title: Assessing the stage of Meniere's disease using vestibular evoked myogenic potentials.
abstract: BACKGROUND
  The staging of Ménière's disease that was proposed by the American Academy of Otolaryngology-Head and Neck Surgery in 1995 was based on the arithmetic mean of the pure-tone thresholds at 0.5, 1.0, 2.0, and 3.0 kHz using the worst audiogram during the 6-month interval before treatment. The stages were classified as follows: stage I, a 4-tone average of less than 26 dB; stage II, 26 to 40 dB; stage III, 41 to 70 dB; and stage IV, more than 70 dB.
  
  
  OBJECTIVE
  Because the saccule, next to the cochlea, is the second most frequent site of hydrops formation, we wanted to find out whether vestibular evoked myogenic potential (VEMP) responses can reflect the stage of Ménière's disease.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary university hospital.
  
  
  METHODS
  Forty patients (23 men and 17 women; mean +/- SD age, 43 +/- 12 years) with unilateral definite Ménière's disease were enrolled in the study.
  
  
  METHODS
  The interaural amplitude difference (IAD) ratio, which was defined as the difference of the amplitudes of peak p13 to peak n23 (p13-n23) in the right (R) and left (L) ears divided by the sum of p13-n23 in both ears (R-L/R + L), was measured, and the stages of the disease were compared with the types of hearing loss, the percentage of unilateral weakness of caloric response, and the IAD ratio, respectively.
  
  
  RESULTS
  Six ears were classified as stage I: the VEMPs were normal in 5 and augmented in 1, with a mean +/- SD IAD ratio of -0.02 +/- 0.20. Twelve ears were classified as stage II: the VEMPs were normal in 7, augmented in 2, depressed in 1, and absent in 2, with an IAD ratio of -0.12 +/- 0.39. Seventeen ears were classified as stage III: the VEMPs were normal in 10, depressed in 4, and absent in 3, with an IAD ratio of -0.30 +/- 0.30. Five ears were classified as stage IV: the VEMPs were normal in 2, depressed in 1, and absent in 2, with an IAD ratio of -0.54 +/- 0.43. A comparison of the IAD ratio and the stage of Ménière's disease demonstrated a significant relationship (P<.05, 1-way analysis of variance test), whereas there was no significant relationship noted between the percentage of unilateral weakness of caloric response and the stage of disease.
  
  
  CONCLUSIONS
  The IAD ratio of VEMPs correlates with the stage of Ménière's disease and can be used as another aid to assess the stage of Ménière's disease.
authors.affiliation: Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan. youngyh@ha.mc.ntu.edu.tw
authors.forename: Yi-Ho
authors.initials: YH
authors.lastname: Young
authors.forename: Tsung-Wei
authors.initials: TW
authors.lastname: Huang
authors.forename: Po-Wen
authors.initials: PW
authors.lastname: Cheng
mesh_terms: D000328:Adult; D000368:Aged; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008575:Meniere Disease / Q000503:physiopathology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D011446:Prospective Studies; D012720:Severity of Illness Index; D014722:Vestibule, Labyrinth / Q000503:physiopathology*