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 Novel Management of Airway Protection in Parkinson's Disease: A Clinical Trial (NCT02927691), a randomized phase 2 study. The primary outcome is Change in Voluntary Cough Peak Flow.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02927691 |
| Phase | Phase 2 |
| Condition | Parkinson's Disease, Dysphagia, Dystussia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 65 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Teachers College, Columbia University |
| Results posted | Yes |
2. Clinical Question
Population
People with Parkinson's disease and dysphagia were the intended study population. The registry record lists Parkinson's disease, dysphagia and dystussia as conditions. It does not report a fuller description of eligibility criteria or the characteristics of participants at baseline, so the extent to which the enrolled group represents a broader clinical population cannot be assessed from this record.
Intervention
The trial included expiratory muscle strength training, abbreviated EMST, and sensorimotor treatment for airway protection, abbreviated smTAP. EMST is identified as a device intervention and smTAP as a behavioral intervention. The study aimed to assess these intensive rehabilitation approaches on airway-protective clinical outcomes.
Comparator
The posted outcome results are separated by EMST and smTAP. The registry record also describes immediate and delayed treatment schedules: the delayed group was to have a five-week period without treatment after baseline, followed by another baseline session and then treatment. It does not report which treatment corresponds to each schedule, or provide a distinct untreated comparison result for the primary outcome.
Primary question
The primary outcome asks how voluntary cough peak flow changed from before treatment to after five weeks of treatment with EMST and smTAP. The registry record reports an estimate for each treatment arm, but no inferential analysis comparing those estimates. Consequently, the posted results describe the arm-level outcome estimates and their ranges rather than establishing whether the treatments differ.
3. Trial Design
This was a phase 2 randomized clinical trial with a parallel-group model and single masking. The registry record lists enrollment of 65 participants and identifies Teachers College, Columbia University as the sponsor. The trial status is completed. Its stated aim was to examine whether two intensive rehabilitation paradigms could affect airway-protective clinical outcomes among people with Parkinson's disease and dysphagia.
The interventions were expiratory muscle strength training (EMST) and sensorimotor treatment for airway protection (smTAP). The record describes EMST as a device intervention and smTAP as a behavioral intervention. It also describes immediate and delayed treatment schedules. Participants in the immediate-treatment description began treatment after baseline testing. Those in the delayed-treatment description had no treatment for five weeks after baseline, completed a second baseline testing session, and then began treatment. The registry record does not map these schedule descriptions to the named interventions in the posted outcome results.
The primary outcome was change in voluntary cough peak flow, with the timeframe described as pre-treatment to post-treatment after five weeks. The measure description states that peak expiratory flow rate was measured before and after treatment. The posted arm-level results are for EMST and smTAP, with the estimate expressed in liters per second and a full range also reported for each arm.
The registry record does not report details of the randomization sequence, allocation concealment, the identity of the masked parties, the treatment delivery procedures, or adherence. It also does not report a protocol-level statistical analysis plan or a sample-size justification. These omissions limit assessment of how the planned methods and the posted results align.
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 | Expiratory Muscle Strength Training (EMST) | Sensorimotor Training for Airway Protection (smTAP) |
|---|---|---|
| STARTED | 34 | 31 |
| COMPLETED | 30 | 28 |
| NOT COMPLETED | 4 | 3 |
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: 65 participants were randomly assigned to either the EMST (n = 34) or smTAP (n = 31) group. Both groups should demonstrate similar demographic characteristics, including age, duration from symptom onset, and disease severity based on randomization. All 65 participants will be analyzed with intent-to-treat statistical analyses.
| Characteristic | Unit | Expiratory Muscle Strength Training (EMST) | Sensorimotor Training for Airway Protection (smTAP) | Total |
|---|---|---|---|---|
| Participants analysed | 34 | 31 | 65 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 9 | 9 | 18 |
| Age, Categorical: >=65 years | Participants | 25 | 22 | 47 |
| Age, Continuous | years | 70.5 (53 to 87) | 69.1 (53 to 81) | 70 (53 to 87) |
| Sex: Female, Male: Female | Participants | 13 | 9 | 22 |
| Sex: Female, Male: Male | Participants | 21 | 22 | 43 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | participants | 34 | 31 | 65 |
| Maximum Expiratory Pressure | cm H20 | 97 (39 to 156) | 112 (10 to 206) | 102 (10 to 206) |
| Voluntary Cough Peak Flow | l/s | 2.98 (1.25 to 6.76) | 3.05 (0.95 to 5.69) | 3.04 (0.95 to 6.76) |
6. Primary Endpoint
The registry lists the primary outcome as Change in Voluntary Cough Peak Flow, measured over Pre to Post treatment (Pre: Baseline and Post Treatment: 5 weeks).
