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 Galantamine Effects on Cognitive Function in Abstinent Cocaine Users (NCT00606801), a randomized na study. The primary outcome is Performance on the Cambridge Neuropsychological Test Automated Battery (CANTAB) - RVIP Reaction Time.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00606801 |
| Phase | NA |
| Condition | Cocaine Abuse |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 34 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Yale University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned abstinent cocaine users. The registry record lists cocaine abuse as the condition and reports enrollment of 34 participants. It does not report detailed eligibility criteria, how abstinence was established, or participant characteristics such as age and sex in the information available for this analysis. Those details matter when considering which people the findings might describe; without them, the population can be characterized only at the level recorded.
Intervention
The active-treatment arm received galantamine 8 mg/day. The record describes galantamine as an acetylcholine esterase inhibitor that also directly potentiates nicotine receptors. It gives the study rationale as evaluating whether galantamine might affect cognitive performance in a group described as having impaired performance on various cognitive tasks. That rationale is not itself evidence of an observed benefit.
Comparator
The comparator was placebo. The record lists a randomized, double-masked, parallel-group design, so the study was intended to compare participants assigned to the two arms. Details about how masking was implemented or assessed are not reported in the registry record.
Primary question
The primary outcome was reaction time on the Rapid Visual Processing test within the Cambridge Neuropsychological Test Automated Battery. Measurements were planned at baseline, Day 5 and Day 10. The clinical question was whether cognitive-test reaction time differed between the galantamine and placebo groups over these assessments. Numerical results for the primary outcome, including an effect estimate and its uncertainty, are not reported in the registry record, so the direction and precision of any between-group difference cannot be described.
3. Trial Design
The registry record describes a randomized, double-masked, parallel-group trial comparing galantamine 8 mg/day with placebo. The study enrolled 34 participants and is marked completed. Yale University is listed as the sponsor. The recorded start was 2007-06, and primary completion was 2009-02. The phase entry is NA.
A parallel design assigns participants to separate treatment groups, while randomization is intended to reduce systematic differences between those groups at the outset. Double masking is intended to limit the influence of treatment knowledge on participant experience and assessment. These are general purposes of the design features; the record does not describe the specific randomization procedure, allocation concealment, which individuals were masked, or whether masking was maintained.
The primary endpoint was CANTAB RVIP reaction time, with assessments at baseline, Day 5 and Day 10. The endpoint description says reaction time to correct answers was measured. The record reports 28 completers, 14 in each treatment group, and notes that CANTAB data were not stored on the hard drive for one participant in the galantamine group. It does not explain how this missing measurement affected the primary analysis or how many observations were included at each assessment.
Other listed cognitive outcomes included errors on Go and NoGo trials and reaction-time measures on the Sustained Attention to Response Task, as well as reaction time, Stroop effect and carry-over effect on the Modified Stroop Task. The record lists 15 outcome measures and 15 analyses. Numerical outcome findings and detailed analysis procedures are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: 55 subjects were screened. 21 subjects were excluded. (Not meeting inclusion criteria n=19, declined to participate n=2). These 34 subjects were then assigned to treatment groups. Prior to the 1st day of intervention, subjects underwent an adaptation session where they were familiarized with study procedures, and baseline measures were obtained.
Adaptation
| Stage | Placebo | Galantamine 8 mg/Day |
|---|---|---|
| STARTED | 17 | 17 |
| COMPLETED | 17 | 17 |
| NOT COMPLETED | 0 | 0 |
Intervention
| Stage | Placebo | Galantamine 8 mg/Day |
|---|---|---|
| STARTED | 17 | 17 |
| COMPLETED | 14 | 14 |
| NOT COMPLETED | 3 | 3 |
Reasons for not completing this period:
| Reason | Placebo | Galantamine 8 mg/Day |
|---|---|---|
| Protocol Violation | 3 | 3 |
Analysis population for the primary outcome, as defined in the registry: There were a total of 28 completers, 14 for each treatment group. However, CANTAB data was not stored on the hard drive for one subject in the Galantamine group.
