title: A clinical study of the efferent auditory system in patients with normal hearing who have acute tinnitus.
abstract: OBJECTIVE
  Etiological diagnosis and treatment of tinnitus still remain challenging in clinical practice. The aim of this study was to determine the potential contribution of a defective cochlear efferent innervation to the onset of tinnitus in patients with normal hearing.
  
  
  METHODS
  Prospective randomized controlled study.
  
  
  METHODS
  Otorhinolaryngology department of a general hospital.
  
  
  METHODS
  The patient group consisted of 18 normal-hearing adults (7 men, 11 women) with acute tinnitus (bilateral in 3 patients).
  
  
  METHODS
  Tympanogram, stapedial muscle reflex, pure tone audiometry, tinnitus pitch matching, spontaneous otoacoustic emissions, and distortion product otoacoustic emissions (DPOAEs) in the absence and presence of contralateral suppression by white noise.
  
  
  METHODS
  DPOAEs suppression amplitudes recorded from tinnitus and nontinnitus ears of the patients' group were compared with each other and with a control group.
  
  
  RESULTS
  The contralateral application of white noise induced the enhancement of DPOAE amplitudes in some patients. The suppression of DPOAE amplitudes by contralateral white noise did not reach statistically significant levels in either ear (with or without tinnitus). On the contrary, under the same conditions, our control group demonstrated statistically significant reduction of DPOAE amplitudes at all frequencies.
  
  
  CONCLUSIONS
  Patients with normal hearing acuity who have acute tinnitus seem to have a less effective functioning of the cochlear efferent system because the application of contralateral noise enhanced the DPOAEs or suppressed them less intensely than it did in a control group. Further studies may establish the clinical applications for the diagnosis of changes in efferent function, in the subjective evaluation, patient etiological grouping, treatment, or prognosis of tinnitus.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Patras, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Riga
authors.forename: Thedoros
authors.initials: T
authors.lastname: Papadas
authors.forename: Jochen A
authors.initials: JA
authors.lastname: Werner
authors.forename: Carsten V
authors.initials: CV
authors.lastname: Dalchow
mesh_terms: D000208:Acute Disease; D000328:Adult; D003051:Cochlea / Q000503:physiopathology*; D004525:Efferent Pathways / Q000503:physiopathology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D011446:Prospective Studies; D012720:Severity of Illness Index; D014012:Tinnitus / Q000175:diagnosis / Q000503:physiopathology*