重心動揺検査によるめまい・平衡障害の診断:ラバー負荷検査と周波数解析を用いて

抄録

　The postural control system coordinates sensory inputs from the vestibular, somatosensory and visual systems with outputs to the musculoskeletal system to maintain body balance. Posturography measures the changes in the center of pressure (COP) during an upright stance. Our group developed a foam posturography system, in which posturography is performed while standing on rubber foam, thereby changing the relative contribution of the somatosensory system. Our studies have shown that this foam posturography system is very useful for detecting unilateral as well as bilateral peripheral vestibular dysfunction. Furthermore, it is also useful for detecting dysfunction of the inferior vestibular nerve system as well as unilateral vestibular dysfunction at the chronic stage. A frequency analysis of the COP has been shown to be useful for characterizing the postural stability of patients with vestibular diseases and various neurodegenerative disorders. We compared the frequency characteristics of postural instability in patients with psychogenic dizziness, bilateral vestibulopathy, and spinocerebellar degeneration. Our analysis showed that patients with psychogenic dizziness exhibited an increase in power across frequencies<1Hz, patients with bilateral vestibulopathy exhibited an increase in power across a broad range of frequencies, and patients with spinocerebellar degeneration exhibited an increase in power across frequencies ranging from 2 to 4Hz. These results indicate that a frequency analysis of the COP is useful for differentiating among psychogenic dizziness, peripheral vestibulopathy and cerebellar diseases.