Dr. Kaminski, What are the diagnostic tests you can do? If it is not related to dopamine deficiency or depression, what do you think it comes from? I am a PD patient and also a clinical social worker. I don't suffer from a lack of motivation or any flatness of affect, but I have thought that I saw it in others, and didn't know it had a name. Can it have something to do with cognitive slowing and/or difficulties with new learning--something to do with the hippocampus and amygdala? Thanks for your thoughts. Claudia