Neurovascular compression syndromes are characterized by recurrent attacks of neurological symptoms and clinical signs depending on the cranial nerve affected. It is assumed that pulsatile compression of the nerve is caused mainly by an artery. The result is segmental
demyelination of the transition zone or the central part of the cranial nerve, which is covered by oligodendrocytes, and subsequent ephaptic axonal transmission. Compression of the vestibular nerve can cause attacks of spinning or non-spinning
vertigo: vestibular paroxysmia. Compression of the trochlear nerve is characterized by attacks of monocular oscillopsia:
superior oblique myokymia. Damage to ocular motor nerves due to local radiation or rarely neurovascular compression can also lead to oscillopsia and
double vision precipitated by sustained excentric gaze: ocular
neuromyotonia. It is important to note that controlled trials have so far not been performed for any of these three syndromes, mainly because of their low prevalence. Therefore, treatment recommendations are based on single cases or small case series and thus have the lowest level of evidence. The
sodium channel blockers carbamazepine (50 to 200 mg tid) or
oxcarbazepine (100 to 300 mg tid) are evidently effective in most of the patients who have these three syndromes. However, one should always keep in mind the
contraindications, side effects, and interactions with other drugs of
carbamazepine ( http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682237.html ) All patients require regular laboratory examinations. Alternatives are other
sodium channel blockers such as
phenytoin (100 to 300 mg tid),
gabapentin (100 to 600 mg tid), or
valproic acid (100 to 300 mg tid). Furthermore, there are also few reports on the effects of beta blockers, which may be explained by their reduction of the amplitude of blood pressure. Patients who do not respond to
pharmacotherapy require further diagnostics to determine the possibility of other etiologies. Some of these patients benefit from
surgical decompression of the affected nerve.