Age changes in the two‐point discrimination threshold in human oral mucosa

Abstract

Fifty young and fifty elderly subjects were tested by a two-point discrimination method applying an aesthesiometer to the mucous membr'ane of lips, cheeks and tongue. Two changes characteristic of ageing wer'e disclosed: (1) higher threshold values wer'e found in the older age group eoneomitant with (2) a gr'eater range of variation in these values. The importance of the perception of tactile stimuli from the structures tested is discussed in relation to adaptation to full dentures. It is suggested that signals arising from lips, cheeks and tongue assist the process of adaptation, whereas signals from the dentur'e foundation ean, on occasion, pr'event adaptation. IntroductionIt has been shown that three areas of facial skin innervated by the trigeminal nerve, when subjeeted to two-point discrimination tests exhibited a significant decrease in response in old people, compared to that in a group of young subjects (Brill et at., 1974). It was suggested that this decr'ease was due to the r'etrograde changes which occur thr'oughout the sensorium with ageing. Signs of involution in older subjeets have been found in receptors (Ronge, 1944), in intercalated nerve fibres (Cottrell, 1940), in spinal cell bodies (Gardner, 1940) and in the cerebr'al cor'tex (Brody, 1955). If the explanation offer'ed in r'elation to faeial skin is valid, at least in par't, then a similar decrease in sensibility should prevail when tactile stimuli ar'e applied to the oral mucosa. The pr'esent investigation was undertaken to test this hypothesis.A second objective was to discuss the assumption that perception of oral tactile stimuli has a bearing on the ability of patients to adapt to full dentur'es. The importance of this factor in relation to other's is still uncertain (Berr-y & Mahood, 1966).

Dimension discrimination at two different degrees of mouth opening and the effect of anaesthesia applied to the periodontal ligaments

“…This problem has been investigated indirectly by comparing the discrimination ability in dentate and edentulous subjects (Manly et al, 1952;Kawamura & Watanabe, 1960). Although, in both studies, differences in dimension discrimination could be demonstrated between the two types of subjects, the differences could also, in part at least, be attributed to reduced sensory acuity following age changes in the sensorium (Brill et al, 1974), and/or denture displacement during the testing procedures. Preferably, the critical experiment to determine the contribution by periodontal receptors should be performed on the same subjects, comparing results obtained before and after application of anaesthesia to the periodontal ligaments.…”

Spatial mapping of electrotactile sensation threshold and intensity range on the human tongue: Initial results

“…The various tactile sensors in the anterior aspect of the tongue are innervated by 2 cranial nerves (CN): the lingual branch of the trigeminal nerve (CN-V), and the chorda tympani branch of the facial nerve (CN-VII). Additionally, receptor densities are highest at the tip of the tongue, slightly lower at the lateral perimeter, and progressively decline toward the posterior and midline [9][10][11]. The electrode array we have developed spans all these regions, leading to substantial differences in the perceived intensity of the tactile sensation as a function of the stimulus location.…”

Ageing and the Accuracy of Jaw Muscle Control

“…Evidence of deterioration in tactile sensitivity of the skin innervated by the trigeminal nerve with ageing has been demonstrated by Brill et al [1974b]. Similar changes [Brill et al, 1974a] occur intra-orally, and might be expected to compound with the other documented findings by further reducing the accuracy of performance in elderly patients, especially the edentulous, who lack the refined feedback available from the periodontal structures.…”