Classification
Five varieties have been
distinguished on clinical grounds.
A. Progressive Bulbar Palsy:
Bulbar involvement predominates owing to disease processesaffecting primarily the motor
nuclei of the cranial nerves.
B. Pseudobulbar Palsy: Bulbar
involvement predominates in this variety also, but it is due to bilateral corticobulbar
disease and thus reflects upper motor neuron dysfunction.
C. Progressive Spinal Muscular
Atrophy: This is characterized primarily by a lower motor neuron deficit in the limbs due to
degeneration of the anterior horn cells in the spinal cord.
D. Primary Lateral Sclerosis:
There is a purely upper motor neuron deficit in the limbs.
E. Amyotrophic Lateral
Sclerosis (Lou Gehrig’s Disease): A mixed upper and lower motor neuron deficit is found in the
limbs. This disorder is sometimes associated with dementia or parkinsonism |
