global rating scale is a scale used to summarize a patient's
cognitive profile based on neuropsychological
testing and/or clinical assessment. Two examples are the
Global Deterioration Scale
(GDS) and the Alzheimer
Disease Assessment Scale (ADAS).
to evaluate effectiveness of a drug or other treatment is
often measured in terms of changes in a global rating scale.
For example, in a hypothetical experminent, a number of Alzheimer's
patients are each randomly assigned to one of two groups.
One group, the experimental group, is assigned to take a new
experimental drug. The second, control
group, is assigned to take a currently-available drug.
At the start of the experiment, both groups have equivalent
global ratings on a scale such as the GDS or ADAS. At the
end of six months' time, both groups are again assessed in
terms of the global rating scale. If the experimental group's
scores have declined less than the control group's scores,
this would suggest that the new drug may be more effective
as a treatment for Alzheimer's disease.
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain