Can anyone tell me what is paralysis agitans?

Parkinson's disease. 'paralysis' - latin for palsy or muscle weakness; 'agitans' = shaky; this expression use started about 1817. Today it is called parkinson's disease, or if just the symptoms of this disease 'parkinsonism'. Disease is characterized by a non-intention tremor and the hallmark of the disease is an slowing of all movements, called bradykinesis (brady = slow, kinesis=motion).