Q&A with Natalia Rost, MD, MPH, Neurology, Director of the Mass General Acute Stroke Service
Below is a glossary of commonly used clinical terms used in the Stroke Service.
- Active Treatment
This is the group receiving the investigational therapy. This may be a drug already in use, a newly developed drug, or a non-medicinal treatment such as exercise/physical therapy, psychological intervention, or increased education.
This refers to keeping knowledge of treatment assignment undisclosed. Often studies are "double blind" so that neither the investigator nor the study participant knows which treatment is being used. In these cases, for safety reasons, all participants are assumed to be getting the active treatment. Of course, there are always provisions made to "unblind" the treatment assignment if a safety issue arises.
Blinding is done to prevent deliberate or inadvertent bias on the part of the investigator or the study participant in terms of reporting positive or adverse effects of the treatment. For example, if an investigator believes a treatment will be beneficial and knows which patients are receiving it, he/she might subconsciously over-estimate the degree of improvement in those receiving active treatment.
- Clinical Trial
A research study design which compares two or more therapies by assigning patients to receive the various treatments and monitoring them prospectively for some pre-defined endpoint.
In an experiment, in order to gauge the effect of a therapy, the response in the treatment group must be compared to a group on untreated "normals". The untreated group is called a control. In clinical trials, controls may receive the standard treatment (with the active treatment group receiving a new therapy) or a placebo.
The outcome of interest for a study. For example, if a new cholesterol lowering drug is being studied to prevent cardiovascular disease, the primary endpoint may be a heart attack or stroke. A study may also have secondary endpoints for which patients are monitored throughout the course of the study.
- Informed Consent
Prior to entering a study, participants are informed about the nature of the study, their commitment to the project, and the potential risks and benefits. This may be done verbally or in the form of a written document. A review board at the institution will have already reviewed the consent form for clarity and safety issues prior to granting approval for the study. A representative of the study will always be available to answer questions about the protocol.
An inactive treatment.
- Placebo Effect
It has been observed that roughly 30% of people who are told they are taking a cure, even if it is a placebo (i.e. a sugar pill), will have improvement in their symptoms.
To randomly (e.g. by flipping a coin) assign patients to one treatment group or another.