What is pseudobulbar palsy?
Pseudobulbar palsy is a syndrome of upper motor neuron paralysis that affects the corticobulbar system above the brain stem bilaterally.
Although it presents with most of the signs and symptoms of bulbar palsy, the causative lesion is not in the brain stem.
This condition causes dysphagia, dysarthria, and paresis of the tongue (without atrophy or fasciculations). In contrast to bulbar palsy, the reflex movements of the soft palate and pharynx are frequently hyperactive.
The jaw jerk is brisk. Frontal signs (grasp, snout, suck, and glabellar reflex) may be present. Emotional incontinence with exaggerated crying (or, less often, laughing), known as pseudobalbar affect, is also common and may be due to disruption of frontal efferents subserving emotional expression.
Multiple lacunar infarcts or chronic ischemia in the hemispheres affecting bilateral corticobulbar fibers usually causes this syndrome.
Other causes are amyotrophic lateral sclerosis (ALS) and multiple sclerosis.
In ALS, a combination of upper and lower motor neuron disease often results in coexisting bulbar and pseudobulbar palsies (wasting and fasciculations of the tongue associated with brisk jaw jerk).