Detecting perturbed steps with an ambulatory method. And a comparison with a laboratory method.

Huls, K. (Kirsten) (2009) Detecting perturbed steps with an ambulatory method. And a comparison with a laboratory method. thesis, Human Movement Sciences.

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Abstract

Introduction: This study aimed at finding a method to identify perturbed balance based upon an ambulatory method and compare this to a laboratory method. The approach which has been developed may be helpful in selecting older people at risk of falling, since evidence is strongest that an intervention to reduce falls is most effective in that population. Method: Ten healthy participants walked on a treadmill and received perturbations in eight directions, at two moments in the stride cycle and at two walking velocities. With an instrumented treadmill centre of pressure was measured. The centre of pressure was used to calculate the extrapolated centre of mass. With a hybrid wireless sensor, 3D acceleration, 3D magnetization and 3D angular velocity at the sacrum were measured. Data analysis: For the laboratory method, the margin between the centre of pressure and the extrapolated centre of mass at footcontact was used as a measure for balance. The new ambulatory method used a peak detection approach to identify perturbed balance. It was analyzed whether giving perturbations resulted in perturbed balance measured with both the laboratory method and the ambulatory method. Also the level of agreement between the laboratory and ambulatory method was determined. Results: Analyses revealed an overall sensitivity of 84.5 % and specificity of 94.8% for ambulatory method and a overall sensitivity of 77.8% and specificity of 96.3% for the laboratory method. Direction of the perturbation and walking velocity had little influence on the probability of detection. When the ambulatory method was compared with the laboratory method, a sensitivity of 69.0% and a specificity of 93.4% were found. Discussion: Detection of perturbed steps with both the laboratory and ambulatory method showed high sensitivity and specificity. Sensitivity was not dependent on direction of perturbation, moment of stride cycle and walking velocity. When the ambulatory method was compared with the laboratory method, a moderate sensitivity and high specificity was found. With further refinement and study, this ambulatory method may be useful in selecting older people at risk of falling for interventions to reduce falls.

Item Type:	Thesis (Thesis)
Supervisor name:	Zijlstra, W. and Hof, A.L.
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:55
Last Modified:	25 Jun 2020 10:55
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1581

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