Welcome to Just Answer and thanks for your question. Can you tell me where you saw this term so I can put it in context for you?
Welcome to Just Answer and thanks for your question. Parkinson's is a degenerative disorder of the nervous system that causes problems with movement, speech, and some other things. It involves lack of a neurotransmitter called dopamine in the brain.
The pyramid of the brain is also known as the corticospinal tract. Problems with the left side of the corticospinal tract typically cause motor difficulties on the right side of the body and vice versa. There are several diseases that exhibit this kind of pattern. Pseudopyramidal just means that it could be a weakness in the pyramidal system, but it doesn't say what it could be. Basically, the letter is just suggesting possibilites so your GP can order further testing.