Neurological Voice Disorders
This group of voice disorders is caused by loss or abnormal function in nerve supply to the larynx, anywhere from the brain all the way to the nerve fibers (“nerve endings”) that “plug in” to the tiny muscles of the larynx.
An example of a brain source of the voice disorder is injury to the motor cortex of the brain, such as might occur after a stroke, or head injury. Dysfunction in the “switching station” deeper in the brain can cause dystonia of the larynx, which manifests as spasmodic dysphonia. Damage to peripheral nerves that directly insert into the muscle fibers of the larynx, such as after thyroid surgery or penetrating injury would cause vocal cord paralysis or paresis.
The additional functions, besides voice production, that are potentially disturbed by neurological laryngeal disorders include breathing and swallowing. See also the comprehensive list below.
Palate paralysis (technically causes a disorder of resonance, not a pure voice disorder)
Vocal cord paralysis