Effect of Postural Control Biomechanical Gain on Psychophysical Detection Thresholds in Anterior Horizontal Translation of Standing Blindfolded Subjects

Shahrokh N Sani 1 and Charles J Robinson 2        

1Department of Computer Science, Morehead State University, Morehead KY, USA

2 Depts of Electrical & Computer Engr, Clarkson University, Potsdam, NY, USA


A Sliding Linear Investigative Platform for Assessing Lower Limb Stability (SLIP-FALLS) was employed to study postural control biomechanical reaction to external perturbations in a short ≤16mm postural perturbation. Head acceleration were evaluated while blindfolded subjects stood on a platform that was given a short anterior perturbation presented in one of 2 sequential 4s intervals (2-Alternative-Forced-Choice) for a set of 30 trials. Anterior-Posterior head acceleration (Head Accl AP) were investigated among the movement and non-movement intervals for the healthy adults. A strong ringing signal was observed in Head Accl AP movement interval that was absent in non-movement interval. A positive power law trading relationship was found between Head Accl AP gain and move length standing blindfolded subjects. This could explain the observed negative power law relationship between translation length and peak acceleration threshold in previous psychophysical detection threshold studies