registry gives a timeframe of up to 4 weeks after the swab is completed. Because no samples were analyzed for the outcome measures, the registry does not report whether the samples were adequate or what marker staining was found.
In statistical terms, the planned question was about the feasibility of obtaining material suitable for laboratory evaluation, not whether a treatment changes a clinical outcome. The record does not report an analyzed comparison of marker levels among the clinical groups. It therefore cannot establish how well the proposed sampling approach distinguishes the disorders or voice dysfunction categories.
3. Trial Design
NCT03299062, titled “Smell, Voice and Nasal Swabs as Markers for Neuro-degenerative Disorders,” is registered as a completed study sponsored by the University of Arkansas. The record lists its phase as NA, allocation as non-randomized, masking as none, and model as parallel. These design labels describe an observational grouping structure rather than a randomized, masked intervention comparison.
The arm descriptions identify people with Parkinson’s disease and voice dysfunction, people with other neurodegenerative disorders and voice dysfunction, and people with voice dysfunction but no evidence of Parkinson’s or another neurodegenerative disease. Each arm description refers to 20 people. The registry reports enrollment of 9, and its primary outcome description says enrollment ended early, leaving an insufficient number of samples to process. These details indicate that the groups described in the record were not all represented at their stated size in the enrolled study.
The intervention is listed as the diagnostic test Cytology and Immunohistochemistry. The stated purpose was to assess nasal swab material using cytology and immunohistochemistry for alpha-synuclein, A-beta, and p-tau staining. The primary outcome is titled “Alpha-synuclein Levels From Nasal Swabs,” with a timeframe of up to 4 weeks after swab completion.
The registry gives a start date of 2017-11-14, a primary completion date of 2021-12-21, and a completed status. Completion of the study record does not mean that the primary outcome was analyzed: the registry explicitly reports that no samples were, or would be, analyzed for the listed outcome measures. There are no reported outcome results beyond participant flow. Consequently, the design can be described, but its intended laboratory comparison cannot be assessed from outcome data in the 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
| Stage | Parkinson's Disease With Voice Dysfunction Patients | Other Neurodegenerative Disorders With Voice Dysfunction |
|---|---|---|
| STARTED | 4 | 5 |
| COMPLETED | 4 | 5 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Due to early termination of subject enrollment, there were an insufficient number of samples to process for this analysis. As such, none of the samples were (or will be) analyzed for the outcome measures listed and therefore there are no results to report beyond participant flow.
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: Enrollment was stopped due to COVID-19 pandemic after 4 subjects with PD and 5 with other neurodegenerative disorders with voice dysfunction were enrolled.
| Characteristic | Unit | Parkinson's Disease With Voice Dysfunction Patients | Other Neurodegenerative Disorders With Voice Dysfunction | Voice Dysfunction | Total |
|---|---|---|---|---|---|
| Participants analysed | 4 | 5 | 0 | 9 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 3 | 0 | 3 |
| Age, Categorical: >=65 years | Participants | 4 | 2 | 0 | 6 |
| Sex: Female, Male: Female | Participants | 2 | 2 | — | 4 |
| Sex: Female, Male: Male | Participants | 2 | 3 | — | 5 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 4 | 5 | 0 | 9 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Alpha-synuclein Levels From Nasal Swabs, measured over Up to 4 weeks after swab is completed.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled “Alpha-synuclein Levels From Nasal Swabs.” Its description frames the measurement as a test of whether nasal swabs provide an adequate sample for cytology and immunohistochemistry evaluation. The planned staining targets were alpha-synuclein, Amyloid-beta (A-beta), and Phospho-tau (p-tau). The outcome timeframe is up to 4 weeks after the swab is completed.
As a general statistical concept, a feasibility endpoint asks whether a planned measurement procedure can yield material suitable for the intended assessment. This differs from an endpoint that evaluates a clinical benefit or a diagnostic accuracy claim. To assess accuracy, for example, investigators would need a defined reference classification and reported comparison of test results against it; the registry does not report such an analysis.
The record states that early termination of enrollment left too few samples to process, so none of the samples were or would be analyzed for the listed outcome measures. Thus there is no reported measurement of marker levels, sample adequacy rate, or group-specific staining result. The endpoint’s title and planned purpose should not be mistaken for an observed finding. The record identifies what the investigators intended to assess, but it does not provide evidence about the performance of the nasal swab procedure.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main interpretive fact is that the primary outcome was not analyzed. The registry says enrollment ended early and that the number of samples was insufficient for processing. It further states that none of the samples were or would be analyzed for the outcome measures, leaving no results beyond participant flow. Accordingly, there is no reported estimate of alpha-synuclein levels, no reported evaluation of sample adequacy, and no inferential result for the planned staining assessment.
