title: Factors relating to the vertigo control and hearing changes following intratympanic gentamicin for intractable Ménière's disease.
abstract: OBJECTIVE
  To look for factors relating to the vertigo control and hearing changes after intratympanic injections of gentamicin (GM).
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Tertiary referral medical center.
  
  
  METHODS
  Twenty-eight patients with intractable Ménière's disease.
  
  
  METHODS
  Three intratympanic injections of GM (once per day for three consecutive days).
  
  
  METHODS
  Although five patients needed further GM injections or vestibular neurectomy because of poor control (Group I), 23 patients had their vertigo controlled for more than two years without further treatment (Group II). The number of vertigo spells per month, pure-tone audiometry, electrocochleography, caloric response, post-head shake nystagmus, and plasma vasopressin as a stress marker were examined.
  
  
  RESULTS
  Before GM injections, there was no difference in the number of vertigo spells per month between Groups I and II. However, the hearing thresholds were higher in Group I. Hearing improvement, increase in percentage of canal paresis and induction of post-head shake nystagmus were observed after GM injections only in Group II. Even in the 11 patients who showed an improvement in hearing of more than 10 dB (hearing improvement group), percentage of canal paresis was increased after GM. More, premedication plasma vasopressin levels were lower in the hearing improvement group as compared with the hearing loss/no changes group. Four of eight patients became negative for dominant negative summating potential in electrocochleography after GM injections in the hearing improvement group.
  
  
  CONCLUSIONS
  Our data indicate that the frequency of vertigo is not a key factor in the vertigo control after GM injections, that induction of vestibular damage in the injected ear is essential for the control of vertigo and this effect is mostly pronounced in patients with milder hearing loss, and that hearing improvement is not only a consequence of good vertigo control but also affected by the stress level before treatment.
authors.affiliation: Department of Otolaryngology, Osaka University Medical School, Japan. ahorii@ent.med.osaka-u.ac.jp
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.forename: Takanori
authors.initials: T
authors.lastname: Saika
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.forename: Suetaka
authors.initials: S
authors.lastname: Nishiike
authors.forename: Kenji
authors.initials: K
authors.lastname: Mitani
authors.forename: Masato
authors.initials: M
authors.lastname: Nishimura
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Munehisa
authors.initials: M
authors.lastname: Fukushima
authors.forename: Aya
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Chisako
authors.initials: C
authors.lastname: Masumura
authors.forename: Tomo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kizawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001300:Audiometry, Evoked Response; D005260:Female; D005839:Gentamicins / Q000008:administration & dosage / Q000627:therapeutic use*; D034381:Hearing Loss / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D015552:Injections, Intralesional; D008297:Male; D008575:Meniere Disease / Q000150:complications / Q000188:drug therapy*; D008875:Middle Aged; D009759:Nystagmus, Pathologic; D011446:Prospective Studies; D014432:Tympanic Membrane; D014717:Vertigo / Q000209:etiology / Q000517:prevention & control*; D014724:Vestibular Function Tests
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins