A number of symptoms and signs are found in almost all cases of advanced MS. Among them are spastic paresis, ataxia of gait and the extremities, central visual loss, double vision, paresthesia, dysarthria, bladder and sexual disturbances, and fatigue. Although they are not specific for MS, they are so typical of the disease, particularly when occurring in combination, that they are accepted as clinical characteristics. However, it is not really helpful to consider combinations of a few individual symptoms as particularly characteristic. The combination of intention tremor, nystagmus, and scanning speech was identified by Charcot as the “classical triad”; pale optic discs, cerebellar ataxia, and pyrimidal signs were another combination identified by Marburg and Pette. If clinical diagnosis were limited to those cases in which these syndromes occur, a large number of MS cases verified at post mortem would be missed, or would only be diagnosed in the terminal stages.

Symptoms and signs which occur only rarely in definite cases of MS, such as aphasia, hemianopia, involuntary movements, marked muscular atrophy, or fasciculations, require specific and repeated differential diagnostic considerations.

There are also symptoms and signs which occur rarely in the MS population as a whole, but which are relatively typical for its diagnosis, even if they occur in single instances. Among them are Lhermitte's symptom, facial myokymias, painful tonic brainstem seizures and other paroxysmal phenomena, trigeminus neuralgia in young adults, and certain oculomotor disturbances such as internuclear ophthalmoplegia.