The onset of symptoms in multiple sclerosis usually occurs between the second and the fourth decade of life. Its diagnosis, with few exceptions, is rarely entertained when signs of involvement of the central nervous system make their appearance in the fifth or the sixth decade of life. Wilson,1 in a series of 1,107 cases of multiple sclerosis, found onset of symptoms after the age of 40 in 186, or 17 per cent, while von Hoesslin2 found onset after the age of 50 in only 4 per cent. In many of the aforementioned cases the diagnosis was not verified by autopsy. Isolated examples of a very late onset with autopsy include Nielsen's3 case, in which illness began in the late sixties, and Taga's4 cases, in which the disease began after the age of 60.
In a series of 310 patients with multiple sclerosis who had been admitted
ARNOLD P. FRIEDMAN, CHARLES DAVISON. MULTIPLE SCLEROSIS WITH LATE ONSET OF SYMPTOMS. Arch NeurPsych. 1945;54(5):348–360. doi:10.1001/archneurpsyc.1945.02300110032005