In the current study, we adopted the hypothesis that the body scheme disturbances occurring during adolescence might lead subjects to transiently neglect proprioceptive information and that adolescents might rely more strongly on vision to control their orientation and stabilize their body. To check this point, we asked adolescents 14–15 years to maintain vertical stance while very slow sinusoidal oscillations in the frontal plane were applied to the supporting platform at 0.01 Hz (below the detection threshold of the semicircular canal system) and at 0.06 Hz (above) with the eyes open and closed. Two postural components, orientation and segmental stabilization, were analyzed at the head, shoulder, trunk, and pelvis levels. At the lowest frequency without vision, the performances of adolescents were much less efficient than those of adults. Moreover, this study showed that vision plays a predominant role in adolescents’ control of orientation and body stabilization. At 0.06 Hz without vision, a clearcut difference was observed between the strategies used by girls and boys; specifically, the maturation of the segmental stabilization processes was found to be more advanced in girls than in boys. However, no such difference was observed at 0.01 Hz. Lastly, comparisons between the data obtained in adolescents and those previously obtained in young adults (Vaugoyeau, Viel, Amblard, Azulay, & Assaiante, 2008) clearly show that adolescents use different postural strategies and that they are not yet capable of reaching comparable postural performance levels to those observed in adults. Because adolescents were not able to use the proprioceptive information available to improve their postural control, we concluded that they showed a maturational lag in comparison with adults. This suggests that the mechanisms underlying postural control are still maturing during adolescence, which might constitute a transient period of proprioceptive neglect in sensory integration of postural control.
Sébastien Viel, Marianne Vaugoyeau and Christine Assaiante
Fabien Cignetti, Sébastien Caudron, Marianne Vaugoyeau and Christine Assaiante
There is evidence that adolescence is a critical period in development, most likely involving important modifications of the body schema and of the sensorimotor representations. The present study addressed this issue, by investigating the differences between adolescents and adults regarding the integration of proprioceptive information at both perceptual and postural levels and the visual recognition of human movement. Proprioceptive integration was examined using muscle-tendon vibration that evoked either a postural response or an illusory sensation of movement. The ability to recognize human movement was investigated from a paradigm where the participants had to discern between human movements performed with and without gravity. The study produced three main findings. First, the adolescents had larger postural responses to tendon vibrations than the adults, with visual information enabling them to reduce this exaggerated postural reaction. Second, the adolescents had a greater illusory perception of movement compared with the adults. Third, the adolescents had the same perceptual ability as adults in the human movement perception task. In conclusion, we were able to highlight notable differences between adolescents and young adults, which confirms the late maturation of multisensory integration for postural control and the privileged visual contribution to postural control.