A psychophysical analysis of acupuncture analgesia.
by
Price DD; Rafii A; Watkins LR; Buckingham B ]
From: Pain, 19: 1, 1984 May, 27-42
A psychophysical analysis of acupuncture analgesia was carried out in
which low back pain patients made visual analogue scale (VAS) responses
both to their chronic pain and to different levels of experimental heat
pain (5 sec exposures to 43-51 degrees C) before and after
electroacupuncture. VAS (sensory) responses to chronic pain, direct
temperature matches to chronic pain, and VAS (sensory) responses to
experimental pain were reduced in an internally consistent manner 1-2 h
after treatment. The magnitude of this analgesic response was similar
for dermatomes within the region of chronic pain and acupuncture needle
placement (lower back) as well as for dermatomes remote from needle
placement and chronic pain (forearm). Individual patients manifested
either (1) a central-inhibitory pattern of analgesia wherein
experimental and chronic pain in back regions and experimental pain in
forearm regions were reduced, or (2) an origin-specific pattern wherein
only the chronic low back pain was reduced. Patients tested several
days after treatment all manifested the latter pattern of analgesia.
VAS sensory and VAS affective analgesic responses to electroacupuncture
treatment showed a delayed onset (1-24 h) to maximum effect and a
duration of 10-14 days. Cumulative sensory and affective analgesic
effects were observed at the end of 4 months of biweekly acupuncture
treatments. The results of this analysis reveal the unique spatial and
temporal properties of electroacupuncture analgesia and the extent to
which it is mediated by at least two different mechanisms.