What is primary lateral sclerosis?
Primary lateral sclerosis is a rare, adult-onset, slowly progressive acquired motor neuron disease in which only signs of corticospinal tract dysfunction are seen.
The diagnosis of primary lateral sclerosis requires the presence of symptoms for more than 4 years and the absence of lower motor neuron findings, family history of similar disorder, and sensory signs on examination.
Laboratory evaluation for other causes of myelopathy and craniospinal imaging should be normal.
Electrodiagnostic tests show normal nerve conduction study, and the EMG should not satisfy the El Escorial criteria for ALS.
