Oral mucosal versus cutaneous sensory testing: a review of the literature

Abstract

The innervation of skin and oral mucosa plays a major physiological role in exteroception. It also has a clinical interest as illustrated by sensory changes after neurosurgical procedures. These sensory changes often rely only on the patients' subjective reports, although objective assessments are possible. This review compares the neurophysiological features of the trigeminal sensory pathways with those of cutaneous sensory innervation. In this review, three receptor groups will be discussed: mechanoreceptors, thermoreceptors and nociceptors. Differences between receptors in the glabrous skin, the hairy skin and the oral mucosa will be highlighted. Sensory testing devices have been developed to quantify psychophysiological parameters such as the threshold level for receptor activation upon mechanical stimulation, but such devices have been merely developed to determine the threshold of skin receptors (tactile, thermal). Later on, some have been adapted to suit the particularities of the oral environment. This review attempts to compare the available literature on test devices for oral versus cutaneous tactile function. It summarizes what is common or rather particular to the devices used to study either cutaneous or oral receptors.

Age Differences in Orofacial Sensory Thresholds

“…These improvements over previous work point to a more global sensory-perceptual difference between older and younger individuals than was possible with single-modality studies. The observed greater sensitivity of the upper lip compared with the chin site is consistent with previous reports (Rath and Essick, 1990;Jacobs et al, 2002) and offers a measure of task validity. The observed elevation in thresholds of both the somatosensory and gustatory stimuli with increasing age is consistent with reported findings, for taste (Grzegorcyk et al, 1979;Schiffman, 1979;Cowart, 1981;Weiffenbach et al, 1982), smell (Schiffman, 1979;Murphy, 1983;Cain and Stevens, 1989), mechanoreception (Kenshalo, 1979(Kenshalo, , 1986Lautenbacher et al, 2005), and pain (Harkins et al, 1984).…”

A case-control study on the psychophysical and psychological characteristics of the phantom tooth phenomenon

“…It should be mentioned that high intersubject variability was noted with regard to sensory threshold determination, which may have masked some of the differences. In addition, even with a highly standardized setup, intersubject variability cannot be eliminated from psychophysical test results [15]. When extrapolating the present findings to limb amputation in general, the results are opposite to these of Braune and Schady [3]: the tactile thresholds were elevated in the territory of the injured nerve in a graded fashion, sensitivity being poorest in the patients with the most recent injuries [3].…”

Intraoral Tactile Sensitivity in Adults With Diabetes

“…The highest ITS was found for the posterior tongue, followed by the soft palate and the anterior tongue. Differences in innervation may explain these findings, which are consistent with other studies on oral mucosal sensory testing (18).…”