Aging effect on tactile perception: Experimental and modelling studies

We investigated the effects of aging on tactile perception. Ageing reduces the elasticity and extensibility of the skin throughout the epidermis, dermis and subcutaneous tissues, which greatly affects their mechanical properties as well as the layer thickness. These changes lead to a decrease in the overall Young modulus of the skin and the skin ability to detect different textures. The effects of ageing on touch perception are studied by means of experimental work and finite element simulations. Ageing behaviors are studied through the investigation of the skin geometrical and mechanical properties. As an experimental approach, we have developed two different systems: the air flow system to identify the rheological properties of the skin and the tribo-haptic system which allows the quantification of the vibrations transmitted to the finger in a tactile perception test. To better understand the mechanics of touch and the effect of ageing, new 2D finite element models of a viscoelastic multilayer finger are developed under ABAQUS environment. These models simulate the friction (finger/surface) of two groups of healthy young and old men in order to understand the effect of ageing on tactile perception and calculate the vibrations transmitted through the human finger tissue during a touch test under the same experimental conditions. The decline in tactile sensory capacity in older subjects has been highlighted. Results proved that the sense of touch decreases with age.