COMPUTERIZED DYNAMIC POSTUROGRAPHY VALIDITY & EFFICACY STUDIES

Peripheral/Central Vestibular Deficits
Medical Necessity
Central Nervous System and Movement Disorders
Metabolic Diseases and Drug Effects
Disorders Associated with Aging
Sports and Occupational Medicine

Peripheral/Central Vestibular Deficits

Validity of CDP
Source	Design	Reference Standards	Conclusions
Stewart MG, et al (1999) "Cost-effectiveness of the diagnostic evaluation of vertigo." The Laryngoscope 108: 600- 605	Diagnostic cost-effectiveness study Patients with dizziness (N=192) Retrospective Blinded statistical analysis	Classification by: Audiometry Bithermal Calorics Electronystag-mography Magnetic Resonance Imaging	CDP was one of the most cost-effective tests of the battery of tests in the dizzy patient population.
El-Kashlan, et al, (1998) "Evaluation of clinical measures of equilibrium." Laryngoscope 108: 311-319	Evaluate the clinical utility of measures of balance in vestibular disorder patients (N=35) and normal controls (N=69) Prospective Blinded statistical analysis	Classification by: History Bithermal Calorics Electronystag-mography	CDP plays an important role in the functional evaluation and management of vestibular disorder patients.
Yardley, et al, (1998) "Neuro-otological and psychiatric abnormalities in a community sample of people with dizziness: a blind, controlled investigation." J Neurol Neurosurg Psychiatry 65(5): 679-684	Discriminate between dizziness patients (N=37) and controls (N=22) Prospective Blinded statistical analysis	Classification by: Audiometry Bithermal Calorics Electronystag-mography Tympanography Rotational Chair	CDP was the most sensitive diagnostic test for identifying abnormality in the dizzy patient population.
Ben-David, et al, (1997) "Evaluation of tullio phenomenon by computerized dynamic posturography." International Tinnitus Journal 3(2): 105-112	Discriminate between noise induced hearing loss (NIHL) patients with and without Tullio Phenomenon patients (N=20), with normal controls (N=15) Prospective Blinded statistical analysis	Classification by: History Audiometry	CDP discriminated between NIHL patients with and without Tullio phenomenon, and discriminated both NIHL groups from the normal controls.
Sargent, et al, (1997) "Idiopathic bilateral vestibular loss." Otolaryngol Head Neck Surg 116(2): 157-62	Discriminate between idiopathic bilateral vestibular loss patients (N=13) and normal controls (N=194) Prospective Blinded statistical analysis	Classification by: Physical Exam Bithermal Calorics Rotational Chair	CDP discriminated between patients with idiopathic bilateral vestibular loss (BVL) and normal controls. CDP was the only test that quantified differences in sensory impairments among the BVL patients.
Cass, et al, (1997) "Migraine-related vestibulopathy." Ann Otol Rhinol Laryngol 106: 182-189	Identify vestibular system abnormalities in patients (N=100) with migraine Retrospective	Classification by: History Physical Exam Bithermal Calorics Electronystag-mography	CDP was the most effective test for identifying patients who could benefit from vestibular rehabilitation treatment.

Efficacy of CDP in Improving Health Outcomes
Source	Design	CDP Impact on Outcome
Black, et al (2000) "Outcome analysis of individualized vestibular rehabilitation protocols." The American Journal of Otology 21: 543-551	Outcome of rehabilitation treatment in peripheral vestibular disorder patients (N=37), with a normal control (N=12) group Prospective with treat, no-treat, and control groups Blinded statistical analysis	CDP was the most effective diagnostic test (over ENG & Rotary Chair tests) in determining appropriate treatment. Customized vestibular rehabilitation treatment programs based on CDP results significantly improved health outcomes in patients with peripheral vestibular disorders.
Blatt, et al (2000) "The effects of the Canalith Repositioning Maneuver on resolving postural instability in patients with Benign Paroxysmal Positional Vertigo." The American Journal of Otology 21: 356-363	Outcome of canalith repositioning therapy in patients with canalithiasis BPPV (N=33) Prospective Blinded statistical analysis	CDP was the only diagnostic test to identify patients with residual balance deficits following canalith repositioning therapy. Patients with residual balance deficits benefit from additional vestibular rehabilitation.
Di Girolamo, et al (1998) "Postural control in benign paroxysmal positional vertigo before and after recovery." Acta Otolaryngol (Stockh) 118: 289-293	Outcome of canalith repositioning therapy in patients with ideopathic BPPV (N=32), with normal controls (N=32) Prospective Blinded statistical analysis	CDP was the only diagnostic test to identify and monitor otolithic deficits following repositioning therapy. Untreated otolithic deficits place patients at increased the risk for gait instability.
Gillespie, et al (1999) "Prognosis in bilateral vestibular hypofunction." Laryngoscope 109:35-41	Outcome of vestibular rehabilitation therapy in patients with bilateral vestibular hypofunction (N=35) Retrospective Blinded statistical analysis	CDP differentiated bilateral vestibular loss patients with pure vestibular impairment from those with additional sensory and/or motor impairments. Bilateral loss patients with pure vestibular impairments benefited the most from vestibular rehabilitation therapy.

