Chronic progressive spinobulbar spasticity. A rare form of primary lateral sclerosis.

Although it was first described over a century ago (by Charcot in 1865; by Erb in 1875), the concept of primary lateral sclerosis (PLS) is still not universally accepted. Despite this skepticism, several well-documented cases of isolated degeneration with varying degrees of involvement of corticospinal pyramidal pathways have been reported in the literature. The clinical manifestations in these cases can take one of two forms, ie, isolated spasmodic paraplegia or tetraplegia on the one hand or spasmodic tetraplegia associated with a pseudobulbar syndrome featuring severe spastic dysarthria (chronic progressive bilateral spinobulbar spasticity) on the other hand. Obviously, without firm pathologic data, PLS is a hazardous diagnosis for isolated paraplegia or tetraplegia. Conversely, for bilateral spinobulbar spasticity, it would appear to be the only diagnosis possible once investigate findings have eliminated the other possibilities, such as a pyramidal form of amyotrophic lateral sclerosis or a spinal form of multiple sclerosis. To underscore this point, in this report, five cases of chronic progressive bilateral spinobulbar spasticity developed over 5, 10, 12, 10, and 28 years, respectively, for which the only possible diagnosis was PLS. It was concluded that there are three forms of degenerative diseases of the principal motor pathways: one involving both central and peripheral neurons, ie, amyotrophic lateral sclerosis; one involving only peripheral neurons, ie, spinal amyotrophy; and one involving only central motor neurons, ie, PLS.