Dynamic Posturography Findings in Central Nervous System Disorders

Abstract

Dynamic posturography provides functional, selective testing of three sensory modalities for maintenance of balance: Vestibular, visual, and somatosensory. Sensory receptors in vertical semicircular canals and utricles, via the vestibulospinal tract, mediate a disconjugate response to the legs, enabling synchronized reciprocal stabilization of the body for control of motion. The patient is systematically exposed to different combinations of useful and conflicting visual, vestibular, and support surface input. The effect of each on stability is appraised. Early posturography reports dealt primarily with sensory organization test (SOT) results. Improved software for movement coordination (MC) tests offer greater identification of problems involving the central nervous system. One hundred fifty-one patients were studied over a 9-month period. Central disorders were present in 31 cases (20.5%) and 90.3% of these were abnormal in sensory organization tests (SOTs). Abnormal movement coordination (MC) results occurred in 80.6% of central nervous system (CNS) disorders. SOTs 4, 5, and 6 in combination were abnormal in 35.5%, and 70% of these cases were also abnormal in MC responses. False-positive responses occurred in less than 4% of cases. Posturography offers a significantly high detection rate in CNS disorders causing dysequilibrium. Long loop latency reflexes, as they relate to maintenance of balance, appear important in the pathophysiology of abnormal SOT and MC responses.