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Medical Necessity

Validity of CDP
Source	Design	Reference Standards	Conclusions
Krempl and Dobie (1998) "Evaluation of posturography in the detection of malingering subjects." American Journal of Otology 19: 619-627	Discriminate among normal, transient vestibulopathy, and symptoms exaggeration groups (N=50) Prospective Subjects as own controls Blinded ROC statistical analysis	Classification by: History Instructions Experimental procedures	CDP differentiated among the normal, transient vestibulopathy, and symptoms exaggeration groups. CDP was the only diagnostic test to provide positive indications for symptoms exaggeration.
Goebel, et al (1997) "Posturographic evidence of non-organic sway patterns in nor-mal subjects, patients, and suspected malin-gerers." Otolaryn Head-Neck Surg 117 (4): 293-302	Discriminate among three instructed (N=72), selected patient (N=347), and control (N=122) groups Prospective/ retrospective Blinded statistical analysis	Classification by: History Audiometry Bithermal Calorics Electronystag-mography	CDP differentiated among the normal, vestibulopathy, and symptoms exaggeration groups. CDP was the only diagnostic test to provide positive indications for symptoms exaggeration.
Cevette, et al (1995) "Aphysiologic performance on dynamic posturography." Head and Neck Surgery 112:676-688	Develop statistical criteria to discriminate among two selected patient (N=104) and control (N=53) groups Prospective Blinded linear discriminate analysis	Classification by: History Audiometry Bithermal Calorics Electronystag-mography	CDP was the only diagnostic test to provide positive indication for symptoms exaggeration.

Efficacy of CDP in Improving Health Outcomes

Source

Design

CDP Impact on Outcome

Gianoli, et al (2000) "Posturographic performance in patients with the potential for secondary gain." Otolaryngology - Head and Neck Surgery 122 (1): 11-18

Determine the prevalence of symptoms exaggeration in two dizzy patient groups with and without secondary gain (N=100)

Retrospective

Blinded statistical analysis

CDP effectively screened balance disorders for which treatment was medically necessary.
Exaggeration was identified in 76% of patients with secondary gain and 8% of patients without secondary gain.
To maximize outcome in patients without secondary gain, exaggeration suggests anxiety and psychological factors that must be addressed.

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Central Nervous System and Movement Disorders

Validity of CDP
Source	Design	Reference Standards	Conclusions
Di Girolamo, et al (1999) "The role of vision on postural strategy evaluated in patients affected by congenital nystagmus as an experimental model." Journal of Vestibular Research 9: 445-451	Discriminate between patients with congential nystagmus (N=15) and normal controls (N=15) Prospective Blinded statistical analysis	Classification by: Neurological Evaluation Computerized Eye Movement Records	CDP showed a unique pattern of sensory impairment indicating abnormal visual control of balance.
Jauregui-Renaud, et al (1998) "Dynamic and randomized perturbed posturography in the follow-up of patients with polyneuropathy." Archives of Medical Research 29: 39-44	Discriminate between patients with chronic poly-neuropathy (N=14) and normal controls (N=14) Quantify changes over 6-year follow-up period Prospective Blinded statistical analysis	Classification by: Physical Exam Vibration Threshold Tests	CDP demonstrated a unique pattern of sensory and motor impairments in which somatosensory control was abnormal.CDP documented significant declines over the 6-year period.
Williams, NP et al (1997) "Vestibular evaluation in patients with early multiple sclerosis." The American Journal of Otology 18: 93-100	Descriptive study of functional balance problems in patients with multiple sclerosis (N=10) Prospective	Classification by: Magnetic Resonance Imaging Bithermal Calorics Electronystag-mography	CDP provided the most useful balance impairment information in patients with early stage multiple sclerosis.

