Progressive bulbar palsy (PBP), also called progressive bulbar atrophy, attacks the lower motor neurons connected to the brain stem. The brain stem (also known as the bulbar region) controls the muscles needed for swallowing, speaking, chewing, and other functions.

Many ALS experts consider PBP within the spectrum of ALS because the majority of individuals who begin with this form of the disease eventually develop more widespread MND. Indeed, many clinicians believe that PBP by itself, without evidence of abnormalities in the arms or legs, is extremely rare.

Symptoms, which worsen over time, include trouble chewing, speaking, and swallowing. Individuals may also have weakness in their tongue and facial muscles, twitches, and a reduced gag reflex. They may also experience weakness in their arms or legs, but it is less noticeable than other symptoms.

Because they have difficulty swallowing, individuals are at risk of choking and inhaling food and saliva into the lungs. People can also have emotional changes and may begin to laugh or cry at inappropriate times (called pseudobulbar affect or emotional lability). Some symptoms of stroke and myasthenia gravis are similar to those of progressive bulbar palsy and must be ruled out prior to diagnosis.

In about one-third of individuals with ALS, early symptoms begin with the bulbar muscles. Some 75 percent of individuals with classic ALS eventually show some problems swallowing, speaking, and chewing.

Treatments aim to help people cope with the symptoms of progressive bulbar palsy, such as feeding tubes, devices to help with talking, and medicines to treat muscle spasms, weakness, drooling, sleep problems, pain, and depression.