Glossary
Placebo-controlled Principal investigator Statistical significance
A type of clinical trial in which a group
of participants is randomly assigned to
receive a placebo (inactive substance)
for comparison to the standard of care
(control) or intervention. The researcher, often a doctor, who
oversees and leads an entire clinical trial
or study. A number that refers to whether the
study’s results are highly likely to be true
or could have occurred purely by chance.
Note that statistically significant does not
necessarily mean highly important.
See also: placebo
Placebo effect
A beneficial physical or emotional
change that occurs after taking a placebo
(inactive substance). This phenomenon
is thought to result, at least in part,
from expectations of benefit. (In other
words, the more a person believes they
will benefit, the more likely it is they
will experience benefit.) To separate
out this effect from a drug or therapy’s
true benefits, clinical trials typically use
placebo-controlled designs.
See also: placebo; placebo-controlled
Positron Emission
Tomography (PET) scan
A Positron Emission Tomography (PET)
scan is a specialized imaging test that
uses a small amount of radioactive
medication to study the function of
the brain. For example, researchers are
looking to visualize alpha-synuclein
protein in the brain with PET scans; this
could serve as a biomarker and way to
measure the impact of drugs in trials.
See also: alpha-synuclein, biomarker
Pre-clinical
Research that is not conducted on
humans. Before a drug can enter clinical
trials, pre-clinical models must first
evaluate its feasibility and safety.
Protocol
The written description of a clinical trial
or study that describes its objectives,
design and methods, as well as inclusion
and exclusion criteria.
See also: exclusion criteria; inclusion
criteria
Randomized
A strategy in which participants are
assigned to one group in a clinical trial
or study by a methodological process
that mimics chance. In placebo-
controlled interventional trials, one
group of participants is randomized to
an intervention and another is assigned
to placebo.
See also: placebo
Recruiting
A term used to indicate that a
study is open for enrollment and
needs participants.
Repurposing
Taking an existing drug that has been
developed (and typically FDA-approved)
for one condition and using it to treat
another. Clinical trials are necessary to
repurpose, or reposition, a therapy to
ensure that it is safe and efficacious in
those with Parkinson’s.
SNCA
A gene that directs the production of
the alpha-synuclein protein. A mutation
in the SNCA gene is the basis for a rare,
inherited form of Parkinson’s.
See also: alpha-synuclein
48
Navigating Clinical Trials: A Guide for Parkinson’s Patients and Families
Study funder
The study funder provides financial
support for research. Funding can
come from a variety of individuals or
organizations, including foundations,
pharmaceutical companies and federal
agencies, such as the National Institutes
of Health.
Study sponsor
The study sponsor is the individual or
organization who oversees the study.
The sponsor initiates, conducts and is
responsible for the research.
Symptomatic therapy
A treatment that eases the symptoms
of a disease but does not address
the underlying disease process. All
currently available Parkinson’s therapies
are symptomatic; they do not slow
disease progression.
Telemedicine
A field of medicine that delivers health
care through electronic, two-way,
real-time interactive communication
between individuals and their physicians
or other providers.
Tolerability
The degree to which effects of a drug or
therapy can be tolerated by a patient, or
how much these effects impact a person’s
lifestyle or day-to-day activities.