Effect of Verb Network Strengthening Treatment (VNeST) on Lexical Retrieval in Aphasia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Verb Network Strengthening Treatment (VNeST) on Lexical Retrieval in Aphasia (NCT01300624), a na phase 2 study. The primary outcome is Trained Sentence Probe.

2. Clinical Question

The question concerns sentence production following VNeST, rather than a randomized comparison between treatment and control groups. The primary outcome was the percentage of correct sentences on the trained sentence probe. Its time points allow the registry record to pose a within-study question about performance before treatment, immediately after treatment, and at maintenance follow-up.

The study’s brief description also identifies sentence production and connected speech as areas of interest. Secondary outcomes listed in the record include noun naming, verb naming, the Western Aphasia Battery, and Communicative Effectiveness Ratings. The record states that there were seven outcome measures in total, but the additional outcome details are not reported in the registry record. The available information describes the question and measurement plan; it does not report numerical outcome results or establish what change occurred.

3. Trial Design

The registry record identifies this as a Phase 2, single-group study of Verb Network Strengthening Treatment. It lists 11 participants enrolled and describes the intervention as behavioral. The study began in 2011-03, had primary completion in 2013-12, and is marked completed. The sponsor is the US Department of Veterans Affairs.

There is no parallel control group described. Allocation is listed as not applicable, and the study model is single group. Masking is recorded as none. Accordingly, the design does not provide a randomized, like-for-like comparison between people receiving VNeST and people assigned to another treatment or to no treatment. The primary question is instead framed around performance at different assessment times in the treatment group.

The intervention description says that VNeST tasks involve retrieving nouns related to a target verb. For example, the record describes generating people who perform an action and what they act on. The specific example is illustrative; the complete treatment protocol and details about treatment delivery are not reported in the registry record.

The primary outcome was a continuous measure: the percentage of correct sentences on a picture-description task that included trained words. The stated assessment times were pre-treatment, post-treatment, and three-months post-treatment for maintenance. The record lists noun naming, verb naming, the Western Aphasia Battery, and Communicative Effectiveness Ratings as secondary outcomes, and states that there were seven outcome measures overall.

The registry record does not report a sample-size justification, a prespecified statistical analysis plan, or the details of any statistical tests. It also does not describe a control condition or a randomized assignment process. Those omissions limit what can be concluded about how the study was designed to distinguish treatment-related change from other possible explanations for change over time.

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.

Population: Number of participants was based on pilot study results and consistent with the relevant literature.

6. Primary Endpoint

The registry lists the primary outcome as Trained Sentence Probe, measured over pre-treatment, post-treatment and 3-months post-treatment (maintenance).

The primary endpoint, called the Trained Sentence Probe, is the percentage of correct sentences on a picture-description task that includes trained words. The record specifies that the measure is summarized as a mean with a standard deviation and that it is assessed pre-treatment, post-treatment, and at three-months post-treatment for maintenance.

This measure is relevant to the study’s stated aim because it focuses on producing sentences using words addressed in treatment. A sentence-level task can capture performance beyond naming an isolated noun or verb: it concerns whether a participant produces a correct sentence while describing a picture. The focus on trained words also connects the assessment to the treatment content. This rationale is a general explanation of why such an endpoint may be selected; it does not establish that performance on this task represents every aspect of everyday communication.

Repeated assessment at the stated time points permits description of performance at each occasion and of whether performance is maintained at the follow-up assessment. The registry record does not report the actual means, standard deviations, participant-level data, or a numerical estimate of change. It also does not report a definition of a clinically important change or explain how the primary endpoint was selected relative to the other outcomes.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record characterizes the primary outcome as continuous, with a mean and standard deviation. General explanation: a continuous outcome can take values across a scale rather than only falling into categories. Reporting a mean describes the average observed value in a group, while a standard deviation describes how spread out individual measurements are around that average. Neither quantity alone describes uncertainty in an estimated treatment-related change.

What does a mean describe?

For the trained sentence probe, the measured quantity is the percentage of correct sentences on a picture-description task using trained words. A mean at a particular assessment time would describe the average score among the participants included in that calculation. The registry record does not report those means. It also does not report the number contributing to each assessment-time summary, so the analysis population for any such calculation is not specified.

What does a standard deviation describe?

General explanation: the standard deviation summarizes variation among individual observations. A smaller standard deviation indicates that observations are more clustered around the mean, while a larger one indicates greater spread. It is not the same as a standard error or a confidence interval. Standard deviation describes observed variability; a confidence interval describes uncertainty around an estimate under the assumptions of the method used.

