Presentation Title

Non-linear analysis of vector magnitude and step count from activity monitor data

Advisor Information

Brian A. Knarr

Location

Dr. C.C. and Mabel L. Criss Library

Presentation Type

Poster

Start Date

3-3-2017 12:30 PM

End Date

3-3-2017 2:45 PM

Abstract

Older adults diagnosed with osteoarthritis (OA) participate in less activity, often as a result of poor mobility and weight bearing pain [2], and it is important to understand the patterns and complexity of activity in this population in order to assess disease progression and rehabilitation outcomes. In this pilot study, we will determine the differences between vector magnitude and steps in healthy individuals when analyzing the complexity of activity. We hypothesize that while similar, vector magnitude will be less sensitive than the number of steps taken to activity epoch size. Four college age participants were recruited and instructed to wear an ActiGraphs activity monitor on their waist for seven days. The complexity of the activity was calculated using the Detrended Fluctuation Analysis (DFA). Results show alpha values for vector magnitude and steps are decreasing as epoch sizes are increasing for all subjects. Overall, DFA from vector magnitude and steps are similar and either could be used for analysis. The data demonstrates that similar DFA values can be obtained, but sensitivity to epoch size may differ between vector magnitude and steps. Further investigation is needed across a wider range of activity levels and population.

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COinS
 
Mar 3rd, 12:30 PM Mar 3rd, 2:45 PM

Non-linear analysis of vector magnitude and step count from activity monitor data

Dr. C.C. and Mabel L. Criss Library

Older adults diagnosed with osteoarthritis (OA) participate in less activity, often as a result of poor mobility and weight bearing pain [2], and it is important to understand the patterns and complexity of activity in this population in order to assess disease progression and rehabilitation outcomes. In this pilot study, we will determine the differences between vector magnitude and steps in healthy individuals when analyzing the complexity of activity. We hypothesize that while similar, vector magnitude will be less sensitive than the number of steps taken to activity epoch size. Four college age participants were recruited and instructed to wear an ActiGraphs activity monitor on their waist for seven days. The complexity of the activity was calculated using the Detrended Fluctuation Analysis (DFA). Results show alpha values for vector magnitude and steps are decreasing as epoch sizes are increasing for all subjects. Overall, DFA from vector magnitude and steps are similar and either could be used for analysis. The data demonstrates that similar DFA values can be obtained, but sensitivity to epoch size may differ between vector magnitude and steps. Further investigation is needed across a wider range of activity levels and population.