Efficacy of CDP in Improving Health Outcomes
Source	Design	CDP Impact on Outcome
Savino, et al (2000) "The role of ocular oscillations upon visually dependent postural stabilization in patients affected by congenital nystagmus." J of Vestibular Research 10:201-206	Determine if involuntary eye movements or other neurological factors cause loss of balance in patients with congenital nystagmus (N= 9) Prospective Patients as own controls Blinded statistical analysis	CDP demonstrated that deficits in balance were caused by the involuntary eye movements. Balance is improved by reducing the involuntary eye movements.
Roberts-Warrrior, et al (2000) "Postural control in Parkinson's disease after unilateral posteroventral pallidotomy." Brain 123: 2141-2149	Quantify functional improvements in Parkinson's patients (N=27) following unilateral pallidotomy surgery Prospective Patients as own controls Blinded statistical analysis	CDP documented significant balance improvements retained up to 12 months following unilateral pallidotomy surgery. Adaptive balance continued to improve after other clinical measures began to decline.
Ondo, et al (2000) "Computerized posturography analysis of progressive supranuclear palsy." Arch Neurol 57: 1464-1469	Discriminate between Parkinson's disease (N=20) and Progressive Supranuclear Palsy (PSP) (N=20) in their earliest stages, with a normal control (N=20) group Prospective Blinded multivariate analysis	CDP was more effective than standard diagnostic tests (MRI) in differentiating between Parkinson's and PSP in their early stages. Early differentiation improves outcome, because PSP patients do not respond well to dopaminergic medication.
Chong, et al, (1999a) "Sensory organization for balance: specific deficits in Alzheimer's but not in Parkinson's disease." J of Gerontology: Med Sciences 54A (3): M122-M128	Quantify causes for frequent falls in Alzheimer's (N=11) and Parkinson's (N=15) patients, with normal controls (N=17) Prospective Blinded statistical analysis	CDP demonstrated significant differences in sensory impairments between the Parkinson's and Alzheimer's patients. Parkinson's patients demonstrated the ability to improve sensory balance with practice/training, while the prognosis for Alzheimer's patients was less clear.
Chong, et al, (1999b) "Postural set for balance control is normal in Alzheimer's but not in Parkinson's disease." J of Gerontology: Med Sciences 54A (3): M129-M135	Quantify differences in postural instability between Alzheimer's (N=11) and Parkinson's (N=8) patients, with normal controls (N=12) Prospective Blinded statistical analysis	CDP demonstrated significant differences in motor impairments between Parkinson's and Alzheimer's patients. Parkinson's patients are at increased risk for falls when making transitions between supported and unsupported conditions. Parkinson's patients can benefit from rehabilitation training focused on proper transitions.
Kasser, et al (1999) "Balance training for adults with multiple sclerosis: multiple case studies." Neurology Report 23: 5-12	Demonstration case studies of rehabilitation outcome in patients (N=4) with multiple sclerosis (MS) Prospective	Customized balance retraining programs for MS challenged balance and encouraged adaptations by focusing on the specific sensory and motor impairments identified by CDP. Customized balance retraining programs significantly improved health outcomes in patients with MS.

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Metabolic Diseases and Drug Effects

Validity of CDP
Source	Design	Reference Standards	Conclusions
Di Nardo, et al (1999) "The use of dynamic posturography to detect neurosensorial disorder in IDDM without clinical neuropathy." Journal of Diabetes and Its Complications 13: 79-85	Discriminate among insulin-dependent diabetes mellitus (IDDM) patients with and without peripheral neuropathy (N=45) and normal controls (N=24) Prospective Blinded statistical analysis	Classification by: History Physical exam Nerve conduction velocity (NCV) Vibration sensitivity test	CDP results discriminated between IDDM patients with and without neuropathy. CDP motor results correlated with NCV results. Results agreed with Jauregui-Renaud, et al, 1998 and Simmons, et al, 1997.
Simmons, et al (1997) "Postural stability of diabetic patients with and without cutaneous sensory deficit in the foot." Elsevier, Diabetes Research and Clinical Practice 36: 153-160	Discriminate among insulin-dependent diabetes (IDDM) patients with and without cutaneous sensory deficits in the feet (N=50) and normal controls (N=50) Prospective Blinded statistical analysis	Classification by: History Lab tests Monofilament sensory threshold tests	CDP results discriminated between IDDM patients with and without cutaneous sensory deficits. Results supported by Jauregui-Renaud, et al, 1998 and Di Nardo, et al, 1999.

