Clinically Available Assessment Measures for Lingual and Labial Somatosensation in Healthy Adults: Normative Data and Test Reliability

Abstract

Two-point discrimination and Von Frey hair monofilament assessment for both detection- and discrimination-threshold estimates have high test-retest reliability in a healthy young population. These testing measures could be a way to easily complete objective somatosensory testing of the orofacial region in a clinical context.

Assessment of Midline Lingual Point-Pressure Somatosensation Using Von Frey Hair Monofilaments

“…During initial trials of this protocol, researchers selected a ceiling of 15.0 g. Although available monofilaments go up to 300 g, a ceiling was selected a priori to prevent the risk of damaging the skin. Additionally, when testing an area like the tongue for which there is no internal skeletal structure, application of monofilaments higher than 15 g were found to move the entire tongue muscle which could activate sensory nerve endings in surrounding locations 17 . In the representative data sample, many healthy young adults were able to sense the 0.008 g target monofilament -the lowest manufactured Von Frey hair monofilament.…”

“…It is possible this device may provide an opportunity to test at levels less than 0.008 g; however, there are unresolved questions related to calibration of Cochet-Bonnet devices and ability to share findings across studies 27 . This protocol is adapted from recent work by Etter and colleagues 17 with a few key differences. In Etter's original protocol, threshold estimates were not averaged across trials.…”

“…This protocol uses Von Frey Hair monofilaments, commercially-available devices, to complete a relatively cost and time efficient assessment. Quantitative assessments of oral point pressure somatosensation using Von Frey hair monofilaments and this protocol were recently shown to be reliable in a cohort of healthy, young adults 17 for lateral edge of the lips and tongue as a prelude to future work in speech and speech disorders. However, the present protocol and recent work has focused on midline tongue due to its involvement with manipulating foods for tasting and safe and efficient swallowing 20 .…”

Exquisitely heterogeneous : Combining different food textures to boost palatability

“…These dots were used to define a consistent region of testing on the left and right side of the tongue; these marks were placed ~0.5 cm from the tip and ~0.5 cm from the tongue midline. A temporal two alternative forced choice (2-AFC) task was used to establish the lingual tactile detection thresholds in a three-down one-up staircase procedure (Etter et al, 2017;Gescheider et al, 1994;Tracey et al, 2012). In practice, participants were asked to indicate in which of two sequential trials they could perceive the applied stimulus in either the left or right side of the tongue.…”

“…These monofilaments consist of nylon threads and are commonly used to measure tactile pressure sensitivity of the skin. The filaments apply a defined force to a relatively small contact area upon bending of the thread (Aktar et al, 2015b;Etter et al, 2017;Levin et al, 1978). Here, we hypothesized that lingual tactile sensitivity, as 7 measured with Von Frey monofilaments, might correlate with the perception of hard microparticles, as their presence in food might apply localized pressure on the tongue surface during consumption.…”