National Physical Therapy Examination (NPTE) Practice Exam

What is required for a patient to maintain stability while standing on an unstable surface with eyes closed?

1. Intact vestibular system

2. Good proprioceptive feedback

3. Strong visual input

4. Muscle strength

The correct answer is: Intact vestibular system

Maintaining stability while standing on an unstable surface with eyes closed primarily relies on the function of the vestibular system. The vestibular system, located in the inner ear, provides critical information about the head's position and motion relative to gravity. When visual input is removed, as it is when the eyes are closed, the body must rely more heavily on the vestibular system and proprioceptive feedback to maintain postural control. Without intact vestibular function, a patient may struggle to determine their body's orientation and stabilize themselves effectively on an unstable surface. This is because the vestibular system plays a key role in balance by detecting changes in head position and motion, thereby influencing muscle activation to maintain equilibrium. While proprioceptive feedback is also important for balance, especially in a scenario where visual input is not available, it is the vestibular system that compensates for the loss of visual cues when the eyes are closed. Muscle strength is crucial for overall stability and support, but without proper sensory input from the vestibular system, achieving stability on an unstable surface would be significantly compromised.