Parameters of the crossing points between center of pressure and center of mass signals are potential markers of postural control efficiency

Abstract

Posturographic signals were recorded for 384 subjects of different ages and with old persons with gait disturbances. Four conditions were used: Eyes Open/Closed vs. Head Normal/Bent Back. ‘Center of Pressure’ (CoP) signals were decomposed into ‘Center of Mass’ (CoM) and the remaining difference between Center of Pressure and Center of Mass (CoPM). The Zero-Crossing points in which the Center of Mass and Center of Pressure paths cross each other have been extracted. Velocity of CoM, velocity of CoPM and acceleration of CoPM in Zero-Crossing points were analyzed to be potential markers of balance efficiency. Three factors causing the deterioration of balance quality were analyzed: closing eyes, bending the head back and patient age. The influence of the given factors was measured using the significance p of the t-Student test and Cohen's d effect size and applied to differences for the logarithms of three of the mentioned above variables measured without and with the given deteriorating factor. In the majority of comparisons, the proposed new parameters of balance quality possessed higher statistical power to detect deteriorated balance quality than the standard parameters: standard deviation of the signal and ellipse area covering 90% of the signal envelope. Most valuable are the velocity and acceleration of CoPM for the medio-lateral direction. Logarithms of the analyzed parameters are proposed to be used in analyses because they possess normal or close to normal distribution and they are less sensitive to single high values occurring often in measurements.

Computerised dynamic posturography for postural control assessment in subjects wearing multifocal contact lenses dedicated for myopia control

“…The data obtained here confirms the earlier findings 17,21,40–44 that visual signals are crucial for control of body balance. The rate of stabilisation was higher, and stabilisation time longer when the eyes were closed compared with open eye conditions.…”

“…It could be argued these changes in the accommodative response and convergence posture produced by the MFCLs, as well as the decrease in the quality of central and peripheral vision, may disturb everyday visuo‐motor functions dependent on visual signals such as body balance control 17–19 . Body balance depends on vestibular information, proprioceptive information and, to a significant extent, on visual information 17,19–21 . Thus, disturbing visual information may impair postural control, especially under dynamic conditions.…”

“…[17][18][19] Body balance depends on vestibular information, proprioceptive information and, to a significant extent, on visual information. 17,[19][20][21] Thus, disturbing visual information may impair postural control, especially under dynamic conditions.…”

Spatial Parameters of Statograms in Diagnosing Pathologies of the Human Locomotor System

“…The studies were performed on a Statographer-01. The obtained numerical indicators were processed statistically; for the comparison of the groups, the analysis of variance was used [8]. Parameters have been proposed and developed that describe the planes of a statogram and their relation, the geometry of the scatter, and the angular parameters and their asymmetry.…”

“…Therefore, the efforts of biomechanics today are aimed at finding diagnostic criteria for statograms that would be able to identify abnormalities in individual elements of the LS. Another problem is that different researchers evaluate statistics using different criteria and coefficients, which makes it difficult to compare and generalize the results obtained [3,8,9].…”