Sensory contributions to standing balance in unilateral vestibulopathy

Patients with unilateral peripheral vestibular disorder (UPVD) have diminished postural stability and therefore the aim of this study was to examine the contribution of multiple sensory systems to postural control in UPVD. Seventeen adults with UPVD and 17 healthy controls participated in this study. Centre of pressure (COP) trajectories were assessed using a force plate during six standing tasks: Forwards and backwards leaning, and standing with and without Achilles tendon vibration, each with eyes open and eyes closed. Postural stability was evaluated over 30s by means of: total COP excursion distance (COPPath) and the distances between the most anterior and posterior points of the COPPath and the anterior and posterior anatomical boundaries of the base of support (COPAmin and COPPmin). In addition, the corrected COPAmin and COPPmin was assessed by taking the corrected base of support boundaries into account using the anterior and posterior COP data from the leaning tasks. UPVD patients showed a tendency for smaller limits of stability during the leaning tasks in both directions. Subject group and task condition effects were found (P<0.05) for COPPath, (i.e. higher values for patients compared to controls). UPVD patients showed lower (P<0.05) COPPmin values compared to the control group for all conditions (more pronounced with the corrected COPPmin). Disturbance of the visual system alone lead to a distinct postural backward sway in both subject groups which became significantly more pronounced in combination with Achilles tendon vibration. The individual limits of stability should be considered in future research when conducting posturographic measurements.
Listed In: Biomechanics, Neuroscience, Physical Therapy, Posturography