Late onset multiple sclerosis. A clinical study of 16 pathologically proven cases.

In 70 pathologically proven MS cases, we found 16 cases with onset after 45. Sex ratio (3/1) was the same in the late onset cases and early onset control group. There was no positive family history of MS. The diagnosis was more frequently never considered in late onset cases (3/16) than in control cases (3/54). Mean duration of the disease was 8.6 +/- 6 years (8.1 +/- 6 in female patients). This was significantly shorter (P less than 0.05) than in the control group. In addition, in remittent-progressive courses and in progressive courses, it appeared that the duration of the disease was shorter in late onset MS - although this was not statistically significant. Progressive courses (8 cases) and acute courses (4 cases) were more frequent (P less than 0.05) than in control cases. Initial signs and symptoms were not significantly different from those of control cases. The length of the evolution of the disease was higher in cases with vestibular-cerebellar onset. New signs and symptoms occurred at the same rate in the late onset cases as in the control cases. Although motor, sensory and bladder disturbances were more frequent in the late onset cases than in the control cases, this was not statistically significant. Amyotrophy was more frequent in late onset MS; on the contrary optic neuritis, vestibulo-cerebellar disturbances and nystagmus were less frequent in late onset MS than in the control group (P less than 0.05).