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | Full Range |
| Unit | l/s |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in voluntary cough peak flow from before treatment to after five weeks of treatment. The registry record describes measurement of peak expiratory flow rate before and after treatment with EMST and smTAP. The unit is liters per second, and the outcome is reported as a least-squares mean with a full range for each treatment arm.
As a general measurement concept, peak flow during a voluntary cough describes the maximum airflow achieved during that maneuver. It can therefore provide a quantitative measure of cough-related airflow. In this trial's stated context, the investigators were interested in airway protection in people with Parkinson's disease and dysphagia, including the concern about aspiration without an appropriate cough response. Cough peak flow is a clinical outcome related to that airway-protection question, but the registry record does not establish that it directly measures aspiration events, aspiration pneumonia, or every aspect of airway protection.
The posted values are estimates of change, not a direct comparison between treatments. The EMST estimate is 0.17 l/s, with a full range from -2.32 to 3.85; the smTAP estimate is 0.51 l/s, with a full range from -1.07 to 5.82. These ranges are not identified as confidence intervals. The registry record does not report additional uncertainty measures or a statistical test for a difference between arms.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record reports a least-squares mean change in voluntary cough peak flow of 0.17 l/s for EMST and 0.51 l/s for smTAP. The reported full range is -2.32 to 3.85 for EMST and -1.07 to 5.82 for smTAP. These are arm-level summaries for a change measured from before treatment to after five weeks. They do not, by themselves, quantify the uncertainty in the difference between treatment arms.
Both reported ranges include negative and positive values. As a general statistical point, a range extending on both sides of zero indicates that the listed participant-level values include changes in both directions. A full range is not a confidence interval: it describes the extremes reported for the observations, rather than an interval designed to express uncertainty around an estimated mean. The registry record does not report a standard error, confidence interval, or other inferential measure for either arm estimate.
The difference between the posted arm-level estimates has not been recalculated in this interpretation. The record contains no posted analysis entry for the primary outcome and no reported test or confidence interval for an EMST-versus-smTAP contrast. Accordingly, the numerical estimates should not be read as evidence that one treatment produced a larger change than the other. A comparison requires an analysis that accounts for the trial design and quantifies uncertainty around the between-arm effect.
The trial is described as randomized and parallel-group, but the outcome results do not show a separate untreated comparison estimate. The record's descriptions of immediate and delayed treatment do not state which schedule corresponds to each intervention in the posted results. It is therefore not possible to use these arm summaries to isolate change attributable to treatment from change associated with time, repeated measurement, or other influences.
These results are also specific to the endpoint and timeframe reported. They concern voluntary cough peak flow measured before and after five weeks of treatment; the record does not post a result for aspiration events, pneumonia, or another secondary endpoint. The estimates can be described as the posted arm-level summaries, but neither the clinical importance of the changes nor a causal comparative conclusion is established by those summaries alone.
9. Statistical Methods Explained
The primary outcome is presented as a least-squares mean change in voluntary cough peak flow, with a full range. The record reports an estimate of 0.17 l/s for EMST and 0.51 l/s for smTAP. The corresponding full ranges are -2.32 to 3.85 and -1.07 to 5.82. The record does not report the model used to obtain the least-squares means, the covariates included, or the standard errors associated with the estimates.
What does a least-squares mean represent?
As a general statistical concept, a least-squares mean is a model-based estimate of an average. Depending on the model, it may adjust for other terms included in that model, unlike a simple arithmetic average. Interpretation requires knowing the model specification and the population or covariate settings used to derive the estimate. Since those details are not reported in the registry record, the adjustment represented by these least-squares means cannot be described more specifically. The estimates should be reported using the registry's stated label rather than treated as unadjusted sample means.
What does the full range communicate?
A full range gives the lower and upper observed values identified in the record. It can show that participant-level changes varied, and whether the reported values include increases and decreases. It is not a measure of precision for the arm mean. A confidence interval or standard error would be needed to characterize sampling uncertainty around an estimate. Neither is reported for this outcome. The full range also does not reveal the distribution of values between its endpoints, so it cannot show whether most observations clustered near the estimate or were spread across the range.
Why is a between-arm estimate important?
In a randomized parallel-group trial, the key comparative question is generally whether outcomes differ between assigned groups. General statistical reasoning distinguishes an arm-specific change from a treatment contrast: the former describes an outcome within an arm, while the latter estimates how the outcomes compare between arms. A numerical contrast without an uncertainty measure would still be incomplete, because the reader would not know how precisely the contrast was estimated. The registry record does not post an inferential analysis or a between-arm confidence interval for this endpoint. No comparative conclusion can therefore be drawn from the arm summaries alone.
