Enhanced somatosensory information decreases postural sway in older people

The somatosensory system plays an important role in balance control and age-related declines in somatosensory function have been implicated in falls incidence. Different types of insole devices have been developed to enhance somatosensory information and improve postural stability. However, they are often too complex and expensive to integrate into daily life and textured insole surfaces may provide an inexpensive and accessible means to enhance somatosensory input. This study investigated the effects of textured insole surfaces on postural sway in ten younger and seven older participants performing standing balance tests on a force plate under three insole surface conditions: (1) barefoot; (2) with hard; and (3), soft textured insole surfaces. With each insole surface, participants were tested under two vision conditions (eyes open, closed) on two standing surfaces (firm, foam). Four 30s trials were collected for different combinations of insole surface, standing surface and vision. Centre of pressure measurements included the range and standard deviation of anterior-posterior and medial-lateral displacement, path length and the 90% confidence elliptical area. Results revealed a significant Group*Surface*Insole interaction for five of the dependent variables. Compared to younger individuals, postural sway was greater in older people on both standing surfaces in the barefoot condition. However, both textured insole surfaces reduced postural sway for the older group especially in the eyes closed condition on a foam surface. These findings suggest that textured insole surfaces can reduce postural sway in older people, particularly during more challenging balance tasks. Textured insole surfaces may afford a low-cost means of decreasing postural sway, providing an important intervention in falls prevention.