tract in lateral columns of the spinal cord, not due to structural (spinal stenosis from degenerative arthritis) or metabolic (vitamin B-12 deficiency) lesions. Weakness is accompanied by the upper motor neuron signs of spasticity, hyper-reflexia, and Babinski signs. Pseudobulbar palsy encompasses several disorders where only the corticobulbar tract is involved, causing facial weakness, impaired chewing, dysarthria, dysphagia, and hoarseness. The jaw jerk is typically increased, while fasciculations and atrophy are absent despite significant weakness. Pseudobulbar palsy may be caused by bilateral, multiple cerebral infarctions, brain tumors, lesions of multiple sclerosis, or brain trauma. Rarely is it from a degenerative disorder. It should be noted that the diagnosis of any of these motor neuron diseases is made with more certainty over a long period of observation, since amyotrophic lateral sclerosis may begin with only upper or lower motor neuron signs and symptoms in one part of the body Unfortunately the most common motor neuron disease, amyotrophic lateral sclerosis (ALS), is the most severe. It begins at 40 to 70 years of age with men outnumbering women. Initially there may be focal weakness and atrophy in a limb, such as a shoulder or leg (foot drop), which subsequently spreads and becomes bilateral. Other patients may first have dysarthria, hoarseness, or impaired swallowing (bulbar ALS).