The Incapacitance test represents an unsurpassed method for assessing spontaneous pain in laboratory animal model with inflammation or nerve injury in one hind paw (neuropathy, carrageenin, incisionÉ). Indeed, classic measurements of nociceptive thresholds as used in most of the experimental studies allows assessment of only a pain sensitivity level, not a spontaneous pain level, in the absence of experimental nociceptive stimuli.

In the incapacitance test, the animal is located in a holder specially designed to maintain the animal comfortably positioned on two separated sensor plates. The Panlab/Harvard Apparatus Incapacitance tester enables then to quantify the spontaneous postural changes reflecting spontaneous pain by independently measuring the weight that the animal applies each hind paw on two separate sensors. In the absence of hind paw injury, rats applied equal weight on both hind paws, indicating a postural equilibrium. After unilateral hind paw tissue injury, a change in the weight distribution on the sensor can be detected, with a lower weight applied by the injured paw.

The current value of the weight applied on each sensor is shown on the LCD display of the LE7950 control unit in a user-selected unit (grams, Newton or oz/lbs). A remote foot-switch controls the test start/stop allowing rapid hands-free experiments. The control unit also allows to compute and display statistics (mean, SD) for the groups of animals under test during the measurements. No PC is required for running the incapacitance test, although the possibility is given to send collected data from the instrument to a PC through the integrated RS-232 interface SeDaCom.