The differential effects of foot sole sensory on plantar pressure distribution between balance and gait

Foot sole tactile sensation provides valuable feedback to the central nervous system. Acutely reduced foot sensation changes plantar pressure distribution in standing and gait; however, the effect of chronic foot sole sensory impairment on plantar pressure distribution is unclear.PurposeThis study aims to examine the effects of peripheral neuropathy (PN) induced chronic sensory loss on plantar pressure distribution in walking and standing.MethodsFoot sole sensitivity was tested at the five sites: big toe (BT), 1st metatarsal (M1), 5th metatarsal (M5), mid-foot (MF) and heel (HL). Relative peak pressures (RPP) of the five sites were collected during a 20-s walking on a treadmill at .45 m/s and a 30-s quiet standing with eyes open. Five-way MANOVA was used to examine the influence of sensitivity of each site on overall plantar pressure distribution for standing and walking separately. Tukey's test was used to examine the significant associations.ResultsIn standing, the sensitivity of BT affected average RPP at BT significantly (P < .05), where RPP associated with insensitive BT (8.1 ± 5.7%) was greater than with sensitive BT (4.5 ± 4.9%). Furthermore, the RPP at HL was greater for insensitive MF (36.1 ± 17.9%) compared with sensitive MF (23.6 ± 7.4%) (P < .05). No pressure distribution changes were observed in walking.ConclusionsFeedback from foot sole tactile sensation in gait is not as significant as in standing, showing standing balance control relies more on feedback control mechanism while gait control relies more on feed forward control mechanism.

► Big toe tactile insensitivity increases pressure under it during standing. ► Mid-foot tactile insensitivity increases pressure under the heel during standing. ► Foot sole numbness did not lead to change of pressure distribution during walking. ► Foot sole tactile sensation feedback seems more important for standing than gait. ► Standing balance relies more on feedback while gait on feed forward control mainly.