What is a bulbar syndrome?

The brainstem is located in the lower part of the brain—at the junction with the spinal cord. This anatomical region of the central nervous system contains motor neurons that are responsible for controlling the muscles of the tongue and throat. Degeneration of motor neurons in the bulbar brain and the associated weakness of the tongue and throat muscles is referred to as bulbar syndrome. Typical symptoms associated with bulbar syndrome include speech impairment (dysarthria) and swallowing difficulties (dysphagia). The motor neurons in the bulbar brain are under the control of motor neurons in the brain (first motor neuron).

In a specific scenario, degeneration of the upper motor neuron may occur while the nerve cells in the bulbar brain itself remain intact. In this case, spasticity of the tongue and pharynx is present, a condition known as “pseudobulbar syndrome.” Bulbar and pseudobulbar syndromes, along with their associated symptoms of dysarthria and dysphagia, are a common part of the clinical picture of ALS.