Human balance control during cutaneous stimulation of the plantar soles

Do spike insoles enhance postural stability and plantar-surface cutaneous sensitivity in the elderly?

“…The absence of correlation between PS sensitivity and postural control suggested that the spikes stimulated other receptors such as the deep ones. As indicated by Maurer (2001), PS receptors are mainly involved in the evaluation of the support surface whereas deep receptors contribute to the continuous control of CoP displacements. As we only tested the Merkel cells and Ruffini endings, vibratory testing at different frequencies is needed to check this assumption.…”

“…Different types of mechanoreceptors [plantarsurface (PS) and deep receptors] are involved and are widely distributed under the foot sole (Kennedy and Inglis 2002). As the feet interface directly with the ground, cutaneous cues provide very detailed spatial and temporal information about the support surface properties, and about the variations of pressure under the feet that directly result from a shift of the centre of foot pressure (CoP) displacements (Maurer et al 2001;Perry 2006). The plantar sole is a "dynamometric map" (Kavounoudias et al 1998).…”

“…Perry (2006) concluded that both vibratory and touch detection thresholds decline with age: The loss of cutaneous sensation correlated with an impaired control of balance and an increased likelihood of falling. Other authors showed that applying vibration (Dhruv et al 2002;Priplata et al 2003;Priplata et al 2006) or rotary plantar massages (Bernard-Demanze et al 2004) to the foot soles enhances both cutaneous sensation (Dhruv et al 2002) and balance control (Maurer et al 2001;Bernard-Demanze et al 2004). Placing a raised edge underneath the perimeter of the plantar foot surface also facilitates postural stability (Maki et al 1999).…”

“…Whereas reducing/suppressing or stimulating the plantar afferents are two relevant methods to explore the role of tactile messages in postural control, a third approach consists of changing the characteristics of the supporting surface (Watanabe and Okubo 1981;Maki et al 1999;Maurer et al 2001). The aim of the study was to reproduce, to some extent, the effects of a massage of the plantar sole, via a "mechanical" and continuous system that does not require a therapeutic intervention.…”

A wireless embedded tongue tactile biofeedback system for balance control

“…Indeed, plantar cutaneous mechanoreceptors (deep and plantar-surface) could potentially provide detailed spatial and temporal information about contact pressures under the foot and shear forces resulting from body movement that constitute valuable feedback to the postural control system. For instance, anaesthetising [23], altering [31] or stimulating [2,19,21,29,30,37] plantar cutaneous receptors of the plantar soles have previously been shown to affect postural control during quiet standing. In addition, as the neuromuscular constraints acting on the individual increase, as is the case following muscular fatiguing exercise, the availability and integrity of cutaneous inputs from the plantar soles become of Vuillerme et greater importance in the appropriate control of balance [44,47].…”