This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Guillian Barre syndrome & Alzheimer's disease, Subject name: Medicine
[{'content': "Saccadic movement present in all except: \nSelect and explain. \nA. Alzheimer's disease, B. Huntington's chorea, C. Progressive supranuclear palsy, D. Spinocerebeller ataxia", 'role': 'user'}, {'content': "Answer: A \nExplanation: Saccades Rapid, ballistic movement of eyes that abruptly change the point of fixation. Can be elicited voluntarily, but occur reflexly whenever the eyes are open, even when fixated on a target. Rapid eye movement that occur during sleep are also saccades. Site -Basal ganglia or cerebellum. Option B- Huntington's chorea - damage to caudate nucleus Option C- Progressive supranuclear palsy - damage to Basal ganglia Option D- Spinocerebellar ataxia- damage to cerebellum falls backwards But in Alzheimer's - coical dementia", 'role': 'assistant'}]