How is primary lateral sclerosis diagnosed?

a rare disease that causes progressive weakness in voluntary muscles such as in the legs, hands, and tongue. PLS is one of the diseases, along with amyotrophic lateral sclerosis, that are grouped...

Motor neuron diseases like primary lateral sclerosis develop because the nerve cells that normally control the movement of voluntary muscles degenerate and die.

PLS affects a part of the neuron called the cell body (or soma). Specifically, it is the cell bodies of upper motor neurons that are affected.

PLS is not fatal, and people with the disorder can usually maintain mobility with the use of canes or other assistance.

ALS is known to affect two to three people per 100,000. Tentative estimates of the occurrence of PLS are on the order of one person in 10 million