Proximal conduction abnormality of the facial nerve in Miller Fisher syndrome: a study using transcranial magnetic stimulation.
OBJECTIVE
To investigate facial nerve conduction, including its proximal segment, in Miller Fisher syndrome.


METHODS
Three patients underwent facial nerve conduction studies comprising stylomastoid electrical stimulation and transcranial magnetic stimulation at the entrance of the facial canal within the skull and of the cortical representation area. All 3 patients presented with acute bilateral complete ophthalmoplegia, areflexia, mild ataxia and varying other symptoms. One of the patients had bilateral facial palsy; the other two had normal facial innervation.


RESULTS
Findings suggestive of demyelination of the proximal segment of the facial nerve were observed in each of the 3 patients with Miller Fisher syndrome. The patient with bilateral facial palsy had absent responses to canalicular stimulation on both sides, while the other two showed increased temporal dispersion and prolonged latency in the proximal nerve segments.


CONCLUSIONS
Our findings suggest that the primary pathology of facial nerve lesion in Miller Fisher syndrome is demyelination and that it is localized to the proximal nerve segment. This is in line with the known vulnerability of proximal nerve segments (spinal roots) in other dysimmune demyelinating polyneuropathies.


CONCLUSIONS
Facial nerve conduction study with magnetic stimulation can localize and detect even subclinical facial nerve dysfunction in patients with Miller Fisher syndrome. The technique may contribute to the diagnosis of this disease, where electrophysiologic findings are scanty.
Arányi
Zsuzsanna
Z
Department of Neurology, Faculty of Medicine, Semmelweis University, Balassa u. 6, 1083 Budapest, Hungary. zsuzsi@neur.sote.hu
Szabó
Györgyi
G
Szepesi
Borbála
B
Folyovich
András
A
D003937:Diagnosis, Differential; D004558:Electric Stimulation; D005154:Facial Nerve / Q000033:anatomy & histology / Q000473:pathology / Q000503:physiopathology*; D005155:Facial Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D019846:Miller Fisher Syndrome / Q000175:diagnosis / Q000503:physiopathology*; D009186:Myelin Sheath / Q000473:pathology; D009431:Neural Conduction; D011237:Predictive Value of Tests; D011930:Reaction Time; D050781:Transcranial Magnetic Stimulation / Q000379:methods*