The cerebellum functions as a central control for the bodily movements and equilibrium. One may be particularly conscious of a malfunctioning cerebellum when moving. For this study we recorded and analyzed the stability of the center of gravity in patients with known cerebellar disorders when attempting to stand erect and still. The analysis included the spatial extent of the movements as a parameter of the magnitude of sway and the different 8 directional sway velocities in order to determine the sway characteristics. The patients had tumors confined to the cerebellum.
If the lesion was confined to a cerebellar hemisphere the spatial magnitude of the sway and the sway velocities were within the normal range, despite increased variability. When the velocities to the lateral and antero-posterior directions were compared, the former predominated. The Romberg value was somewhat smaller than that of normal controls. There were increasing spatial magnitude of sway and directional velocities in patients with paravermian and vermian lesions. The Romberg value was larger. The lateral sway velocity exceeded that of antero-posterior sway with eyes open or were closed ; the difference was more obvious when the eyes clsoed. There was no correlation between uni-hemispheric and hemisphericparavermian lesions as to lateral sway velocities and laterality of the lesion.
Restricted cerebellar hemispheric lesions show no clearcut abnormalities in central gravitational movements. However, when the pathology begins to involve the median part of the cerebellum, the sway becomes abnormally large. Vermian lesions are associated with obviously larger sway. This study implies that the midline portion of the cerebellum plays important role in the control of body stability. The negative Romberg value may mean that the sway increases proportionally when the eyes are closed in both patients groups and normal controls.