Aspects of Balance
- Sensory reception and integration
– Visual, Somatosensory and Vestibular
– Ex: Berg. TUG, Tinetti - Volitional (Anticipatory) postural control
– Limits of stability/BOS - Non-volitional (Reactionary/Non voluntary) postural control
– Unexpected pertibations (Stepping strategy) - Musculoskeletal Integrity
– Ankle, knee and hip strength and ROM clinical exam
Posturography
Strian guagues within a force platform + Computer Software = Objective and Precise Data for Postural Sway
Posturography measurements are taken based on…
Center of Pressure
ML, AP
COP excursion is typically ____ than COM excursion and has more ____
- larger
- oscillations
COP is at the feet, COM is located more over the ____
torso.
COP has much more force/movement than COM.
In order to keep natural stability humans need postural stability. Neurological dependence would be too taxing. What strategies do we use?
- Stances
- Rely on muscles and bones
- Direct our force above the COM NOT through it
Why do taller people have more stability?
Inverted Pendulum
- Taller people fall slower due to inertia and therefore have more time to correct and counter the angular inertia through more strategies.
How can spinning your arms help in prevention from falling?
Spinning the arms adds angular momentum in the proper direction to prevent falling by opposing the angular inertia.
Measures commonly reported for posturography
- Area outline by the COP Path; Ex: 95% ellipse (green)
- Path Length: total distance traveled
- Maximal Excursion (width of trace in both ML and AP) (Blue)
- Variability (Ex: SD)
- Velocity (how fast someone is moving) (Red)
- Time to contact (before falling off balance)
COP can be measured with one or two platforms looking at…
the pressure of each foot or the global pressure (both combined)
Can allow to see if one foot has more weight than the other.
____ is often built for standing. You need to compare ____ to COP to normalize data.
- Piezioelectric
- BOS from foot measurements
Someone who has sensory detrement can be tested by a ____ Test.
Sensory Organization
NeuroCom Balance Master
- Most research support
- Static postural tasks
Bertec Balance Advantage CDP
- Allows more interactive, live tasks to be performed with changing conditions
- Bottom foot plate can move and slide
- Can perform a sensort deprevation test on it
- Can be used for interventions
Biodex Balance System
- Similar to Bertec
- Base platform moves a little bit
- Has games
Motek Medical
- Static and dynamic balance assessment and training
- 0.5-1.0 Million Dollars
- Machine can do pertibations
- Games
Indications for Posturography
Who:
* Pts with dizziness or imbalance complaints
* Pts with known or non-specific Dx of sensory-motor impairments
* Pts suspected of exaggerating Sx
Why
- Help Dx
- Guide prescription and monitor results
- Quanitify balance objectively
- Customized balance training and outcome assessment
How do you determine what you are going to measure?
- Relative to the pts condition and the type of question you are asking
- Look in the literature for variables!
Standardization
- Number of platforms
- Foot Placement
- Conditions (Eyes O/C; Surface: H/S)
- Dual task (Cognitive, Sensorimotor)
Data Processing
- Sampling frequency (50-100 Hz good for standing tasks)
- Duration of recording (Generally 10-30 seconds)
- Decision of Filtering Noise
- Normalize Data (Height, Foot size, etc.)
Alternative methods for balance training/assessment
- Wii balance board
- Smart phone accelerometer (measures angular sway from inverted pendulum model)
