Title

Validation of the MiniSun IDEEA data recorder for the analysis of walking on uneven ground

Date of Award

2011

Degree Name

M.S. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Kimberly E. Bigelow

Abstract

Recent developments in portable systems used to analyze human walking have made it possible to collect information about gait in the field, as opposed to studying walking under controlled laboratory conditions. One wearable system, the Intelligent Device for Energy Expenditure and Activity System (IDEEA, MiniSun, LLC), has been reported to record gait parameters with accuracy comparable to common laboratory analysis systems when used to analyze gait on even terrain. This study examined the validity of using the MiniSun IDEEA to study human gait when walking upon an uneven surface. The results obtained using the IDEEA were compared to a proven gait analysis method using a triaxial accelerometer placed on an individual's lower back. Thirty two healthy individuals were recruited for this study in two age groups: Sixteen people aged 18-25 years and sixteen people aged 46-61 years. Each individual walked six, fifty meter walking trials: three while walking on even ground and three while walking on uneven ground. Information on gait speed, step length, cadence, and gait cycle duration was calculated using raw acceleration patterns and recorded by the IDEEA for each walking trial. The results obtained using the accelerometer and IDEEA on even and uneven ground were compared for each age group using paired t-tests with a=0.05. The results showed that that the IDEEA was not influenced by the type of surface walked upon. However, the values recorded by the IDEEA for speed, step length, and cadence on even and uneven surfaces were significantly different than the raw acceleration calculations (p < .05). These results indicate that the IDEEA is not accurate in recording these gait parameters regardless of surface type. The IDEEA showed high levels of agreement with the raw accelerometer calculations for the recorded values of gait cycle duration on both surfaces (p > .05), which may be indicative of the system correctly recording moments of foot contact. Modifications may need to be made by the manufacturer in order to improve its ability to accurately analyze gait. As an extension of this study, the use of the IDEEA with people who had an above the knee amputation was also examined. Two people with an above the knee amputation who used a prosthetic limb with a microprocessor controlled knee joint participated in this experiment. The IDEEA recorded inaccurate results for one subject and malfunctioned for the other. Although additional research could be conducted to examine the system's accuracy, the results of the healthy population in this study indicate a serious concern with the IDEEA's ability to accurately record gait parameters. As a result, the use of this system is not recommended in lieu of other proven methods of analyzing gait.

Keywords

Accelerometers Testing, Gait in humans Measurement

Rights Statement

Copyright 2011, author

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