Stabilization of the head position in pitch plane: study of imbalance during a multisegment posturography examination

Our purpose was to evaluate head stabilization in pitch plane in patients with different kinds of imbalance when standing over firm and movable surfaces. We used the STATITEST (Société Mumedia, Belgium), a multisegment platform for recording and computing postural adjustments at different body levels. We detected these data by two sensors placed on the head and hip of each subject in four situations: eyes open on a firm surface (EOFS); eyes closed on a firm surface (ECFS); eyes open on a movable surface (EOMS); and eyes closed on a movable surface (ECMS). For each recording, a magnetic field was broadcast by an antenna placed in front of the patients. First, as the manufacturer did not provide the normal range limits for shoulder sway, we conducted a statistical analysis on a population and selected a sample of 31 normal individuals. Second, we performed the experiment with 91 patients in two steps: standard examination and an assessment with sensors on the head and shoulder. The following values of increased head-shoulder relationship were found: on EOFS, 6; on ECFS, 5; on EOMS, 6; and on ECMS, 11. We noted the predominance of smaller head adjustments, reflecting accurate head stability. However, a small percentage of patients showed increased head movement, a pigeonlike sway. A correlation of these individuals with postural strategies revealed that almost all adopted ankle strategies.