Nonlinear Computational Analysis of Postural Stability and its Relationship to Estrogen Deficiency in Postmenopausal Women

Mitchell, Zachary (2018) Nonlinear Computational Analysis of Postural Stability and its Relationship to Estrogen Deficiency in Postmenopausal Women. Undergraduate thesis, under the direction of Dwight Waddell from Biomedical Engineering, University of Mississippi.

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Abstract

This study aims to determine if multi-scale entropy analysis will more accurately differentiate the postural stability of postmenopausal women as a function of their estrogen status than traditional measures of postural assessment. The study participants included 7 non-Hormone Replacement Therapy (HRT) postmenopausal women (mean age = 57) and 4 HRT postmenopausal women (mean age = 55). Postural stability was measured with the NeuroCom Equitest and the use of conditions 1-4 of the Sensory Organization Test (SOT). The subjects received an equilibrium score for each condition with a score near 100 representing good postural stability. A modification of the “Multi-Scale Entropy Analysis” Matlab program created by Costa et al. was used to analyze the raw center of pressure (COP) trajectory data measured for each condition in both the medial-lateral (x-direction) and anterior-posterior (y-direction) directions. The Matlab program created complexity index (CI) scores where a high CI is indicative of low postural stability and a low CI is representative of good postural stability. A basic t-test of unequal variances was performed on the CI scores between non-HRT and HRT subjects, in addition to the equilibrium scores between non-HRT and HRT subjects. The t-test revealed both the NeuroCom Equitest and MSE analysis identified a significant difference in postural stability between non-HRT subjects and HRT subjects an equal number of times (n=2), where HRT subjects exhibited better postural stability than non-HRT. The MSE analysis method was able to significantly differentiate postural stability between non-HRT and HRT subjects in SOT 1 (p=0.0432), whereas the NeuroCom Equitest did not. This is of significance because the subject is standing still on the force plate without having their balance disrupted. Previous studies have had to manipulate the surroundings and perturb the subject’s balance to significantly differentiate postural stability between non-HRT and HRT subjects. The findings from this study indicate that MSE analysis may provide a higher level of sensitivity necessary to assess postural stability as a function of estrogen status. The effect of estrogen on the preservation of postural stability in postmenopausal women may provide further evidence for the consideration of estrogen as a neuroprotectant.

Item Type: Thesis (Undergraduate)
Creators: Mitchell, Zachary
Student's Degree Program(s): B.E. in General Engineering
Thesis Advisor: Dwight Waddell
Thesis Advisor's Department: Biomedical Engineering
Institution: University of Mississippi
Subjects: Q Science > Q Science (General)
Q Science > QP Physiology
T Technology > TA Engineering (General). Civil engineering (General)
Depositing User: Mr. Zachary Mitchell
Date Deposited: 14 May 2018 19:31
Last Modified: 14 May 2018 19:31
URI: http://thesis.honors.olemiss.edu/id/eprint/1186

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