For Study Participants

Your participation matters.

By joining a clinical trial, you help bring advanced medical treatments to those who need them most.

What is a clinical trial?

Clinical trials are key to discovering new ways to prevent, detect and treat disease to improve the health of current and future generations. They are research studies performed by certified professionals to find out whether a product – such as a drug or medical device – is safe and effective for people.

The people who participate in trials are volunteers. They may be patients with a specific disease, or healthy people wanting to contribute to the advancement of medical knowledge.

Clinical trials are done in phases.

The four phases of drug trials


Phase I – These trials test an experimental drug on a small group (20-100) of healthy volunteers for the first time.

The purpose is to:

  • Assess the drug’s safety and tolerance
  • Find out what a safe range would be for dosage
  • Identify major adverse effects

Phase II – The drug is given to a larger group of people (usually 100 or more) to:

  • Obtain preliminary data on the effectiveness of the drug for a particular disease or condition
  • Further assess the drug’s safety
  • Determine the best dose

Phase III – The drug is given to even larger groups of people (hundreds or thousands) to:

  • Confirm its effectiveness
  • Monitor side effects, determine minor adverse effects
  • Compare it to commonly used treatments, and determine drug-drug interactions
  • Collect information that will allow the drug to be used safely on the market

Phase IV – These trials are done after the drug is approved and is on the market. They gather information on things like the best way to use a drug, and the long-term benefits and risks.


Potential Risks – Each study will have its own unique risks and benefits – these will be described clearly to you during the consent process before any study activities begin.

While you may participate in a study to gain access to a promising new treatment, you should be aware this is not a guarantee. Clinical trials often compare new treatments to a placebo or an existing treatment, so you may end up being assigned to a group that does not get the new treatment.

The three phases of device trials


Overview – Device trials may initially be conducted in a smaller “pilot” population with the disease or condition being studied, before moving into the larger “pivotal” population.

The total number of subjects needed to show safety and effectiveness is often only one or two hundred, rather than thousands needed for drug trials.


Pilot – The device is tested in a smaller (10-30) “pilot” population with the disease or condition being studied in order to:

  • Determine preliminary safety and performance information

Pivotal – The device is tested in a larger (150-300) population with the disease or condition being studied in order to:

  • Determine effectiveness and adverse effects

Post-Approval study – These studies are performed after the device is approved and is on the market. They gather information on things like the long-term benefits and risks.


Potential Risks – Each study will have its own unique risks and benefits – these will be described clearly to you during the consent process before any study activities begin.

While you may participate in a study to gain access to a promising new treatment, you should be aware this is not a guarantee. Clinical trials often compare new treatments to a placebo or an existing treatment, so you may end up being assigned to a group that does not get the new treatment.

Why It Matters

Through clinical research, many common treatments and medical devices have been tested and evaluated before being made available to the public. With your help, we can continue to make medical advances to treat a variety of neurological conditions, and optimize brain health.

Register for a Study

Our list of active studies changes frequently.