After endless hours studying human pathology, it's not uncommon for medical students to become convinced they suffer from a rare disease or two... or eight. During a psych block, for example, the incidence of obsessive compulsive disorder self-diagnosis among my first year class shot up astronomically.
With much of this week's schedule devoted to discussing brain tumors, I feel a bit of prophylactic cautionary advice is in order. See, in learning how to make a diagnosis, we're taught to remember Occam's razor - that, in general, the simplest explanation is most likely. In other words, that dropped pen or sudden muscle jerk in lecture probably results from dozing during class and not a cerebellar lesion.
Moral of the story: you probably don't have a brain tumor. And if Occam isn't a funny enough last name for you, take it from this guy...