How should the trial structure inform interpretation?
The record identifies random allocation and a parallel model. Randomization can support a causal comparison when the analysis follows the assignment structure and handles outcomes appropriately, but the record does not contain the analysis details needed to assess that process. It also describes immediate and delayed treatment schedules. The delayed schedule includes a five-week period without treatment and a second baseline assessment before treatment begins. The registry record does not identify how those schedules map onto the EMST and smTAP outcome groups or report a separate result for the waiting period. It is not possible to determine from the posted primary outcome whether the reported summaries use all relevant trial periods or how repeated measurements were handled.
What does the absence of inferential results mean?
The record lists one outcome measure and no analysis entries. It does not report a p-value, confidence interval, standard error, model specification, or analysis population for the primary outcome. Absence of these items is not evidence that an effect is absent; it means the registry record does not allow readers to evaluate statistical evidence for a between-arm difference. General statistical interpretation should keep the descriptive information separate from inferential claims. The reported estimates and full ranges describe the posted results, while precision and comparative uncertainty remain unreported.
How should planning calculations be understood?
Sample-size calculations based on an observed effect are planning illustrations, not observed trial results and not observed power. The record's planning assumptions describe a two-sided significance level of 0.05, equal allocation, a normal approximation, and a target effect expressed as a fraction of the observed effect. Such calculations can illustrate how a future study's planned size might depend on its target effect and assumptions. They do not demonstrate that the current trial had a particular probability of detecting an effect, and they are not a substitute for the missing primary-outcome analysis. No numerical planning results are stated in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and does not list secondary outcome results. It also contains no posted analysis entries. With only the primary outcome result available in the record, there is no reported family of endpoint tests from which to assess how multiplicity was handled. Any multiplicity adjustment or prespecified hierarchy is not reported in the registry record. The record does not state whether interim analyses were planned or conducted.
Missing-data methods are not reported in the registry record. There is no description of how missing post-treatment measurements were handled, whether imputation was used, or whether participants with incomplete follow-up were included in the outcome analysis. The analysis population is also not reported: the record does not say whether the estimates use all randomized participants, participants who completed treatment, or another group. These details matter because exclusions and missing outcomes can affect both the estimate and its interpretation.
The posted participant counts are 34 for EMST and 31 for smTAP. The record does not explain whether these counts represent randomized participants, participants with an available primary outcome, or the population used to calculate the least-squares means. The enrollment figure is 65, but the record does not provide a participant flow accounting for the relationship between enrollment, arm counts, and endpoint data.
Thus, the record permits a description of the posted arm-level estimates and ranges, but it does not permit evaluation of multiplicity control, missing-data sensitivity, or the analysis population. Those aspects should not be inferred from the randomized design alone.
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 |
|---|---|---|---|
| EMST | 0 | 34 | 0.0% |
| smTAP | 0 | 31 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| EMST | 0 of 34 |
| smTAP | 0 of 31 |
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 |
|---|---|
| EMST | 0 of 34 |
| smTAP | 0 of 31 |
The registry record reports zero serious adverse events among 34 participants at risk in the EMST group and zero among 31 participants at risk in the smTAP group. It also reports zero other adverse events in each group and zero deaths in each group. No serious adverse event terms are listed.
These figures describe what was posted for the groups and the at-risk counts reported in the record. A zero count means no events of that category were recorded in these groups; it does not establish that the risk is absent. As a general statistical consideration, the ability to detect uncommon events depends on the amount and duration of safety observation, and neither detailed follow-up duration nor event-collection procedures are reported in the registry record.
The figures should also be read as registry safety summaries, not as a detailed account of every symptom, treatment interruption, or clinical event. Definitions of serious and other adverse events, methods for attribution, and completeness of reporting are not reported in the registry record. These counts do not establish a safety comparison between EMST and smTAP, and they do not support a conclusion about safety beyond the events recorded for the trial.
12. What the Result Does, and Does Not, Mean
The posted primary-outcome estimates describe change in voluntary cough peak flow from before treatment to after five weeks. The registry reports an EMST least-squares mean of 0.17 l/s and an smTAP least-squares mean of 0.51 l/s, each accompanied by a full range. These summaries communicate the values recorded for the two treatment groups, but they do not establish which treatment, if either, produced a greater change.
The ranges include both negative and positive values, indicating that the reported observations varied in direction. They are not confidence intervals and do not express precision around the group estimates. The registry record does not provide the inferential statistics needed to judge uncertainty in either estimate or in a contrast between groups. It also does not post an analysis entry for the primary outcome.
