Sensory and motor differences between young and older adults: somatosensory contribution to postural control.

OBJECTIVES

The aim of this study was to compare the performance of the sensory and motor systems and the contributions of possible differences to postural control.

METHODS

Twenty older adults (68.9+/-3.7 years of age) and twenty young adults (21.9+/-2.1 years of age) underwent visual, somatosensory (tactile and kinesthetic sensitivity), motor tests (joint torque and muscle activation latency) and postural control assessments (upright semi-tandem posture).

RESULTS

MANOVA and ANOVA indicated that older adults had a poorer performance in the sensory tests: visual acuity (p=0.001), visual contrast sensitivity (p=0.009), tactile sensitivity (p<0.001) and kinesthetic sensitivity of the knee (p<0.001) and ankle (<0.001); and in the motor tests: female (p=0.010) and male (p<0.001) knee flexion torque; female (p=0.002) and male (p<0.001) knee extension torque; female (p=0.029) and male (p=0.006) ankle dorsiflexion torque; female (p=0.004) and male (p=0.004) ankle plantar flexion torque; and muscle activation latency (p<0.001). The older adults also had greater body sway amplitude on the anterior-posterior direction (p=0.035). Multiple regression analysis revealed that perception of passive motion was the only variable that contributed to greater body sway on the anterior-posterior direction among older adults (R(2)=0.142; p<0.05).

CONCLUSIONS

There are differences in sensory and motor performance between young adults and older adults, and attention should be directed toward the contribution of the proprioceptive system to postural control among older adults.