Primary lateral sclerosis: more than just an upper motor neuron disease

Advances in clinical care and recent research achievements:Primary lateral sclerosis(PLS)has traditionally been regarded as a pure upper motor neuron condition,a view perpetuated by most medical textbooks.Recent research has challenged the classical view that only the motor cortex and the descending corticospinal tracts are affected in PLS and the clinical and radiological profile of the condition has now been characterized by more nuanced descriptions.