The cerebellar nodulus: perceptual and ocular processing of graviceptive input

Current concepts postulate a decisive role of the cerebellar nodulus in the processing of otolith input. We hypothesized that nodular lesions abolish otolith-perceptual integration, predicting alignment of perceived direction of earth vertical with the z-axis of the head and not with gravity. In an 80-year-old patient with acute heminodular infarction, the subjective visual vertical deviated contralesionally by -21.1° when the patient was upright. After subtracting this offset, perceived vertical closely matched the patient's head orientation when the patient was roll-tilted. Otolith-ocular reflexes remained normal. This is the first report on abolished earth verticality perception in heminodular stroke and underlines the importance of the nodulus in spatial orientation.