ASYMMETRIC SMOOTH PURSUIT IMPAIRMENT AND NYSTAGMUS IN MOTOR-NEURON DISEASE

Eye movements were recorded using infrared oculography in 17 patients with motor neurone disease (MND) and in 17 age-matched controls. Major findings were a marked reduction in pursuit gain for the severely affected patient group as target speed increased from 10 deg/sec to 20 deg/sec and asymmetric pursuit (leftward gain lower than rightward) in these patients. The authors' study illustrates the effect of MND on the central pathways of the nervous system which control eye movements and shows that an association may exist between specific ocular motor defects and severity.