Posturography is a general term that covers all the techniques used to quantify postural control in an upright stance, in either static or dynamic conditions.
Among those techniques is computerized dynamic posturography (CDP), also called test of balance (TOB).
CDP is a non-invasive specialized clinical assessment technique used to quantify the central nervous system adaptive mechanisms (sensory, motor and central) involved in the control of posture and balance, both in normal (such as in physical education and sports training) and abnormal conditions (particularly in the diagnosis of balance disorders and in physical therapy and postural re-education).
Due to the complex interactions among the sensory, motor, and central processes involved in posture and balance, CDP requires different protocols to differentiate among the many defects and impairments, which may affect a subject’s postural control system. CDP challenges that system by using several different combinations of visual and support surface stimuli and parameters. It has been proven effective in assessing vestibular as well as some neuromuscular disorders affecting balance.
Static posturography is carried out by placing a subject in a standing posture on a fixed instrumented platform (force plate) connected to sensitive detectors (force and movement transducers), which are able to detect the tiny oscillations of the body.
Dynamic posturography differentiates from static posturography in that it usually involves perturbing the subject’s posture by means of a foam cushion or a special apparatus with a movable horizontal and tilting platform. As the subject makes small movements, the sensitive detectors transmit this time-varying information in real time to a computer. Thus, the dynamic posturography test protocols can quantify the ability of a subject to maintain balance in non-static conditions. Usually coupled with the ability to test the subject either with or without visual references (eyes open or closed) or with a moving environment that gives conflicting visual information, dynamic posturography makes it possible to quantify a subject’s vestibular functions. This is because, in certain testing conditions, the visual and proprioceptive systems cannot be used, and the subject must rely only on the vestibular system to maintain balance.