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.
| Characteristic | Unit | Galantamine 8 mg/Day | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 17 | 17 | 34 | |
| Age, Continuous | years | 42.1 (SD 5.9) | 42.7 (SD 6.3) | 42.5 (SD 6.2) |
| Sex: Female, Male: Female | Participants | 7 | 7 | 14 |
| Sex: Female, Male: Male | Participants | 10 | 10 | 20 |
| Region of Enrollment: United States | participants | 17 | 17 | 34 |
6. Primary Endpoint
The registry lists the primary outcome as Performance on the Cambridge Neuropsychological Test Automated Battery (CANTAB) - RVIP Reaction Time, measured over Baseline, Day 5 and Day 10.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | milliseconds |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was mean reaction time, measured in milliseconds, for correct responses on the Cambridge Neuropsychological Test Automated Battery Rapid Visual Processing test. The RVIP is described as a measure of sustained attention with a small working-memory component and as sensitive to cholinergic enhancers. During the task, participants detect odd or even three-digit sequences that appear in a box in a pseudo-random order at 100 digits per minute. Reaction time is the time taken to respond correctly.
Reaction time is used as a continuous measure: it retains information about how quickly correct responses occur rather than reducing performance to a simple correct-or-incorrect outcome. In general, the mean describes the average response time, while the standard deviation describes the spread of individual measurements around that average. Neither statistic, by itself, describes the uncertainty in a comparison between treatment groups.
The endpoint was assessed at baseline, Day 5 and Day 10. Repeated assessments can describe performance at different stages, but interpreting a treatment comparison requires knowing how those measurements were analyzed and what between-group estimates were obtained. Those numerical results and analysis details are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary outcome and the assessment schedule but does not report numerical results for the CANTAB RVIP reaction-time comparison. It therefore does not establish from the recorded results whether the groups differed, how large any difference was, or how precisely it was estimated. No effect estimate, confidence interval, or primary-outcome significance test is reported in the registry record. A conclusion about the direction or statistical strength of the primary finding cannot be drawn from the available record.
The primary endpoint has three stated assessments: baseline, Day 5 and Day 10. The record flags that the primary outcome has several categories or time points and was not reduced to one comparison. That is important for interpretation. A treatment contrast at one assessment, a change from baseline, and a model using all assessments can answer different statistical questions. Without reported estimates and a defined analysis, it is not possible to know which contrast the investigators emphasized or how they handled the repeated measurements.
The study reports 28 completers, with 14 in each group, and notes that CANTAB data were not stored for one participant in the galantamine group. This information indicates a limitation in the available endpoint data, but it does not identify the analysis population or the amount of missingness at every time point. The registry record does not report whether analyses included all randomized participants, only participants with endpoint data, or another population. It also does not report a method for handling missing observations.
General statistical interpretation distinguishes the estimated effect from its uncertainty. An effect estimate describes the observed contrast under the chosen analysis; a confidence interval describes a range of values compatible with the data and model assumptions. A p-value, if reported, would address the data’s compatibility with a specified null hypothesis, not the size or practical importance of a difference. Here, these numerical results are not reported in the registry record, so such interpretation is not possible.
The registry record lists secondary cognitive outcomes and a total of 15 outcome measures and 15 analyses. Testing multiple outcomes or contrasts can increase the chance of at least one apparently unusual finding, so the planned handling of multiplicity is relevant. That plan is not reported in the registry record. The record also does not report an interim-analysis plan, covariate adjustment, or the model used for the primary endpoint. These omissions limit assessment of how robustly the analysis addressed the design and outcome structure.
The safety entries list zero serious adverse events and zero other adverse events in each treatment group, with 17 participants at risk in each group. These registry counts are descriptive entries. Death counts are not reported in the registry record. The safety information should not be interpreted as a complete account of every possible event or as evidence about cognitive efficacy.
