Prediction of Postural Control Performance in Blind and Sighted Individuals: Role of Lower Body Strength and Proprioception
Individuals with visual impairments are known to have postural control deficiencies resulting in increased risk for falls. It is important, therefore, to understand how factors beyond vision loss are used for controlling balance within this population. Lower body strength parameters, especially muscle forces around the ankle, and Proprioceptive sensations are thought to be essential for postural control However, there is no documented research examining the relationships among lower body proprioception, strength and postural control performance in blind population. Ankle strength was not significantly different between two groups.
However, visually impaired subjects were found to have significantly more accurate dorsiflexion proprioception (p=0.007) than the sighted group. Closing eyes (EC) significantly reduced TTBmin (p<0.05) and increased iTTB (p<0.05) in sighted subjects. In EO condition, the sighted group had higher TTBmin (p<0.05) and lower iTTB (p<0.05) than the visually impaired group whereas no significant postural control performance differences were found in EC condition.
No significant adaptation differences were found between two groups on perturbation tests. However Sighted group displayed immediate adaptations in eyes open but not eyes closed conditions.
While limited to a cross sectional design and small sample size the finding that muscle strength is more important than proprioception could have important implications to avoiding fall risks in this population. Availability of vision may effect the relationships between muscle strength and postural control performance in sighted subjects.