I had not heard of the term but found some information here
Several primary neurodegenerative disorders share parkinsonian features, such as bradykinesia, rigidity, tremor, and gait disturbances. These disorders have complex clinical presentations that reflect degeneration in various neuronal systems. However, because of the common parkinsonian features, the disorders have been collectively named Parkinson-plus syndromes.
Parkinson-plus syndromes respond poorly to the standard treatments for Parkinson disease (PD). An inadequate response to treatment in a patient with parkinsonian symptoms suggests the possibility of a Parkinson-plus syndrome and warrants a search for the signs and symptoms of degeneration in other neuronal systems.
In addition to lack of response to carbidopa/levodopa (Sinemet) or dopamine agonists in the early stages of the disease,
I will try to answer your question. Parkinsonn Plus is I think also called Atypical Parkinson, and I believe people with a diagnosis of Parkinson PLus, have a sub-classification of PSP. MSA and others I cannot remember now. One could look this up in Google under Parkinson PLus or Atypical Parkinson. THe prognosis is much worse than regular parkinson and they seem not to be responsive to levodopa carbidopa.. Here is a link to The National Parkinson Foundation about Pakinson Plus: http://www.pdf.org/parkinsonism_parkinson_syndrome.
As dodong said they are slightly different than typical Parkinson's disease. Is it "worse" well...it depends on how you view things. I have watched my Grandpa Lindsey die from ALS. I myself deal day to day basis. Attitude determines how well you do in life. Hope you find information about Parkinson's plus on the website informative. All the best Austin.
Parkinson's plus as I understood is worse than Parkinson's. He was on that carbidopa-levodopa meds but in 2-3 months he lost 40 lbs. He lost his appetite, was dizzy a lot, fell more, so he took him off. And would not put him on another med cuz of dizziness and so on. Such a complicated disease