Physiology
Maintaining balance while standing in the stationary position relies on intact sensory pathways, sensorimotor integration centers and motor pathways.
The main sensory inputs are:
- Joint position sense (proprioception), carried in the dorsal columns of the spinal cord;
- Vision
- Vestibular apparatus
Crucially, the brain can obtain sufficient information to maintain balance if any two of the three systems are intact.
Sensorimotor integration is carried out by the cerebellum and by the dorsal column-medial lemniscus tract. The motor pathway is the corticospinal (pyramidal) tract and the medial and lateral vestibular tracts.
The first stage of the test (standing with the eyes open with hands on hips), demonstrates that at least two of the three sensory pathways is intact, and that sensorimotor integration and the motor pathway are functioning. The patient must stand unsupported with eyes open and hands on hips for 30 seconds. If the patient takes a step or removes a hand from the hip, the timer is stopped. The patient may make two attempts to complete the 30 seconds.
Similar to the sensory organization test, the visual pathway would then be removed by closing the eyes. If the proprioceptive and vestibular pathways are intact, balance will be maintained. But if proprioception is defective, two of the sensory inputs will be absent and the patient will sway then fall. Similar to the Romberg Test, the patient must stand unsupported with eyes closed and hands on hips for 30 seconds. The patient may make two attempts to complete the 30 seconds.
A variation of the Romberg Test, the Sharpened Romberg Test, consists of narrowing the patient’s base of support by placing feet in a heel to toe position. Nonetheless, test instructions do not specify which foot, preferred or non-preferred, should be placed in front of the other. The patient should be instructed to keep hands on hips for the whole 30 seconds. If the patient takes a step or removes hands from hips, the timer is stopped and the patient may attempt the test one more time. The sharpened Romberg does have an early learning effect that will plateau between the third and fourth attempts.
Read more about this topic: Romberg's Test
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