Disorders of the 12th cranial nerve (hypoglossal nerve) cause weakness or wasting (atrophy) of the tongue on the affected side. This nerve moves the tongue.
- Hypoglossal nerve disorders may be caused by tumors, strokes, infections, injuries, or amyotrophic lateral sclerosis.
- People with hypoglossal nerve disorder have difficulty speaking, chewing, and swallowing.
- Doctors usually do magnetic resonance imaging and/or a spinal tap to identify the cause.
- The cause is treated.
(See also Overview of the Cranial Nerves.)
Causes of hypoglossal nerve disorders include
- A tumor or bone abnormality at the base of the skull
- A bulge (aneurysm) in an artery at the base of the brain
- A stroke
- Infection of the brain stem
- An injury to the neck, as may occur after surgical removal of a blockage from an artery in the neck (endarterectomy)
- Amyotrophic lateral sclerosis (Lou Gehrig disease)
The tongue becomes weak on the affected side and eventually wastes away (atrophies). As a result, people have difficulty speaking, chewing, and swallowing. Damage due to amyotrophic lateral sclerosis causes tiny, subtle twitching movements (fasciculations) on the surface of the tongue.
- Magnetic resonance imaging
- Sometimes a spinal tap
Magnetic resonance imaging (MRI) is usually done to look for a tumor or evidence of a stroke.
A spinal tap (lumbar puncture) may be necessary if cancer or infection is possible.
- Treatment of the cause
Treatment of hypoglossal nerve disorders depends on the cause.