title: 'Is tinnitus accompanied by hemifacial spasm in normal-hearing patients also a type of hyperactive neurovascular compression syndrome? : A magnetoencephalography study.
abstract: BACKGROUND
  Traditionally, tinnitus accompanied by hemifacial spasm has been considered a type of hyperactive neurovascular compression syndrome that is similar to hemifacial spasm alone because of the anatomically close relationship between the facial nerve and cochlear nerve as well as the hyperactive clinical nature.
  
  
  METHODS
  Participants were 29 subjects who presented with hemifacial spasm and neuroradiological evidence of vascular compression of the cranial (facial/cochlear) nerve. We used magnetoencephalography (MEG) to estimate the activity of the cochlear nerve in patients with and without tinnitus on the ipsilateral side. We compared the difference in the latency and the ratio of the equivalent current dipole (ECD) strength between the ipsilateral and contralateral sides of the spasm and tinnitus.
  
  
  RESULTS
  Cochlear nerve activity in patients with tinnitus was increased with a shorter latency (p = 0.016) and stronger ECD strength (p = 0.028) compared with patients without tinnitus.
  
  
  CONCLUSIONS
  The MEG results from normal-hearing patients who had tinnitus accompanied by hemifacial spasm suggest that the hyperactivity of the auditory central nervous system may be a crucial pathophysiological factor in the generation of tinnitus in these patients. The neurovascular compression that causes sensory input from the pathologic facial nerve activity may contribute to this hyperactivity of the central auditory nervous system.
authors: Department of Neurosurgery, Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Won Seok
authors: WS
authors: Chang
authors: Bong Soo
authors: BS
authors: Kim
authors: Ji Eun
authors: JE
authors: Lee
authors: Hyun Ho
authors: HH
authors: Jung
authors: Kiwoong
authors: K
authors: Kim
authors: Hyuk Chan
authors: HC
authors: Kwon
authors: Yong Ho
authors: YH
authors: Lee
authors: Jin Woo
authors: JW
authors: Chang
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D019569:Hemifacial Spasm / Q000150:complications*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000150:complications*; D011930:Reaction Time / Q000502:physiology; D014012:Tinnitus / Q000175:diagnosis* / Q000209:etiology*
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