The complexity of
fatigue is well illustrated by the number of decisions that
must be made by the investigator who is developing a study protocol.
Measurement can focus on one dimension, usually severity, or
multiple dimensions. Ancillary measurements can be used to capture
additional information about fatigue quality or impact, or about
phenomena conceptually related to fatigue.
Unidimensional
Fatigue Measurement
Fatigue measurement
using simple unidimensional scales typically focuses on the
important dimension of severity. Similar to pain measurement,
a variety of unidimensional severity scales can be used in research
or clinical settings. The most common are four or five-point
verbal rating scales, numeric scales, and visual analogue scales
(also called a linear analog scale assessment, or LASA).
| Table
6.1 Fatigue Measurement
|
|---|
| Four-point
verbal rating scale
|
|---|
| None
Mild
Moderate Severe |
| Five-point
verbal rating scale
|
|---|
| None
Mild
Moderate Severe Very
severe |
| 11-point
numeric scale
|
|---|
| "On
a 0 to 10 scale, where "0" equals no fatigue
and "10" equals the worst fatigue imaginable,
how severe has fatigue been, on average, during the
past week" |
| 4-
point numeric scale (e.g., Common Toxicity Criteria
of the National Cancer Institute)
|
|---|
| 0 | 1 | 2 | 3 | 4 |
| None | Increased
fatigue over baseline, but not altering normal activities | Moderate
(e.g. decrease in performance status by 1 ECOG level
or 20% Karnofsky or Lansky) or causing difficulty
performing some activities | Severe
(e.g. decrease in performance status by 2 ECOG level
or 40% Karnofsky or Lansky) or loss of ability to
perform some activities | Bed-ridden |
| 10
cm Visual analogue scale
|
|---|
|
No
Fatigue |-----------------------------------------------|
Worst Possible Fatigue |
|