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Glossary

Active, not recruiting

Although the clinical trial is ongoing, it is not looking for participants.1

Adverse event

A (favorable or unfavorable) change in the health of a participant, including abnormal laboratory findings, that happens during a clinical study or within a certain amount of time after the study has ended. This change may or may not be caused by the intervention/treatment being studied.1

Alzheimer’s disease

Alzheimer's disease is the most common type of dementia. An estimated 6.7 million Americans aged 65 years and older had Alzheimer's disease in 2023.2 People with Alzheimer's disease experience a decline in cognitive function, like memory impairment.3 They also experience symptoms that disrupt their thoughts, emotions, and actions.4

Care partner

A person helping to care for a loved one who is unable to manage day-to-day life alone due to an illness. This role includes helping with daily needs, managing the household, and supervising health care.5

Clinical trial (or research study)

A clinical trial, also called a research study, is a voluntary interventional study conducted in people and designed to test the safety or effectiveness of drugs, vaccines, and other therapies, or new ways of using existing treatments.1

Clinical Trial Participant

An individual who participates in a clinical trial or research study.5

Clinical trial phases

Clinical trials are conducted in a series of parts. Those parts are called “phases,” and they test how safe and effective a drug is, as well as dosing and side effects.1

Cognitive disorder

Any disorder that impairs the mental functions of an individual, which may or may not interfere with day-to-day activities.6

Condition

The disease, disorder, syndrome, illness, or injury that is being studied.1

Chorea

Chorea is a movement disorder that causes sudden, unintended, and uncontrollable jerky movements of the arms, legs, and facial muscles. Chorea is seen in many diseases and conditions and is caused by overactivity of the chemical dopamine in the areas of the brain that control movement.7

Dystonia

A neurological movement disorder characterized by involuntary (unintended) muscle contractions that cause slow repetitive movements or abnormal postures that can sometimes be painful.8

Early access

A way for qualified patients with serious diseases or conditions who cannot participate in a clinical trial to access a medical product that has not been approved.1

Eligibility criteria

The main requirements to join a clinical trial, which may include a person’s age, sex, and health. Eligibility criteria have two parts: inclusion criteria (what allows someone to participate) and exclusion criteria (what prevents someone from participating).1

Enrollment

Signing consent to participate in a clinical trial.9

Epilepsy

Epilepsy is a brain disorder that causes recurring, unprovoked seizures.10 About 1 out of 26 people will develop the disorder.11

Exclusion criteria

Reasons a person is not allowed to participate in a clinical trial.1

Essential tremor

Essential tremor is the most common movement disorder,12 affecting approximately 7 million people in the United States.13 It is a progressive, often inherited, condition that causes trembling of the head, hands, voice, and/or legs.14

Huntington’s disease

Huntington's disease (HD) is an inherited disorder that causes nerve cells (neurons) in parts of the brain to gradually break down and die. The disease attacks areas of the brain that help to control voluntary (intentional) movement, as well as other areas. People living with HD develop uncontrollable dance-like movements (chorea) and abnormal body postures, as well as problems with behavior, emotion, thinking, and personality.15

Inclusion criteria

Reasons that allow a person to participate in a clinical trial.1

Informed consent

Clinical trial information provided to potential and enrolled participants that goes over the details of a clinical trial, including the risks and benefits to participation.1

Informed consent form (ICF)

The document a potential clinical trial participant must sign to acknowledge they have reviewed and understand what participation in the clinical trial entails.1

Investigational drug

An investigational drug is not approved for use or by prescription from doctors for the condition being studied. Investigational drugs are tested during clinical research studies to see if they are safe and effective for a specific medical condition and/or group of people.9

Investigational use

The use of an already approved drug in a clinical trial to see if it may be safe and effective for a different medical condition or population.9

Institutional Review Board (IRB)

A group of people who make sure a clinical trial is performed in an ethical manner and that participants’ rights are protected. IRBs include doctors, advocates, and experts. 
An IRB may also be known outside of the United States as an independent ethics committee (IEC).16

Placebo

A substance that does not contain an active drug, but looks, tastes, and is given like the actual drug being studied.1

Postpartum depression (PPD)

PPD can occur up to 1 year after having a baby, but most commonly starts about 1 to 3 weeks after childbirth. Women with postpartum depression have intense feelings of sadness, anxiety, or despair that can prevent them from being able to do daily tasks.17

Protocol

The description of a clinical trial, including goals, design, methods, data, and background information.1

Looking for answers to a specific question?

Learn about clinical trials and more

ABOUT CLINICAL TRIALS

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Everything you need to know about clinical trials from the steps for participation to the steps to get investigational drugs approved.

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WHAT TO EXPECT AS A PARTICIPANT

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Resources potential participants may need for finding clinical trials, understanding clinical trial listings, and more.

Read more

WHAT TO EXPECT AS A CARE PARTNER

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Care partners play a vital role in clinical trial participation. We have created resources just for you.

Read More
Reference
  1. Clinicaltrials.gov Glossary Terms. National Library of Medicine. Accessed December 6, 2023. https://clinicaltrials.gov/study-basics/glossary
  2. Alzheimer's Disease and Related Dementias. Centers for Disease Control and Prevention. Accessed December 6, 2023. https://www.cdc.gov/aging/alzheimers-disease-dementia/about-alzheimers.html
  3. Alzheimer’s disease fact sheet. National Institute on Aging. Accessed December 6, 2023. https://www.nia.nih.gov/health/alzheimers-and-dementia/alzheimers-disease-fact-sheet#:~:text=The%20first%20symptoms%20of%20Alzheimer's,early%20stages%20of%20the%20disease
  4. How Alzheimer’s disease changes the brain. Alzheimer Society of Canada. Accessed December 6, 2023. https://alzheimer.ca/en/about-dementia/what-alzheimers-disease/how-alzheimers-disease-changes-brain
  5. Glossary of Terms on Clinical Trials for Patient Engagement Advisory Committee Meeting. U.S. Food & Drug Administration. Accessed December 6, 2023. https://fda.report/media/108378/Clinical-Trail-Glossary-Terms.pdf
  6. Neurocognitive disorder. National Library of Medicine. Accessed December 6, 2023. https://medlineplus.gov/ency/article/001401.htm
  7. Chorea. National Institute of Neurological Disorders and Stroke. Accessed December 6, 2023. https://www.ninds.nih.gov/health-information/disorders/chorea#
  8. Dystonia. National Institute of Neurological Disorders and Stroke. Accessed December 6, 2023. https://www.ninds.nih.gov/health-information/disorders/dystonia#
  9. Institutional Review Board. Definition of Terms. Mayo Clinic. Accessed December 6, 2023. https://www.mayo.edu/research/institutional-review-board/definition-terms
  10. What is epilepsy? Epilepsy Foundation. Accessed December 6, 2023. https://www.epilepsy.com/what-is-epilepsy
  11. Who can get epilepsy? Epilepsy Foundation. Accessed December 6, 2023. https://www.epilepsy.com/what-is-epilepsy/understanding-seizures/who-gets-epilepsy
  12. Tremor. NIH/National Institute of Neurological Disorders and Stroke. Accessed December 8, 2023. https://www.ninds.nih.gov/health-information/disorders/tremor
  13. Louis ED, Ottman R. How many people in the USA have essential tremor? Deriving a population estimate based on epidemiological data. Tremor Other Hyperkinet Mov (NY). 2014; 4: 259. doi: 10.7916/D8TT4P4B
  14. Essential tremor disorder. Johns Hopkins Medicine. Accessed December 6, 2023. https://www.hopkinsmedicine.org/health/conditions-and-diseases/essential-tremor-disorder
  15. Huntington’s Disease. National Institute of Neurological Disorders and Stroke. Accessed December 6, 2023. https://www.ninds.nih.gov/health-information/disorders/huntingtons-disease
  16. Learn About Clinical Studies. U.S. National Library of Medicine. Accessed December 1, 2023. https://classic.clinicaltrials.gov/ct2/about-studies/learn
  17. Postpartum Depression. American College of Obstetrics and Gynecology. Accessed December 6, 2023. https://www.acog.org/womens-health/faqs/postpartum-depression