POSTUROGRAPHY

Presented by: Mike Darnell

Objectives

What is Posturography? Force Platforms Stabilographic analysis Computerized Dynamic

Posturography Sensory Organization Test (SOT) Motor control Test (MCT) Adaptation Test (ADT)

Posturography

Posturography - A term covering all of the techniques used to quantify postural control in upright stance, in either static or dynamic conditions.

Static Posturography (stabilometry) - Places the subject in a standing posture on a force plate connected to force and movement transducers, which are able to detect the tiny oscillations of the body.

Dynamic Posturography (CDP) – Disturbs the subject’s posture by means of a special apparatus with a movable platform.

Force Platforms / Plates

Measure the ground reaction forces generated by a body standing on or moving across the platform.

Used to quantify balance, gait, and other parameters of biomechanics.

Forces in three perpendicular directions are usually plotted against time Vertical (Fz) Horizontal –antero-posterior (Fy) Lateral –medio-lateral (Fx)

Stabilographic analysis:Terminology

Postural Sway – A measure of the movement of the center of gravity within the base of support.

Postural Stability – Measured on the basis of the horizontal difference in sway motion between center of gravity and center of pressure.

Stabilographic Analysis Measures stability of stance or postural

equilibrium. Highlights poor posture, instability and asymmetry. Variables that can be altered

Base of support (feet together/separated, standing on one foot, etc)

Surface (hard or foam) Vision (opened v. closed)

Sample Graphs - Stabilometry

Computerized Dynamic Posturography

Most common method of measuring postural sway.

Is balance getting better or worse?

Three types of tests: Sensory Organization Test (SOT) Motor Control Test (MCT) Adaptation Test (ADT)

Sensory Organization Test (SOT)

Identifies problems with the patient's ability to effectively use visual, vestibular, and proprioceptive information.

Sensory information is eliminated through calibrated "sway referencing" of the support surface and/or visual surround.

Patients may display an inability to make effective use of individual sensory systems.

SOT: six sensory condition

1. Eyes open, fixed surface and visual surround. 2. Eyes closed, fixed surface. 3. Eyes open, fixed surface, sway referenced visual surround. 4. Eyes open, sway referenced surface, fixed visual surround. 5. Eyes closed, sway referenced surface. 6. Eyes open, sway referenced surface and visual surround.

Scenario – before 35-year-old female with a chief complaint of

dizziness. Patient history, physical exam, and other diagnostic

tests are inconclusive. Data from CDP indicate vestibular impairment.

Scenario – after As a result of CDP data, the patient was referred

to physical therapy After several PT sessions supplemented by an

individualized home exercise program, the patient was re-evaluated with CDP.

Motor Control Test (MCT)

Assesses the patient's ability to quickly and automatically recover from unexpected external provocations.

Measurements include onset timing, strength and lateral symmetry of responses.

Sample Graph - MCT

Adaptation Test (ADT)

Assesses the patient's ability to modify motor reactions and minimize sway when the support moves unpredictably in the toes-up or toes-down direction.

This adaptive test simulates daily life conditions such as irregular support surfaces.

Sample Graph - ADT

Points to Remember

Static v. Dynamic Posturography

Relationship of Newton’s laws to force plate analyses

How to differentiate between the various tests

What the individual tests are used to determine

References: Allum, J.H., Shepard, N.T., (1999). An overview of the

clinical use of dynamic posturography in the differential diagnosis of balance disorders. Journal of Vestibular Research, 9, 223-252.

Jones, R., (2008). The relationship between postural stability and virtual environment adaptation. Neuroscience Letters, 435(3), 204-209.

Parker, K., (2001). Use of force platforms in physics and sport. Physics Education, 36, 18-22.

Riley, M.A., Clark, S., (2003), Recurrence analysis of human postural sway during the sensory organization test. Neuroscience letters, 342, 45-48.

http://resourcesonbalance.com/neurocom/protocols/motorI mpairment/index.aspx