9. Statistical Methods Explained
General statistical concepts can help clarify what the trial’s design and outcome description mean, but they cannot replace the missing numerical findings. The registry record names a continuous primary outcome and several measurement times, yet does not report an effect estimate or the analysis used to obtain one.
What does randomization contribute?
In general, randomization uses chance to assign participants to treatment groups. Its purpose is to make systematic differences between groups less likely at the start of a trial, including differences that researchers may not have measured. Randomization does not guarantee that groups will be identical, especially in a study with a limited number of participants. It also does not address later missing data, departures from assigned treatment, or measurement problems. The record says allocation was randomized, but the specific sequence-generation and allocation-concealment methods are not reported in the registry record.
What does double masking mean?
In general, masking is intended to reduce the influence of knowing an assignment on participant behavior, care, or outcome assessment. The record labels the trial double-masked and identifies placebo as the comparator. It does not specify which two groups of people were masked, how the placebo was matched, or whether participants or assessors were asked to guess assignment. Those implementation details are not reported in the registry record, so the label alone cannot establish how masking worked in practice.
How should a continuous endpoint be read?
Reaction time is continuous: it can take a range of measured values rather than only a few categories. The recorded endpoint is the mean reaction time for correct responses, in milliseconds, and the dispersion measure is the standard deviation. In general, a mean conveys the average level of a measure, whereas a standard deviation conveys how spread out individual measurements are. They answer different descriptive questions. Neither provides the uncertainty of a treatment contrast unless combined with an appropriate analysis and information about the data structure.
The RVIP assessment is described as involving detection of odd or even three-digit sequences presented pseudo-randomly at 100 digits per minute. Reaction time for correct answers focuses on response speed among correct responses. This means the outcome description does not by itself summarize incorrect responses or all aspects of attention. Those features are relevant when deciding what the measure captures and what it leaves outside its scope.
Why do repeated assessments matter?
Measurements at baseline, Day 5 and Day 10 are repeated observations on participants. In general, measurements from the same person tend to be related, so an analysis may need to account for that within-person dependence. A comparison of groups at a single follow-up, a comparison of changes from baseline, and a model that uses all recorded times are distinct approaches. They can produce different estimates and answer different questions. The registry record does not report which approach was used, whether a group-by-time contrast was evaluated, or how baseline measurements entered the analysis.
The record notes that the primary endpoint has several time points and was not reduced to one comparison. This signals that a single numerical summary is not available in the registry record. Without the specified contrast and its estimates, readers cannot determine whether a reported result would refer to one time point, an average pattern over time, or another summary.
What do uncertainty and significance describe?
In general, a confidence interval expresses uncertainty around an estimated quantity under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, while either interval can include values of different practical importance. A p-value evaluates compatibility between the observed data and a specified null model. It does not measure the probability that the null hypothesis is true, nor does it describe effect size. The registry record does not report a primary-outcome confidence interval or p-value, so neither precision nor statistical significance can be assessed.
Statistical significance and practical importance are also separate. A small estimated difference may be precise, while a larger estimate may remain uncertain; what matters substantively depends on context and an interpretable effect scale. No threshold for a meaningful difference in RVIP reaction time is reported in the registry record. Therefore, even a hypothetical significance result would not, on its own, establish practical importance.
Why does multiplicity require attention?
When a study examines multiple outcomes, time points, or contrasts, the chance of at least one result appearing notable by chance can rise. General approaches include defining a primary contrast in advance, adjusting for a family of tests, or treating secondary analyses as exploratory. The record lists 15 outcome measures and 15 analyses, but does not report a multiplicity plan or identify which comparisons were adjusted. It is therefore not possible to tell how the record’s analyses account for the number of opportunities to observe a difference.
What does the planning assumption describe?
