MONTREAL--A new instrument for measuring pain intensity--the visual
analogue thermometer (VAT)--developed to overcome some of the
disadvantages of the conventional visual analogue scale (VAS)--has
proved "valid, accurate, and clinically useful" in two
studies, say Manon Choinière, PhD, of the Burn Centre,
Hotel-Dieu Hospital of Montreal and the University of Montreal,
and Rhonda Amsel, MSc, of the Department of Psychology, McGill
With the VAS, patients must make a mark along a 10-cm line that
has "no pain" and "unbearable pain" as the
two extremes. The scale is then scored by measuring the distance
in millimeters from "no pain" to the patient's mark.
Dr. Choinière describes the potential disadvantages of
this scale as follows: (1) It may be physically awkward to complete
for burn patients who have difficulty holding a pen or for those
with perceptual or motor problems; (2) it does not provide an
immediate result since the line has to be measured; and (3) it
may be difficult for some patients to understand.
The VAT, an adaptation of the VAS, was developed at the Burn Centre,
Hotel-Dieu Hospital of Montreal. It does not require any writing
or use of the hands by the patient.
The VAT consists of a rigid white cardboard strip with a horizontal
black opening through which a red band can be moved from left
to right using a tab on the back of the device.
The left and right extremities of the opening are labeled "no
pain" (or "aucune douleur") and "unbearable
pain" ("dou-leur insupportable"). The patient is
told that the device works like a thermometer except that it is
measuring pain intensity in millimeters rather than body temperature
The patient or an assistant slowly moves the red band to a position
indicating the patient's pain intensity. "The more intense
the pain, the more the red band lengthens toward the limit of
unbearable," Dr. Choinière explains. This can then
be read as a numerical value by using the 10-cm ruler printed
on the reverse side of the device.