DICTIONARY

biomarker, or biological marker is a measurable indicator of some biological state or condition. It can be a level of something in your blood or hormon levels for instance.  Biomarkers are often measured and evaluated to examine normal biological processes – like measuring the level of hemoglobin in your blood or your blood pressure.  In reference to research on Huntingtons disease, a biomarker is an indicator of disease progression.  Examples are changes within the cells related to so-called metabolism (energy processes) or levels of mutant Huntingtin in nervecells. It can also be changes in organs – like loss of muscle or brain volume.  We use biomarkers to measure how the disease progress and potentially how a treatment influence the disease progression.

Direct stimulation of the brain using electrical impulses through tiny wires

A research study involving human volunteers (also called participants) that is intended to add to medical knowledge. There are two types of clinical studies: interventional studies (also called clinical trials) and observational studies.

Medical research involving people.

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

A type of intervention model describing a clinical trial in which groups of participants  receive two or more interventions in a specific order. For example, two-by-two cross-over   assignment involves two groups of participants. One group receives drug A during the initial phase of the trial, followed by drug B during a later phase. The other group receives drug B during the initial phase, followed by drug A. So, during the trial, participants “cross-over” to the other drug. All participants receive drug A and drug B at some point during the trial but in a different order, depending on the group to which they are assigned.

A measure of whether a treatment works or not.

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

A type of eligibility criteria. These are reasons that a person is not allowed to participate in a clinical study.

A type of eligibility criteria. These are the reasons that a person is allowed to participate in a clinical study.

A process used by researchers to communicate to potential and enrolled participants the risks and potential benefits of participating in a clinical study.

The general design of the strategy for assigning interventions to participants in a clinical study. Types of intervention models include: single group assignment, parallel assignment, cross-over assignment, and factorial assignment.

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

A type of clinical study in which participants are assigned to groups that receive one or more intervention/treatment (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes. The assignments are determined by the study’s protocol. Participants may receive diagnostic, therapeutic, or other types of interventions.

A clinical trial design strategy in which one or more parties involved in the trial, such as the investigator or participants, do not know which participants have been assigned which interventions. Types of masking include: open label, single blind masking, and double-blind masking.

A type of clinical study in which participants are identified as belonging to study groups and are assessed for biomedical or health outcomes. Participants may receive diagnostic, therapeutic, or other types of interventions, but the investigator does not assign participants to a specific interventions/treatment.

A patient registry is a type of observational study.

A type of intervention model describing a clinical trial in which two or more groups of participants receive different interventions. For example, a two-arm parallel assignment involves two groups of participants. One group receives drug A, and the other group receives drug B. So during the trial, participants in one group receive drug A “in parallel” to participants in the other group, who receive drug B.

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study’s objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.

Describes trials without defined phases, including trials of devices or behavioral interventions.

An inactive substance or treatment that looks the same as, and is given in the same way as, an active drug or intervention/treatment being studied.

An arm type in which a group of participants receives a placebo during a clinical trial.

The main reason for the clinical trial. The types of primary purpose are: treatment, prevention, diagnostic, supportive care, screening, health services research, basic science, and other.

The person who is responsible for the scientific and technical direction of the entire clinical study.

The written description of a clinical study. It includes the study’s objectives, design, and methods. It may also include relevant scientific background and statistical information.

A type of allocation strategy in which participants are assigned to the arms of a clinical trial by chance.

  • Not yet recruiting: The study has not started recruiting participants.
  • Recruiting: The study is currently recruiting participants.
  • Enrolling by invitation: The study is selecting its participants from a population, or group of people, decided on by the researchers in advance. These studies are not open to everyone who meets the eligibility criteria but only to people in that particular population, who are specifically invited to participate.
  • Active, not recruiting: The study is ongoing, and participants are receiving an intervention or being examined, but potential participants are not currently being recruited or enrolled.
  • Suspended: The study has stopped early but may start again.
  • Terminated: The study has stopped early and will not start again. Participants are no longer being examined or treated.
  • Completed: The study has ended normally, and participants are no longer being examined or treated (that is, the last participant’s last visit has occurred).
  • Withdrawn: The study stopped early, before enrolling its first participant.

The organization or person who initiates the study and who has authority and control over the study.

Treatments

The official title of a protocol used to identify a clinical study or a short title written in language intended for the lay public.

The acronym or initials used to identify a clinical study (not all studies have one). For example, the title acronym for the Women’s Health Initiative is “WHI.”

A figure estimating how many people there are in a particular population who have a certain medical condition.