There are a number of symptom of PD which are often neglected because they are not seen as central to the disease. Examples are: depression, pain and fatigue.

I have included a link below from the MJ Fox Foundation to a study that they are currently funding on the topic of fatigue:

https://www.michaeljfox.org/foundati...p?grant_id=690

It is unclear what leads to the fatigue, but it can be quite pronounced. There is also a recent study indicating that sleep is very beneficial to reducing PD symptoms:

http://www.************/parkinsons.d...ews/120623.pdf

For some people the fatigue can be overwhelming.

Howard