Shaking palsy, first adequately described by Parkinson1 in 1817 and since generally known as Parkinson's disease, appears mostly in persons in the latter half of life. It is characterized by muscular rigidity and weakness, tremor, a propulsive gait and masklike facies, without disturbances of sensation or reflexes. The most striking symptom, tremor, is characterized by short oscillations of the head or extremities at the rate of from 4 to 7 a second and is most pronounced during rest, as contrasted with the intention tremors of senility and of multiple sclerosis.
According to J. Ramsay Hunt,2 "Paralysis agitans . . . is not a disease sui generis but a syndrome referable to the efferent neurons of the corpus striatum (striatal and pallidal). This syndrome may be produced by a variety of pathologic lesions, viz., primary atrophy, senile degeneration, and vascular, inflammatory and neoplastic lesions. Therefore, primary and secondary forms are recognized." Medical
ALLAN W. INHERITANCE OF THE SHAKING PALSY. Arch Intern Med (Chic). 1937;60(3):424-436. doi:10.1001/archinte.1937.00180030041003