Nodding head

Hello - I'm new here and for a while have been concerned for my m-in-law who was diagnosed a couple of years ago. She has very bad head nodding which develops as the day progresses and really exhausts her. I have found it hard to believe that it can't be relieved. Can anyone share their experience with this symptom? Thanks!
Is this head nodding her most troublesome symptom? It is more common among people suffering from ET(Essential Tremor) and you might find some treatment for it on an ET site. Some people have both PD and ET
Hi qwerty

Is your m-i-l on any medication? I suffer from a nodding head sometimes, which is due to dyskensia, which can be a side effect of levadopa. I have been prescribed a drug called Amantadine, which has helped with reducing the dyskensia.
Kate & Jem
Thank you so much for your responses! I will follow both routes with her.