title: Frequency dynamics shift of vestibular evoked myogenic potentials in patients with endolymphatic hydrops.
abstract: OBJECTIVE
  To measure the frequency dynamics of the vestibular evoked myogenic potential in patients with endolymphatic hydrops.
  
  
  METHODS
  A prospective study.
  
  
  METHODS
  A university hospital.
  
  
  METHODS
  The endolymphatic hydrops group consisted of 28 affected ears of patients with definite unilateral Ménière's disease and a control group of 36 ears of 20 healthy volunteers.
  
  
  METHODS
  Vestibular evoked myogenic potentials generated by tone bursts at 250, 500, 700, 1,000, 1,500, 2,000, and 4,000 Hz were measured in both groups. Vestibular evoked myogenic potentials were also measured after furosemide administration in six patients in the endolymphatic hydrops group.
  
  
  METHODS
  The frequency sensitivity of vestibular evoked myogenic potential, as evaluated by p13-n23 normalized amplitude.
  
  
  RESULTS
  Peak amplitudes were noted at 500 Hz in the control group and at 1,000 Hz in the endolymphatic hydrops group. After furosemide loading, peak amplitude shifted to a lower frequency in four of six ears.
  
  
  CONCLUSIONS
  The peak amplitude of vestibular evoked myogenic potentials in the endolymphatic hydrops group was at a higher frequency than in the control group. The frequency of the saccule (nu) should be proportional to radical(tau/sigma), where tau is the tension of membrane and sigma is its density. We advocate the hypothesis that the shift in frequency dynamics of vestibular evoked myogenic potential in patients with endolymphatic hydrops originates from the morphologic features of the saccule, analogous to an expanded balloon.
authors.affiliation: Department of Otolaryngology, Hyogo College of Medicine, Nishiniomiya, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Node
authors.forename: Toru
authors.initials: T
authors.lastname: Seo
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Adachi
authors.forename: Misako
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Masafumi
authors.initials: M
authors.lastname: Sakagami
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D018159:Endolymphatic Hydrops / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005665:Furosemide / Q000008:administration & dosage; D006801:Humans; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D008297:Male; D008575:Meniere Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D008875:Middle Aged; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D014725:Vestibular Nerve / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D005665:Furosemide