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
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 (brain stem encephalitis)
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)
Symptoms of Hypoglossal Nerve Disorders
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.
Diagnosis of Hypoglossal Nerve Disorders
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 Hypoglossal Nerve Disorders
Treatment of the cause
Treatment of hypoglossal nerve disorders depends on the cause.
