What does sensory integration refer to in postural control?

• A. Brainstem reflex for posture
• B. Sensory reweighting of input only
• C. Muscular synergy for gait
• D. CNS integrating visual, somatosensory and vestibular info for postural control

Answer: (D)

In postural control, sensory integration means the central nervous system takes input from the visual system, somatosensory information from the body, and vestibular signals from the inner ear, and combines them to form a coherent sense of body position and movement. This integrated signal guides the appropriate muscle responses to keep us upright and balanced, and it can adjust which inputs are weighted more heavily depending on the situation. For example, standing on a firm surface with eyes open uses all three sources to verify orientation; on a foam surface with eyes closed, somatosensory input is less reliable, so the brain shifts to rely more on vestibular and visual cues to maintain balance. This goes beyond a simple reflex or a single cue, encompassing the dynamic coordination of multiple sensory streams to control posture.