The trial's stated clinical context concerns airway protection in Parkinson's disease and dysphagia, including aspiration without an appropriate cough response. The endpoint is voluntary cough peak flow, not a direct posted count of aspiration events or aspiration pneumonia. A change in this measure alone cannot establish a change in those clinical outcomes, and the record does not report results for them.
The registry describes random allocation and a parallel-group design, but it does not report the analysis methods, missing-data handling, or the analysis population. It also describes immediate and delayed treatment schedules without mapping them to the EMST and smTAP results. As a result, the posted summaries do not establish a causal treatment effect or allow a complete assessment of the design's comparative question.
The results therefore support a descriptive account of the arm-level estimates and ranges only. They do not demonstrate that either intervention is effective or ineffective, do not establish equivalence, and do not provide a basis for choosing between interventions. Those conclusions would require appropriately reported comparative analyses and clinically relevant outcomes, neither of which is available in the registry record.
13. Why This Trial Matters Statistically
This trial raises a useful statistical distinction between measuring change in each group and estimating a difference between groups. The primary outcome is reported for EMST and smTAP as separate least-squares mean changes. Those values are informative descriptions, but the comparative question in a randomized trial depends on a direct contrast and an account of its uncertainty. The registry record does not report that analysis.
The presentation of a full range alongside a group estimate also illustrates why different summaries should not be conflated. A range describes the endpoints of the reported observations, while a confidence interval addresses uncertainty around an estimate under a statistical model. The ranges in the record extend across negative and positive changes, but they do not show how precisely the arm estimates were obtained or whether an observed difference between arms is distinguishable from chance variation.
The record also highlights the importance of documenting analysis choices. Least-squares means are model-based quantities, yet the model and its covariates are not reported. The registry does not identify the analysis population or explain how missing outcomes were handled. Without these details, readers cannot fully evaluate what data contributed to the estimates or how the results relate to random assignment.
Finally, the intervention schedule descriptions include immediate and delayed treatment, while the posted outcome results are identified by intervention. Because the record does not map the schedules to the interventions or provide separate schedule-specific results, the reader cannot reconstruct the role of the delayed period in the primary outcome analysis. Clear reporting of these links, along with a prespecified comparative estimate and its uncertainty, would make the statistical evidence easier to interpret.
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 main limitation of the posted results is that the registry record contains arm-level estimates but no inferential analysis of the primary outcome. It does not report a direct between-arm effect, confidence interval, standard error, or p-value. Therefore, the precision of the estimates and the statistical evidence for a treatment contrast cannot be assessed.
The least-squares means are not accompanied by the model specification or the covariates used. Their adjustment and target population are consequently unclear. The full ranges indicate the span of reported changes but do not describe the distribution of observations or serve as uncertainty intervals.
The record does not report the analysis population, missing-data procedures, or participant flow connecting enrollment to the counts reported for the arms. The relationship between the immediate and delayed treatment schedule descriptions and the intervention-specific outcome results is also not reported. This limits assessment of how the trial periods and repeated baseline measurements contributed to the estimates.
Only the primary outcome is posted, with no secondary outcome results listed. The registry record does not report whether other planned outcomes were measured, why results are absent, or whether multiplicity was considered. A protocol-level statistical plan, sample-size justification, and interim-analysis details are not reported in the registry record.
Finally, the primary endpoint is voluntary cough peak flow after five weeks, not a direct measure of all airway-protection outcomes described in the study rationale. The safety summary reports zero events in the posted categories, but event definitions and safety follow-up procedures are not reported. These limitations restrict what can be concluded from the available record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Novel Management of Airway Protection in Parkinson's Disease: A Clinical Trial — NCT02927691.
- Registry record last updated 2023-12-22; status last verified 2023-12.
- Results first posted 2023-12-22.
- 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
The registry record describes a completed randomized, single-masked, parallel phase 2 trial with enrollment of 65. The interventions were EMST and smTAP, and the primary outcome was change in voluntary cough peak flow from before treatment to after five weeks.
The posted least-squares mean changes are 0.17 l/s for EMST and 0.51 l/s for smTAP. Their full ranges are -2.32 to 3.85 and -1.07 to 5.82, respectively. The record reports no primary-outcome analysis entry or inferential comparison between the interventions. Model details, analysis population, and missing-data methods are not reported in the registry record.
The safety summary reports zero serious adverse events, other adverse events, and deaths in each group. Those counts describe recorded events and do not establish absence of risk. Overall, the registry supports a descriptive reading of the posted outcome and safety summaries, but not a comparative efficacy conclusion.