This distinction matters because a registered endpoint is not itself a result. The outcome title describes the intended measurement, while the outcome description supplies the question the investigators wanted to address. Neither supplies an observed value. A reader cannot conclude from the record that nasal swabs did or did not yield adequate material, or that any marker was present at a particular level.
The study’s non-randomized design also limits what its group structure could establish. The groups are defined by clinical category and voice dysfunction, rather than created by random assignment. Even if laboratory results had been available, differences across those groups would not automatically demonstrate that the diagnostic category caused a difference in marker levels. Interpretation would depend on the actual measurements, how participants were selected, and the analysis plan. Those outcome data and analysis details are not reported in the registry record.
The registry lists an enrollment of 9, while the arm descriptions refer to 20 people in each group. The primary outcome text explains that enrollment ended early and samples were insufficient for processing. The stated group descriptions therefore should not be read as evidence that those group sizes were achieved or that their planned comparisons were completed.
The posted safety information reports no serious adverse events among the participants listed as at risk in the two adverse-event groups, and no deaths are reported in those groups. This is a description of the registry’s safety counts, not evidence about the unreported laboratory outcome. The safety record does not fill the gap created by the absence of primary outcome measurements.
Overall, the record documents an intended feasibility-oriented laboratory assessment and an early end to enrollment before the samples could be analyzed. It does not provide a positive or negative estimate of the test procedure’s performance. Any conclusion about diagnostic usefulness, marker levels, or differences between clinical groups would go beyond the posted results.
9. Statistical Methods Explained
What does the design label imply?
The registry describes the study as non-randomized, with no masking and a parallel model. In general, randomization is a method for assigning participants to groups in a way that helps balance measured and unmeasured characteristics across groups. This record does not describe randomized assignment. Its groups are instead defined by clinical category and voice dysfunction. Therefore, the group labels should not be interpreted as treatment assignments, and group comparisons would not have the same causal interpretation as a randomized comparison.
Masking refers generally to keeping participants, investigators, or assessors unaware of assigned group or intervention information. The record lists no masking. Because the primary outcome was not analyzed, the record does not show whether knowledge of clinical group could have influenced laboratory assessment or interpretation. Details of any procedures to limit that possibility are not reported in the registry record.
What is the primary outcome trying to measure?
The named outcome concerns alpha-synuclein levels from nasal swabs. Its description asks whether a swab can provide adequate material for cytology and immunohistochemistry, with staining for alpha-synuclein, A-beta, and p-tau. In general, a laboratory endpoint requires an operational definition: the record should specify what counts as an adequate sample, how staining is assessed, and what summary will be reported. Those details are not reported in the registry record. More importantly, the registry says no samples were analyzed for the outcome measures, so there is no observed endpoint value to interpret.
The timeframe, up to 4 weeks after swab completion, indicates when the outcome was intended to be assessed. A timeframe alone does not tell the reader what result was obtained or how many samples met an adequacy criterion. The registry does not provide those results.
Why does the absence of an estimate matter?
Statistical inference generally starts with observed data and a defined analysis. An estimate describes a feature of the observed sample, while uncertainty measures express how much precision the data support. A confidence interval, for example, is a range constructed by a statistical procedure to express uncertainty around an estimate. It cannot be interpreted when the underlying outcome was not measured or summarized. The registry reports no primary outcome analysis, no effect estimate, and no confidence interval.
A p-value is a measure of how compatible the observed data are with a specified statistical model under a null hypothesis; it is not a measure of clinical importance or proof that a hypothesis is true. Since no outcome data were analyzed, the record contains no p-value for the primary endpoint. The registry also lists zero analyses. This absence should not be translated into a null finding or into evidence that the groups were equivalent.
What can a sample-size illustration say?
As a general concept, sample-size planning depends on the outcome, its variability, the effect the study aims to detect, the chosen significance level, allocation, and analysis method. A planning illustration is not an observed result and is not “observed power.” The registry’s stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of an observed effect. Time-to-event illustrations are described as total event counts using the Schoenfeld method, while other illustrations are described as participants per arm.
Those assumptions do not create an observed effect for this study. Because no samples were analyzed for the primary outcome, the registry does not provide an observed effect on which an effect-based planning illustration could be anchored. Nor does the record report a trial-specific sample-size justification. A planning calculation under hypothetical assumptions must not be confused with evidence that the completed enrollment could detect an effect.
