Session Information
Date: Wednesday, June 22, 2016
Session Title: Neurophysiology (non-PD)
Session Time: 12:00pm-1:30pm
Location: Exhibit Hall located in Hall B, Level 2
Objective: To study the destabilizing force needed to reach the limit of stability (LoS), the displacements of the center of pressure (CoP) and the postural stabilizing strategies while performing the pull test (PT) in healthy subjects.
Background: The PT is the only item that assesses postural stability in the motor part of the Unified Parkinson’s disease Rating Scale. The applied force to perform the PT is a recognized source of variability which has not been analyzed quantitatively.
Methods: Healthy subjects were studied. Using a system of weights and pulleys and a harness surrounding the shoulders, sequential and sudden pulls were applied in an anterior-posterior direction, with progressive increase in the applied force until the subject had to step back (LoS). During the procedure, subjects stood on a posturographic platform and electromyographic recordings were obtained from anterior tibialis, lateral gastrocnemius, lateral vastus, biceps femoris, abdominal anterior rectus and paravertebral muscles.
Results: 54 healthy subjects were studied: age 25-81, 57% females, height 140-194 cm and weight 43-108 kg (ranges). The mean force to reach the LoS in males was 129,1±11,2 N (Newtons) and 78,1±6,6 N in females (p<0,001), and it was observed an inverse statistically significant correlation with age (p=0,002), but not with height (p=0,232) and weight (p=0,791). The velocities of the displacement of the CoP (anterior, posterior and average) and its displacement areas (circular, rectangular and ellipse95%) correlated with the magnitude of the destabilizing force (p<0,001). The electromyography recordings showed a predominant ankle strategy to maintain balance, either in isolation for small forces or combined with hip strategy for greater forces.
Conclusions: The magnitude of the force applied to reach the limit of stability in the Pull Test varies depending on age and gender. The destabilizing force correlates with the velocity and the area of displacements of the center of pressure and determines ankle and hip strategies to maintain postural stability.
LXVII Reunion Anual de la Sociedad Espanola de Neurologia 2015.
To cite this abstract in AMA style:
J.R. Pérez-Sánchez, B. De La Casa-Fages, A. Contreras, J.M. Velázquez, A. Muñoz-González, F. Grandas. The pull test in healthy subjects: Quantitative, posturographic and electromyographic analysis [abstract]. Mov Disord. 2016; 31 (suppl 2). https://www.mdsabstracts.org/abstract/the-pull-test-in-healthy-subjects-quantitative-posturographic-and-electromyographic-analysis/. Accessed May 9, 2025.« Back to 2016 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/the-pull-test-in-healthy-subjects-quantitative-posturographic-and-electromyographic-analysis/