Never seen anyone with it or heard of it before, but my trusty Merck Manual (17th Edn) describes it as:

A disorder of neuromuscular transmission.

Unknown cause, predominantly limb symptoms. Affects peripheral nerves.
Symptoms include: muscle twitching, arm & leg spasms, intermittent cramps, increased sweating and pseudomyotonia (impired muscle relaxation after a strong contraction but without true EMG changes).

Symptom relief is via Carbamazepine or phenytoin.

No info on physical treatment modalities or prognosis, unfortunately.
hope this helps a wee bit
Mike