MRCP2-3101

An 80-year-old man comes to the clinic with a festinant gait. His wife reports that he has been drooling saliva and his voice has become quieter over the past six months. During the examination, it is observed that he has a resting tremor in his right hand and increased rigidity in his right upper limb. What factor would make idiopathic Parkinson’s disease less likely in this case?