Evaluation of Lingual Tactile Sensitivity Using a Pneumatic Multi-Point Stimulation Device

The sensory function of the tongue is critical for mastication and swallowing. However, its assessment methods remain insufficiently established.

In this study, we developed a pneumatic multi-point stimulation system capable of controlling the location, timing, and pressure of small balloon inflations to simulate the movement and elasticity of food within the oral cavity. Using this system, we established a new method to quantify lingual tactile sensitivity, specifically the ability to detect stimulus point movement under passive touch and pressure differences under active touch.

We evaluated the age-related differences in lingual tactile sensitivity in 16 young men (mean age ± standard deviation, 21.9 ± 1.2 years) and 20 older men (74.1 ± 4.1 years) with no history of tongue or related disorders.

The results demonstrated significant age-related declines in lingual tactile sensitivity under both passive and active touch conditions. Furthermore, these measures showed no significant correlations with conventional sensory tests, including the Semmes-Weinstein monofilament test and the two-point discrimination test. This suggests that the proposed method captures aspects of lingual sensory function not assessed by existing approaches.

By enabling the quantitative evaluation, using a single device, of not only dynamic sensory perception during passive touch but also active touch, which involves the integration of sensory input (superficial and deep sensation) and motor output, this method has the potential to serve as a novel tool for screening oral hypofunction in older adults and for supporting the assessment of dysphagia, including masticatory dysfunction.