The record describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. In general, such a calculation estimates a sample size under stated assumptions; it is not a result observed in the trial and is not observed power. The record does not report a trial-specific sample-size justification, and no numerical planning results are available in the registry record. The illustration’s assumptions should not be confused with documented features of the original design.
What can be inferred from the participant counts?
The record reports 34 enrolled participants and 28 completers, with 14 completers per group. It also reports that CANTAB data were not stored for one participant in the galantamine group. In general, a completer count is not necessarily the same as the number analyzed for a particular endpoint or at every assessment. The record does not report the analysis population, missing-data method, or a participant flow by treatment and assessment. Those details are needed to evaluate how the observed data contributed to the endpoint estimate.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 15 outcome measures and 15 analyses, including the primary CANTAB RVIP reaction-time endpoint and secondary measures from the Sustained Attention to Response Task and Modified Stroop Task. Examining multiple outcomes, time points, or contrasts raises a multiplicity question: without a prespecified strategy, the chance of at least one apparently notable result can increase. The record does not report whether the analyses used an adjustment, a hierarchy of outcomes, or an explicitly exploratory approach. It also does not report an interim-analysis plan.
Missing data are relevant to the primary outcome. The record reports 28 completers, 14 in each treatment group, and says CANTAB data were not stored for one participant in the galantamine group. It does not say which assessment was affected, whether any other CANTAB observations were missing, or how the unavailable data were handled. No imputation method, sensitivity analysis, or missingness assumption is reported in the registry record.
The analysis population is also not specified. In general, an analysis of all randomized participants and an analysis limited to people with observed outcome data can target different quantities, particularly when data are missing or treatment adherence varies. The registry record does not state which population was used, whether participants were analyzed according to assignment, or how deviations from assigned treatment were handled. These gaps prevent a full assessment of the primary analysis and its susceptibility to missing-data or selection effects.
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 |
|---|---|---|---|
| Galantamine 8 mg/Day | 0 | 17 | 0.0% |
| Placebo | 0 | 17 | 0.0% |
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 |
|---|---|
| Galantamine 8 mg/Day | 0 of 17 |
| Placebo | 0 of 17 |
The safety entries report zero serious adverse events among 17 participants at risk in the galantamine 8 mg/Day group and zero among 17 participants at risk in the placebo group. The entries for other adverse events also report zero in each group, with 17 participants at risk per group. These are counts recorded for the listed categories; they are not estimates of comparative risk, and the registry record does not provide additional event descriptions.
Zero recorded events does not establish that an event is impossible or that the treatments have identical safety profiles. In general, event counts depend on how events were defined, collected, followed and reported. The registry record does not provide further detail on those procedures or the observation period for adverse events. Death counts are not reported in the registry record.
These safety entries should be read separately from the cognitive endpoint. They do not provide evidence about reaction time or the comparative cognitive effect. The record’s counts are descriptive, and the information available does not support a broader conclusion about safety beyond those recorded entries.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized, double-masked comparison of galantamine 8 mg/day with placebo in abstinent cocaine users, with CANTAB RVIP reaction time as the primary outcome. It describes assessment at baseline, Day 5 and Day 10 and reports 28 completers, 14 per group. It also notes that CANTAB data were not stored for one participant in the galantamine group. These registry entries describe the study’s design and available endpoint information, not the direction or magnitude of an outcome difference.
Numerical primary-outcome results are not reported in the registry record. There is no reported contrast, uncertainty interval, or significance test from which to assess whether the treatment groups differed on the endpoint. As a result, the record does not support a claim that reaction time improved, worsened, or remained unchanged in one group relative to the other. It also cannot establish how precise an estimated comparison would be.
General interpretation requires separating an observed estimate from its uncertainty and from its practical meaning. An estimate describes the contrast under a particular analysis; an uncertainty interval indicates how much the data and model leave unresolved. A judgment about practical importance additionally requires context and a meaningful threshold, neither of which is reported for this endpoint. No inference about cognitive performance beyond the recorded outcome can be justified from the endpoint description alone.
