From Signs of illness and Retirement medical issues
Progressive bulbar palsy involves the brain stem. The brain stem is the part of the brain needed for swallowing, speaking, chewing, and other functions. Signs and symptoms of progressive bulbar palsy include difficulty swallowing, weak jaw and facial muscles, progressive loss of speech, and weakening of the tongue. Additional symptoms include less prominent weakness in the arms and legs, and outbursts of laughing or crying (called emotional lability).
Progressive bulbar palsy is considered a variant form of amyotrophic lateral sclerosis (ALS). Many people with progressive bulbar palsy later develop ALS. While there is no cure for progressive bulbar palsy or for ALS, doctors can treat symptoms.
See also NIH Motor Neuron Diseases Fact Sheet and https://rarediseases.info.nih.gov/diseases/10928/progressive-bulbar-palsy