Efficacy of CDP in Improving Health Outcomes
Source	Design	CDP Impact on Outcome
Roebuck, et al (1998a) "Neuromuscular responses to disturbances of balance in children with prenatal exposure to alcohol." Alcoholism: Clinical and Experimental Research 22: 1992-1997	Determine whether balance system impairments in children with prenatal alcohol exposure (N=12) are likely to be central processing or peripheral vestibular, with normal controls (N=12) Prospective Blinded statistical analysis	CDP demonstrated that alcohol exposed children make ineffective use of competing visual and vestibular signals. Central processing deficits are a likely cause. Intervention programs should be developed that focus on the sensory integration deficits.
Roebuck, et al (1998b) "Prenatal exposure to alcohol affects the ability to maintain postural balance." Alcoholism: Clinical and Experimental Research 22: 252-258	Determine the prevalence of balance system impairments in children with prenatal alcohol exposure (N=11), with normal controls (N=11) Prospective Blinded statistical analysis	CDP demonstrated that alcohol exposed children make ineffective use of competing visual and vestibular signals. Intervention programs should be developed that focus on the sensory integration deficits.
Gill, et al (2000) "Effects of Dimenhyrinate on computerized dynamic posturography." The Journal of Otolaryngology 29 (6): 337-339	Determine whether dimenhydrinate (motion sickness medication) impairs balance in 10 normal subjects Prospective, crossover control design with meds and placebo Blinded statistical analysis	CDP results indicate no significant drug effects and no re-test learning. When nausea reduces the accuracy of test administration, dimenhydrinate can be reliably used during CDP to provide a more accurate characterization of the patient's balance problem.

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Disorders Associated with Aging

Validity of CDP

Source

Design

Reference Standards

Conclusions

Topp, et al (1998) "Determinants of four functional tasks among older adults: an exploratory regression analysis." J Orthopedic Sports Physical Therapy 27: 144-153

Discriminate differences in functional abilities within a random sample of 28 older adults and to correlate impairment test results with daily life activities

Prospective

Exclusion by history

Blinded statistical analysis

Classification by:

History
Clinical rating scales for pain and daily life activities
Strength tests

CDP measures of dynamic postural control were significant predictors of performance on all daily life functional tasks.CDP provided unique information related to balance impairment.

Efficacy of CDP in Improving Health Outcomes
Source	Design	CDP Impact on Outcome
Rose, et al (2000) "Can the control of bodily orientation be significantly improved in a group of older adults with a history of falls?" JAGS 48: 275-282	Determine the outcome effectiveness of a biofeedback intervention program customized to CDP documented impairments in reducing fall risk in elderly community dwelling individuals (N=45) with a history of falls Prospective, double cross-over controlled design Blinded statistical analysis	Only the CDP-based intervention group showed significant improvements in dynamic motor and sensory integration impairments, which were correlated with improvements in all clinical measures of balance and mobility. Best outcomes were achieved through progressive challenges that met, but did not exceed, the individual patient's capabilities, as documented by CDP.
Forizetti, et al (2000) "Use of computerized dynamic posturography in the assessment of elderly fallers." Neurorehab and Neural Repair 14(1): 83	Determine the value of CDP in the prospective assessment of fall risk in elderly individuals with potential risk factors (N=36) Prospective design Blinded statistical analysis	Visual balance impairments documented by CDP were most strongly predictive of subsequent falls. CDP impairment information identifies individuals at fall risk and provides impairment information to customize effective intervention programs.

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Sports and Occupational Medicine

Validity of CDP
Source	Design	Reference Standards	Conclusions
Guskiewicz KM, et al (1997) Alternative approaches to the assessment of mild head injury in athletes." Med Sci Sports Exerc 29 (7): S213-S221	Document functional impairments following mild head injury and monitor recovery in young adult athletes (N=36), with normal controls (N=36) Blinded statistical analysis	Classification by: History Neuropsych. tests: Trail Making A Wechsler Digit Span Stroop	CDP was the only test to document significant sensory impairment following mild head injury. Average time to full recovery was 4 to 7 days

Efficacy of CDP in Improving Health Outcomes
Source	Design	CDP Impact on Outcome
Black, et al (1999) "Disruption of postural readaptation by inertial stimuli following space flight." Journal of Vestibular Research 9: 369-378	Document the post space-flight recovery of balance function and identify factors influencing recovery times of NASA astronauts (N=38) Prospective controlled design	1CDP documented a normal 72-hour recovery period that was delayed for 168 hours in an astronaut participating prematurely in disruptive, post-flight high performance activities. Documenting full recovery prior to the resumption of high performance activities can prevent prolongation of balance deficits that diminish performance and increase risk of accidents.
Paloski, et al Recovery of postural equilibrium control following space flight. In: Savin CF, et al eds. (1999) Extended duration orbiter medical project. NASA/SP-1999-534	Document the effect of prior space flights on astronauts' ability (N=45) to adapt to space flight Prospective design with separate rookie and experienced groups Blinded statistical analysis	CDP documented that rookie astronauts required significantly longer to re-adapt to earth conditions compared to experienced astronauts. Understanding how experience speeds adaptation will allow development of effective training programs for rookie astronauts.

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