Why is over-dispersion relevant in general?
For count outcomes, a statistical model may assume a particular relationship between the mean and variability. Over-dispersion means the observed variability is greater than that assumed by a model, which can make standard errors too small if the model is not adapted. This is a general consideration, not a reported issue in this study: the registry gives no analyzed count outcome, fitted model, or dispersion estimate.
What analysis details remain unknown?
The registry does not report a statistical analysis plan, an interim analysis, a sample-size justification, or methods for handling missing outcome data. It also does not report analysis populations, adjustments for covariates, or criteria for interpreting marker staining. These omissions prevent assessment of whether the planned laboratory question had a prespecified analysis procedure or how incomplete enrollment would have been handled. The record does state the reason the primary outcome has no results: early termination of enrollment left an insufficient number of samples to process.
In general, a non-significant result is not the same as no result. A non-significant finding would require analyzed data and a statistical test or estimate; no such primary outcome analysis is reported. The correct statistical reading is that the intended outcome remains unanswered in the registry record, rather than that the study demonstrated no difference or no marker signal.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome, “Alpha-synuclein Levels From Nasal Swabs,” and states that the planned assessment included alpha-synuclein, A-beta, and p-tau staining. It also reports zero analyses and says that none of the samples were or would be analyzed for the outcome measures. Therefore, there are no reported outcome tests, estimates, or results whose multiplicity can be evaluated.
Multiplicity is a general statistical concern that arises when several hypotheses or outcomes are tested. Testing multiple markers or comparisons can increase the chance of at least one apparently unusual finding unless the analysis accounts for the testing strategy. The registry does not report whether a multiplicity adjustment or hierarchy among marker assessments was planned. Since no marker analyses were performed, it is not possible to assess how such a strategy would have affected interpretation.
The record says that early termination of subject enrollment left too few samples to process. This is an explanation for the absence of primary outcome data, but detailed missing-data methods are not reported. The record does not describe imputation, exclusion rules, or sensitivity analyses. It also does not define analysis populations for the laboratory outcome. Without processed samples, those analytic choices cannot be evaluated from results.
Participant flow is the only stated source of results beyond the design information. No outcome data should be inferred from the absence of analyzed samples. In particular, missing outcome measurements are not equivalent to measured values showing no marker signal, and they do not support a comparison among the clinical groups.
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 |
|---|---|---|---|
| Parkinson's Disease With Voice Dysfunction Patients | 0 | 4 | 0.0% |
| Other Neurodegenerative Disorders With Voice Dysfunction | 0 | 5 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Parkinson's Disease With Voice Dysfunction Patients | 0 of 4 |
| Other Neurodegenerative Disorders With Voice Dysfunction | 0 of 5 |
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 |
|---|---|
| Parkinson's Disease With Voice Dysfunction Patients | 0 of 4 |
| Other Neurodegenerative Disorders With Voice Dysfunction | 0 of 5 |
The registry reports serious adverse-event counts for two groups. For Parkinson’s Disease With Voice Dysfunction Patients, 4 participants were listed as at risk for serious adverse events, 0 were listed as affected, and deaths were 0. For Other Neurodegenerative Disorders With Voice Dysfunction, 5 participants were listed as at risk, 0 were listed as affected, and deaths were 0. The registry lists no serious adverse-event terms.
These are descriptive counts in the safety record. They do not establish that no adverse events of any kind occurred: the posted figures distinguish serious adverse events from other adverse events, and the groups shown do not include the voice dysfunction group without evidence of neurodegenerative disease. The record lists 4 at risk for other adverse events in the Parkinson’s disease group and 5 in the other neurodegenerative disorders group, with 0 affected in each; deaths are 0 in both listed groups.
Small safety counts provide limited information about uncommon events. More generally, observing no events in a group does not prove that the underlying event risk is absent. These figures should be read as the registry’s reported counts, not as a comprehensive safety conclusion for every enrolled participant or every study group.
12. What the Result Does, and Does Not, Mean
The record establishes that investigators planned to evaluate nasal swabs using cytology and immunohistochemistry for alpha-synuclein, A-beta, and p-tau. It also establishes that the study was non-randomized, that enrollment ended early, and that no samples were analyzed for the outcome measures. These are the boundaries of what the posted results support.
The study does not show whether nasal swabs produced adequate material. It does not report alpha-synuclein levels, staining results, or comparisons across the clinical categories. It therefore cannot establish diagnostic accuracy, distinguish among neurodegenerative disorders, or show that a marker identifies any particular condition. The outcome title should not be treated as though it were a reported finding.
