Tic convulsif: the association of trigeminal neuralgia and hemifacial spasm.

Both trigeminal neuralgia and hemifacial spasm are sometimes caused by a posterior fossa mass lesion. When these two disorders co-exist, a rare association known as ‘tic convulsif’, a lesion involving the fifth and seventh cranial nerves in the cerebellopontine angle is extremely likely. Twenty-eight cases of tic convulsif have been mentioned in the literature and two more case are reported here. They are of interest in that both cases many years elapsed between specialist opinion being first sought and the discovery of the underlying lesion.