Electrical stimulation of tooth pulp in humans. I. Relationships among physical stimulus intensities, psychological magnitude estimates and cerebral evoked potentials

Abstract

Brief electrical pulses were applied to the pulp of individual pre-molar teeth of 14 healthy, adult volunteers via wire electrodes implanted and sealed in dentine. The sensation threshold was estimated in each individual by the Two-Alternative Forced-Choice Staircase (2AFCS) method. Seven, 5 or 4 stimulus intensities were employed which were equally spaced in a logarithmic scale between 10 microA above threshold and 500 microA. Magnitude estimates of the subjective intensity of the sensation produced by individual dental excitations were obtained. Cerebral tooth pulp-evoked potentials were simultaneously recorded in 11 subjects. The growth of psychological sensory magnitude with increasing strength of electrical stimulus conformed to the general psychophysical power law. Individual power function exponents varied from 0.204 to 0.907 with a mean of 0.475 and a standard deviation of 0.190. The amplitude of TPEPs, measured between components N135 and P293, also was a power function of stimulus intensity. The exponents of individual TPEP amplitude-intensity functions ranged from 0.055 to 0.362 with a mean of 0.144 and a standard deviation of 0.100. These last exponents were substantially smaller than those describing the growth of psychological magnitude estimates. Neither magnitude estimation nor TPEP amplitude-intensity functions displayed abrupt changes in slope which might accompany transition from one operating sensory mechanism to another and/or changes in qualities of subjective sensations from 'innocuous' to 'uncomfortable' to 'painful.' The result of our psychophysical and electrophysiologic experiments indicate that: (1) albeit highly specialized both morphologically and functionally, human tooth pulp has certain fundamental properties in common with other sensory systems and (2) late midline TPEP components may provide measures of central events that, within a range of stimulus intensities, are associated with the perception of pain, but should not be looked upon as specific indicators of pain processes.

The detectability, discriminability, and perceived magnitude of painful electrical shock

“…An analysis similar to the present one can be performed on the data presented by Fernandes de Lima et al (1982), who obtained sensation thresholds, power functions, and cerebral evoked potentials for brief electrical pulses applied to the tooth pulp of II observers. The behavioral data alone were obtained from 3 other subjects as well.…”

What Are the Parameters for Predictive Selection of Patients Requiring Anesthesia for Extracorporeal Shockwave Lithotripsy?

“…It is assumed that cutaneous superficial nociceptors and visceral nociceptors are responsible for the pain event during lithotripsy. Many algisemetric methods of pain measurement are described in the literature [8, 12, 15, 26]. It was not possible to adapt these methods in our own assessments as, firstly, the acceptance under volunteers was very low and secondly, the cost of appropriate instruments was high without guarantee of practicability.…”

The Benzodiazepine (+)-Tifluadom (KC-6128), but Not Its Optical Isomer (KC-5911) Induces Opioid kappa Receptor-Related EEG Power Spectra and Evoked Potential Changes

“…But most importantly, the amplitude of the Nioo peak is significantly reduced after the third injec tion when a total of 140pg/kg has been administered. Since a decrease of amplitude of the late evoked potential purportedly is closely related to attenuation of subjective painful sensations [11,13], (+)-tifluadom seems to induce a significant analgesia only in doses greater than lOOpg/kg. A similar analgesic potency is reported for nalbuphine, another kappa agonist with mu antagonistic profile [26], The kappa-mediated amplitude suppression of the N too peak is unmasked by reversal with a specific antagonist.…”

“…Attention was focused on am plitude changes of the late Nioo peak which, as re ported previously, seems to reflect the attenuation of painful perception by analgesics [11][12][13],…”

“…Additionally, the ef fects of both enantiomers on the sequential activation of elements in the sensory conduc tion system using somatosensory-evoked po tentials (SEP) were measured. SEP data are of special interest as other opioid kappa ago nists, such as pentazocine [10] and bremazocine [2], induce a slowing in conduction ve locity which is closely related to a reduction in subjective pain in man [11], Introduction A 1,4-benzodiazepine (KC-5103; fig. 1) with affinity for the opioid kappa receptor and little binding at the benzodiazepine re ceptor [1] seems of clinical interest.…”