CDP Tests For Providing Assessment of Sensory and Motor Impairments

Submitted on March 27, 2012

Computerized Dynamic Posturography (CDP)

Computerized dynamic posturography, or CDP as it is more commonly known, is the often used test to determine postural stability. CDP testing provides you with information about motor control and balance function by testing them under varying conditions.

Essentially, this test is done to determine a person's balance by testing all balance components of the body, i.e. the vestibular system and the somatosensory system.

Since an individual's motor and sensory skills are being tested, he/she is made to stand on a platform and asked to focus on or observe a visual target. The platform and the visual target are then moved. There are pressure gauges placed under the platform which record the individual's shift in body weight (in other words swaying of the body). When a person's balance control is suspect, a safety harness is provided to prevent falling.

The key to maintaining balance is not only dependent on the eyes and vestibular system, but also on information received by the brain from the joints and muscles that tell the body which direction the head should turn, and how much grip needs to be applied on the surface keeping in mind its texture and slope.

By conducting a CDP test you can determine how well you can maintain balance in challenging conditions. This then helps doctors figure out other specific tests, as well determine an appropriate treatment plan.

Since the nature of interaction between the sensory motor and central adaptive processes is complex, CDP testing requires distinct protocols to differentiate between balance impairments. Therefore, the challenge is to put you through a situation that helps quantify failure of adaptive process mechanisms, if any, identify sensory inputs or lack thereof, and determine movement response patterns. As mentioned above, all this is tested by way of controlling visual inputs while varying the support of the walking/standing surface by rotating and/or tilting it.

There are three specific tests through which CDP provides assessment of sensory and motor impairments:

Sensory Organization Test (SOT)

The aim of this test is to objectively observe your postural control. This is done by assessing your ability to effectively use visual and vestibular information, and respond accordingly. So your responses, i.e. swaying of the body and eye movements, will help determine if the sensory and vestibular responses are in order. In cases of dizziness or lack of balance, you body will not adjust to the movement of the platform and your eyes may not be able to follow the visual target. If you are dizzy, the first response is to close your eyes.

Adaptation Test (ADT)

The ADT aims to evaluate your ability to alter your motor responses and minimize your body swaying, especially when the surface support moves or unexpectedly tilts, and you are in a toes-up or toes-down condition. As the platform rotates/tilts, the pressure gauge will provide energy scores which quantify the force response you are required to give to the provoked postural instability.

Motor Control Test (MCT)

The motor control test (MCT) determines your ability to be on your feet literally. In other words, this test checks how quickly and effectively you recover from unpredictable provocations. Here, a series of small, large, or medium platform translations occur in forward as well as backward directions, thereby eliciting reflex postural responses. In an MCT, lateral symmetry, onset timing, and strength of responses are measured.

There is no specific cause for dizziness or balance disorders. However, studies indicate that the impairment reduction strategy is the most successful way of reducing the symptoms associated with imbalance and dizziness disorders, especially when these disorders are a result of multiple causes.