Nor does the record establish that the planned approach failed. Failure to obtain analyzable outcome data is different from an analyzed result showing inadequate samples. The primary question remains unanswered in the registry record. The lack of an estimate, confidence interval, or statistical test reflects the absence of outcome analysis, not evidence for equivalence or for no biological signal.
The non-randomized group structure also matters to interpretation. Had data been available, observed differences among clinical categories would have required cautious interpretation, because participants were not randomly assigned to those categories. The registry does not report an adjusted analysis or other outcome analysis that could address differences among participants.
Finally, the safety counts describe reported adverse events in the listed groups; they do not answer the laboratory feasibility question. The study’s statistical contribution, as represented in the registry, is therefore primarily a record of its intended assessment and the reason an outcome result is unavailable. It should not be used as evidence for or against the diagnostic performance of nasal swabs.
13. Why This Trial Matters Statistically
This study raises a statistically important distinction between planning to measure a biomarker and obtaining interpretable biomarker data. The stated purpose was to assess whether nasal swabs could yield material for cytology and immunohistochemistry. Yet the registry reports early termination of enrollment and no sample analysis. As a result, the central feasibility question cannot be answered from the posted results.
That distinction is relevant to clinical research because a test concept may be biologically plausible while still requiring evidence about specimen collection, processing, and measurement. Statistical conclusions depend on observed data that correspond to a clearly defined endpoint. If samples are not processed, there can be no estimate of adequacy, variability, or differences among clinical groups. A study can document an intended measurement and an enrollment problem without supplying evidence about the test’s performance.
The record also illustrates why design labels should be read carefully. The groups are non-randomized clinical categories, not assigned treatment conditions. Any future comparison using this kind of structure would need to consider how participant characteristics and selection into groups relate to the laboratory measurements. The registry does not report such an analysis for this study.
For biostatisticians and clinical researchers, the case underscores the need to distinguish an unobserved outcome from a negative result, and a planned sample-size calculation from information about achieved precision. With no outcome data, there is no basis for an effect estimate or observed statistical power. The registry’s clearest contribution is transparency about the gap between the planned laboratory assessment and the results that could be reported after early enrollment termination.
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 is that no samples were analyzed for the outcome measures. The registry attributes this to early termination of enrollment and an insufficient number of samples to process. Consequently, the record has no measured marker levels, sample adequacy findings, or reported laboratory comparisons.
The registry reports enrollment of 9, while the arm descriptions refer to 20 people in each of the described groups. The record does not give a full group-by-group participant flow in the information reported for the primary outcome, so the relationship between the stated arm descriptions and the enrolled participants cannot be further characterized. The primary outcome text says only that enrollment ended early and samples were insufficient for analysis.
The study is non-randomized and unmasked. These design features would require caution in interpreting any group contrasts, but no outcome contrasts are reported. Details about recruitment, diagnostic ascertainment, sample handling, laboratory scoring, adequacy criteria, and quality control are not reported in the registry record. The statistical analysis plan, missing-data procedures, and sample-size justification are also not reported.
The registry’s safety figures cover the listed adverse-event groups and should not be taken as a complete outcome assessment across every clinical group. More broadly, the absence of a primary outcome analysis means that the study cannot provide precision estimates or support conclusions about diagnostic performance. Its completed status does not change that limitation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Smell, Voice and Nasal Swabs as Markers for Neuro-degenerative Disorders — NCT03299062.
- Registry record last updated 2022-11-25; status last verified 2022-10.
- Results first posted 2022-11-25.
- 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.
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18. Record Summary
NCT03299062 is a completed, non-randomized, unmasked, parallel study sponsored by the University of Arkansas. Its title is “Smell, Voice and Nasal Swabs as Markers for Neuro-degenerative Disorders.” The registry lists enrollment of 9 and dates of 2017-11-14 for study start and 2021-12-21 for primary completion.
The study planned to assess whether nasal swabs could provide material for cytology and immunohistochemistry, including staining for alpha-synuclein, A-beta, and p-tau. The primary outcome timeframe was up to 4 weeks after swab completion. The registry states that enrollment ended early, leaving too few samples to process, and that no samples were analyzed for the outcome measures. No primary outcome results are reported beyond participant flow.
The safety record lists zero serious adverse events and zero deaths in each of the two adverse-event groups reported. The registry does not report outcome analyses, statistical analysis methods, or a sample-size justification. The central laboratory question therefore remains unanswered in the posted record.