Control of balance involves complex and inter-connected physiologic pathways for the purpose maintaining posture, facilitating appropriate movements, and restoring equilibrium (2,3). These tasks are achieved by the coordination of multiple body systems including vestibular (detection of angular and linear translations or accelerations), visual (visual representation of the world around you), and proprioceptive (perception of spatial orientation via muscle and joint positioning), all integrating in the brainstem (2-7), an important area of the brain that also has associations with the coordination of eye movements and regulation of autonomic functions (3).

CAPS^® allows a subject to be tested both statically and dynamically through a series of 10, 25-second tests. Static tests are completed on a solid surface with the subject’s eyes open, eyes closed, and eyes closed with mathematical calculations. Dynamic tests are completed on a perturbed surface, or foam pad, including the same tests already mentioned, as well as, eyes closed with the head in different positions. The completion of each test is recorded, and the subject is given an overall stability score compared against normative data for their age, height, and weight.

Manipulating the subject’s sensory environment by decreasing visual (eyes closed), proprioceptive (perturbed surface) and vestibular (head in different positions) feedback, in addition to introducing a secondary task (mathematical calculations), gives insight to how each system is contributing the subject’s overall balance and stability (8), as well as the ability of those systems to process the available sensory information and recalibrate accordingly (9), potentially revealing underlying sensorimotor mechanisms contributing to balance disorders (10).

Although specific stability scores do not directly correlate to any disease or dysfunction, the subject’s performance can be assessed based on sway patterns, center of pressure changes, response latencies, etc. reflecting what systems or parts of the brain may not be functioning optimally, such as seen in concussion, traumatic brain injury (11), peripheral neuropathies, multiple sclerosis (12), Parkinson’s Disease and other neurodegenerative diseases, stroke, vestibular disorders, aging (13-15), and many other different conditions that impact neurological function.