how different we are. I hear very well, in fact almost as well as a dog.. I think Todd gets to the point that hearing is more of a "mechanical" process, and the auditory nerves are not involved in the cell losses seen in PD.
There is a well known theory that cells in the olfactory bulb are "highjacked into producing dopamine", and that this contributes to the fact that a lot of PWP lose their ability to smell things as intensely as they used to, But i've never heard of hearing loss a being a common "marker" for "parkinsonism".