James Parkinson was a general practitioner who first described the 'shaking palsy', which later came to be known as paralysis agitans. Its features are due to degeneration of nerve cells in the extra-pyramidal system -- the basal ganglia and nuclei in the upper brain stem. There are several varieties of the disease; (a) paralysis agitans, the cause of which is unknown; (b) post-encephalitic Parkinsonism, following some years after an encephalitis; (c) arteriosclerotic Parkinsonism, due to defective blood supply to the basal nuclei; (d) post-traumatic Parkinsonism, when the same parts of the brain have been directly injured or rendered short of oxygen; (e) syphilitic Parkinsonism -- a rare complication of syphilis.
Symptoms: The three main symptoms are tremor, rigidity of the muscles, and akinesia, i.e. the inability to initiate movements or to perform them quickly enough.
Treatment: Belladonna used to be the main drug, but now there are a number of more effective remedies. These include anti-spasmodics such as benzhexol (Artane), and orphenadrine (Disipal). One of the required remedies would be given to the patient to calm the tremors, and help get power over their movements back.