Brainstem findings in Huntington's disease. Possible mechanisms for slow vertical saccades.

Quantitative, morphometric studies of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) were performed on the brains of four patients with Huntington's disease (HD) who had shown slow vertical saccades, and on the brains of three control subjects. Only one HD brain showed a statistically significant decrease in the number of larger neurons in the riMLF though all four brains showed non-specific gliosis. Taken with results from physiological and other clinical studies, the present data suggest that slow vertical saccades in HD are due, at least in part, to disordered inputs to the riMLF.