Palatal myoclonus is a rapid spasm

Spasm

In medicine a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice. It is sometimes accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes...

 of the palatal (roof of the mouth) muscles, which results in clicking or popping in the ear

Ear

The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....

. Chronic clonus is often due to lesions of the central tegmental tract

Central tegmental tract

The central tegmental tract is a structure in the midbrain and pons.* The central tegmental tract includes ascending axonal fibers that arise from the caudal nucleus solitarius and terminate in the ventral posteromedial nucleus of thalamus...

 (which connects the red nucleus

Red nucleus

The red nucleus is a structure in the rostral midbrain involved in motor coordination. It comprises a caudal magnocellular and a rostral parvocellular part.-Function:...

 to the ipsilateral inferior olivary nucleus

Inferior olivary nucleus

The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.-Function:It is closely associated with the cerebellum, meaning that it is involved in control and coordination of movements, sensory processing and cognitive tasks likely by encoding the...

). Uniquely, the clicking noise does not subside when the patient sleeps.

When associated with eye movements, it is known as oculopalatal myoclonus

General references

• http://www.tchain.com/otoneurology/disorders/central/opm.html