Anesthesiology. 1976 Feb; 44(2): 147-50.

Acupuncture analgesia and radiant-heat pain: a signal-detection analysis.

Lloyd MA, Wagner MK.

Responses to radiant-heat stimulation to the back of the hand were obtained during baseline conditions and during acupuncture sessions. Signal-detection methodology and analysis were used to determine whether acupuncture affects d' (changes physiologic processes) relative to pain report. A binary rather than a rating-scale procedure was used to obtain more accurate measures of sensitivity. Results indicated that acupuncture decreased sensitivity only at intensity levels that were never described as painful.