How should a confidence interval be read?

General explanation: a confidence interval gives a range of estimates compatible with the observed data and the statistical procedure, under that procedure’s assumptions. Its width conveys precision: a wider interval generally indicates less precision than a narrower one. A confidence interval does not guarantee that the true value lies within the particular interval, and it does not remove limitations in the design or measurement. The registry record does not report a confidence interval for the primary endpoint.

What can a p-value establish?

General explanation: a p-value measures how unusual data at least as incompatible with a specified statistical null model would be, if that model and the test assumptions held. It is not the probability that the null hypothesis is true, nor a direct measure of the size or importance of a change. A p-value without an effect estimate and a measure of precision gives an incomplete account of results. No p-value or analysis result is reported in the registry record information.

Why does the design affect interpretation?

General explanation: in a single-group design, measurements taken at different times can describe temporal change within the group. Without a separate comparison group, the analysis cannot directly contrast that change with what would have happened over the same period under another condition. Random assignment, when used, can support a more balanced comparison of groups; this record lists allocation as not applicable and describes a single group. The record does not describe a randomized comparison.

What is over-dispersion?

General explanation: over-dispersion arises when data vary more than a statistical model assumes. It can make uncertainty estimates too small if the model understates the variation, and can make inferential results unreliable. Whether over-dispersion is relevant depends on the outcome scale and analysis model. The record describes a continuous mean outcome and does not report a statistical model or an over-dispersion assessment, so no such issue can be evaluated for this study.

How should sample-size illustrations be understood?

The stated planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. General explanation: such calculations ask how many participants would be needed under specified assumptions to detect a target effect with a chosen statistical power. They are planning calculations, not evidence about the power of the completed study. In particular, they are not observed power. The record’s study model is single group, so an equal-allocation, two-arm planning scenario is not a description of the actual trial design. The trial’s own sample-size justification is not reported in the registry record.

The record lists zero analyses. It does not identify a statistical test, model, adjustment method, or approach to repeated measurements. Without those details and without outcome estimates, it is not possible to assess whether analysis assumptions were met or how precisely the primary outcome was estimated. The general concepts above explain how common summary statistics and design features are interpreted; they do not fill in methods or results absent from the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists the trained sentence probe as the primary outcome and names Noun Naming, Verb Naming, Western Aphasia Battery, and Communicative Effectiveness Ratings as secondary outcomes. It also states that seven outcome measures were included. The remaining outcome details are not reported in the registry record. The record lists zero analyses, so no outcome-specific analysis results are available in the record information for this study.

When a study examines multiple outcomes or multiple comparisons, the chance of finding at least one apparently notable result can increase. General explanation: multiplicity procedures are methods for controlling or describing that issue, for example by adjusting statistical thresholds or by specifying a hierarchy of outcomes in advance. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or a statistical analysis plan. It is therefore not possible to determine how multiple outcomes were handled.

Missing-data methods and the number of participants contributing data at each assessment time are not reported in the registry record. Enrollment of 11 does not establish that all 11 participants completed every assessment or were included in every analysis. The record also does not report an analysis population definition, such as which participants were included in the primary analysis, or how missing observations were handled. These gaps make it difficult to assess completeness of follow-up and the potential influence of missing data on any result.

These are reporting limits, not evidence that a particular method was or was not used outside 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 registry record lists 11 participants at risk for serious adverse events in the Verb Network Strengthening Treatment group and records 0 serious adverse events. It also lists 11 at risk for other adverse events and records 0 other adverse events. The death count is not reported in the registry record.

These figures are counts in the registry safety record. They do not, by themselves, describe the completeness or duration of safety monitoring, the criteria used to classify events, or whether any events were considered related to the intervention. Those details are not reported in the registry record. The figures also should not be interpreted as evidence that no adverse events could occur; they describe what is recorded for this study.

There is no separate comparison group in this single-group study, so the safety counts do not support a direct comparison of event rates between treatment conditions. The number at risk is the recorded denominator for the event counts, but the record does not provide additional detail about exposure or follow-up for safety reporting.

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

The record establishes that a completed Phase 2 study evaluated Verb Network Strengthening Treatment in a single group of 11 participants with aphasia. It identifies a specific primary measure: the percentage of correct sentences on a picture-description task using trained words. The measure was intended to be assessed pre-treatment, post-treatment, and at three-months post-treatment for maintenance. This information explains what the study set out to measure and when.

