Stance duration under sensory conflict conditions in patients with hemiplegia

Standing balance was evaluated in ten subjects with hemiplegia using a sensory organization balance test (SOT). The SOT is a timed balance test which evaluates somatosensory, visual, and vestibular function for maintenance of upright posture. The duration of bilateral stance was assessed using combinations of three visual and two support surface conditions. Stance time was measured with eyes open, eyes closed, and with each patient wearing a visual dome to produce inaccurate visual information. The support surface conditions involved stance on a hard flat floor followed by attempted stance on a compliant foam surface. Visual deprivation or visual conflict conditions did not cause a loss of balance when stance was performed on a stable surface. However, a lower stance duration was found when patients stood on a compliant surface (p less than .05). Visual compensation was evident during the compliant-surface condition because stance duration showed the greatest reductions with eyes closed and with the visual dome. These findings suggest that the ability to integrate somatosensory information from the lower extremities for balance is compromised after cerebrovascular disease. The implications for diagnosing the specific cause of balance dysfunction and for developing sensory-specific therapeutic interventions are discussed.