Force platform measures of balance impairment
Author | : Chris Burdis |
Publisher | : |
Total Pages | : 100 |
Release | : 2015 |
ISBN-10 | : OCLC:1153420626 |
ISBN-13 | : |
Rating | : 4/5 (26 Downloads) |
Book excerpt: Introduction: Parkinson’s Disease (PD) is a highly prevalent neurodegenerative disorder with incidence increasing annually in the growing elderly population in the United States. Complex movement and balance impairments in PD contribute to high fall risk and devastating consequences of all-related injuries in this population. Therefore, comprehensive balance assessment is warranted to identify intrinsic fall risk factors and direct intervention for fall prevention. The purpose of this study was to examine the test psychometric properties of three balance measures on the NeuroCom Force Platform (FP) system in persons with PD. Methods: Forty-two community dwelling individuals with Idiopathic PD (mean age 66.21 years, Hoehn & Yahr stage I-IV) were included in the study. Participants were included if they met the functional mobility criteria for the study and were excluded if they had other neurologic disorders, dementia, peripheral neuropathy, or deep brain stimulation. Test retest reliability was assessed for the Limits of Stability (LOS), Motor Control Test (MCT) and Sensory Organization test (SOT) by administering the FP tests twice within 10 days during on time of PD medications. Intraclass correlation coefficients (ICC) were calculated to determine test-retest reliability of the FP measures. Minimal detectable change (MDC) was calculated using standard error of mean from ICC values. Concurrent validity was assessed by comparing the FP measures with criterion gait (10 meter walk test [10MWT], six minute walk test [6MWT]), and clinical balance measures (Functional Gait Assessment [FGA], Mini balance Evaluation Systems test [MiniBEST], Rapid Step Up test [RST] using Pearson Product Moment correlations. Convergent validity of FP measures and PD characteristics was analyzed using both multiple linear regression and correlation values. Results: All FP variables demonstrated excellent test-retest reliability (ICC range 0.78-0.92), with the exception of LOS average reaction time and LOS falls, which were moderately reliable (ICC0.69,0.62). The strongest reliability was found for the MCT variables (average latency ICC=0.92, average amplitude ICC=0.92). The MDC values for FP measures were as follows: SOT composite equilibrium (11.64), LOS average end-point excursion (13.79), and MCT average latency (7.43). SOT and LOS demonstrated fair to good correlations with gait and clinical balance measures. The strongest correlations were found between SOT composite equilibrium score and the balance measures, MiniBEST (r=0.69), FGA (r=0.60 ) and RST (r=0.55). Convergent validity findings demonstrated significant relationships of both SOT composite equilibrium and MCT average latency with disease severity. Discussion: FP measures are reliable and valid measures of balance impairment in persons with PD and are able to detect balance deficits in this population, One third of this studies sample had SOT composite equilibrium scores below normative values, reflecting impairment in sensory integration for balance. Additionally, the SOT composite equilibrium and MCT average latency differentiated individuals based on disease severity, perhaps reflecting that these tests are sensitive indicators of decline in postural control with disease progression. Conclusion: A battery of balance measures is needed to accurately assess balance deficits at both the functional and impairment levels in PD. Force platform measures may provide valuable quantitative information about underlying balance impairments in PD to guide therapeutic interventions for fall risk reduction.