The record does not report numerical results for that primary endpoint. It therefore does not support a description of whether scores increased, decreased, or remained similar, nor how large or precise any change was. The registry record also does not report the outcome-analysis methods, assessment-time sample sizes, or missing-data handling needed to assess the estimates.

Even if within-group measurements showed a change, the single-group design would not by itself establish that the change was caused by VNeST. In general, a control group can help distinguish change associated with an intervention from other influences that may occur over time. This study is not recorded as a randomized comparison and has no separate comparator described.

The listed secondary outcomes indicate that the study’s interests extended beyond the trained sentence probe, including naming, aphasia assessment, and communicative effectiveness. The available record does not report numerical findings for those outcomes either. The safety entries record 0 serious adverse events and 0 other adverse events among 11 at risk in each category, while the death count is not reported.

The appropriate statistical reading is therefore limited to the study’s design, its planned measurement focus, and the recorded safety counts. The available information does not establish an effect estimate, its precision, or a causal treatment effect.

13. Why This Trial Matters Statistically

This study is statistically notable for the distinction between measuring change and estimating a comparative treatment effect. Its single-group design and repeated assessment times frame a question about performance before and after VNeST and at maintenance follow-up. Those observations can describe the group’s course over time if results are available, but without a comparator they do not directly show how the same participants would have performed under a different condition.

The primary outcome is closely tied to the intervention’s focus: correct sentence production using trained words. That alignment makes the measurement question clear, while also defining its scope. Performance on a trained-word picture-description task does not, by itself, encompass every aspect of language or communication. The record separately lists naming, aphasia assessment, and communicative effectiveness outcomes, reflecting additional areas of interest.

The registry record also illustrates why outcome definitions and statistical results should be kept distinct. It specifies the primary measure, its summary type, and the assessment times, but does not report the numerical outcome results or analyses. Without estimates and uncertainty measures, the size and precision of any change cannot be evaluated. Without analysis-population and missing-data details, the completeness of the outcome record is also unclear.

Finally, planning illustrations should not be confused with the design or statistical power of a completed study. The stated illustration assumptions concern a two-arm planning scenario, whereas the actual study is recorded as single group. The registry record does not report a sample-size justification for the trial. These distinctions matter when readers interpret study descriptions, planned measurements, analyses, and evidence separately.

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 trial-specific limitation is the absence of a comparator group. The record identifies a single-group design, allocation as not applicable, and no masking. Consequently, the design does not provide a direct controlled contrast for interpreting changes over time. This limits causal interpretation independently of the numerical outcome results.

The registry record does not report the primary outcome results, including means, standard deviations, estimates of change, or confidence intervals. It lists zero analyses, and the statistical tests or models used are not reported. As a result, neither the direction nor the precision of primary outcome findings can be assessed from the record information available.

Although 11 participants were enrolled, the number contributing data at each assessment time is not reported. The record does not describe follow-up completion, missing-data procedures, or the analysis population. It also does not report a sample-size justification or a statistical analysis plan. The number of outcome measures is stated as seven, but only four secondary outcome names are listed; details for the other measures are not reported in the registry record.

The treatment description gives an example of a VNeST task but does not report the full treatment protocol or delivery details. The registry information also does not report participant characteristics beyond the condition of aphasia. These omissions limit assessment of how broadly the study findings might apply, even if outcome results were available. The limitations described concern what the registry record documents; they do not establish that additional information was unavailable elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of Verb Network Strengthening Treatment (VNeST) on Lexical Retrieval in Aphasia — NCT01300624.
• Registry record last updated 2015-06-09; status last verified 2015-06.
• Results first posted 2015-06-09.
• 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

NCT01300624 is a completed Phase 2, single-group study of Verb Network Strengthening Treatment for lexical retrieval in aphasia. The registry record lists 11 participants enrolled, no masking, and allocation as not applicable. The sponsor is the US Department of Veterans Affairs; the study began in 2011-03 and had primary completion in 2013-12.

The primary outcome was the percentage of correct sentences on a trained-word picture-description task, assessed pre-treatment, post-treatment, and at three-months post-treatment for maintenance. Secondary outcomes listed are Noun Naming, Verb Naming, Western Aphasia Battery, and Communicative Effectiveness Ratings. Seven outcome measures are reported overall, with zero analyses listed.

The record lists 0 serious and 0 other adverse events among 11 at risk for each category; deaths are not reported in the registry record. Numerical outcome results, statistical methods, missing-data handling, analysis populations, and a trial-specific sample-size justification are not reported in the registry record.