Kathrine Hepburn Syndrome

Something that you don't hear a lot about is a condition that is commonly mistaken for Parkinson's Disease and only known about because of the high celebrity status of it's namesake. Kathrine Hepburn Syndrome is marked by the shaking of the head and hands that the actress was so known for in later years.

I've looked for information on the condition and found little aside from an article in the Harvard Health website about "Essential tremor".

If anyone knows anything about Kathrine Hepburn Syndrome I would really like to find out more sources for information on this condition. Thank you!