A dolorimeter is an instrument used to measure

pain threshold The threshold of pain or pain threshold is the point along a curve of increasing perception of a stimulus at which pain begins to be felt. It is an entirely subjective phenomenon. A distinction must be maintained between the stimulus (an externa ...

and

pain tolerance Pain tolerance is the maximum level of pain that a person is able to tolerate. Pain tolerance is distinct from pain threshold (the point at which pain begins to be felt).pain sensitivity or pain intensity". Dolorimeters apply steady pressure, heat, or electrical stimulation to some area, or move a joint or other body part and determine what level of heat or pressure or electric current or amount of movement produces a sensation of

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

. Sometimes the pressure is applied using a blunt object.

History

In 1940, James D. Hardy, Harold G. Wolff and Helen Goodell of

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to ...

introduced the first dolorimeter as a method for evaluating the effectiveness of analgesic medications. They did their work at

New York Hospital Weill Cornell Medical Center (previously known as New York Hospital or Old New York Hospital or City Hospital) is a research hospital in New York City. It is part of NewYork-Presbyterian Hospital and the teaching hospital for Cornell University. ...

. They focused the light of a 100 watt projection lamp with a lens on an area of skin that had been blackened to minimize reflection. They found that most people expressed a pain sensation when the skin temperature reached 113 °F (45 °C). They also found that after the skin temperature reached 152 °F (67 °C), the pain sensations did not intensify even if the heat were increased. They developed a pain scale, called the "Hardy-Wolff-Goodell" scale, with 10 gradations, or 10 levels. They assigned the name of "dols" to these levels. Other researchers were not able to reproduce the results of Hardy, Wolff and Goodell, and the device and the approach were abandoned.

Harvard Medical School Harvard Medical School (HMS) is the graduate medical school of Harvard University and is located in the Longwood Medical and Academic Area, Longwood Medical Area of Boston, Massachusetts. Founded in 1782, HMS is one of the oldest medical schools ...

Professor and

Massachusetts General Hospital Massachusetts General Hospital (Mass General or MGH) is the original and largest teaching hospital of Harvard Medical School located in the West End neighborhood of Boston, Massachusetts. It is the third oldest general hospital in the United State ...

anaesthetist Anesthesiology, anaesthesiology, or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medici ...

Henry K. Beecher Henry Knowles Beecher (February 4, 1904 – July 25, 1976) was a pioneering American anesthesiologist, medical ethicist, and investigator of the placebo effect at Harvard Medical School. An article by Beecher's in 1966 on unethical medical e ...

(1957) expressed skepticism about this method of measuring pain. In 1945, ''

Time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, t ...

'' reported that Cleveland's Lorand Julius Bela Gluzek had developed a dolorimeter that measured pain in grams. Gluzek stated that his dolorimeter was 97% accurate.

Palpometer

A dolorimeter known as the ''Sonic Palpometer'' was developed at the

University of Victoria The University of Victoria (UVic or Victoria) is a public research university located in the municipalities of Oak Bay and Saanich, British Columbia, Canada. The university traces its roots to Victoria College, the first post-secondary insti ...

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. Patents have been applied for worldwide. The Sonic Palpometer uses ultrasound and computer technology to automate the physician's technique of

palpation Palpation is the process of using one's hands to check the body, especially while perceiving/diagnosing a disease or illness. Usually performed by a health care practitioner, it is the process of feeling an object in or on the body to determine ...

to determine sensitivity of some part of the patient's body. The related pressure controlled palpometer (PCP) uses a pressure-sensitive piece of plastic film to determine how much pressure is being applied in palpation. This technique appears to be more reliable than unaided palpation.

Algorimeter and other methods

Techniques using lasers

Svensson et al. (1997) describe the use of a CO₂ laser or a contact thermode to heat the skin and elicit a pain response. A laser-based dolorimeter called a ''Dolorimeter Analgesia meter'' is marketed by IITC Life Sciences.

Techniques using heat lamps

Another pain measurement device uses heat from a 500 watt

incandescent Incandescence is the emission of electromagnetic radiation (including visible light) from a hot body as a result of its high temperature. The term derives from the Latin verb ''incandescere,'' to glow white. A common use of incandescence is ...

heat lamp Infrared lamps are electrical devices which emit infrared radiation. Infrared lamps are commonly used in radiant heating for industrial processes and building heating. Infrared LEDs are used for communication over optical fibers and in remote c ...

which is delivered to a small area of

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

Other dolorimeters

* Björnström's algesimeter measures sensitivity of the skin to pain. * Boas' algesimeter measures sensitivity over the

epigastrium In anatomy, the epigastrium (or epigastric region) is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane. Pain may be referred to the epigastrium from damage to structures derived from the fo ...

* The AlgiScan, used for measuring the analgesia level in patients during anesthesia, quantifies within seconds the reflex papillary dilatation through an integrated nociceptive stimulator. Other terms for similar instruments include ''algesiometer'', ''algesichronometer'' (which also takes time into consideration), ''analgesia meter'', ''algometer'', ''algonometer'', ''prick-algesimeter'', ''pressure-algometer''.

Dolorimetry for animals

Dolorimetry in animals involves application of pain to various body parts. It is occasionally used as a diagnostic tool, and routinely used in basic pain research and in the testing of analgetics.

Tail

* Tail-withdrawal tests * Tail-pinch tests *

Tail flick test The tail flick test is a test of the pain response in animals, similar to the hot plate test. It is used in basic pain research and to measure the effectiveness of analgesics, by observing the reaction to heat. It was first described by D'Amour ...

Paw

* Randall-Selitto test (paw pressure test) *

Hot plate test The hot plate test is a test of the pain response in animals, similar to the tail flick test. Both hot plate and tail-flick methods are used generally for centrally acting analgesic, while peripherally acting drugs are ineffective in these tests ...

Notes

References

''Dorland's Illustrated Medical Dictionary''
W. B. Saunders, Harcourt Health Sciences

Palpometer official site
{{pain Pain scales 1940 introductions