Search Strategies for Healthy Subjects

Overseen By Jeremy M Wolfe, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Brigham and Women's Hospital

Disqualifiers: Vision less than 20/25, neuromuscular or visual disorders

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

40 Participants Needed

Trial Summary

What is the purpose of this trial?

The goal is to look for qualitative differences in visual search behavior when one search is performed many times in a row compared to when multiple search tasks are intermixed. Four search tasks are tested. In the Mixed condition, the four tasks are randomly changed from trial to trial. In the Blocked condition, each task is run as a block of 100 trials.

Do I need to stop taking my current medications for this trial?

The trial protocol does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment Blocked Trials, Mixed trials?

The research suggests that block randomization, a method used in Blocked Trials, helps ensure balanced treatment groups, which can improve the validity of trial results, especially in smaller studies. This method reduces bias and enhances the reliability of the findings, potentially supporting the effectiveness of the treatment being studied. ^{1 2 3 4 5}

What safety data exists for the treatment evaluated under different names like Blocked Trials and Mixed Trials?

The research articles discuss methods for detecting safety signals in clinical trials using Bayesian approaches, which help identify potential risks by analyzing adverse events without unblinding the study. These methods are designed to ensure participant safety by monitoring for any unexpected increase in adverse events, even when the study is blinded. ^{6 7 8 9 10}

How does the treatment in the 'Search Strategies for Healthy Subjects' trial differ from other treatments?

The treatment in this trial uses a unique approach called 'blocked trials' and 'mixed trials', which involves a dynamic randomization process to ensure balanced group assignments even when the exact composition of participants is unknown beforehand. This method is distinct because it adapts to the presence of unknown factors, maintaining the integrity of the trial's randomization process. ^{11 12 13 14 15}

Research Team

Jeremy M Wolfe, PhD

Principal Investigator

Brigham and Women's Hospital

Eligibility Criteria

This trial is suitable for individuals with Attention Deficit Disorder, healthy volunteers, and those interested in vision research. Specific eligibility criteria are not provided, so it's best to contact the researchers for detailed requirements.

Inclusion Criteria

Pass Ishihara color vision test

Exclusion Criteria

Vision less than 20/25 with correction

I have a history of muscle or vision problems.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Training

Observers are trained on four different search tasks

1-2 weeks

Experimentation

Participants perform 400 trials in both Mixed and Blocked conditions

4-8 weeks

Follow-up

Participants are monitored for response time and accuracy

4 weeks

Treatment Details

Interventions

• Blocked Trials
• Mixed trials

Trial Overview The study examines differences in visual search behavior by comparing 'Mixed trials', where four different tasks change randomly each time, against 'Blocked Trials', where each task is repeated for a block of 100 trials.

Participant Groups

Group I: Mixed Trials Experimental Treatment 1 Intervention

There are four search tasks in this experiment. All tasks will be randomly mixed in a single block of 400 trials.

Group II: Blocked Trials Experimental Treatment 1 Intervention

There are four search tasks in this experiment. Each task will be presented in a separate block of 100 trials

Who Is Running the Clinical Trial?

Brigham and Women's Hospital

Lead Sponsor

Trials

1,694

Recruited

14,790,000+

National Eye Institute (NEI)

Collaborator

Trials

572

Recruited

1,320,000+

Findings from Research

The FDA recommends that sponsors create a Safety Surveillance Plan to systematically monitor safety data, suggesting two methods: analyzing serious adverse events (SAEs) by treatment group or using a trigger rate for unblinded analysis if SAEs exceed expected background rates.

The article introduces a procedural workflow for a blinded review of safety data, utilizing the Bayesian detection method (BDRIBS) to quantitatively assess risks, and provides tools for visualizing and analyzing safety data across multiple studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Using the Bayesian detection of potential risk using inference on blinded safety data (BDRIBS) method to support the decision to refer an event for unblinded evaluation. Waterhouse, B., Hartford, A., Mukhopadhyay, S., et al.[2022]

The new safety monitoring procedure introduced for two-arm blinded clinical trials effectively addresses the FDA's requirements for expedited safety reporting by using a Bayesian hierarchical model to analyze adverse event rates.

This procedure has demonstrated good performance in detecting unexpected rates of adverse events in the treatment group, making it suitable for use in multi-armed clinical trials with blinded data.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Bayesian Exposure-Time Method for Clinical Trial Safety Monitoring With Blinded Data. Schnell, PM., Ball, G.[2020]

The active comparator new user design is a preferred method in observational drug safety research because it helps reduce bias by comparing a new drug to a similar treatment that does not affect the outcome, but it can be challenging to implement due to the need for suitable comparators.

This analysis explored alternative study designs for drug safety assessments, demonstrating that various designs can be effectively implemented by adjusting patient selection criteria, which allows researchers to choose the most appropriate design based on specific study factors like treatment patterns and sample size.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Selection of Comparator Group in Observational Drug Safety Studies: Alternatives to the Active Comparator New User Design. Wintzell, V., Svanström, H., Pasternak, B.[2022]

References

1. England pubmed.ncbi.nlm.nih.gov

Adaptive assignment versus balanced randomization in clinical trials: a decision analysis. [2022]

2. France pubmed.ncbi.nlm.nih.gov

What's new in trial design: propensity scores, equivalence, and non-inferiority. [2021]

3. England pubmed.ncbi.nlm.nih.gov

Propensity score stratified MAP prior and posterior inference for incorporating information across multiple potentially heterogeneous data sources. [2023]

4. United States pubmed.ncbi.nlm.nih.gov

Randomization procedures in orthopaedic trials. [2008]

5. United States pubmed.ncbi.nlm.nih.gov

Complementarity comes of age. [2019]

6. England pubmed.ncbi.nlm.nih.gov

Using the Bayesian detection of potential risk using inference on blinded safety data (BDRIBS) method to support the decision to refer an event for unblinded evaluation. [2022]

7. England pubmed.ncbi.nlm.nih.gov

A Bayesian method for safety signal detection in ongoing blinded randomised controlled trials. [2023]

8. Switzerland pubmed.ncbi.nlm.nih.gov

A Bayesian Exposure-Time Method for Clinical Trial Safety Monitoring With Blinded Data. [2020]

9. United States pubmed.ncbi.nlm.nih.gov

Bayesian hierarchical model for safety signal detection in multiple clinical trials. [2021]

10. United States pubmed.ncbi.nlm.nih.gov

Selection of Comparator Group in Observational Drug Safety Studies: Alternatives to the Active Comparator New User Design. [2022]

11. England pubmed.ncbi.nlm.nih.gov

Group sequential designs with prospectively planned rules for subpopulation enrichment. [2018]

12. United States pubmed.ncbi.nlm.nih.gov

Designs for efficient clinical trials. [2007]

13. England pubmed.ncbi.nlm.nih.gov

Study design with staggered sampling times for evaluating sustained unresponsiveness to peanut sublingual immunotherapy. [2019]

14. United States pubmed.ncbi.nlm.nih.gov

A dynamic block-randomization algorithm for group-randomized clinical trials when the composition of blocking factors is not known in advance. [2022]

15. United States pubmed.ncbi.nlm.nih.gov

Imbalance in treatment assignments in stratified blocked randomization. [2019]