Ocular neuromyotonia

Ocular neuromyotonia is a rare, albeit treatable, ocular motor disorder, characterised by recurrent brief episodes of diplopia due to tonic extraocular muscle contraction. Ephaptic transmission in a chronically damaged ocular motor nerve is the possible underlying mechanism. It usually improves with carbamazepine. A 53-year-old woman presented with a 4-month history of recurrent episodes of binocular vertical diplopia (up to 40/day), either spontaneously or after sustained downward gaze. Between episodes she had a mild left fourth nerve palsy. Sustained downward gaze consistently triggered downward left eye tonic deviation, lasting around 1 min. MR scan of the brain was normal. She improved on starting carbamazepine but developed a rash that necessitated stopping the drug. Switching to lacosamide controlled her symptoms.

Endoscopic-Assisted Microvascular Decompression

Diseases of ephaptic transmission are commonly caused by vascular compression of cranial nerves. The advent of microvascular decompression has allowed for surgical intervention for this patient population. This chapter highlights the technique of endoscopic-assisted microvascular decompression for trigeminal neuralgia and hemifacial spasm. Endoscopy and keyhole techniques have resulted in a minimally invasive and effective treatment of symptoms for patients with neuralgia.