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Blinding

Blinding

Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.

Randomized Experiments

Randomized Experiments

The randomization process involves assigning study participants randomly to experimental or control groups based on their probability of being equally assigned. Randomization is meant to eliminate selection bias and balance known and unknown confounding factors so that the control group is similar to the treatment group as much as possible. A computer program and a random number generator can be used to assign participants to groups in a way that minimizes bias.
Simple randomization
Simple...

Blind Procedures

Blind Procedures

Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which child was...

Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches

Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches

Biopharmaceutical studies constitute a vital field aiming to enhance drug delivery methods and refine therapeutic approaches, drawing upon diverse interdisciplinary knowledge. In research methodologies, the choice between controlled and non-controlled studies significantly influences the study's reliability and accuracy.
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...

Clinical Trials

Clinical Trials

Clinical trials are prospective experimental studies conducted on humans to determine the safety and efficacy of treatments, drugs, diet methods, and medical devices. Using statistics in clinical trials enables researchers to derive reasonable and accurate conclusions from the collected data, allowing them to make wise decisions in uncertain situations. In medical research, statistical methods are crucial for preventing errors and bias.
There are four phases in a clinical trial. A phase one...

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Related Experiment Video

Updated: Jun 10, 2026

Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke

Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke

Published on: June 6, 2025

Methodological aspects of randomized controlled trials on cognitive interventions.

Alessandra Solari¹

¹Unit of Neuroepidemiology, Foundation IRCCS Neurological Institute C. Besta, Milan, Italy. solari@istituto-besta.it

Neurological Sciences : Official Journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology

|July 17, 2010

Summary

This summary is machine-generated.

Methodological challenges in randomized controlled trials (RCTs) for multiple sclerosis cognitive interventions were assessed. Study quality was generally low, with issues in population selection and sample size, particularly in rehabilitation trials.

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Last Updated: Jun 10, 2026

Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke

Randomized, Triple-Blind, and Parallel-Controlled Trial of Transcranial Direct Current Stimulation for Cognitive Rehabilitation after Stroke

Published on: June 6, 2025

Working Memory Training for Older Participants: A Control Group Training Regimen and Initial Intellectual Functioning Assessment

Working Memory Training for Older Participants: A Control Group Training Regimen and Initial Intellectual Functioning Assessment

Published on: September 20, 2020

Area of Science:

Neurology
Clinical Trials
Rehabilitation Science

Background:

Multiple sclerosis (MS) cognitive impairments necessitate effective interventions.
Randomized controlled trials (RCTs) are crucial for evaluating intervention efficacy.
Methodological rigor in MS intervention RCTs requires careful examination.

Purpose of the Study:

To assess methodological challenges in RCTs for cognitive interventions in multiple sclerosis.
To identify specific problems within rehabilitation trials for MS.
To evaluate the quality of existing RCTs on cognitive and rehabilitation interventions for MS.

Main Methods:

A bibliographic search was conducted to identify relevant RCTs.
Selected RCTs were evaluated using five methodological quality criteria.
Criteria included population description, allocation concealment, masking, outcome measures, and analysis.

Main Results:

Twelve RCTs published between 1996 and 2010 were identified (5 drug therapy, 7 rehabilitation).
Overall study quality was low, with frequent limitations in target population selection and small sample sizes.
No clear improvement in methodological quality was observed in recent studies; rehabilitation trials faced challenges in intervention definition and reproducibility.

Conclusions:

Significant methodological challenges persist in RCTs for cognitive interventions in multiple sclerosis.
Low study quality and specific issues in rehabilitation trials hinder reliable evidence synthesis.
Future research requires improved methodological standards for effective MS intervention evaluation.