Practical use

A number of patients can benefit from the results of posturography testing as practitioners can analyze the paths of neurological and vestibular problems and evaluate existing balance disorders.

According to the American Geriatric Society,3 one-third of the population in the U.S. over the age of 65 experience unintentional falls.

"When problems with sluggish reflexes, the sensory system, the vestibular system, visual changes, and minor weakness occur, there is an increased chance of a fall," said Ray Hedenberg, a physical therapist with South Valley Physical Therapy in Denver. "The EquiTest gives information about the patient's ability to use sensory systems and how the information is integrated through the midbrain, cerebellum, and brain stem and then coordinated with the motor systems so the patient can respond in an appropriate fashion," he said.

Hedenberg works with elderly patients to more effectively use the vestibular system and try to reactivate and use the function they have. Posturography systems can look at postural strategies that patients use to maintain their center of gravity on unstable surfaces.

"That information is particularly helpful with geriatric patients to help a clinician customize treatment based on assessment findings," he said.

The information from the SOT is useful, he said, in determining whether patients display an appropriate response pattern to maintain balance under particular conditions.

"If they are using an inappropriate strategy, that puts the patient at a very high risk for falling," he said.

Strength and range of motion play a role in effective postural strategies, as does a patient's cognitive level. Sometimes the automatic responses of patients with Alzheimer's disease and dementia can be retrained to safely recruit their muscle groups and sensory systems and be effective even without full cognitive ability.

More than one million people in the U.S. are living with Parkinson's disease. Difficulty with balance is one of the symptoms of the condition.4 With no cure available yet, medication is the best form of treatment for the neurological disorder.

Researchers at Stanford University Medical Center studied the role of medication in postural stability for Parkinson's patients in order to determine which medications and which dosages were most helpful.5 Posturography equipment can help track progress and note changes medication dosage may have on a patient's tendency to sway. The researchers used the SOT to gather data on postural sway before and after patients were medicated. They found a correlation between medication and tremors.

Sports and sway

Posturography may offer opportunities for evaluating athletic performance and rehabilitation after injury. Postural stability and neuropsychological testing are becoming integral parts of postconcussion assessment in athletes.6 Given that one in five high school football players sustains a concussion each year and 50% of college athletes have a history of concussion,7 postconcussion evaluation is important in determining whether an injured athlete can return to play. General concussion assessment recommendations of the Atlantic Coast Conference (ACC) for collegiate sports include general cognitive and postural stability testing to determine the severity of concussion. Once an athlete has been assessed postrecovery and determined to be symptom-free, return to play can be considered.8

Kevin Guskiewicz led a recent study on postural stability and neuropsychological deficits after concussion in college athletes. He used the SOT to look at postural stability assessment for return to play. He concluded that the acute balance deficits demonstrated by athletes with cerebral concussion were likely the result of ineffective use of information from the vestibular and visual systems.9 These balance deficits can affect performance and place the athlete at risk.

Limits of posturography

High equipment costs have so far kept force-plate posturography technology from making the leap from research facilities to rehabilitation practices.

"The expense associated with high-tech equipment can be something of a deterrent to a clinic or a clinician," Hedenberg said. "That includes not just NeuroCom equipment, but also isokinetic or motion analysis equipment."

Reimbursement is allowable for dynamic posturography and there is an evaluation code for Medicare, but unfortunately not all insurance companies follow Medicare's lead.

"With today's reimbursement environment, it is a risk to buy the systems with high cost because you may not get reimbursed and there is the worry that you won't be able to pay for it," Hedenberg said. "We deal with what we have and utilize our clinical skills. That's unfortunate but that's the way healthcare is today."

Advancements in biomechanical devices are changing postural stability research and evaluation. With new additions like the PSI, data collection capabilities are evolving. Research will gain from newly available information and practitioners fortunate enough to have access to a dynamic posturography equipment system have a richer assessment tool.

Michelle Butera is a freelance writer based in San Francisco with a BS in kinesiology.

References

1. Chaudhry H, Findley T, Quigley KS, et al. Measures of postural stability. J Rehabil Res Dev 2004;41(5):713-720.

2. Chaudhry H, Findley T, Quigley KS, et al. Postural stability index is a more valid measure of stability than equilibrium score. J Rehabil Res Dev 2005;42(4):547-556.

3. Rubenstein LZ. Falls and balance problems. Patient Education Forum, American Geriatrics Society. http://www.americangeriatrics.org/ed.../falling.shtml, accessed March 2006.

4. Parkinson's Action Network. About Parkinson's: What is Parksinson's disease. http://www.parkinsonsaction.org/abou...parkinsons.htm, Accessed June 2006.

5. Bronte-Stewart HM, Minn AY, Rodrigues K, et al. Postural instability in idiopathic Parkinsons disease: the role of medication and unilateral pallidotomy. Brain 2002;125(Pt 9):2100-2114.

6. Moser RS. Knock Knock: concussions from sports injuries. N J Med 1998;95(11):27-29.

7. Hausdorff JM, Rios DA, Edelberg HK. Gait variability and fall risk in community-living older adults: a 1-year prospective study. Arch Phys Med Rehabil 2001;82(8):1050-1056.

8. Guskiewicz KM. Sport-related concussions: Are we headed in the right direction. The Atlantic Coast Conference (ACC). Sports Sciences, October Features: Soccer. www.theacc.com/genrel/100104aac.html, accessed June 2006.

9. Guskiewicz KM, Ross SE, Marshall SW. Postural stability and neuropsychological deficits after concussion in collegiate athletes. J Athl Train 2001;36(3):263-273.