Normal and radiculopathic cutaneous pain tolerance levels evaluated by heat-beam dolorimetry

Abstract

The heat-beam dolorimeter has previously been used to obtain cutaneous pain tolerance measures in normal volunteers and patients with chronic pain. In the present study, normal reference data were collected at two stimulus intensities for 24 volunteers, and the stimulus-effect relationship (decreasing tolerance latency with increasing stimulus intensity) was found significant (p less than 0.001) for all body sites tested. No overall sex differences were found; males behaved slightly more stoically than females, with differences significant only at the T3 site over the breasts. At the second evaluation at the higher stimulus intensity, females exhibited lower pain tolerance (greater pain sensitivity) at the right breast than males (p less than 0.05). No significant lateral asymmetry was found in cutaneous pain tolerance except at the dorsum of the hand: the right hand evinced elevated pain tolerance compared with the left hand in both right- and left-handed subjects. Eight radiculopathic pain patients with clinically involved left L5 nerve roots were evaluated and their responses were compared with the volunteer normal reference data. The radiculopathic group evinced elevated tolerance levels in both the radiculopathic dermatome and noninvolved sites compared with normal individuals (p less than 0.05).

Pathophysiology of Pain Perception

“…In eight patients with radiculopathy elevated cutaneous pain tolerance was found in the affected dermatome and in non-affected sites (Lipman, Blumenkopf & Lawrence, 1990), suggesting a generalized decrease of pain sensitivity in these patients .…”