Variations in pain complaint threshold in psychiatric and neurological patients with pain.

The threshold at which noxious stimulation with a pressure algometer gives rise to a complaint of pain has been studied in neurological and psychiatric patients with pain and in two patients with fluctuating pain of organic origin. A correlation of r = 0.69 (P less than 0.0025) was demonstrated between two observers using the pressure algometer independently. Patients with organic causes for their pain had higher pain complaint thresholds. The threshold was also raised, outside the affected areas, in the two patients with fluctuating pain when the latter was more severe. Some requirements for an improved technique of pressure algometry are discussed.