The trial’s stated rationale explains why the investigators examined cognitive performance, but rationale is not a result. Similarly, the absence of recorded adverse-event counts in the listed categories does not fill the gap in efficacy results. The record is informative about the trial’s question, intervention, comparator and planned outcome, while leaving the primary comparative finding unreported.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of the distinction between a clearly named endpoint and a fully interpretable result. The record identifies a continuous measure, its unit, the broad task used to obtain it, and three assessment occasions. It also supplies a summary of completers and identifies a loss of CANTAB data for one galantamine participant. These details help readers understand what was intended to be measured and flag a data-availability issue.
At the same time, a design description cannot substitute for an estimated treatment contrast. Without numerical outcome results, readers cannot evaluate the direction, size or precision of a difference. Without a reported model and contrast, readers also cannot determine how repeated measurements were incorporated or exactly which question an analysis would answer. This illustrates why registration and results information need to be read as distinct components of trial interpretation.
The record also makes the multiplicity issue visible by listing 15 outcome measures and 15 analyses, alongside a primary outcome assessed at multiple times. A statistical interpretation depends on knowing which comparison was primary and how the other analyses were handled. The relevant plan is not reported in the registry record. This is an important limitation for understanding how to interpret any isolated result, even though the numerical results themselves are also unavailable.
Finally, the participant counts and missing CANTAB data show why analysis populations and missing-data handling matter. A count of completers does not reveal how every measurement entered an analysis. For clinical researchers and biostatisticians, the record underscores the value of reporting estimates, uncertainty, analysis definitions and data-handling decisions alongside design details.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most direct limitation for interpreting this trial is that numerical results for the primary cognitive endpoint are not reported in the registry record. There is no estimate of the galantamine-versus-placebo contrast, confidence interval, or significance test. Consequently, the direction, magnitude and precision of the primary finding cannot be assessed from the record.
The primary endpoint includes assessments at baseline, Day 5 and Day 10, but the record does not specify the primary contrast or statistical model. It flags that the outcome has several time points and was not reduced to one comparison. The record also does not report how within-participant dependence was handled, whether baseline was adjusted for, or whether any covariates were included. These missing analysis details limit reproducibility and make the intended estimand unclear.
The participant information is incomplete for evaluating endpoint data. Although the record reports 28 completers, 14 in each group, it notes that CANTAB data were not stored for one galantamine participant. It does not identify the affected assessment, explain whether further values were missing, specify the analysis population, or describe a missing-data method. No sensitivity analysis is reported in the registry record.
Multiplicity is another unresolved issue because 15 outcome measures and 15 analyses are listed, while the adjustment strategy and distinction between confirmatory and exploratory analyses are not reported. Detailed eligibility criteria, participant characteristics, masking procedures, randomization methods, adherence information, and an original sample-size justification are also not reported in the registry record. These limitations constrain assessment of internal validity, generalizability and the analysis choices; they do not establish that any particular bias occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Galantamine Effects on Cognitive Function in Abstinent Cocaine Users — NCT00606801.
- Registry record last updated 2021-03-15; status last verified 2021-02.
- Results first posted 2013-07-31.
- 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, double-masked, parallel-group trial sponsored by Yale University. It enrolled 34 participants and compared galantamine 8 mg/day with placebo among abstinent cocaine users. The primary outcome was mean CANTAB RVIP reaction time in milliseconds, assessed at baseline, Day 5 and Day 10. The record reports 28 completers, 14 per group, and notes that CANTAB data were not stored for one galantamine participant.
Secondary outcomes included SART and Modified Stroop Task measures. The record lists 15 outcome measures and 15 analyses. It reports zero serious and zero other adverse events in each group among 17 participants at risk per group; deaths are not reported in the registry record. Numerical primary-outcome results, detailed statistical methods, multiplicity handling and missing-data procedures are not reported in the registry record, so the comparative cognitive finding cannot be interpreted from these entries.